THE FEASIBILITY OF ESTABLISHING SICKLE CELL
DISEASE SCREENING SERVICES AT HEALTH CENTERS
IN UGANDA
By
OKWI ANDREW LIVEX, MSc., University of Wales, UK
A THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE
STUDIES FOR THE AWARD OF THE DEGREE OF DOCTOR OF
PHILOSOPHY OF MAKERERE UNIVERSITY
OCTOBER 2009
Table of Contents
Declaration
ix
Dedication
x
Acknowledgement
xi
List of Table
xii
List of Figures
xvii
List of Abbreviations
xviii
Definition of terms
xix
Abstract
xxiv
1.0 Chapter One: Introduction
1
1.1. Background of the study
1
1.2. Problem statement
3
1.3 Research questions
3
1.4. Objectives
4
1.4.1. General objective of the study
4
1.4.1. Specific objectives
4
1.5. Justification of the study
4
Chapter Two: Literature review.
6
2.1. Emergence of non-communicable diseases
6
2.2 Early history sickle cell disease
9
2.3. The genetic characteristics of human heamoglobins
10
2.3.1. Genetics of normal human haemoglobins
10
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2.3.2. Genetics of haemoglobin variants
13
2.4. Mode of transmission and inheritance of sickle cell anemia and its traits
14
2.5. Epidemiology of sickle cell disease
15
2.5.1. Global prevalence of sickle cell disease
15
2.5.2. Status of sickle cell disease in Uganda
17
2.6. Pathophysiology of sickle cell disease
18
2.7. The management of sickle cell disease
23
2.7.1. Awareness about SCD and community education programmes
23
2.7.2. Screening the communities for sickle cell disease
25
2.7.2.1. Principles of screening
26
2.7.2.2. Screening models
26
2.7.2.3. Screening programmes
29
2.7.2.4 Screening for sickle cell disease
29
2.8. Sickle cell screening methods
30
2.9. Cost benefit analysis of screening for sickle cell disease
34
Chapter Three: Materials and Methods
36
3.1. Study design
36
3.2. Study sites
36
3.3. Study population selection
40
3.3.1. Knowledge gaps of the study populations about sickle cell disease
40
3.3.1.1. Household participants selection
40
3.3.1.2. Selection of health staff and secondary school students
42
3.3.2. Selection of the population for prevalence study
44
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3.3.3. Selection of the population for reliability study
45
3.3.4. Selection of study sites and sampling procedure for
cost benefit analysis
46
3..4. Sample size determination
47
3.4.1. Sample size determination for knowledge gaps and attitudes
47
3.4.1.1. Sample size determination for household survey
47
3.4.1.2. Sample size determination for secondary schools and health centers
50
3.4.2 Sample size for prevalence studies
51
3.4.3 Sample size for reliability study
51
3.4.4. Sample size determination for cost benefit analysis study
52
3.5 Data collection procedure
53
3.5.1. Data collection for knowledge gaps and beliefs
53
3.5.1.1. Data collection from household participants
53
3.5.1.2. Data collection from health staff and secondary school students
54
3.5.2.. Data collection for sickle cell disease prevalence
55
3.5.3. Data collection for reliability study
57
3.5.3.1 Sickling screening test principle
57
3.5.3.2. Solubility screening test principle
57
3.5.3.3. Peripheral blood film screening method principle
58
3.5.3.4. Hb electrophoresis screening method principle
58
3.5.4 Data collection for determination of costs and benefits of different
sickle cell screening methods
60
3.5.4.1. Training laboratory technicians
60
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3.5.4.2. Measure of technical feasibility
61
3.5.4.3. Cost benefits analysis of different sickle cell screening methods
61
3.6 Data analysis
63
3.6.1 Data analysis on knowledge gaps and beliefs on sickle cell disease
63
3.6.2. Data analysis on prevalence of sickle cell disease
63
3.6.3 Data analysis on reliability study
64
3.6.4. Data analysis on cost benefit analysis
66
3.6.5 Ethical issues
74
Chapter Four: Results
76
4.1 Socio-demographic characteristics
76
4.2 Knowledge gaps on sickle cell disease
76
4.2.1 Knowledge gaps of the communities about sickle cell disease
77
4.2.2 The beliefs of the respondents about sickle cell disease
81
4.2.3 Attitudes of the communities about sickle cell disease
82
4.2.4 Sources of information about health.
84
4.3 Prevalence of sickle cell disease
86
4.4 Comparative analysis of reliability of different screening methods
91
4.5 Determination of the cost effective methods for screening for SCD
at health centers
96
4.5.1 Measure of technical feasibility
96
4.5.2 Cost benefit analysis of different screening tests for SCD
97
4,5.2.1 Comparative analysis of scenarios A1 and A2 (automated
capillary Hb elctrophoresis)
98
4.5.2.2 Scenarios B1 versus B2 (Automated Hb electrophoresis and sickling)
-v-
101
4.5.2.3 Automated Hb electrophoresis and solubility
104
4.5.2.4 Automated Hb electrophoresis and peripheral blood method.
107
4.5.2.5 Scenarios A1 and A2 (cellulose acetate Hb elctrophoresis.
110
4.5.2.6 Scenarios B1 versus B2 (Cellulose acetate Hb electrophoresis and
Sickling).
113
4.5.2.7 Scenarios B1 versus B2 (Cellulose acetate Hb electrophoresis
and solubility test
116
4.5.2.8 Scenarios B1 versus B2 (Cellulose acetate Hb electrophoresis
and peripheral blood film method).
119
4.5.2.9 Establishment of the screening services in Bundibugyo hospital
using the automated and Cellulose acetate Hb electrophoresis.
122
4.5.2.10 Establishment of the screening services in Bundibugyo hospital
using the automated and Cellulose acetate Hb electrophoresis and
sickling test
124
4.5.2.11 Projection of the costs (USh) of the automated Hb electrophoresis
screening service with time
126
4.5.2.12 Projection of the costs (USh) of cellulose acetate Hb
electrophoresis screening service with time.
129
4.5.2.13 Projection of the costs (USh) of sickling and automated Hb
electrophoresis screening service with time.
132
4.5.2.14 Projection of the costs (USh) of solubility and automated Hb
electrophoresis screening service with time.
4.5.2.15 Projection of the costs (USh) of peripheral blood film method and
- vi -
135
automated Hb electrophoresis screening service with time.
138
4.5.2.16 Projection of the costs (USh) of sickling and cellulose acetate Hb
electrophoresis screening service with time.
141
4.5.2.17 Projection of the costs (USh) of solubility and cellulose acetate Hb
electrophoresis screening service with time.
144
4.5.2.18. Projection of the costs (USh) of peripheral and cellulose acetate Hb
electrophoresis screening service with time.
147
4.5.2.19. Projection of the costs (USh) of automated and cellulose acetate Hb
electrophoresis screening services with time in Bundibugyo hospital .
150
4.5.2.20. Projections of the costs (USh) of establishing automated and
cellulose acetate Hb electrophoresis screening services with time
in Bundibugyo hospital
147
4.6 Methodological issues
4.6.1. Logistics
152
4.6.2. Knowledge, attitudes and beliefs of the communities
in Eastern and Western Uganda about sickle cell disease and its
detection (KAP
152
4.6.3. Current prevalence of sickle cell disease in Eastern,
Mbarara/Ntungamo and Bundibugyo in the West.
152
3.6.3. Reliability study
153
3.6.4 Cost benefit analysis study
153
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Chapter Five: Discussion .
154
5.1 Knowledge gaps attitudes and beliefs about SCD
154
5.2 Prevalence of sickle cell disease
157
5.3 Reliability of the different methods for sickle cell disease screening
160
5.4 Cost benefit analysis of sickle cell disease screening methods
161
Chapter Six: Conclusions and Recommendations
166
6.1: Conclusions
166
6.2 Recommendations
167
References
169
Appendices
194
Appendix (i) Questionnaire :Attitudes, beliefs and knowledge gaps of
the rural and urban people about sickle cell disease (SCD) and its detection
in the districts of Mbale and Sironko in Eastern Uganda and Ntungamo
and Mbarara in the West
194
Appendix (ii) Questionnaire : Attitudes, beliefs and knowledge gaps
of the health workers about sickle cell disease (SCD) and its detection in
the districts of Mbale and Sironko in Eastern Uganda and Ntungamo and
Mbarara in the West.
204
Appendix (iii) Consent form
206
Appendix (iv) Laboratory request form
210
Appendix (v) Sickling test protocol
211
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Appendix (vi) Solubility test protocol
212
Appendix (vii) Peripheral blood film method protocol
213
Appendix (viii) Hb electrophoresis cellulose acetate method
215
Appendix (ix) Paper on knowledge gaps, attitudes and beliefs of
the communities in Eastern and Western Uganda about SCD ( attached)
Appendix (x) Paper on an up-date on the prevalence of SCD in
Eastern and Western Uganda ( attached)
Appendix (xi) Manuscript on the reliability of SCD screening methods accepted .
for publication in Clinics in Mother and Child Health 2010. (attached)
Appendix (xii) Paper on: A cost benefit analysis of sickle cell
disease screening methods (attached)
- ix -
DECLARATION
I hereby declare that this thesis is the result of my own work and due references are made
where necessary to the work of other researchers and authors.
I further declare that this thesis has not been accepted in substance for any former degree
and is not currently been submitted in candidature for any degree other than mine.
CANDIDATE
OKWI ANDREW LIVEX, MSc., UNIVERSITY OF WALES, UK
SIGNATURE………………………………………………………………………….
SUPERVISORS
PROF. WILSON BYARUGABA; (MSc, PhD) …………………………..Date…………………
PROF. CHRISTOPHER M NDUGWA (M.Med, DTM &H)………………………Date………...
PROF. MICHAEL OCAIDO (MSC, PhD)…………………………………….Date……………...
DR. ARTHUR PARKES (MSc, PhD)……………………………………Date……………………
- ix -
DEDICATION
I would like to dedicate this thesis to the following: my late mother and father Mrs Ajore
Magdalena and Mr. Okwi Enos respectively, who nurtured me up to the time they parted
from me. My daughter, Martha Alupo and all the children with sickle cell anemia whose
condition inspired me to carry out this study. My wife Rose Okwi and all the rest of my
children namely:- Clare Ajore, Emmanuel Okwi and Esther Mamu who stood by me
throughout the difficult times especially when I was away in the University of Wales, in
the field and during the writing of this thesis.
-x-
ACKNOWLEDGEMENTS
First and foremost I would like to thank all my supervisors Professor Wilson Byarugaba ,
Professor Ndugwa Christopher Magala, Professor Ocaido Michael,
Dr. Arthur Parkes for guiding me throughout this study and Professor Tumwine James
K. for his
mentorship. I would also like to thank the College of Health Sciences, Makerere
University for the approval and the Innovations at Makerere University Committee
(I@Mak.Com) for funding this study.
My sincere gratitude goes to the National Council for Science and Technology (UNCST)
for their approval.
I thank the district leaders, the staff in charge of health centers and the mothers of the
participant children for their cooperation. I also thank Mrs Nangosa Hamida Ngira. Mr.
Ayika Ponsiano, Mr. Patrick Byanyima all of Mulago hospital, Dr. Othieno Emmanuel,
Mr. Kiguba Ronald and Mr Ekwaru Amos for their assistance.
- xi -
List of Tables
Table1 : The population distribution, counties, sub-counties, schools
and health centers of the study districts.
39
Table 2: The sites surveyed for urban and rural populations in Eastern
and Western Uganda.
42
Table 3: The sites identified for student and health staff populations in
Eastern and Western Uganda.
44
Table 4: The Socio-Demographic Characteristics of all the respondents.
71
Table 5: Knowledge of respondents about SCD in Eastern and Western regions
of Uganda
79
Table 6: Beliefs of the rural and urban household respondents with primary
education about the causes of SCD in Eastern and Western Uganda.
80
Table 7: Beliefs of respondents about SCD in Eastern and Western Uganda
82
Table 8: Attitude of respondents about SCD in Eastern and Western Uganda.
84
Table 9: The main sources of information of the household and student
respondents about health in Eastern and Western
85
Table 10: The main sources of information of the household and student
respondents about health in Eastern and Western
86
Table 11: The statistical difference in the prevalence of AS and SS between
the study districts.
88
Table 12 : The percentage prevalence of AS in the study districts of Uganda
by the current and Lehman study.
Table 13: Observed prevalence of AS and SS and expected prevalence
- xii -
89
90
Table 14: The summary of the children detected with SS according to age.
92
Table 15: The summary of the haemoglobin AA, AS /SS detected by Hb electrophoresis
(Gold standard) and demonstrated by the sickling and solubility tests and
peripheral blood film method
93
Table 16: Reliability detectability of sickling and solubility tests and peripheral
blood film method.
96
Table 17: The turn around time (TAT) in minutes of sickling, solubility and
peripheral blood film methods
97
Table 18: The costs (Ug Shs) incurred in the first three months in scenario A1
and A2 in Mbale and Sironko in the East and Mbarara, Ntungamo and
Bundibugyo in the West when using only automated capillary Hb
electrophoresis.
100
Table 19: The costs (Ug Shs) incurred in the first three months in scenario B1 and
B2 in Mbale and Sironko in the East and Mbarara, Ntungamo and
Bundibugyo in the West when using automated capillary Hb
electrophoresis and sickling test.
103
Table 20: The costs (Ug Shs) incurred in the first three months in scenario B1 and
B2 in Mbale and Sironko in the East and Mbarara, Ntungamo and
Bundibugyo in the West when using automated capillary Hb
electrophoresis and solubility test.
106
Table 21 The costs (Ug Shs) incurred in the first three months in scenario B1 and
B2 in Mbale and Sironko in the East and Mbarara, Ntungamo and
Bundibugyo in the West when using automated capillary Hb
electrophoresis and peripheral blood film method.
- xiii -
109
Table 22: The costs (Ug Shs) incurred in the first three months in scenario A1 and
A2 in Mbale and Sironko in the East and Mbarara, Ntungamo and
Bundibugyo in the West when using only cellulose acetate Hb
electrophoresis.
112
Table 23: The costs (Ug Shs) incurred in the first three months in scenario B1 and
B2 in Mbale and Sironko in the East and Mbarara, Ntungamo and
Bundibugyo in the West when using cellulose acetate Hb
electrophoresis and sickling test.
115
Table 24: The costs (Ug Shs) incurred in the first three months in scenario B1 and
B2 in Mbale and Sironko in the East and Mbarara, Ntungamo and
Bundibugyo in the West when using cellulose acetate Hb
electrophoresis and solubility test.
118
Table 25 The costs (Ug Shs) incurred in the first three months in scenario B1 and
B2 in Mbale and Sironko in the East and Mbarara, Ntungamo and
Bundibugyo in the West when using cellulose acetate Hb
electrophoresis and peripheral test.
121
Table 26: The costs (Ug Shs) incurred in the first three months when automated
and cellulose acetate Hb electrophoresis methods are used in
Bundibugyo hospital.
123
Table 27: The costs (Ug Shs) incurred in the first three months when automated
and cellulose acetate Hb electrophoresis methods are used with
sickling test in Bundibugyo hospital.
Table 28: The reflection of the accumulative costs (Ug Shs) with time in A1
- xiv -
125
and A2 using automated Hb electrophoresis screening method in Mbale
and Sironko in the East and Mbarara, Ntungamo and Bundibugyo in the
West.
128
Table 29 : The reflection of the accumulative costs (Ug Shs) with time in A1
and A2 using cellulose acetate Hb electrophoresis screening method
in Mbale and Sironko in the East and Mbarara, Ntungamo and
Bundibugyo in the West.
131
Table 30: The reflection of the accumulative costs (Ug Shs) with time in B1
and B2 using automated Hb electrophoresis with sickling test in
Mbale and Sironko in the East and Mbarara, Ntungamo and Bundibugyo
in the West.
134
Table 31: The reflection of the accumulative costs (Ug Shs) with time in B1
and B2 using automated Hb electrophoresis with solubility test in
Mbale and Sironko in the East and Mbarara, Ntungamo and Bundibugyo
in the West.
137
Table 32: The reflection of the accumulative costs (Ug Shs) with time in B1
and B2 using automated Hb electrophoresis with peripheral
blood film method in Mbale and Sironko in the East and Mbarara,
Ntungamo and Bundibugyo in the West.
140
Table 33: The reflection of the accumulative costs (Ug Shs) with time in B1
and B2 using cellulose acetate Hb electrophoresis with sickling
test in Mbale and Sironko in the East and Mbarara,
Ntungamo and Bundibugyo in the West.
- xv -
143
Table 34: The reflection of the accumulative costs (Ug Shs) with time in B1
and B2 using cellulose acetate Hb electrophoresis with solubility test
in Mbale and Sironko in the east and Mbarara, Ntungamo and
Bundibugyo in the West.
146
Table 35: The reflection of the accumulative costs (Ug Shs) with time in B1 and B2
using cellulose acetate Hb electrophoresis with peripheral blood film
method in Mbale and Sironko in the East and Mbarara, Ntungamo and
Bundibugyo in the West.
149
Table 36: Projection of the accumulative costs (Ug Shs) of automated
and cellulose acetate Hb electrophoresis screening services
and sckling test with time in Bundibugyo hospital.
- xvi -
151
List of Figures
Figure 1: The schematic diagram of the beta gene clusters.
12
Figure 2. : Conceptual frame work for genetic screening and policy
28
Figure 3: The map of Uganda showing the location of the study districts
38
Figure 4 : Simple random sampling chart
41
Figure 5: Graph for sample size determination using the reliability coefficient.
52
Figure 6: The flow chart on data collection procedure for prevalence studies.
56
Figure 7: The flow chart of laboratory procedure
59
Figure 8: A Simple decision model for sickle cell disease screening suing
scenarios A1 and A2.
70
Figure 9: A Simple decision model for sickle cell disease screening
suing scenarios B1 and B2.
71
Figure 10: The flow chart for scenarios A1 and A2.
72
Figure 11: The flow chart for scenarios B1 and B2.
73
Figure 12: The percentage of haemoglobin A, AS and SS detected in the study
population of Mbale and Sironko (East); Mbarara, Ntungamo
and Budibugyo in the (West).
87
Figure 13: Photomicrograph of Hb electrophoresis from Mbale district
91
Figure 14: Photomicrograph of Hb electrophoresis from Ntungamo district
91
Figure 15: Photomicrograph of Hb electrophoresis from from Bumdibugyo district
91
Figure 16: Sickling method showing SS (photomicrograph taken after 30 minutes).
94
Figure 17: Solubility method showing Hb SS
94
Figure 18: The peripheral blood film method showing Hb SS.
95
- xvii -
List of Abbreviations
ADAMS 13
a distergrin-like and metalloproteases domain with
thrombospondin type 13 mortifs.
CAM
Cellulose Acetate Membrane strip
CBA
Cost Benefit Analysis
CI
Confidence Interval
DDHS
Directors of District Health Services
DEOS
District Education Officers
EDTA
Ethylene Diamine Tetracetic Acid
HCV
Hepatitis C virus
HHV8
Human Herpes Virus 8
HPFH
Hereditary Persistence of Heamoglobin F
HPLC
High Performance Liquid Chromatography
HU
Hydroxyurea
KAPs
Knowledge gaps, Attitudes and Practices
SMR
Survival Mean Ratio
SPSS
Software Package for Social Science
OPENEPI
Open Source Epidemiologic Statistic Programme for Public Health
PCR
Polymerase Chain Reaction
PBMC
Peripheral Blood Mononuclear Cells
SAO
South East Asian Ovalocytosis
SCA
Sickle Cell Aneamia
SCD
Sickle Cell Disease
- xviii -
SCT
Sickle Cell Trait
TAT
Turn Around Time
TNFα
Tumour Necrosis Factor alpha
ULVWF
von Willerbrand Factor Multimers
WHO
World Health Organization
- xix -
Definitions of Terms
Screening: According to Concise Medical Dictionary, 2nd Edition, screening may simply
be defined as the detection of persons in the population who probably have a
specified disease from those who do not have it.
Sensitivity: Is the ability of a test to correctly detect those who have a disease among
persons with the disease. It means therefore that a test with high sensitivity
will have few false negatives.
Specificity: It is the ability of a test to correctly detect those who do not have a disease.
among persons without the disease In other words it means that a test with
high specificity will have few false positives.
Predictive value: This measures whether an individual actually has a disease or
not given the results of a screening test. So there is positive predictive
value and negative predictive value.
Positive predictive value: Is defined as a proportion of persons who actually have the
disease (true positive) among all the positive results of the screening test.
Negative predictive value: Is the proportion of individuals who actually do not have the
disease (true negative) among all the negative results of the screening test.
- xx -
Confidence interval: Defines the variability of estimate say of a disease in certain
samples. That is to say how likely the disease occurs in certain samples. It uses upper and
lower limits .
Confidence limits: This are upper and lower levels (ends) of confidence interval.
Frequency: Is the measure of the occurrence of a disease in the population.
Prevalence: This is the proportion of the population that are cases of a disease during a
specific period of time.
Incidence: This is a rate at which new cases of a disease occur in a population during
specific period of time.
Cross sectional study: This is a study in which a representative sample of study
subjects from the population is obtained regardless of exposure or outcome status.
Cost effectiveness analysis: Is the method applied to evaluate the economic outcomes or
gains of interventions (test methods or treatments). It usually provides policy makers and
health providers critical data needed for decision making or informed judgment about
problem case management. Usually money is assigned to an increase in health benefits.
Cost benefit analysis: Just like cost effective analysis, cost benefit analysis is the
analysis of the costs and benefits of a new programme such as medical care programme.
- xxi -
It usually measures costs and benefits in monetary terms. However, it is usually difficult
to assign monetary value to an improved health out come.
Hereditary persistence of sickle cell heamoglobin: Is an inherited condition in which
fetal heamoglobin levels persistently remain higher than 2% of the total heamoglobin.
Sickle cell anemia: Is a group of inherited red blood cell disorders, or a collection of
recessive genetic disorders characterised by a heamoglobin variant called heamoglobin S.
Sickle cell anemia is at times used interchangeably with sickle cell disease.
A sample: Is a special sub-set of a population observed for the purposes of making
inferences about the nature of the total population itself.
A sampling frame: Is actual or quasi-list of sampling units from which the sample or
some stage of sampling is selected. The representativeness of the sample depends directly
on the extent to which a sampling frame contains all the members of the total population
which the sample is meant to represent.
Haemoglobin: It is the normal colouring matter of the red blood cells of vertebrate
animals. It has haematin and globulin and is at times known as haematoglobulin. In
arterial blood it is combined with oxygen and is called oxyhaemoglobin.
- xxii -
However, in different animals, it crystallizes into different forms where it is called
haemoctyocrystallin.
Odds Ratio: Is the ratio of the chance or likely hood of the occurrence of the disease to
the chance of it not occurring.
- xxiii -
ABSTRACT
A cross sectional study was done to determine the feasibility of introducing sickle cell
disease (SCD) screening services at health centers in the districts of Uganda. The
knowledge gaps, attitudes and beliefs of the communities about SCD and its detection
were determined. The prevalence of SCD among infants was established. The reliability
and cost benefit analysis of solubility and sickling tests; and peripheral blood film
method was done.
Respondents from the East were more aware of SCD than those from the West (p
<0.001). Less than 20% of the respondents knew their SCD status and (<14%) of the
health staff knew how to screen it. The prevalence of sickle cell trait (AS) was higher in
the East (17.5%) and Bundibugyo (13.4%) than in Mbarara and Ntungamo (3%)
(p<0.001), The difference in the prevalence of homozygous genotype (SS) was
statistically insignificant between Bundibugyo (3%) and the East (1.7%) (p>0.05). No SS
was detected in Mbarara and Ntungamo.
The sickling test had sensitivity and specificity (65%; 96.5%) and positive and negative
predictive values (61.9%; 96.1%) respectively. The solubility test and peripheral blood
film method had sensitivities of 45.0% and 35.0% respectively. Their positive and
negative predictive values were (33.3%; 85.5%) and (53.9% ; 93.1%) respectively.
Screening children at health centers using sickling test, then confirming positive samples
- xxiv -
at the regional hospital using cellulose acetate Hb electrophoresis would be both sensitive
and cheaper than confirming positives in Mulago National referral hospital. Detection of
SCD children would be expensive for districts far from the regional hospitals.
There is a need to sensitize the communities about SCD and screen children for SCD at
district health centers using sickling test, then confirm positive cases at regional hospital
(for near districts) or at district hospitals (for districts far from regional hospital) using
cellulose acetate Hb electrophoresis.
- xxv -
CHAPTER ONE
INTRODUCTION
1.1. Background of the study
Sickle cell disease (SCD) is a genetic blood disease which is due to the presence of an
abnormal form of hemoglobin S which precipitates under low oxygen tension and results
in the cell assuming the shape of a sickle. Sickle cell disease is at times used
interchangeably with sickle cell aneamia (SCA) which is a recessive genetic disorder due
to a point mutation in globin gene chain on chromosome 11 that leads to substitution of
glutamic amino acid by valine amino acid at the sixth postion of the beta globin chain 1.
Sckle cell anemia is associated with high morbidity and mortality among sickle cell
suffers in developing countries2. The emergence of sickle cell hemoglobin S in some
populations including those from Africa, India, the Mediterranean area and Saudi Arabia
has been linked to the selective advantage which sickle cell carriers enjoy as they have
some resistance to P. falciparum 3,4,5,6. The available data on the prevalence of sickle cell
trait (SCT) and annually estimated number of SCA cases in Uganda is based on the past
survey by Lehman and Rapper 7. The prevalence of SCT varied among Ugandan tribes,
with the Karimojong, Bakiga, Banyakole and Bahima recording the lowest frequency of
1-5%, Baganda, Iteso, Acholi and Banyoro recording 16-20%, Basoga, Bagisu and
Lugbara recording 20-28% and Bamba recording the highest frequency of 45% which is
believed to be the highest in the whole world7.
-1-
In Uganda, sickle cell anemia remains the most frequent and traumatizing genetic
disease which continues to devastate the families of sickle cell patients both mentally and
economically. It is estimated that approximately 20% of the population in Uganda are
carriers (AS) and 0.1% of children are born with sickle cell anemia each year. Therefore
with the current population of about 30.000.000 8, approximately 30.000 children are
born with SCA and 80%) of this children probably die before their 5th birth day9. This
number probably contributes to16.2% of all children who die annually in Uganda.10. This
may be because there are limited health care resources in the country and it makes early
detection and management of SCD very difficult.
Although developed countries such as USA and UK are today making successful
attempts to cure sickle cell disease using bone marrow transplants11, such technologies
are expensive for resource poor countries including Uganda. However, advances have
been made by some developing countries such as Jamaica and Ghana to establish
comprehensive cost effective SCD screening and intervention programmes for
management of SCD among patients with improved survival
12,13.
In Uganda sickle cell
identification and management programmes are still limited to teaching University
hospitals, Mulago national referral hospital and some private health institutions thus
leaving the entire country without these services. It was therefore found imperative to
explore the feasibility of establishing SCD screening services at health centers in the
districts of Uganda in order to detect sickle cell disease among infants as early as possible
so that they can benefit from medical interventions. .
-2-
1.2.
Problem statement of the study
According to the available literature on SCD in Uganda, no population based studies have
been carried out on knowledge gaps, attitudes and beliefs of the communities and health
workers about SCD. Besides, the current prevalence of SCA and its variants in all
districts of Uganda remains unknown. Availability and accessibility to diagnostic
services for SCD in the rural settings is lacking. The reliability of sickle cell screening
methods is not known and above all the most beneficial sickle cell screening method to
be used at rural health centers in Uganda has not been determined.
1.3.
Research questions of this study
i.
What are the knowledge gaps, attitudes and beliefs of the communities in the
districts of Uganda about sickle cell disease?
ii.
What is the current prevalence of sickle cell disease in the districts of Uganda?
iii.
How reliable are the currently used methods (sickling and solubility tests and,
peripheral film method) in the detection of sickle cell anemia?
iv.
What is the cost benefit of using the currently used methods (sickling and
solubility tests and, peripheral film method) for the detection of sickle cell
disease?
-3-
1.4.
Objectives
1.4.1
General objective of the study was:-
To study the feasibility of establishing sickle cell disease screening services at district
health centers in Uganda.
1.4.2 Specific objectives were:-
i)
To determine the knowledge gaps, attitudes and beliefs of the communities in
some districts of Uganda about sickle cell disease and its detection.
ii)
To establish the current prevalence of sickle cell desease in five districts of
Uganda.
iii)
To determine the sensitivity, specificity and predictive values of currently
used sickle cell screening methods.
iv)
To carry out a cost benefit analysis on three existing sickle cell screening
methods.
1.5.
Justification of the study
If SCD screening services are not established at health centers in the country, deaths
among infants and pregnant mothers with sickle cell anemia will continue unabated
despite the possibility of controlling the infant and maternal mortality. Hence it was
found necessary to determine the knowledge gaps, attitudes and beliefs of the
communities and health workers about SCD in some districts of Uganda, establish the
-4-
current prevalence of sickle cell anemia and its variants in five districts of Uganda,
determine the reliability of the currently used SCD screening methods and carry out cost
benefit analysis on these screening methods to determine the most beneficial method for
detection of SCD at district health centres. These findings would be used as a basis for
the proper planning and provision of sickle cell management programmes at district
health centers IV in the country.
-5-
CHAPTER TWO
LITERATURE REVIEW
2.1.
Emergence of non-communicable diseases
While infectious diseases are being put under control, more genetic diseases and diseases
of life style are becoming more significant in the world, including the African setting.
Such diseases include cardiovascular diseases, lung cancer, diabetes mellitus,
hypertension and haemoglobinopathies such as sickle cell anemia (SCA) which is an
important problem in Uganda.
Early biomedical studies using different restriction endonucleases showed that the origin
of the sickle cell gene was linked to certain haplotypes (chromosome loci) which were
different from those bearing haemoglobin A14. From these studies the origin of sickle cell
gene in Africa came to be associated with three haplotypes namely; Benin, Senegal and
Bantu haplotypes, while the origin of sickle cell gene in Saudi Arabia and India came to
be linked to Asian haploype. The Benin and Senegal haplotypes are the most common in
West Africa while Bantu haplotype is the one which is probably most commonly seen
today in East Africa14,15.
All these areas in question were, and some are still, endemic for malaria which probably
explains why factors such as malaria have been associated with the emergence of sickle
cell haemoglobin S (HbS) in some populations including those from Africa, India, the
-6-
Mediterranean area and Saudi Arabia. The emergence of sickle anemia in malaria
endemic areas has been linked to the selective advantage which sickle cell carriers enjoy
as they have some resistance to P. falciparum
3,4,5,6.
These carriers are therefore able to
survive and perpetuate the sickle cell gene. Several mechanisms are believed to be
playing the role in this persistence. It has been thought that accelerated acquisition of
malaria specific immunity could be conferring the sickle cell traits with resistance to
malaria. This is probably due to the ability of the ring forms of P.falciparum developing
in infected red blood cell to stimulate the production and expression of hemichromes
associated with enhanced oxidant membrane damage, which results into an aggregation
of band 3 protein and binding of immunogloblin G (IgG) and complement C3c. This
process culminates in enhanced phagocytosis and clearance of the sickled AS red blood
cells infected with ring shape P.falciparum parasites16. Other studies from Gabon have
also postulated that more increase in number of P.faciparum strains in Hb AS individuals
could be exposing these persons to a plethora of P.falciparum antigens capable of
inducing malaria specific immunity17. According to studies from Gambia, it was found
that the expression of the variant surface antigen called P.falciparum erythrocyte
membrane protein-1 on the surface of malaria infected red blood cell, caused the
increased production of antibodies towards P.falciparum antigens leading to the
destruction of the malaria infected red blood cell18. Other studies also noted that the
production of peripheral blood mononuclear cells (PBMC) against P.falciparum
circulating soluble antigens in AS children was higher than in AA and SS children and
were therefore protected against malaria
19.
However, studies in Kenya, showed that the
protective effect of AS against malaria among children was only very pronounced after
-7-
sixteen months of age probably because children below sixteen months were still
enjoying maternal immunity before the development of their own protective immunity 20.
Other protective mechanisms of AS individuals against malaria include defective
invasion or growth of parasites in AS red blood cells which has been linked to acidity and
increased sickling of the red blood cells and formation of the rigid fibres
21.
The studies
by Eugene22 have equally associated protection against malaria in sickle traits with a
condition called glucose 6-phopshate dehydrogenase deficiency which inhibits the
growth of P.Falciparum in the cells probably because of its inability to maintain
glutathione in its reduced state and inability to generate ribose for purine nucleotide
synthesis 22. Besides hemoglobin AS, protection against malaria has also been associated
with conditions such as homozygous hemoglobin C, E, alpha thalassaemia trait and
Southeast Asian Ovalocytosis (SAO)4.
Although some of the studies have linked the emergence of sickle cell disease in other
areas such as the USA, United Kingdom, Spain, France, Begium, Holland, German and
Sicily to the slave trade, migration and travel
2,23,24,
other studies have hypothesized that
the sickle cell gene probably existed in some of these communities, e.g. Sicily, before the
start of the slave trade, probably as a result of the selective pressure of malaria infection
which was endemic to these regions at the time
25.
Besides malaria, the high persistence
of sickle cell anemia in certain communities in countries such as India, Saudi Arabia and,
probably, the Bambas in Uganda among others has been linked to factors such as
inbreeding (consanguinity)26,27. This is a phenomenon in which first cousins or closely
related persons share a set of grandparents. It has been noted that the marriage between
-8-
the first cousins or closely related persons leads to the generation of autosomal recessive
diseases such as sickle cell anemia.
2.2. Early history of sickle cell anemia
The first documented data on sickle cell anemia was first published by Herrick in the
United States in 1910
28.
The first diagnosis of SCA was made from a dental student
whose blood film was shown to contain irreversibly sickled red blood cells. Although
sickle cell anemia is believed to have originated among the Venddoits in the Middle East,
there are still conflicting reports on the origin of the disease in Africa. According to Desai
and Hiren, it is believed that the first presentation of SCD was in 1670 in one of the
Ghanian families in Africa15. While others believe that SCD was first reported from a
Nigerian patient by Africanus Horton in 1874
29,
some of the authors believe that sickle
cell disease was first reported from a Sudanese patient by Achibald in 1925 30.
Initially sickle cell anemia was believed to be familial until it was later found that sickle
cell anemia was an autosomal recessive inheritable disease associated with the sickling of
the red blood cell as a result of oxygen depletion31. The association between sickle cell
anemia and abnormal haemoglobin was first noted 1945 in which abnormality was found
within the haemoglobin molecule and sickle cell haemoglobin could be separated from
the normal haemoglobin using gel electrophoresis. Later studies found that sickle cell
anemia was due to substitution of glutamic amino acid by valine amino acid at the sixth
position of the beta globin chain32,33,34..
-9-
2.3.
The genetic characteristics of human haemoglobins
2.3.1. Genetics of normal human haemoglobins
Early studies have shown that human haemoglobins are derived from zeta (ε), epsilon
( ζ ), alpha (α), beta (ß), delta (δ) and gamma (γ) chains
32,35.
The gene cluster of alpha
family chain is located on the short arm of chromosome 16, on the 25 kilo-base (kb)
region and has 141 amino acids. The alpha globin locus contains four alpha globin genes
which constitute for the synthesis of the alpha globin protein. The alpha gene cluster also
has zeta gene which is only expressed during the early weeks of embryogenesis for the
synthesis of zeta chains needed for production of embryonic haemoglobins called grower
1 and portland 2 but are later on replaced by the production of alpha genes. Grower 1 has
two zeta and two epsilon chains (ε2 ζ2) while potland 2 has two zeta and two gamma
chains (ε2 γ2).
The gamma, beta and delta genes are located within the beta gene cluster located on the
short arm of chromosome 11 on 60 kb region and has 146 amino acids32. Within the beta
gene cluster there is epsilon gene which is synthesized only during embryogenesis for the
production of grower 1 and 2 haemoglobins. Grower 2 has two alpha chains and two
epsilon chains (α2 ζ2). The gamma gene is required mostly during foetal (HbF)
hemoglobin formation after which its synthesis reduces while beta gene production rises
and plays a major role together with alpha gene in the synthesis of adult hemoglobin (Hb
- 10 -
A). The schematic diagram of the globin gene clusters is shown in figure 1 adapted from
http://sickle.bwh.havard.edu/haemoglobinopathy.html 36.
The normal detectable haemolobins in an adult have been found to be hemoglobin A
(HbA) and haemoglobin A2 (HbA2). The haemoglobin A has two α chains and two ß
helix chains (α2ß2) while haemoglobin HbA2 has two α chains and two delta δ chains
(α2δ2).
- 11 -
Figure I: The schematic diagram of the beta gene clusters.
BETA GLOBIN GENE CLUSTER LOCATED ON CHROMOSOME 11
Epsilon
Gamma
G
Delta
Gl
Val (Hbs)
Beta
A
6th
5/
3/
Grower 1 & 2
Hb F
Hb A2
Hb A
ALPHA GLOBIN GENE CLUSTER LOCATED ON
CHROMOSOME 16
Zeta 2
Zeta1
Alpha2
5/
Alpha 1
3/
Grower 1 and Potland 2
Hb A
Epsilon, alpha, gamma and zeta genes play Delta, beta and alpha genes play an important
a major role in the synthesis of
role in the synthesis of adult haemoglobins.
embryonic and fetal haemoglobins.
- 12 -
However, a small amount of foetal haemoglobin (HbF), which is in form of two α and
two γ chains (α2γ2) and is a major haemoglobin seen in foetus, has been detected in an
adult in less significant amounts (less than 1% to 2%). Levels higher than 2% of the total
have been observed in certain conditions of sickle cell disease, beta thallaseamia and
inherited condition known as hereditary persistence of foetal haemoglobin (HPFH) which
is common among Kuwaitis 37.
2.3.2. Genetics of haemoglobin variants
However, today many structural haemoglobin variants have been identified that are due
to a point mutation in globin gene chain on chromosome 11 that leads to the generation of
a single amino acid substitution in a globin chain. According to Clarke and Berlin, most
of the substitutions have been seen to occur in ß globin chain, in which the evolvement of
heamoglobin S has been based on the substitution of glutamic amino acid by valine
amino acid in the 6th position of beta globin chain (β6 Glu → Val)33. The occurrence of
haemoglobin C has been found to be due to substitution of glutamic amino acid by lysine
amino acid in the 6th position of the beta globin chain (β6 Glu → Lys). Haemoglobin D
Punjab and haemoglobin D Ibadan have been linked to the substitution of glutamic amino
acid by glycerine amino acid in the 121st position of the beta globin chain (β121 Glu →
Gly) and threonine amino acid by lysine amino acid in the 7th position of the beta globin
chain (β7Thr → Lys) respectively. Other haemoglobin variants such as alpha and beta
thallasemias have equally been associated with mutation in the alpha and beta globin
- 13 -
chain genes with loss of alpha and beta globin genes and abnormal production in alpha
and beta chains respectively38.
2.4.
Mode of transmission and inheritance of sickle cell anemia and its traits
It is well documented that sickle cell anemia is an autosomal recessive inherited
haemoglobinopathy which is due to acquisition of two abnormal genes, one from each
parent. This disease is therefore transmitted from one generation to another. Sickle cell
anemia evolves when a heterozygote (AS) (carrier) marries either a fellow carrier or a
homozygote (SS) (sufferer). The marriage between carriers has been found to have 25%
chance of having sickler, 25% normal and 50% carrier39. The marriage between
heterozygote (AS) and homozygote (SS) has been shown to have 50% chance of having a
sickler and 50% carrier. The marriage between normal (AA) and homozygote (SS) has
been shown to have 100% chance of having carriers. There is 50% chance of having
normal children and 50% carriers between the normal and the carrier marriage. The
marriage between sicklers is very rare. If it occurs then it has 100% chance of having
sicklers. Sickle cell heamoglobin has also been inherited in association with other
heamoglobin variants such as Hb SC, Hb SD, Hb SE and Hb S alpha or beta thalassemia.
These sickle cell traits occur when a gene for sickle cell haemoglobin is inherited from
one parent and a gene for either haemoglobin A,C,D,E alpha or beta thalassemia is
inherited from the other parent 40.
Although many of the sub-types such as heterozygote haemoglobin HbSD and HbSE are
of little clinical significance, a few important sub-types such Hb SC, HbS beta
- 14 -
thalassemia and HbS alpha thalassemia have been isolated that may present with clinical
conditions similar to sickle cell disease40. Today sickle cell disease synonymously called
sickle cell anemia is the commonest and most severe variant widely distributed
throughout the world.
2.5.
Epidemiology of sickle cell disease
2.5.1. Global prevalence of sickle cell disease
The true global data on the incidence and prevalence of sickle cell disease is currently not
available41. However, sickle cell disease is believed to be the most commonly inherited
blood disorder on the globe affecting an estimated 100 million people word-wide and, in
particular, the black races and persons of Mediterranean origin42. Approximately 5% of
the world population is believed to be carrying the genes responsible for the different
haemoglobinopathies and about 300,000 infants are born annually with major
haemoglobin disorders including sickle cell disease43. In the United States of America
(USA), sickle cell anemia has been found to be the most frequent autosomal recessive
gene disorder affecting approximately 1:375 persons of African ancestry44, with a
prevalence of 0.2%. Notably, sickle cell variants such as haemoglobin S alpha and beta
thalassemia have been found to be highly prevalent in some of the Euopean countries
such as Turkey, Italy and Greece45.
- 15 -
In India, the frequency of sickle cell gene has been found to be as high as 0.31 in some
parts of the country. Studies in the Tuluka district of the Indian State of Maharashtra
showed that out of 4116 persons screened for sickle cell anemia, 814 (19.8%) were
carriers and 44 (1.07%) were sicklers46. Studies carried out among the Pradesh and Orissa
tribes in India found the frequencies of sickle cell trait and sickle cell anemia to vary
among these tribes respectively47 with some communities having haemoglobin variants
SD and SE. The prevalence of sickle cell gene in the Arab countries of Saudi Arabia,
Kuwait
and
Iran has
been found to
be very low comparable to
other
haeamoglobinopathies such thalassemia and SE39. In Iran the prevalence of sickle cell
trait has been estimated to be 1.43% while that of Hb SS is 0.1% 48.
In some parts of the African continent, sickle cell anemia has been found to affect 1 in 60
newborn infants49, giving a prevalence of (2%), whilst the sickle cell trait ranges between
10% to 40% across wet equatorial Africa and decreases to less than 2% in the dry parts
of Northern and Southern Africa. According to Diallo et al;(2002), the African continent
has been regarded as the epicenter of sickle cell disease with an annual estimated number
of 200,000 new born affected by sickle anemia50. This constitutes 66.6 % of the children
born with the haemoglobin disorders in the whole world. Approximately 5% of these
children are believed to die before they reach five years of age. However, according to
Kwaku, it is believed that over 400,000 children are born with sickle cell disease per year
in Africa and about 15,000 children are born with sickle cell disease in Ghana annually13.
According to the Tropical Health and Education Trust Nigeria, it is estimated that 25,000
children are born with sickle cell anemia every year in Nigeria and over 80% of these
- 16 -
children die before they celebrate their fifth birth day51. However, today it is actually
believed that about 150,000 children are born with sickle cell disease every year in
Nigeria
52.
Haemoglobins such as heamoglobin C have equally been found to be
prevalent in West Africa and among persons with heritage from West Africa. Whilst the
prevalence of haemoglobin C and other variants are believed to be very low in East
Africa except in migrants from areas where these variants do occur7, it may be possible
that the prevailence of these variants could now be increasing due to travel and
intermarriage.
2.5.2. Status of sickle cell disease in Uganda
Sickle cell anemia was first described in Uganda in 1945 by Trowel 53. The studies
undertaken in the late 1940s indicated that the prevalence of sickle cell trait varied among
Ugandan tribes, ranging from 1-5% among Karimojong, Bakiga, Banyankole and
Bahima, 16-20% among Baganda, Iteso, Acholi and Banyoro, 20-28% among Basoga,
Bagisu and Lugbara and 45% among Baamba which is believed to be the highest in the
whole world7. Of the 900,000 thousand children born annually in Uganda8 approximately
2.8% have sickle cell aneamia and a staggering 20,000 (70-80%) of sickle cell anemia
patients possibly die before their 5th birth day98. This number constitutes 16.3% of all
children (123,000) who die annually in Uganda
10.
However, the available data on the
prevalence of sickle cell trait and the estimated annual number of sickle cell anemia cases
in Uganda is based on the past survey by Lehman and Raper7, and reports by Serjeant and
Ndugwa 9 respectively.
- 17 -
2.6.
Pathophysiology of sickle cell disease
The clinical symptoms of sickle cell anemia originate from the unique properties of sickle
cell haemoglobin and from haemolytic anemia. The sickling process at times known as
polymerization is due to exhibition of low oxygen tension by the red blood cells. This is
believed to be due to the loss of the negative charge during the substitution glutamic acid
by valine leading to inability of the red blood cell to bind ferric iron. This results into the
insolubilization of the haemoglobin in reduced or deoxygenated state
54..
This
phenomenon causes deoxygenated haemoglobin molecules to rigidify into rods called
polymers which culminate into the distortion of the shape of the red blood cell which
assumes a sickle or cresent shape 55. This process is possibly due to increased binding of
calpromotin to the red blood cells membranes56. Other factors such as haemoglobin
concentration and acidity have been linked to sickling. Increased acidity has been shown
to stimulate the release of potassium ions from the cell resulting into increased
concentration of calcium ions in the cell. The loss of potassium ions therefore affects the
normal function of the cell membrane pump resulting into the failure of the Gardos
channels to close leading to excess release of water from the cell. This process finally
causes dehydration which increases the density of the haemoglobin S within the cell,
thereby accelerating the sickling process leading to excessive disruption of red blood
cells which is characteristic of anemia in sickle cell patients57. Some molecular studies
have showed that dehydration is probably due to over expression of phosphotidylserine
on the surface of dense and older sickle cells
58.
It may therefore be hypothesized that
sickling process involves apoptosis since phosphotidylserine is usually expressed by cells
- 18 -
that are undergoing shrinkage during early apoptosis59. However, further studies need to
be done to elucidate these molecular processes.
Some of the clinical symptoms include the painful crisis due to vaso-occlusion or
blockage of the micro-vascular vessels by sickled cells. This is thought to be due to high
affinity interaction of rigid polymers with vascular endothelium membrane and
leucocytes through adhension process involving the sub-endothelial extracellular matrix
molecules such as intergrins60. These processes culminate into vaso-occlusion and painful
crisis among sickle cell patients 61,62,63.
It has also become evident that adhension between sickle red blood cells and activated
endothelium further enhances vascocclusion process by prolonging their transit time
leading to further polymerization. Many other adhension molecules and their receptors
have been implicated in sickle cell adhesion. One mechanism is linked to von
Willerbrand factor ULVWF multimers of 20,000 kDa or bigger which are normally
released at the site of blood vessel injury from activated endothelial cells known as
Weilbel Palade bodies and act as binding sites for platelets. The release of von
Willerbrand factor is believed to be due to increase of cytosolic calcium ions and increase
of permeability as a result of the activation of endothelial protease receptor 2 (PAR2)
probably by mast cell trypsin64. Normally (ULVWF) are cleaved into smaller particles by
plasma proteases such as metallo-protease ADAMSTS 13 “a distergrin–like and metalloprotease domain with thrombospondin type 13 motifs. However, the deficiency of these
proteases has been associated with the persistence of ULVWF multimers in sickle cell
- 19 -
disease which have been found to act as receptors for adhesion of young sickle red blood
cells to the endothelium thus precipitating vasocclussion process 65.
However, the high levels of haemoglobin F among persons with sickle cell disease has
been found to ameliorate this condition37. A vasocclusion crisis due to polymerization of
HbS has been shown to be inhibited by the high binding oxygen capacity of HbF. For
example, increased synthesis of HbF in sickle cell patients following treatment with
hydroxyurea (HU) was linked to decreased morbidity due to vaso-occlusion conditions
among these patients66,67. The molecular mechanism of hyroxyurea is still unclear,
however, according to Orringer and DePass, the role of hyroxyurea in reducing morbidity
due to vasocclusion is believed to be due to its ability to increase the water content of red
blood cells and decrease the adhesion of sickled red blood cells to the endothelium 68,69.
Other researchers have linked heamoglobin F production during hyadroxyurea treatment
to the transcription of genes within the X-linked F-cell production locus which has been
found to account for 40% of Hb F production in certain persons with Hb SS
70.
The
vasoclusion inhibitory effect of HbF has further been supported by findings showing that
Kuwaitis have mild sickle cell anemia because they have a hereditary persistent of HbF37.
Whether increased synthesis of HbF has a role to play in amelioration of vasoclusion in
other sickle cell variants remains to be elucidated.
Other complications in children with sickle cell disease include stroke, in which
increased levels of prothrombin and decreased levels of anti-coagulators or coagulation
- 20 -
inhibitors namely protein S and heparin factor II, has been found to be associated with
cerebrovascular disease 71. In some of the studies, it is believed that patients with sickle
cell disease are predisposed to inflammation and tissue damage probably due to protein
91 (p91 phox) gene expression and glycoprotein 47 (gp47 phox) phosphorylation which
results in the release of the cytokine interferon gamma (INFγ) from the monocytes
culminating in increased inflammatory activity of these cells72. Other complications, such
as pulmonary hypertension arising from the inhibition of nitric oxide activity, has been
linked to sickle cell disease. This condition has been found to be prevalent in sub-saharan
Africa especially Nigeria41. However, published data on the incidence and prevalence of
pulmonary hypertension in association with sickle cell disease in Uganda remains scanty.
Association between SCD and viral, bacterial and parasitic infections have been
documented. Although, according to the studies in Uganda, higher levels of HHV-8 were
detectable in transfused than non-transfused sickle cell patients 73, the role of HHV–8 in
the pathophysiology of sickle cell disease remains to be elucidated. Sickle cell patients
have also been found to be at a risk for acquiring hepatitis C Virus (HCV) infection
through transfusion of blood74 in which combination between HCV and iron over load
has been linked to progressive liver disease characterized by haemolysis75.
The most notable bacterial infection in sickle cell patients has been found to be
pneumonia caused by Streptococcus pneumoniae and is responsible for high mortality
among infants probably due to low immunity76. However, use of prophylactic penicillin
has been found to be beneficial in the amelioration of this condition 77. The most common
- 21 -
parasitic infection among sickle cell patients has been found to be P.falciparum malaria
and is responsible for severe anemia and thus high morbidity and mortality in sickle cell
patients from developing countries78. The studies in Kenya indicated that P.falciparum
was a cause of severe anemia among children reporting to health centers with sickle cell
anemia and was responsible for high morbidity and mortality
79,80.
Similar studies on
SCD mothers have been reported in Western Tanzania81. Anemia manifests from infancy
and is usually associated with high fatality before 30 years. Hb levels are between 5 and
11.5 g/dL whilst in clinical conditions with increased haemolysis, the Hb levels can fall
to 5g/dL in which sicklers have characteristic jaundice. Anemia may also occur in
sicklers due to mechanical break down of the red blood cells in circulation and from bone
marrow failure from primary hyperactivity (hyperplasia) in response to chronic anemia
and infection. Haemolytic anemia is occasionally linked to dactylitis of the hands and feet
in childhood 82
Weight loss is also common in patients with SCD. This has been linked to a number of
factors including the over expression of TNF-α in sickle cell patients with infections
compared to normal individuals83. The molecular mechanism for this occurrence remains
to be elucidated. Loss in body weight in sickle cell patients has also been linked to
increased calorific value and protein intake with deficient intake of zinc, folic acid and
vitamin A, C and E probably due to socio-economic variations84,85.
Another condition which has been linked to sickle cell disease is called priapism, and has
been found to affect about 30-45% of male patients suffering from SCD86. It is worth
- 22 -
mentioning here that, although sickle cell trait state rarely causes any major
complications, it has been associated with fatality from hypoxia, severe axertion and
abnormal renal function leading to rhabdomyolysis87. Laboratory haematological
indicators include low Hb, marked poikilocytosis, macrocytosis due to folate deficiency
or microcytosis due to beta-thallasemia variants, polychromasia due to reticulocytosis
with heavy blue stippling in the background of thick films, leucoytosis due to bacterial
infection and thrombocytosis following infarctive crisis and neutophilia often with a left
shift
88.
Therefore sickle cell disease covers a larger group of pathological conditions
which require proper management.
2.7.
Management of sickle cell disease
2.7.1. Awareness about sickle cell disease and community education prorammes
The management of SCD has remained a matter of concern in both developed and
developing countries, A greater awareness and understanding of the communities and
health care personnel about SCD and its detection has been found to be beneficial in the
management of the disease
89,90.
Such models include:- (a) continued community
education especially for areas with high prevalence of the disease (b) use of prophylactic
drugs namely chloroquine and penicillin (c) ongoing basic and clinical research (d)
provision of primary health care (access of sickle cell children to health centers) and (e)
improved standard of living and better feeding for patients with SCD. Today, developed
countries such as USA and Britain have successfully reduced morbidity and mortality due
- 23 -
to SCD with life expectancy now standing at 50 years 44. In developing countries such as
Jamaica, children with sickle cell disease have survival rate of 85% for SS compared to
95% with heamoglobin AS/SC and 99% with normal hemoglobin AA91 and they have
median survival at 53 years for men and 59 years for women 92.
Some of the studies have found that increased understanding within communities about
sickle cell disease and the continuous assessment of parental beliefs about SCD was
necessary for the management of this disease at home through the programmes targeting
the prevention of malarial and pneumoccocal infections 93.
It has also been noted that improvement in scientific understanding of SCD within the
caretakers leads to improvement of the conditions and increase in life expectancy in
sickle cell patients 42. Understanding of the risk factors and benefits of screening has been
found to play a vital role for the surveillance, prevention and /or management of sickle
cell disease 94. Indeed some of the studies found that, in communities where parents had a
high level of awareness about SCD, they were more willing to take their children for
screening 95. Notably intensive and wide spread education programmes in areas where βthallasemia was more prevalent was associated with the reduction of the prevalence of βthallasemia in these communities89.
However, limited community education programmes and knowledge about
haemoglobinopathies among parents has been associated with late diagnosis of these
diseases and subsequent poor management
96.
- 24 -
Lack of familiarity with SCD among the
health professionals in areas with low prevalence of SCD, was associated with low
awareness about the disease and lack of skills on screening tests97,98. In some studies, it
was found that although most of the respondents, including health workers, were more
knowledgeable about the genetic basis of sickle cell anemia and its pathophysiology, they
were not aware of their own sickle cell status90. However, according to the available
literature on SCD in Uganda, no population based studies have been carried out on
knowledge gaps, attitudes and beliefs of the communities and health workers about SCD
and its detection.
2.7.2. Screening
Screening is a medical procedure used to detect or predict the presence of disease in
individuals at risk for disease within a population, family, or workforce 99.Screening may
be performed to monitor disease prevalence, manage epidemiology, aid in prevention, or
strictly for statistical purposes
100.
Normally screening is done to identify the disease as
early as possible so that the affected persons benefit from early medical interventions.
Today screening is widely used in early identification of several conditions such as
precancerous lesions in cervical cancer using Pap smear, breast cancer using
mammography and colonoscopy for early detection of colorectal cancer and early
detection of heamoglobinopathies such as sickle cell disease to mention but a few.
- 25 -
2.7.2.1 Principles of screening
According to World Health Organisation guide lines
101,
several factors have been found
to be prerequisites or determinants of any screening programme. They include the
following: The magnitude of the disease or condition on the ground should be known
and the disease should be in its latent stage, the natural history of the disease should be
adequately understood, the diagnostic and treatment facilities should be available, the
screening cost of finding a case should be economically balanced in relation to medical
expenditure as a whole, the screening test must be reliable and acceptable by the
population, there should be an agreed policy on who to treat and screening programme
must be a continuous process in other words it must be sustainable.
2.7.2.2. Screening models
Today there are conceptual framework models which have been developed for genetic
screening and policy making. These include a model shown in figure 2 adopted after
Anne Andermann102. This frame work describes the broad and complex arena within
which genetic screening policy-making is carreid out. Population-based genetic screening
interventions have been shown to interface between the spheres of genetics and public
health, each with their own patterns, frames of reference, and approaches to improving
health. The area of genetics has been found to be centered on individual patient and
family at risk as opposed to public health which is also concerned with improving the
overall health outcome of the general community. So their should be a balance between
these factors before any policy can be formulated and approved. It has been noted that
- 26 -
genetic screening policy-making be may be influenced by pressures both nationally and
internationally. For instance, the introduction of a new technology in a state or country
has been found to exert pressure on other authorities to agree even if there are many other
complex issues to be considered before making such a decision. For example, it has been
found that before any screening is done, there is a need to know whether such a screening
programme will reduce suffering, provide hope, promote research, and stimulate industry.
Besides, there is a need to determine the cost benefit and risks associated with such a
programme. It has equally been found imperative to find out whether a screening
programme respects human rights. It is believed that before any decision to screen is
carried out, a concept must be developed first, followed by piloting, implementing,
evaluating and sustaining the programme.
- 27 -
Figure 2: Conceptual frame work for genetic screening and
Policy-making (adopted after Anne Andermann 2010)
KEY STAKEHOLDERS
Society
Medicine
Patient support Patients and
Groups
families
Community
groups
General public
Government
Health sector
Health profess- Pharmaceuticals Other sector
ionals
Researchers
Biomedical
VALUES, EXPECTATIONS, PREFERENCES, CONCERNS
Pressure in favour of
screening
- reduce suffering
- provide hope
- promote research
- stimulate industry
Assessment process
- meet criteria ?
- evidence based ?
- values up-held ?
- feasible?
- worth developing?
Industry
Biotechnology
Ethical
Legal
Autonomy
Privacy
Justice
Laws
Jurisprudence
Declaration
Social
Other
Individuals
Families
Communities
Psychological
Economic
Political
Genetic screening
programme
1. DECISION TO
DEVELOPMENT
1.Pilot and
Development
2. Programme
implementation
3. Evaluation of performance
3. DECISION TO CONTINUE
Screening \criteria and
principles
- improve health
- cost effective
- benefits and risks
- respect human rights
2.7.2.3 Screening programmes
- 28 -
2. DECISION TO
IMPLEMENT
Different types of screening programmes or approaches have been adopted for specific
situations. Targeted screening is used to identify or detect disease among individuals in a
population with very low prevalence of the disease, while universal screening is applied
when the prevalence of the disease is very high. These programmes have been widely
used in developed countries such as USA and UK 92.
Screening has been found to have both advantages and disadvantages. Screening has the
advantage that it allows early detection of a medical condition before symptoms advance
and paves away for early treatment with good prognosis than when the disease is detected
later. Usually this type of intervention is associated with improved survival outcome.
Screening has been associated with several disadvantages. In a number of cases the
results generated by the screening test may turn out to be false positive. False positives
have been linked to stigmatization, stress and anxiety, unnecessary treatment intervention
and waste of resources, while false negative results have been found to lead to repeats,
waste of resources and delays in interventions with poor outcomes. There are two types
of stage screening namely one in which a test of high sensitivity is used in the first stage
and a test of high specifity in the second stage. This is usually done in order to get a test
which is both highly sensitive and specific.
- 29 -
2.7.2.4 Screening for sickle cell disease
Screening the communities for haemoglobinopathies including SCD has been found to be
vital for the management and control of these conditions. Sickle cell screening is used to
identify children with sickle cell anemia and sickle cell trait. Identification of affected
infants and carriers by screening provides opportunities for educational and medical
interventions that significantly reduce morbidity and mortality during childhood and
adolescence103. In some of the developed countries such as Belgium, Brazil and USA,
screening of all newborns for sickle cell anemia regardless of ethnic race has been made
mandatory103. In developing countries namely Jamaica and Ghana programmes for
screening of SCA have been introduced in the rural communities with considerable
success12,13. The success in these screening programmes was attributed to the introduction
of the most comprehensive sickle cell screening programmes.104 . In Uganda sickle cell
screening is limited to Mulago National referral hospital, some teaching hospitals and
private health institutions thus leaving the entire country without these services..
2.7.2.4.1
Sickle cell disease screening methods
Several methods of varying cost, accuracy, efficacy and ease of applicability are today
available for sickle cell screening105,106. In developed and highly resourced countries such
as USA, UK, Italy, Canada and France, more advanced methods such as high
performance liquid chromatography (HPLC) and iso-electric focusing (IEF) are the
principle tools for neonatal screening for sickle cell disease 107,108
- 30 -
More detailed analysis of the genetic basis of the disease can also be obtained using
polymerase chain reaction (PCR) which detects mutations in a beta globin chain
associated with sickle cell anemia. Polymerase chain reaction (PCR) is particularly useful
for both pre-natal and neonatal diagnosis of haemoglobinopathies, including sickle cell
disease109. The principle of PCR is based on the use of bi-directional allele specific PCR
amplifications protocol which amplifies a 517 bp fragment from the normal β-globin
gene (wild-type primer set) and a 267 bp fragment from homozygous mutant DNA (Hb
S/S) conferring sickle cell anemia (mutant primer set) .The bands (amplicons) formed are
then compared with the known bands characteristic of Hb A, Hb S/S or Hb A/S.
Although the PCR method is used for prenatal diagnosis in developed countries109, its
application in the developing countries is not possible because it is not cost effective
110.
Therefore the use of these methods in developing countries including Uganda remains
elusive because of high costs.
Methods using monoclonal antibodies for sickle cell screening are also available111. The
HemoCard monoclonal antibodies have been designed to differentiate between
heamoglobin variants which cannot be differentiated by Hb electrophoresis because they
have similar charges and therefore have similar electrophoretic migration patterns.
Although results of some of the studies have found monoclonal antibodies reliable for
sickle cell screening112, other studies have found them unsuitable for sickle cell screening
because they are unreliable and production costs are high54. Besides, samples with very
low and very high haemoglobin levels have been found to give erroneous results and
samples containing heamoglobin S and E have been found to give false positive results
- 31 -
for haemoglobin A54. These monoclonal antibodies have also been associated with cross
reactivity with haemoglobin A113. Their use for sickle cell screening is yet to be clinically
accepted.
Hb electrophoresis method has been found to be reliable for routine sickle cell screening.
Today, it is extensively used in Jamaica, Ghana and Brazil as a sickle cell screening
procedure
12,13,114.
The principle of this method is based on the fact that proteins carry
positive and negative charges determined by their charged amino acid structure and the
balance of these positive and negative charges will give the whole molecule either a
positive or negative charge. When an electric field is applied to a solution containing
these protein molecules, positively charged proteins will move to the cathode and
negatively charged proteins will migrate to the anode. Depending on their charges, size
and shape, different haemoglobins will separate and migrate at different rates. They can
then be visualized by staining and the bands compared with the known controls54.
However, its use in most of the resource constrained countries, including Uganda, is
limited due to the high running costs of this procedure13. In Uganda, the availability of
Hb electrophoresis equipment is limited to some of the teaching hospitals, the national
referral hospitals such as Mulago and some private health institutions.
There are other more affordable methods of varying reliability, ease of applicability and
cost available for early screening for SCD in low income countries; these include the
sickling and solubility tests and the peripheral blood film methods115,116. The solubility
- 32 -
test is based on the formation of turbidity whilst the sickling test and peripheral blood
film methods are based on the formation and detection of sickle cell shapes.
Notably all screening tests have been found to give at least incorrect results, with
resultant stigmatization, stress and/or anxiety. It has therefore been noted that before any
screening programme is implemented there is a need to carry out statistical analysis to
ensure that it is associated with minimal risks and high outputs. Randomized studies have
been used to evaluate a screening test to find out whether it will be associated with
minimal risks and improved out comes
117.
This usually involves comparing statistics of
mortality due to a disease in a screened and unscreened population.
Most of the
screening tests have been found to be associated with lead time bias, length time bias,
selection bias, over diagnosis bias and avoidance bias. In lead time bias, the survival time
since diagnosis has been found to be longer although the life span may be shorter. In
length time bias, the screening test may detect a condition which probably would not
have killed the patient or even been detected before death from other causal factors. In
selection bias, certain factors have been found to influence the decision of an individual
to undertake screening. The decision to screen persons at a higher risk of a disease has
been seen to favour only persons who have family history of that condition since they
will be the only ones who will go for screening. So in this way, the reliability/validity of
a screening test will be influenced as the test may turn out to be more reliable than it
really is. Notably, some tests have been found to detect abnormal cases that are
sometimes not necessarily harmful leading to over-diagnosis bias, while using a large
- 33 -
study sample which may take a long time and is costly has been linked to avoidance of
bias.
However, studies on cost benefit analysis are necessary to determine which of these
methods is most appropriate for sickle cell screening in low income countries such as
Uganda.
2.7.2.5 Cost benefit analysis of screening for sickle cell disease
Many developing countries including Uganda, find it difficult to fund all the health
programmes because of limited resources118. It is therefore imperative that resources
should be allocated in the most efficient and beneficial manner. Cost benefit analysis is
performed to determine the programmes or options which offer the greatest benefits at
minimum cost and provides decision makers with information on which programme to
recommend119. Just like preventive services, establishment of cost effective sickle cell
screening and intervention programmes has been found to be beneficial in the reduction
of morbidity and mortality among children with sickle cell disease with improved
survival out come120,,121,122.
The cost benefit of any screening programme is influenced by several factors which
include the risk or prevalence of the disease in the population, reliability and ease of
applicability of the screening method (s) adopted, the cost of these screening services and
their acceptability to the community123. For example, some studies found that the cost
- 34 -
benefit of the screening intervention decreased as the prevalence decreased, notably
because high costs would be incurred on detecting one person in the population with the
disease120. Similarly, the cost benefit of the screening programme decreased as the
reliability of the screening tool decreased 124,125
In health care, cost benefit analysis is used to evaluate the costs of an intervention and to
determine those interventions which are associated with the highest survival outcomes 125
In some of the developed countries such as USA, Belgium, France and UK and Belgium,
cost effective screening tools are today available for mandatory screening of all newborns
for sickle cell disease regardless of ethnic race92,24,124 125.126
Although most of the governments in the developing countries, including Uganda, are
finding it difficult to fund all the medical pogrammes because of scarce resources, some
of the developing countries including Jamaica and Ghana have made remarkable effort to
introduce cost effective sickle cell screening programmes with considerable success using
affordable methods
12,13.
In Kenya, studies on cost benefit analysis recommended the
peripheral blood film method for screening SCD at district health centers116. In Malawi,
the most cost effective methods such as HemoCue AB-haemoglobin photometer has been
recommended to be used for haemoglobin estimation at district hospitals and health
centers 127. While the countries mentioned above have carried out cost benefit analysis on
sickle cell screening tests/methods, no such studies have been done in Uganda.
- 35 -
CHAPTER THREE
MATERIALS AND METHODS
3.1. Study design
Four varieties of study designs were used in this work as follows:- A descriptive cross
sectional study was carried out to determine the knowledge gaps, attitudes and practices
of the communities about sickle cell anemia and its detection. A cross sectional survey
was used to determine the prevalence of sickle cell anemia and its variants in five
selected districts of Uganda.. A descriptive laboratory based study was used to determine
the sensitivity, specificity and reliability of the current sickle cell screening methods.
Calculation of costs, hypothetical scenarios and assumptions were used for cost benefit
analysis on the existing sickle cell screening methods.
Study sites
The districts of Sironko and Mbale in the East, Mbarara, Ntungamo in the West were
conveniently selected because these were the districts that had been involved in
Innovations at Makerere University Committee (I@Mak.Com) project. However, the
district of Bundibygyo in the West was purposively identified as one of the study sites
because of its uniqueness in that a prevalence of 45% of SCT had been reported as the
highest in the whole world according to Lehman and Raper study 7.
- 36 -
The locations of the districts are shown in Figire 3 (Map of Uganda adopted from
Monitor News Paper)128. According to Uganda District Information Hand Book130
Sironko district boarders Kapchorwa in the East, Kumi in the West, Nakapiripirit in the
North and Mbale in the South. The district of Mbale boarders Sironko in the North,
Tororo in the South-West, Kumi in the North-West, Pallisa in the West and Republic of
Kenya in the East.
Mbarara district boarders Rakai in the East, Bushenyi in the West, Masaka in the NorthEast, Kabarole in the North, Ntungamo and the Republic of Tanzania in the South.
Ntungamo district boarders Mbarara in the East, Bushenyi in the North, Rukungiri in the
North-East, Kabale and Rwanda in the South. The district of Bundibugyo boarders
Kabarole district in the East, Kasese in the South, Lake Albert in the North and
Democratic Republic of Congo in the West. It is in the extreme Western part of the
former District of Toro.Figure 3 shows the location of the study districts 129.
- 37 -
Figure 3: The map showing the location of the study districts 128.
N
W
E
S
Ntungamo
Mbarara
Mbale
Sironko
Bundibugyo
The population distribution of the study districts and the number of counties, subcounties, schools and health centers in each district are as shown in Table 1.
- 38 -
Table 1: The population distribution, counties, sub-counties, schools
and health centers of the study districts.
Sironko
Mbale
Mbarara
Ntungamo
Bundibugyo
Rural
280,671
650,488
996,636
373,474
198,732
Urban
11,235
70,437
92,115
13,342
14,161
Total
291,906
720,925
1,089,051
386,816
212,884
Females
146,488
368,856
552,046
200,469
109,732
Males
146,418
357,069
537,005
186,347
103,732
No counties
2
4
8
4
3
No subcounties
HC III
19
13
46
15
8
19
9
38
6
2
HCIV
3
4
6
3
1
Hospitals
0
2
2
1
1
Secondary
schools
26
64
102
27
11
- 39 -
3.3. Study population selection
From the general populations of the districts, sub-set of the populations were selected to
suit the study objectives as follows:
3.3.1. Knowledge gaps, attitude and beliefs of the study populations about sickle
cell disease
3.3.1.1. Household participantants selection
The stratified random sampling chart for knowledge gap study is as shown in Figure 4.
Adult participants between 18-60 years were identified from counties, sub-counties,
parishes and villages for knowledge gap population (KAP) studies because it was hoped
that all participants in this age bracket would be able to personally consent and were
physically fit to participate in the KAP interview. Both rural and urban females and males
were selected. The parents or caretaker were identified only from households which had
children to avoid bias. One county was selected from each district using random sampling
procedure. The names of the counties were written in small pieces of paper and then
folded and put in a basket. They were mixed and one was independently picked. Using
the same sampling procedure, one sub-county, two parishes and four villages were
selected.
- 40 -
Fig 4: Simple stratified random sampling chart
DISTRICT
COUNTY
SUB-COUNTY
PARISH
PARISH
village
village
village
village
village
village
village
The sites surveyed for urban and rural populations are as shown in Table 2. In Sironko
district, Budadiri County, Busulani Sub-county, Bugumunye and Nakiwodwe parishes
were identified within the rural community. The urban community was sampled in
Sironko Town Council. In Mbale district, Bungonko county, Busiu sub-county and
Bumasikye and Bunabutye parishes were identified in the rural community. The urban
population was interviewed from Mbale Municipality.
In Mbarara district, the rural community was interviewed from Ibanda county,
Nyabuhikye sub-county and Ruhoko and Bufunda parishes, while the urban community
- 41 -
village
was interviewed from Mbarara Municipality. In Ntungamo district, the rural community
was sampled from Rushenyi county, Rubaare sub-county, Itojo and Omugyenyi parishes.
The urban community was interviewed from Ntungamo Town Council.
Table 2. The sites surveyed for urban and rural populations in Eastern and
Western Uganda
District
County
Sub-county
Rural Communities
(parishes)
Urban communities
Sironko
Budadiri
Busulani
Bugimunye and Nakiwodwe
Sironko Town Council
Mbale
Bungonko
Busiu
Bumesikye and Bunabutye
Mbale Municipality
Mbarara
Ibanda
Ibanda
Ruhoko and Bufunda
Mbarara Municipality
Ntungamo
Rushenyi
Rubaare
Mutojo and Omugyenyi
Ntungamo Town Council
3.3.1.2.Selection of health staff and secondary school students
The summary of the sites identified for student and health staff populations in Eastern
and Western Uganda is as shown in Table 3. Nurses, clinical officers and laboratory staff
from district health centers IV were recruited from health centers IV for KAP studies,
while students were identified from both government and private secondary schools. The
health centers where training of laboratory personnel was to be done were not included in
- 42 -
KAP interviews to avoid bias. All participants were above 18 years and none was
mentally ill. Because of limited logistics, only four schools were randomly picked from
each region to generate enough data since a single school had sufficient number of senior
five and six students for the study. Most of these students were eligible to participate in
the interview since most of them were above 18 years. They were selected from cardinal
directions in order to have a proper representation of the district. Using the same
procedure, four health centers IV were also selected from each region. The names of the
health centers and rural and urban secondary schools in each district were obtained from
Directors of District Health Services (DDHS) and District Education Officers (DEOs)
and written on small pieces of paper. They were folded and put in separate containers and
lottery-picked to get two health centers and one rural and one urban school. This gave a
total of four health centers and four schools in each region.
In Sironko district, Highway Secondary School was identified within the rural setting and
Sironko Secondary School was identified within the urban population. Buwasa and
Muyembe health centers IV were selected. In Mbale district, Semei Kakungulu rural and
Mbale Progressive urban schools were identified together with health centers IV of
Bubulo and Kolonyi respectively.
In the district of Mbarara, the urban secondary school students were interviewed from St
Joseph Secondary School and Mary Hill Girls School while rural secondary school
students were interviewed from Nyakayonjo Secondary School respectively. The health
centers IV of Kinoni and Bwizibwera were identified. In the district of Ntungamo, the
- 43 -
urban students were sampled from Hillside Academy while the rural secondary school
students were interviewed from Ntungamo Trust High School. The health staff were
interviewed from Rwashamire and Ruhama health centers IV.
Table 3. The sites identified for student and health staff populations in Eastern and
Western Uganda
District
Rural schools
Urban schools
Health centers
Sironko
Highway Secondary School
Sironko Parents Secondary
Buwasa and Muyembe
HCenters IV
Mbale
Semei Kakungulu High School
Mbale Progressive School
Bubulo and Kolonyi
HCenters IV
Mbarara
Nyakayonjo S.S
St. Joseph S.S (boys) and
Mary Hill Girls School.
Kinoni and Bwizibwera
HCenters IV
Ntungamo
Ntungamo Trust High
Secondary School
Hillside Academy
Rwashamire and Ruhama
3.3.2. Selection of the population for sickle disease prevalence study
Male and female infants or children between 6 months to 5 years were selected for the
establishment of the prevalence of sickle cell anemia irrespective of whether they were
already known cases of sickle cell anemia or not. The reason for this is that
infants/children aged 6 months to 5 years have developed their own hemoglobin which is
in high and detectable quantities. While those less than 6 months have not yet developed
enough of their own haemoglobin which is in high and detectable quantities. However,
- 44 -
all the infants who had received blood transfusion in the last four months were not
recruited into the study in order to avoid getting false negative results. The
infants/children were selected from health centers IV and nursery schools which were
randomly selected.
The nursery schools were taken because most of the children were below 5 years,
representing the high frequency of haemoglobin SS genotype in the population. Secondly
these children were from different parts of the distrcit which had been randomly selected
and were therefore representative of all the areas in the district. The random sampling
procedure was used only when there was more than one health center IV and nursery
school. The eligible children were consecutively recruited into the study after obtaining
consent from their parents or guardians. In the case of nursery schools, consent was
obtained from parents through District Education Officers (DEOs, District Directors of
Health Services (DDHS) and incharge of nursery schools. In Sironko and Mbale districts,
children were identified from Budadiri and Busiu health centers IV. In Ntungamo and
Mbarara districts, children were selected from Rubaare and Ruhoko health centers IV and
from Divine Mercy and Ibanda Junior nursery schools respectively. In Bundibugyo
district, children were sampled from Nyahuka health center IV and from Super and
Bundibugyo Junior nursery schools. Although the study was not about tribes, the children
who were sampled from Mbale and Sironko were predominantly Bagisu, while those
from Mbarara and Ntungamo were predominantly Banyankole. The children sampled in
Bundibugyo district were mostly Baamba.
- 45 -
3.3.3.
Selection of the population for reliability study of sickle screening methods
The 200 blood samples which were used for the determination of the reliability of
sickling and solubility tests and peripheral blood film method were selected from samples
which had been taken from children between 6 months to 5 years for prevalence studies.
All the haemolysed blood samples were excluded for reliability study. The minimum
number of 200 samples were selected using systematic sampling procedure. The samples
were first assigned new numbers and the samples were then picked sytematically starting
with first number in the first raw. The second number was left out then third number was
picked, fourth was left out and fifth was picked and so on until the end of the first raw
was reached. The same procedure was used for the second raw. The remaining numbers
were also sampled until the required number of 200 samples were obtained. The analysis
of the samples was undertaken in the Department of Pathology, Faculty of Medicine
(now known as Makerere University College of Health Sciences), Departments of
Haematology and Clinical Chemistry, Mulago Hospital.
3.3.4. Selection of study sites and sampling procedures for cost benefit analysis
study of sickle cell screening methods
One health center IV and two laboratory technicians were selected in each district to be
trained for the establishment of pilot screening sites using sickling and solubility tests and
peripheral blood film method. The pilot screening sites were not established in
Bundibugyo because it was only selected for prevalence study. With the assistance of
DDHS, the names of the health centers IV with a microscope were obtained in each
- 46 -
district and written in pieces of paper which were folded and put in a basin. One health
center IV was then randomly picked. However, random sampling procedure was only
applied to the districts which had more than one health center IV.
3.4.
Sample size determination
3.4.1. Sample size determination for knowledge gap studies on sickle cell disease
3.4.1.1.
Sample size determination house hold surveys
The minimum sample size of 571 respondents (279 for Mbale and Sironko in Eastern
Uganda and 292 from Mbarara and Ntungamo in the West) was calculated using the Kish
and Leshlie formula130. For the purpose of sample size determination, the prevalence of
23.8% was taken for Eastern and 5% for Mbarara and Ntungamo in Western Uganda as
established by Lehman and Raper7. The precision of 5% was used for estimated
prevalence above 15% in order to get representative sample size. The precision below 5%
was chosen for estimated prevalence below 15% since the frequency of the disease is low
at this prevalence 131. The precision of 5% was therefore taken for Mbale and Sironko in
Eastern and 2.5% was taken for Mbarara and Ntungamo. Ninety five percent confidence
interval was used. The formula is as shown below.
n = Z2 PQ
D2
Where n = minimum sample size.
Z = The confidence interval (95%) where confidence limit (CL) is + 1.96.
- 47 -
P = Estimated prevalence.
Q = 100-P
D = The precision
Using this formula, the estimated sample size for Sironko and Mbale was
n = (1.96)2 x 23.8 x (100-23.8)
52
=
279
while Ntungamo and Mbarara was
n = (1.96)2 x 5 x (100-5)
= 292
2
2.5
The total number of villages which were to be sampled in the districts of Mbale and
Sironko in Eastern region and Mbarara and Ntungamo in the West was calculated using
the formula below.
C
= n x deff
K
where C = the number of villages to be sampled
n == Z2 PQ = calculated sample size.
D2
deff = design error effect value of 2.8 was used because the error which would be
introduced from sampling the cluster of villages would be unknown.
K = cluster size.
Therefore using this formula, the total number of villages which were sampled in Sironko
and Mbale was .
C = 279 x 2.8
= 11 villages
70
The number of villages sampled in Mbarara and Ntungamo districts was
C = 292 x 2.8
70
= 12 villages
- 48 -
iii) The proportional distribution of villages among the districts of Sironko and Mbale
was calculated using probability proportions based on population size of the districts and
estimated sample size of the villages in both districts as shown below:n = a x (b or c)
b + c
where n = required sample size of villages in the district.
a = estimated sample size of villages in both the districts of Sironko and Mbale
b = population of Sironko (291,906)
c = population Mbale (720,925)
The calculated number of villages in Sironko district was:N=
11 x 291,906
291,906 + 720,925
= 3 villages
While in Mbale district the number of villages interviewed were 8.
Using the same formula, the proportional distribution of 4 and 8 villages were identified
and interviewed from the districts of Ntungamo and Mbarara respectively.
The number of rural respondents in each village in the districts of Mbale and Sironko and
Mbarara and Ntungamo was determined using the calculated number of villages and the
estimated samples size of rural respondents in the districts. It was based on the
assumption that equal number of rural and urban respondents would be interviewed. The
calculated number of rural respondents per village is as shown in the formula below:
N
=
a x (b or c)
b + c
where N= number of rural respondents to be interviewed in each village.
- 49 -
a = estimated sample size of rural respondents in both the districts of Sironko and Mable
b = calculated number of villages in Sironko
c= calculated number of villages in Mbale
The calculated number of rural respondents per village in Sironko district was:N=
140 x 3
= 38 (which was approximately 40 respondents
11
= 13 respondents per village).
The calculated number of rural respondents per village in Male district was:N=
140 x 8
11
persons per village)
= 101 (which was approximately =13
Using the same formula, the proportional distribution of approximately 12 rural
repondents were identified and interviewed per village from the districts of Ntungamo
and Mbarara respectively.
3.4.1.2. Sample size determination for secondary schools and health centers
Twenty four female and twenty four male students were to be interviewed from one rural
and one urban secondary school in each district. The selection of equal number of males
and females was based on approximate equal population distribution of females and
males in the districts of Uganda
129
and it was also based on the prevailing movement
towards equal rights and gender balance. This gave a sample size of 192 students. Twelve
health staff were to be selected from each health center IV in each district giving a total
of 96 health workers in each region respectively.
- 50 -
3.4.2. Sample size determination for sickle cell disease prevalence studies
The minimum sample size of 571 calculated for households using Kish and Leshlie
formula130 formula was also used for prevalence studies. Two hundred and seventy nine
household respondents were sampled in Sironko and Mbale districts in Eastern Uganda
and 292 in Mbarara and Ntungamo . The mimimum sample size of 194 was calculated for
Bundibugyo using the same formula (Kish and Leshlie) which was used for KAPs. In this
case, the prevalence of 45% was used as established by Lehman and Raper studies of
1949. The precision of 7% and 95% confidence interval were used in order to get the
manageable sample size 131.
n = (1.96)2 x 45 x (100-45)
72
= 194
3.4.3. Sample size determination for sickle cell screening methods reliability studies
The graph adopted after Browner and Newman for estimation of the minimum sample
size for reliability studies is as shown in Figure 5. The minimum sample size of 200 was
calculated using standard graphs based on correlation (reliability) coefficient132. This was
based on the assumption that at 95% confidence interval, the expected coefficient of
reliability detection of sickle cell disease is 0.05. Using this coefficient, the minimum
sample size of 200 was used for the determination of reliability of the methods.
- 51 -
Figure 5: Graph for sample size determination using the reliability coefficient.
1000
No.
800
C.I. = 0.05
600
400
200
0
0.05
0.06
0.07
0.08
0.09
0.10
Reliability coefficient of detectability at 95% confidence interval.
3.4.4. Sample size determination for studying cost benefit analysis of sickle cell
screening methods
Sample size estimation was not done for the cost benefit analsyis study since it involved
only determination of costs and benefits. However, the number of children sampled for
prevalence studies were first screened at health centers IV pilot sites by the technicians
using sickling and solubility tests and peripheral blood film method before the blood
- 52 -
samples were sent to the Departement of Pathology for confirmation using Hb
electrophoresis method.
3.5. Data collection procedures
3.5.1. Data collection for knowledge gap studies about sickle cell disease
3.5.1.1. House hold survey on knowledge gap studies about sickle cell disease
Households were interviewed according to World Heath Organization (WHO)
protocol133. With the help of local council one (LC1) chairman, the center of the village
was located. The pen was picked and thrown up and the interview began in the direction
where the tip faced, starting with the first home which had a child. The first home with a
child was purposively sampled. In some cases, an estimated 450 turn right or left was
made to select another direction.
The households were first briefed about the purpose of the study. The informed consent
was obtained using the consent form shown in shown in appendix (iii). At times an
interpreter was used to obtain the consent from the participants who did not understand
English using the language they could understand. Although the questionnaire as shown
in appendix (i) was given to them to fill, many of the rural respondents could not
physically fill the questionnaire and were therefore assisted by the investigator and
research assistants who had earlier been trained by investigator on how to administer
- 53 -
questionnaires. In some cases the questionnaire papers were self administered and picked
later. The interview was carried out until the required number of respondents was
obtained. Two hundred and eighty rural and urban household respondents were
interviewed from the districts of Mbale and Sironko and 309 from the districts of
Mbarara and Ntungamo respectively. This gave a total of 589 household respondents,
which was a little (1.03 %) more than the minimum calculated sample size of 571.
3.5.1.2. Perception studies on sickle cell disease by secondary school students
and health staff
In each school, the participants from senior five were selected by random sampling
procedure. The list of names of students were obtained from the head teachers of the
schools. Female and male names were separated and written in small pieces of paper and
put in separate plastic basins. The names were lottery-picked to select 12 female and 12
male respondents. After briefing the participants on the purpose of the study and
obtaining consent, the questionnaire as shown in appendix (ii) was then selfadministered. Eighty eight students were interviewed from Mbale and Sironko and 85
from Mbarara and Ntungamo giving a total of 173 students in all the study populations.
The paramedical health staff to be interviewed were not randomly selected because some
health centers had as few as 6 eligible staff. Instead, all eligible staff at the health center
were consecutively interviewed after obtaining informed consent. Thirty four health
workers respondents were interviewed in Mbale and Sironko in Eastern Ugnada and 42
- 54 -
in from Mbarara and Ntungamo in the West giving a total of 76 health workers
respondents.
3.5.2 Sickle cell disease prevalence studies
The flow chart of the data collection procedures for prevalence studies was as shown in
Figure 6. Using a 21 mm gauge syringe needle, a 2 ml sample of blood was collected
from eligible infants/children (6 months to 5 years) from antecubital vein in ethylene
diamine tetra acetic acid (EDTA) vacutainers. This was done after obtaining consent
from either their parents or guardians or in-charge of nursery schools. In some cases
where blood sample colud not be obtained from antecubital area, blood was collected into
tubes by finger prick or heel puncture. The blood samples were taken with the help of the
clinical officer and research assistants (senior laboratory technologists). Before
withdrawing blood, the area to be punctured was sterilized by methylated spirit using
absorbent cotton wool. Some of the complications due to swelling and venepuncture were
medically managed. The laboratory request form shown in Appendix (iv) was used
during blood collection.
Two hundred and eighty six blood samples were collected from the children in Sironko
and Mbale districts in Eastern Uganda (82 Sironko; 204 Mbale) and 370 blood samples
from Mbarara and Ntungamo (267 in Mbarara and 103 in Ntungamo) in Western region
of Uganda. This gave a total of 656 samples collected in these districts, which was a little
(1.15 %) more than the minimum calculated sample size of 571. Two hundred and one
blood samples were collected from the district of Bundibugyo which was (1.04 %) more
- 55 -
than the calculated sample size of 194. This therefore gave an overall total of 857
samples collected from all these districts. The samples were then transported in cool
boxes to the Department of Pathology, College of Health Sciences for analysis of
hemoglobin S using Hb electrophoresis54,134.
Figure 6: The flow chart on data collection procedure for prevalence studies.
HOUSEHOLDS
DISTRCIT HEALTH CENTERS
FOM (COHS) MAKERERE UNIVERSITY
Hb electrophoresis method
As +ve
ss+ve
Hb A
To be referred to Mbale, Mbarara
or Bundibugyo referral hospitals.
Determination of prevalence
- 56 -
NURSERY SCHOOLS
3.5.3. Reliability studies on sickle cell disease screening methods
The flow chart of the laboratory procedures used is shown in Figure 7. The 200 blood
samples were independently analysed by the principal researcher and two senior
technologist using the solubility and sickling tests and peripheral blood film method
(adopted after Barbara et al; 2001)134. Hb electrophoresis was used as a gold standard
(adopted after Junius et al; 1991) 135.
3.5.3.1.
Sickling test
The sickling test was based on observing the sickling of red blood cells exposed to a low
oxygen tension under the microscope. Twenty micro litres of each blood sample, was
mixed with 20 micro liters of 2% sodium metabisulphite on a cover slip. A slide was then
gently pressed onto the cover slip and after inversion, the cover-slip was ringed with
candle wax. The slide preparations were left in a humidified chamber for 15 minutes at
room temperature and then examined under the microscope (x10). Further observations
were taken after 30 minutes, 1 and 2 hours. Sickling was considered to be positive when
more than 25% of the red blood cells sickled.
3.5.3.2. Solubility test
The solubility method was based on turbidity created when HbS is incubated with sodium
dithionate. Twenty micro-liters of each sample was mixed with 2 ml of 0.02% sodium
dithionate in a test tube and left to stand at room temperature for 5 minutes. The samples
- 57 -
were examined using light against the background of black lines. The results were
interpreted as positive when the black lines were not visible.
3.5.3.3. Peripheral blood film screening method
The peripheral blood film screening method was based on examining the blood film
stained with Giemsa using light microscopy (x100) for red blood cells with sickle shapes.
The results were considered positive when the sickle cell count was greater than 25% of
the total red cell count.
3.5.3.4. Hb elecrophoresis screening method
The cellulose acetate membrane Hb electrophoresis method at pH 9.2 was used to
determine the presence of AA, AS, and SS in the samples and to confirm the results
generated by the above methods. The principle of this method is based on the fact that
proteins normally have either positive or negative charge that is determined by the
charged amino acid they contain. When electric field is applied to a solution containing
protein molecules, positively charged proteins will move to the cathode and negatively
charged proteins will migrate to the anode. Depending on their charges, size and shape,
different haemoglobins will separate and migrate at different rates. They are then stained
with a chromogen and their bands compared with the known controls
134.
the protocols of these methods are shown in Appendices v,vi,vii and viii
- 58 -
The details of
Fig 7: The flow chart of laboratory procedure.
200 BLOOD SAMPLES
Sickling test
+ve
Peripheral
blood film
method
Solubility test
-ve
+ve
-ve
Hb electrophoresis method
AS
Hb AA
SS
- 59 -
+ve
-ve
3.5.4. Determination of the costs and benefits of different screening methods for
SCD at district health centers
3.5.4.1. Training laboratory technicians
Two laboratory technicians were trained from each Health Center IV on how to perform
sickling and solubility tests and peripheral blood film method. The training was based
on:-the average time it took the laboratory technician to take the blood sample from each
child, how long it took her/him to perform each method starting with the preparation of
the solutions to final reading of the tests (generation of results) and the ability of the
individual technician to correctly perform each test.
First, the trainees were shown by the trainers how to prepare solutions using the
chemicals and reagents which had been bought. Each demonstration was timed. The
trainees then independently prepared these solutions using the same reagents and
chemicals and each process was timed. Secondly, while timing, the trainees were then
shown how to take two mls of blood in EDTA vacuutainer tubes from antecubital vein
from children between 6 months and 5 years whose mothers or guardians had been
consented. They were also shown how to take blood from either the finger or heel
prick.This was then followed by the trainees them selves performing the bleeding. The
complications which arose during bleeding were managed with the assistance of either
the clinical or medical officer.
- 60 -
Later, the trainees were shown how to perform sickling and solubility tests and peripheral
blood film method. The positive control (Hb SS) and negative control (Hb AA) unknown
to the trainees were used in parallel with the test samples. The time taken to perform each
test was recorded. Later each trainee independently carried out each test on the same
samples while timing each process. This process continued until each trainee was able to
perform each method correctly. The number of practical tests taken by each trainee
before correctly performing each method was recorded. The trainees then continued to
screen for SCD using these method for a period of six months and 656 blood samples
were brought to Mulago hospital in cool boxes for Hb electrophoresis.
3.5.4.2. Measures of technical feasibility
The turn around time of sickling and solubility tests, and peripheral blood film method
was also determined as one of the measures of technical feasibility. This was done by
timing each process starting with the preparation of working solutions, setting the test and
final reading of the results. The average time taken to collect blood samples from each
child was also taken by timing each process during bleeding.
3.5.4.3. Cost benefit analysis of different SCD screening methods
Cost benefit analysis was done to determine which method is best suited for screening for
SCD at district health centers IV in Uganda. Simple decision models were designed for
- 61 -
cost benefit analysis (CBA) using the hypothetical scenarios and assumptions to
determine the benefits and/or profitability of sickling and solubility tests and peripheral
blood film method. The calculation of the costs was in Uganda shillings (Ug Shs) and
was based on the following:
i)
Costs for buying equipment such as microscopes.
ii)
Cost of buying consumables: the reagents and materials
iii)
Training costs. The calculation was based on mean hourly training allowance
based on monthly salary.
iv)
Transport costs of patients to the SC testing centres and transportation of
blood samples by medical technicians from district health centers to Hb
electrophoresis centers .
v)
Loss of productivity cost by mothers who bring children to health centers for
screening. The calculation was based on income per capita (which is the total
average income each family member received per year)
vi)
Other costs included depreciation cost of the laboratory equipment which was
calculated at each fiscal year. It was done by dividing the total cost of the
equipment by the useful life years of the equipment which was taken as 5 years
for medical equipment 136. The calculations were in Uganda shillings.
- 62 -
3.6.
Data analysis
3.6.1 . Data analysis on knowledge gap studies on sickle cell disease
The data was entered and analysed using soft-ware package for social science 10.0 (SPSS
10.0)
137.
The open source epidemiologic statistic programme for public health version
2.2.1 (Openepi)138 was used for the comparison of these study populations and 95%
confidence interval was used and pvalue of 0.05 was considered statistically significant.
3.6.2. Data analysis on prevalence of sickle cell disease studies
The statistical programmes used for KAP study were also used for data entry, analysis
and comparison of the statistical difference in the prevalence of sickle cell disease in
these study populations. The prevalence of sickle cell disease was calculated by dividing
the true positive tests by the total number of samples and multiplied by 100. The formula
is shown below:
P1 =
P2 X100
N
Where P1 = prevalence
P2 = true positive tests
N = Total number of samples
The calculation of allele frequencies from genotype frequencies was done using
Populations Genetics and the Hardy Weinberg Law 139.
- 63 -
*
Where f are the frequencies of the three genotypes (AA), (Aa) and (aa)
and p and q the frequencies of (A) and (a) alleles respectively.
Expected prevalence of SS was calculated according to Mordell and Darlison formula
shown below140.
E =square root of AS percentage .
Where E= expected prevalence of SS (homozygous sickle cell genotype).
AS is sickle cell trait.
3.6.3. Data analysis on reliability of sickle cell disease screening tests
The entry and statistical analysis of the data was undertaken using the same programme
used for KAP study
137.
The open source epidemiologic statistic programme for public
health version 2.2.1 (Openepi) 138 was used for the comparison of these methods and 95%
confidence interval was used and pvalue of 0.05 was considered statistically significant.
The sensitivity and specificity and predictive values as measures of reliability of SCD
screening tests were calculated using the formulae given by Trap and Dawson 141.
Sensitivity = A
A+C
Where A = the number of persons with a disease who test true positive
C= persons with a disease who test false negative.
The results were recorded as a percentage of persons who truly tested positive among
- 64 -
persons with the disease ( A x100 ) .
A + C.
The method was interpreted to have high sensitivity when it measured nearer to 100%.
ii) Specificity = D
B+D
Where D = number of persons without a disease who test true negative
and B= number of persons without a disease who test false positive.
The results were recorded as a percentage of persons who truly tested negative among
persons without the disease
( D x100 ) .
B+D
The method was interpreted to have high specificity when it measured nearer to 100%.
Positive predictive value of the methods was calculated using the formula below:PV of +ve results =
TP .
TP + FP
Where TP= true positive results
FP= false positive
The results would be recorded as a percentage of true positive results among the positive
results
( TP x100 ) .
TP + FP
The method was interpreted to have high predictive value when it measured nearer to
100%.
Negative predictive value of the methods was calculated as follows:-
- 65 -
PV of -ve results =
TN .
TN + FN
Where TN= true negative results
FP= false negative
The results were recorded as a percentage of true negative results among the negative
results.
( TN x100 ) .
TN + FN
The method was interpreted to have high predictive value when it measured nearer to
100%.
3.6.4. Data analysis on cost benefit analysis
The simple decision model used for choosing either scenarios (A1 or A2) is as shown in
Figure 8. The simple decision model used for choosing either scenarios (B1 or B2) is as
shown in Figure 9. It was assumed that the operations for scenarios A1, A2 and B1, B2
would be as shown in Figures 10 and 11 respectively. The costs and benefits of
establishing each SCD screening method at health centre were compared. The outputs/
benefits of establishing the SC screening services at district health centers was taken as
human lives saved if SCD screening service were introduced at district health centers
besides Mulago. The calculation of human lives saved was based on Lindas theory that if
children with SCD are detected and treated, 85% of the children with SS will grow into
adulthood while 95% of those with AS will live normal life 91.
- 66 -
The accumulative costs of the screening services were projected for a period of five years
and it was projected that more children with SCD would be detected and more money
would be saved because the only costs incurred would be service maintenance costs.
These were calculated annually on 3% basis of the previous year maintenance costs since
there would be an expected 3% annual increase of the general population8.
The following assumptions were considered when cost benefit analysis was performed:
(i)
Each of the sickle cell screening method established at the district health center
would be the recommended method for screening SCD .
(ii)
Both automated capillary and cellulose acetate Hb electrophoresis systems would
be ‘gold standards’.
(iii)
Sample and material storage costs (use of electricity or generator) would not
affect the previous billing costs at the health centers.
(iv)
Cost of laboratory space and its maintenance would not be considered in cost
benefit analysis because the space was already existing.
(v)
All children who test negative at district health centers would be free off the
sickle cell disease except those who later develop symptoms .
(vi)
Only children who test positive at the district health centers would be confirmed
and those found truly positive would benefit from treatment interventions.
(vii)
Only screening costs would be considered but not treatment costs
(viii) The persons performing these tests would be doing routine work and getting
monthly salary.
- 67 -
(ix)
The glassware which does not fall under consumables would be replaced in the
second year
(x)
Basing on Linda theory, 95% of children with sickle cell trait would live normal
life and 85% with sickle cell anemia would grow to adulthood if detected and
treated early91.
(xi)
When no screening and medical intervention services are in place, it would be
assumed that all children with SS would die at early age 91.
(xii)
The costs of running these sickle cell tests would take into account regional
prevalence of SCD among infants.
(xiii) The costs of buying consumables would be increasing annually corresponding to
3% population growth 8.
(xiv)
Based on the three months results of the pilot screening from Eastern Uganda, it
would be assumed that 302 children would be screened in three months in
Bundibugyo district. It would equally be assumed that sickling test would
demonstrate the presence of 21 AS, 9 SS, solubility 11 AS, 6 SS and peripheral
blood film 6 AS, 5SS in these children respectively.
xv)
The automated Hb electrophoresis equipment would depreciate at USh
11,571,750 per year, while cellulose acetate Hb electrophoresis would depreciate
at Ug. Shs 600,000 per year. Each microscope and weighing balance would
depreciate at Ug Shs 300,000 and Ug Shs 50,280 per year respectively.
- 68 -
Cost benefit analysis was performed under the following scenarios :i) When there are no sickle cell screening services at district health centers and all
children would be referred to Mulago hospital for Hb lectrophoresis (scenario A1).
ii) When there are no screening services at district health centers and all children would
be referred to the regional hospital for Hb electrophoresis, (scenario A2).
iii) When there are sickle cell screening services at district health centers and only
positive samples would be brought to Mulago hospital for confirmation usig Hb
electrophoresis (scenario B1).
iv) There are screening services at district health centers and only positive samples would
be brought to the regional hospital for confirmation using Hb electrophoresis
(scenario B2).
- 69 -
Figure 8: A Simple decision model for sickle cell disease screening using scenarios
A1 and A2.
Intervene
Outcome survive
A) No screening
at HC IV
Test +ve
A1) Go to Mulago
Hospital
A2) Go to regional
Hospital
Test -ve
No intervention
- 70 -
Outcome survive
Figure 9: A Simple decision model for sickle cell disease screening using scenarios
B1 and B2.
Intervene
Outcome survive
B) Do screening
at HC IV
Test +ve
B1) Take +ves to
Mulago Hospital
B2)Take+ves to regional
Hospital
Test -ve
No intervention
Outcome survive
square =decision node; circle = probability (chance node); and rectangle =
out come node.
- 71 -
Fig 10:
The flow chart for scenarios A1 and A2.
MOTHERS FROM HOUSEHOLDS
Mulago hospital (A1) or Regional hospital (A2) for Hb
electrophoresis method
ss-ve
No intervention (95%
live normal life)
+ve ss
Intervene (85% grow
to adult hood)
- 72 -
Fig 11:
The flow chart for scenarios B1 and B2.
MOTHERS FROM HOUSEHOLDS
DISTRCIT HEALTH CENTERS
Sickling method
Solubility method
+ve
+ve
Peripheral blood
film method
+ve
Mulago hospital (B1) or Regional
hospital (B2) for Hb electrophoresis
method
+ve (SS)
Intervene (85% grow to
adulthood)
+ve (AS)
Usually no
intervention. 95%
live normal life
- 73 -
-ve ss (AA)
No intervention
(99% live normal
life
The SCD screening methods were compared to the golden standard methods (automated
Hb electrophoresis and cellulose acetate). The costs incurred overtime and benefits of
lives saved were compared. The benefits of costs saved in introduction of SCD screening
tests in Health centre IV were estimated. The percentage of money saved was calculated
using the formula below:
C1-C2
S =
x 100
C1
Where S = percentage of money saved
C1 = Original cost price
C2 = Second cost price
Sensitivity analysis was done on the benefits of introducing SCD screening tests on :
i)
Prevalence of SCD
ii)
Distance of the population to reach Health IV screening centres
iii)
Human population in an area
3.7. Ethical issues
Clearence: The permission to carry out this study and use human materials such as blood
samples was sought from the then Faculty of Medicine, Ethics and Research Committee
(ERC) and Uganda National Council of Science and Technology (UNCST).
- 74 -
Consent: Written informed consent was directly obtaind from adult participants using a
form shown in appendix (iii). All participating children had written informed consent
obtained from a relevant authority parent/guardian.
Justice: The risks due to bleeding and swelling which arose during the taking of blood
samples from the children were medically managed. The information which was
generated from these blood samples was treated as confidential.
Beneficence: If the findings of this study were adopted for policy formulation, the
communities would benefit from sickle cell screening services available at district health
centers. Besides, sickle cell disease would be detected and managed as early as possible
thus minimizing child and mertanal mortality due to the disease
- 75 -
CHAPTER FOUR
RESULTS
4.1 Knowledge gap study .
4.1.1 Socio-demographic characteristics
The details of the socio-demographic characteristics of the respondents are shown in
Table 4. The recruited male and female participants, were aged between 18-60 years and
were from urban and rural settings. The majority of the respondents were peasants and
students with primary and secondary education respectively.
Table 4: The Socio-Demographic Characteristics of all the respondents.
The bracketed figures are in percentages.
Variable
Age: (18-60 years)
Sex:
Male
Female
Education: Informal
Primary
Secondary
Tertiary
University
Eastern
402
188 (46.8)
214 (53.2)
22 (5.5)
129 (32.1)
192 (47.8)
51 (12.7)
8 (2.0)
Western
436
207 (47.5)
229 (52.5)
24 (5.5)
155 (35.6)
157 (36.0)
68 (15.6)
32 (7.4)
Occupation: Employed
Student
Peasant
Self employed
82 (20.4)
121 (30.1)
141 (35.1)
58 (14.4)
120
118
99
209
(27.5)
(27.1)
(22.7)
(47.9)
Religion:
85 (21.1)
142 (35.3)
111 (27.6)
4
(1.0)
10 (2.5)
174
188
18
7
16
(40.0)
(43.1)
(4.1)
(1.6)
(3.7)
215 (53.5)
187 (46.5)
237 (54.4)
199 (45.6)
115
138
81
68
99
103
50
184
Location:
Catholic
Protestant
Moslem
Orthodox
Reedemed
Rural
Urban
Distance to health center:
<3 km
3-10 km
> 10 km
Non-commital
(28.6)
(34.3)
(20.1)
(16.9)
- 76 -
(26.4)
(22.7)
(11.5)
(42.2)
4.1.2 Knowledge gaps of the communities about sickle cell disease
The summary of the knowledge gaps of the respondents about SCD are as shown in
Table 5. Seventy three percent of the household respondents from Eastern Uganda were
aware of SCD compared to 59% from the Western p<0.001) (OR 1.85: 95% CI: 1.312.62) with 49% from the East reporting that persons with SCD had been detected in their
communities compared to only 20% from the west p<0.001) (OR 3.93: 95% CI: 2.466.20). Notably, 3% of the household respondents from the East and 1% from the West
reported to have been screened for SCD.
Seventy one percent of the students from the East were aware of SCD compared to 59%
from the West, while 45% of the students from the East reported that persons with SCD
disease had been detected in their communities compared to 18% from the West
(p<0.001) (OR 3.94: 95% CI: 1.73-8.93). Two percent of the student respondents from
Eastern Uganda and none from the West reported that they knew their sickle cell status.
Fifty two percent of the health staff from the East reported that they knew sickle cell
screening methods compared to 50% from the West, with 14% from the East reporting
that they screened for SCD compared to only 9% from the West. Fourteen percent of the
health staff from the East and 6% from the West reported that they knew their sickle cell
status.
- 77 -
The commonly used name for SCD in the communities of Eastern was ‘Enkaka’
meaning yellow fever and a few correctly calling it ‘siko-cello’ which in English means
sickle cell. The Western communities were mostly calling it ‘siko-celo’ although others
were calling it ‘Okupumpura (plague like), Binyoro (yaws) and Kisipi (herpes zoster).
- 78 -
Table 5: Knowledge of respondents about SCD in Eastern and Western regions of
Uganda.
Eastern
Western
N=280
N=309
Odds Ratio
95% CI
P value
204 (72.9)
183 (59.2)
1.85
1.31- 2.62
<0.001
(Only for those aware of
SCD)
Seen persons with SCD in
community (only for those
aware)
Know they could possibly
have children with SCD.
Knows his/her SC status
100 (49.0)
36 (19.7)
3.93
2.46- 6.20
<0.001
30 (14.7)
5 (2.5)
32 (17.4)
2 (1.1)
1.04
2.78
1.61- 1.76
0.55-20.9
0.887
0.234
Students
n =88
n =85
Awareness about sickle cell
disease (SCD)
62 (70.5)
50 (58.8)
1.67
0.89-3.13
0.114
(Only for those aware of
SCD)
Seen persons with SCD in
his/her community (only those
aware)
Knows his/her SC status
n =62
n =50
28 (45.2)
9
(18)
3.94
1.73-8.98
<0.001
1
0
(0)
-
-
0.052
Health workers
n=34
n=42
29 (85.3)
32 (76.2)
1.81
0.55- 5.93
0.342
27 (79.4)
33 (78.6)
1.05
0.35- 3.20
0.936
n =29
n=32
15
4
4
20
16
3
2
10
1.07
1.55
2.4
4.57
0.39- 2.93
0.32- 7.58
0.41-14.21
1.71-12.24
0.896
0.617
0.366
0.002
Households (nonstudents)
Awareness about sickle cell
disease (SCD)
Awareness about sickle cell
disease (SCD)
Know can be managed if
diagnosed early
(Only for those aware of
SCD)
Correctly know screening
method (s)
Screen for sickle cell disease
Knows his/her SC status
Came across SCD patients
(1.6)
(51.7)
(13.8)
(13.8)
(69)
(50)
(9.4)
(6.3)
(31.3)
The details of the knoeledge about sickle disease of the rural and urban respondents in
Eastern and Western Uganda are as shown in Table 6.
- 79 -
FNotably, 62% of the rural household respondents in Mbale and Sironko were aware of
SCD compared to 76% of the urban respondents (p>0.05) (OR 0.70: 95% CI: 1.41-1.18),
while 55% and 65% of the rural and urban household respodents were aware of SCD in
Mbarara and Ntungamo respectively (p>0.05) (OR 0.66: 95% CI: 0.42-1.04).
Table 6: Knowledge of the rural and urban household respondents about SCD in
Sironko and Mbale in Eastern region of Uganda and Mbarara and Ntungamo in
the West.
Rural
Urban
OR
95% CI
PV
n= 140
n=140
Awareness about sickle cell
disease (SCD)
97 (62.3)
107 (76.4)
0.70
0.41-1.18
0.183
Only for those aware
Person has been detected with
SCD in his/her community
52 (53.7)
48 (34.3)
1.42
0.82-2.47
0.216
16 (16.5)
14 (1.0)
1.32
0.60-2.85
0.500
Mbarara and Ntungamo
n=150
n=159
Awareness about sickle cell
disease (SCD)
82 (54.7)
103 (64.8)
0.66
0.42- 1.04
0.072
Only for those aware
Person has been detected with
SCD in his/her community
11 (7.3)
5 (3.4)
3.04
1.01-9.13
0.047
Know they could possibly have
children with SCD before they
got
11 (7.3)
21 (13.2)
0.61
0.27- 1.34
Sironko and Male
Know they could possibly have
children with SCD
- 80 -
0.220
4.1.3 The beliefs of the respondents about SCD.
The beliefs of the respondents about sickle cell disease from Eastern and Western
Uganda are as shown in Table 7. Fifty seven percent of the household respondents in the
East and 51% from the West believed that SCD could be acquired from parents. Ninety
two percent of the household respondents from the East believed SCD could be prevented
by premarital screening compared to 76% from the West (p<0.001) (OR 3.69: 95% CI:
2.22-6.14). Eight percent of the household respondents in Sironko and Mbale believed
that SCD was a punishment from God compared to 2% from Mbarara and Ntungamo.
Two percent of the household respondents in both regions believed that SCD was due to
witchcraft.
Fifty eight percent of the student respondents from Eastern and 60% from Western
believed that SCD was acquired from parent while 76% from the East and 82% from the
West belived that it could be prevented by premarital screening. Ninety percent of the
health staff from the East and 94% from the West believed that SCD is acquired from
parents, while 93% from the East and 91% from the West believed that it can be
prevented by screening before marriage
- 81 -
Table 7: Beliefs of respondents about SCD in Eastern and Western Uganda.
Households (nonstudents)
Causes of SCD
(Only for those aware of
SCD)
Natural
Punishment from God
Witchcraft
Acquired from parents
Can be prevented by
screening before marriage
Eastern
Western
N=280
N=309
n=204
n=183
59
17
4
117
72
4
3
94
(28.9)
(8.3)
(1.9)
(57.3)
(39.3)
(2.2)
(1.6)
(51.3)
158 (77.5)
135 (73.8)
62
50
22 (35.5)
0
(0)
0
(0)
36 (58.1)
15
0
0
30
47
41 (82.0)
Odds
Ratio
95% CI
P value
0.88
4.92
1.48
1.64
0.60-1.30
1.73- 17.22
0.30- 8.0
1.17-2.30
0.518
0.002
0.63
0.004
1.2
0.77- 1.94
0.403
1.56
0.92
0.74-3.25
0.43- 1.97
0.246
0.84
0.63
0.30- 1.34
0.324
Students
Only for those aware of
SCD)
Natural
Punishment from God
Witchcraft
Acquired from parents
Can be prevented by
screening before marriage
(75.8)
(30)
(0)
(0)
(60)
Health workers
(Only for those aware of
SCD)
Natural
Punishment from God
Witchcraft
Acquired from parents
Can be prevented by
screening before marriage
n=29
n=32
5
0
0
26
(17.2)
(0)
(0)
(89.7)
3 (9.4)
0 (0)
0 (0)
30 (93.8)
2.21
1.30
0.47-12.07
0.46-3.67
0.318
0.634
27
(93.1)
29 (90.6)
1.40
0.22-9.01
0.298
4.1.4. Attitudes of the communities about SCD
The summary of the attitudes of the respondents about SCD are as shown shown in Table
8 Fifty eight percent of the household respondents who reported to have had ill patients
from the East felt sympathetic about patients’ illness compared to 67% from the West.
- 82 -
Thirty eight percent of the household respondents from the East felt depressed about
patients illness compared to 22% from the West(p<0.001) (OR 3.69: 95% CI: 2.22-6.14)..
Ninety two percent of the household respondents from the East and 87% from the West
were willing to be screened. Notably, 12% of the respondents from the West were not
willing to be screened, compared to 8% from the East. Fourty nine percent of the student
respondents from the East and 51% from the West felt sympathetic about patients’
illness, while 22% from the East and 35% from the West felt depressed. Fifteen percent
of the students from the East reported that they were not wiling to be screened compared
to twenty one percent from the West.
- 83 -
Table 8 : Attitude of respondents about SCD in Eastern and Western Uganda.
Household respondents
Attitude towards patients.
Sympathetic
Depressed
Angry
Embarrassed
Not affected
Attitude towards SC
screening
Willing to be screened
Not willing
East
West
n=180*
n=185*
105
69
20
20
2
124
40
7
5
4
(58.3)
(38.3)
(11)
(11)
(1)
Odds
Ratio
95% CI
P value
0.69
2.25
3.18
4.50
0.51
0.45-1.05
1.42-3.57
1.31-7.72
1.65-12.27
0.09-2.81
0.088
<0.001
0.008
0.001
0.469
1.61
0.68
0.94-2.78
0.39-1.18
0.083
0.169
(51.0)
(35.3)
(2.0)
( 2.0)
(5.9)
0.93
0.52
7.73
8.86
0.28
0.44- 1.97
0.22- 1.20
1.18-176.6
1.38- 202.6
0.01- 2.70
0.851
0.132
0.030
0.016
0.299
n= 85
73 (85.9)
18 (21.1)
0.95
0.65
0.41-2.22
0.29-1.42
0.906
0.282
(67)
(21.6)
(3.8)
(2.7)
(2.1)
n=280
n=309
257
23
270 (87.4)
36 (11.7)
(91.8)
(8.2)
Students repondents
n =59*
n =51*
Attitude towards patients.
Sympathetic
Depressed.
Angry
Embarrassed
Not affected
29
13
8
9
1
26
18
1
1
3
(49.1)
(22.0)
(13.6)
(15.3)
(1.7)
Attitude towards SC
screening
Willing to be screened
Not willing
n =88
75
(85.2)
13
(14.8)
Key: * only respondents who reported to have had an ill person.
4.1.5 Sources of information about health.
The summary of the household respondents on the main sources of information about
health is as shown in table 9. The main sources of information of the household
respondents from both regions about health in descending order were radio, health
visitors, community, newspapers and lastly television. The main sources of information
- 84 -
about health of the student respondents in the East were health visitors, radio, news
papers, radio, community and television, whilst those in the West they were health
visitors, radio, television, newspapers and lastly community.
Table 9: The main sources of information of the household and student respondents
about health in Eastern and Western.
Variable
East
West
Households
N=280
N=309
Haealth visitors
Radio
TV
News papers
Community
125
174
41
47
96
188
202
45
68
101
Students
N =88
Haealth visitors
Radio
TV
News papers
Community
53
38
16
20
17
(44.6)
(62.1)
(14.6)
(16.8)
(34.3)
(60.2)
(43.1)
(18.2)
(22.7)
(19.3)
(60.8)
(65.4)
(14.6)
(22.0)
(32.7)
Odds Ratio
95% CI
Pvalue
0.52
0.87
0.61
1.25
1.07
0.37-0.72
0.62- 1.22
0.40- 0.93
0.82-1.92
0.76- 1.51
0.001
0.313
0.016
0.305
0.5 11
1.77
1.09
0.51
1.27
4.81
0.98-3.27
0.54- 1.99
0.26-1.97
0.61- 2.65
1.56-15.08
0.046
0.594
0.048
0.401
0.001
N=85
39
35
27
16
4
(45.9)
(41.2)
(31.8)
(18.8)
(4.7)
The summary of the main sources of information of the rural and urban respondents
from the East and Western Uganda about health are as shown in Table 10.
The main sources of information about health of the rural and urban household
respondents from both regions were mostly radio, health visitors and community. Twenty
one percent of the urban respondents from the East reported that their other sources of
information were television and news papers. Thirty two percent and 26% from the West
- 85 -
reported that their other sources of information about health were television and news
papers respectively.
Table 10: The main sources of information of the rural and urban household
respondents about health in Eastern and Western Uganda.
Variable
Rural
Urban
Eastern
N=140
N=140
Health visitors
Radio
TV
News papers
Community
76 (54.3)
75 (53.6)
7 (5.0)
17 (12.1)
18
(12.9)
50
99
29
30
58
Western
N =150
N=159
Health visitors
Radio
TV
News papers
Community
97
(64.7)
120 (80.0)
10
(6.7)
17 (11.3)
41
(27.3)
4.3.
91
82
42
51
60
(35.7)
(70.7)
(20.7)
(21.4)
(41.4)
(57.2)
(51.6)
(31.8)
(26.4)
(37.7)
Odds Ratio
95% CI
Pvalue
2.14
0.48
0.20
0.51
0.21
1.32-3.45
0.29- 0.78
0.09- 0.48
0.27-0.97
0.11- 0.39
0.001
0.001
0.001
0.0.02
0.001
1.37
3.75
0.20
0.27
0.62
0.86-2.16
2.26- 6.24
0.10-0.21
0.15- 0.50
0.38-1.0
0.09
0.001
0.001
0.401
0.03
Prevalence of sickle cell disease
The percentage of the haemoglobins detected in the study districts is summarized in
Figure 12. In Mbale and Sironko districts, 231/286 (80.8%) children were positive for Hb
AA, 50/286 (17.5%) for Hb AS and only 5/286 (1.7%) were positive for Hb SS. In
Mbarara and Ntungamo districts, 359/370 (97%) children were positive for Hb AA,
11/370 (3%) for Hb AS and none for Hb SS. In Bundibugyo district, 168/201 (83.6%)
were positive for AA, 27/201 (13.4%) for AS and 6/201 (3%) were positive for SS.
- 86 -
Fig 12: The percentage of haemoglobin A, AS and SS detected in the study
population of Mbale and Sironko (East); Mbarara, Ntungamo and Budibugyo in the
(West).
120
100
80
60
40
AA
20
AS
SS
0
Mbale and
Sironko
Mbarara Bundibugyo
and
Ntungmao
The statistical difference in the prevalence of AS and SS between the study districts is as
shown in Table 11. The statistical difference in the prevalence of AS between Mbale and
Sironko in the East 17.5% (50/286) and Mbarara and Ntungamo in the West 3% (11/370)
was highly significant (p<0.001). The statistical difference in the prevalence of AS
between Bundibugyo in the West 13.4% (27/201) and Mbarara and Ntungamo in the
West 3% (11/370) was also highly significant (p<0.001). There was no statistical
- 87 -
difference in the prevalence of AS between Mbale and Sironko in the East (17.5%) and
Bundibugyo in the West 13.4% (p>0.05). The difference in the prevalence of
homozygous state (SS) of sickle cell disease between Bundibugyo in the West 3%
(6/201) and Mbale and Sironko in the East 1.7% (5/286) was statistically insignificant
(p>0.05).
Table 11: The statistical difference in the prevalence of AS and SS between the study
districts.
Variable
Mbaleand Sironko
Mbararaand Ntungamo
Odds Ratio
CI
P-value
AS
50 (286)
11 (370)
6.91
3.53-13-13.6
0.001
Bundibugyo
Mbararaand Ntungamo
27(201)
11 (370)
5.06
2.46-10.45
0.001
Mbaleand Sironko
Bundibugyo
AS
50 (286)
27 (201)
1.36
0.82-2.27
0.110
SS
5 (286)
6 (201)
0.58
0.17-1.92
0.193
AS
The percentage prevalence of SCD in the current and Lehman study is as shown in Table
12. The current study found the prevalence of sickle cell trait and homozygous state as
(17.5%) in the districts of Mbale and Sironko, (3%) in Mbarara and Ntungamo (13.4%)
in the district of Bundibugyo respectively. Lehman study found between (20-28%) of
sickle cell trait in Mbale and Sironko, 1-4% in Mbarara and Ntungamo and 45% in
Bundibugyo.
- 88 -
Table 12: The percentage prevalence of sickle cell trait in the study districts of
Uganda by the Current and Lehman study.
District
Sironko and Mbale districts Mbarara and Ntungamo
Bundibugyo district
(%)
(%)
districts
(%)
Current Study 17.5
Lehman study
20-28
3
13.4
1-4
45
The details of the observed prevalence of AS and SS and expected prevalence of SS in
Eastern and Western Uganda is as shown in Table 13. The observed prevalence of AS
and SS and expected prevalence of SS in Eastern and Western Uganda was as shown in
Table 13. The observed prevalence of homozygous sickle cell genotype (SS) in the
districts of Mbale and Sironk was 1.7% instead of 4.2% and 0.0% instead of 1.70 in
Mbarara and Ntungamo. The prevalence of SS in Bundibugyo was found to be (3%)
instead of (3.7%).
- 89 -
Table 13: Observed prevalence of AS and SS and expected prevalence of SS in
Eastern and Western Uganda, 2007.
Study area
Mbale/Sironko
(eastern Uganda)
n=286
Observed prevalence Observed prevalence of Expected prevalence
of AS (%)
SS (%)
of SS*
17.5
1.7
4.20
[95% CI 13.5-22.3]
[95% CI 0.63-4.15]
Mbarara/Ntungamo
(western Uganda)
N=370
3.0
0.0
[95% CI 1.61-5.31]
[95% CI 0.0-1.24]
Bundibugyo
N=201
13.4
3.0
[95% CI 9.35-18.94]
[95% CI 0.31-4.50]
Key:
1.70
3.70
*Expected prevalence of SS =square root of AS 140
Some of the Hb electrophoresis results of the test samples in these districts are as shown
in Figures 13, 14 and 15.
Using Hardy Weinberg Law139, the total percentage of abnormal genes within the
population of Eastern Uganda was found to be ([17.5/2 +1.7]) or simply 10.45%. This
yielded a gene frequency of 0.105. The expected gene frequency of the homozygotes in
Eastern Uganda, was found to be (0.105)2 or 1.1%
In Western Uganda (Bundibugyo),
percentage of abnormal genes within the population was found to be ([13.4/2 +3]) or
simply 9.7 %. The expected gene frequency of the homozygotes in Bundibugyo was
found to be (0.097)2 or 0.94% .
- 90 -
Figure 13: Photomicrograph of Hb
Figure 14: Photomicrograph of Hb
electrophoresis from Mbale district
electrophoresis from Ntungamo district
AS
AA SS
AA AS (+ve control)
Figure 15: Photo micrograph of Hb
Electrophoresis from from Bundibugyo district
AA AS AA AA
Key:
AA SS AA
Direction of migration of the bands.
- 91 -
AS
AA
AA AA AS (+ve
control)
The summary of the chidren detected with SS according to age is as shown in Table 14.
Out of a total of 11 chidren detected with SS in Mbale and Sironko in the East and
Bundibugyo in the West, 4 children were between 6 months to one year old, 2 were
between one year to two years old , 2 children were between two to three years old, 2
were between three to four years old and 1 was between four to five years old.
Table 14: The summary of the chidren detected with SS according to age.
Age
6mths-1 yr 1 yr-2yrs
Number of 4
SS
2
2 yrs-3 yrs
3 yrs-4yrs
4 yrs-5yrs
2
2
1
Key: mnths =months, yr= year, yrs =years..
4.4.
Comparative analysis of reliability of different sickle cell
disease screening methods
The summary of the haemoglobins detected by Hb electrophoresis (Gold standard) and
demonstrated by the sickling and solubility tests and peripheral blood film method
are as shown in Table 15. Of the 200 blood samples included in the study, Hb
electrophoresis detected 178 samples with Hb AA, 20 AS and 2 SS. Ou of the total of 21
positive detected by sickling test, it The sickling method demonstrated the presence of
172 AA and 13 sickle cell cases, whilst the solubility method demonstrated 162 AA and 9
samples with sickle cells. The peripheral blood film method showed 174 AA and 7 cases
with sickle cells. However, based on the results of cellulose acetate Hb electrophoresis
- 92 -
each of these methods demonstrated the presence of 2 cases of in these samples. Sickling
demonstrated the presence of 11 AS, solubility 7 AS and peripheral blood film 5 AS.
Table 15: The summary of the haemoglobin AA, AS /SS detected by Hb
electrophoresis (Gold standard) and demonstrated by the sickling and solubility
tests and peripheral blood film method
Variable
Sickling
Solubility
Peripheral
blood
Film
Hb electrophoresis
(gold standard)
True negative for
sickle cells
172
162
174
178
False positive for
sickle cells
8
18
6
0
True positive for
sickle cells
13 (11AS, 2SS)
9 (7AS, 2SS)
7 (5AS, 2SS)
22 (18 AS, 2SS)
False negative for
sickle cells
7
11
13
2
Total
200
200
200
200
Some of the photomicrographs of positive samples by sickling and solubility tests and
peripheral blood film method are as shown in Figures 16, 17 and 18 respectively.
- 93 -
Figure 16: Sickling method showing SS (photomicrograph taken after 30 minutes).
Sickle cells
Figure 17: Solubility method showing Hb SS
+ve
-ve
- 94 -
Figure 18: The peripheral blood film method showing Hb SS.
Sickle cell
Summary of reliability detectability of sickling and solubility tests and peripheral blood
film method is as shown in Table 16. Notably, the sickling method showed a sensitivity
of 65% (CI: 43.3-81.9) and specificity of 95.6% (CI: 91.5-97.7) . It had a positive
predictive value of 61.9% and a negative predictive value of 96.1 The level of agreement
(diagnostic accuracy) between the sickling method and the gold standard was 92.5% with
a kappa score of 0.6 (CI: 0.5-0.7). The solubility method had sensitivity of 45% (CI:
25.8-65.8) and specificity 90.0% (CI: 84.8-93.6). It had a positive predictive value of
33.3% and a negative predictive value of 93.6%. The solubility method had diagnostic
accuracy of 85.5% and Cohen kappa of 0.3 (CI: 0.2-0.4. The peripheral blood film
method had a sensitivity of 35.0% (CI: 18.1-56.7) and a specificity of 96.7% (CI: 92.998.5). It had a positive predictive values of 53.9% and a negative predictive value of
- 95 -
93.1$% respectively. The peripheral blood film had diagnostic accuracy of 90.5% and
kappa score of 0.4 (CI:0.2-0.5) respectively.
Table 16. Reliability detectability of sickling and solubility tests and peripheral
blood film method.
Variable
Sickling test
Sensitivity
Specificity
+ve predictive value
-ve predictive value
Diagnostic accuracy
Likelihood ratio of
positive test
Likelihood ratio of
negative test
Diagnostic Odds
Cohen’s kappa
4.5.
Solubility test
%
65
95.6
61.9
96.1
92.5
14.6
95 % CI
(43.3-81.9)
(91.5-97.7)
(40.9-79.3
(92.1-98.1)
(88.8-95.4)
(10.6-20-3)
%
45
90
33.3
93.6
85.5
4.5
95% CI
(25.8-65.8)
(84.8-93.6)
(18.6-52.2)
(89.0-96.4)
(80.0-89.7)
(3.1-6.5)
Peripheral blood
film method
%
95% CI
35
(18.1-56.7)
96.7
(92.9-98.5)
53.9
(29.1-76.8)
93.1
(88.4-95.9)
90.5
(85.6-93.8)
10.5
(4.5-24.5)
0.4
39.9
(0.3-0.5)
(12.5-127.4)
0.6
7.3
(0.5-0.7)
(2.7-20.2)
0.7
15.6
0.6-0.8)
(4.6-53.3)
0.6
(0.5-0.7)
0.3
(0.2-0.4)
0.4
(0.2-0.5)
Determination of the cost effective methods for screening for SCD
at health centers
4.6.
4.5.1.
Measure of technical feasibility
The turn around time (TAT) in minutes of sickling, solubility and peripheral blood film
methods method is as shown in Table 17. The technician performed an average of thirty
tests per 38 minutes per test when using sickling test, 35 tests per 70 minutes per test
when using solubility test and an average of 60 tests per 44 minutes per test when using
peripheral blood film. On average each technicians took 6 minutes to bleed one child.
- 96 -
Table 17: The turn around time (TAT) in minutes of sickling, solubility and
peripheral blood film methods.
Method
Preparation
of stock
Solution
Preparation
of working
Solution
Sickling
-
8 min.
Average time of
performing a test
including reading and
recording results
30 min
Solubility
56 min.
4 min.
Peripheral
blood film
-
20 min.
4.5.2.
Average
number of
tests done
Average
time per
test
30
38 min
10 min
35
70 min
24 min
60
44 min
Cost benefit analysis of different screening tests for sickle cell disease
Based on the results of the pilot screening exercise in which 286 children were screened
for three months in the East, Hb electrophoresis detected 50 AS and 5 SS. The sickling
test demonstrated the presence of 26 AS, 5 SS, the solubility test 13 AS, 4SS and the
peripheral blood film method 7 AS and 2 SS. In the districts of Mbarara and Ntungamo,
Hb detect 11 AS and the sickling test demonstrated the presence of 5 AS, the solubility
test 3 AS and the peripheral blood film method 2 AS out of 370 children who were
screened for SCD. When simulation was performed using the three months’ results from
Sironko and Mbale districts, and prevalence study results from Bundibugyo, 302 children
would be screened in Bundibugyo in three months. Out of these children, Hb
electrophoresis would detect 39 AS and 9 SS, while the sickling test would demonstrate
the presence of 21 AS, 9 SS, the solubility 11 AS, 6 SS and the peripheral 6 AS and 5 SS.
These results were then subjected to different hypothetical scenarios and assumptions to
- 97 -
determine the benefit /profitability of screening for SCD at health centers IV using each
of these methods.
4.5.2.1. Comparative analysis of scenarios A1 and A2 (automated capillary Hb
elctrophoresis)
The summary of the costs in Sironko and Mbale in the east and Mbarara, Ntungamo and
Bundibugyo in the west using only automated capillary Hb electrophoresis are as shown
in Table 18. When automated capillary Hb electrophoresis is used, a cost of Ug Shs
75,655,253 would be incurred on screening 286 children brought to Mulago hospital from
Mbale and Sironko districts (scenario A1), at Ug Shs 264,564 per test in the first three
months. When children are screened at the regional hospital (scenario A2), a cost of Ug
Sh 61,822,853 would be incurred, costing Ug Shs 216,164 per test, saving 22.4% of the
original cost (A1). Fifty children with AS and 5 with SS would be detected in both A1
and A2. In all these scenarios, forty eight AS children would live a normal life and two
would not, while four children with SS would grow to adulthood and only one would
succumb to the disease. In scenario A1 the cost per AS case detected would be Ug Shs
1,513,305 while the cost per SS case detected would be Ug Shs 15,133,052. In scenario
A2 the cost per AS case detected would be Ug Shs 1,236,457 while cost per SS case
detected would be Ug Shs 12,364,571.
In Mbarara and Ntungamo a cost of Ug Shs 82,005,135 would be incurred on screening
370 children brought to Mulago hospital in scenario A1 (costing Ug Shs 221,636 per test)
- 98 -
and a cost of Ug Shs 63,727,135 would be incurred in scenario A2 (costing Ug Shs
172,235/= per test) therefore saving 26.7% of the original cost (A1). Eleven children with
AS and none with SS would be detected in both scenario A1 and A2. In both scenarios,
ten children would live normal life and one would not. In A1 the cost per AS case
detected would be Ug Shs 7,455,012 while cost per AS case detected in A2 would be Ug
Shs 5,793,375.
In Bundibugyo, a cost of Ug Shs 78,473,421 would be incurred on screening 302 children
brought to Mulago hospital in scenario A1 (costing Ug Shs 259,846 per test) and a cost
of Ug Shs 76,661,421 would be incurred in scenario A2 (costing Ug Shs 259,846 per
test) thereby saving 23.1%% of the original cost (A1). Thirty nine children with AS and 9
with SS would be detected in both scenarios A1 and A2. In both scenarios, thirty seven
children would live normal life and two would not. Eight would grow to adulthood and 1
would die. In scenario A1 the cost per AS case detected would be Ug Shs 2,651,078
while cost per AS case in A2 would be Ug Shs 2,606,412. In scenario A1 the cost per SS
case detected would be Ug Shs 8,719,269 while in scenario A2, the cost per SS case
detected would be Ug Shs 8,517,936/=.
- 99 -
Table 18 The costs (Ug Shs) incurred in the first three months in scenarios A1 and A2 in Mbale
and Sironko in the East and Mbarara, Ntungamo and Bundibugyo in the West when using only
automated capillary Hb electrophoresis.
Sironko and Mbale
Mbarara
and
Bundibugyo
Ntungamo
Variable
Scenario
A1
Scenario
A2
Scenario
A1
Scenario
A2
Scenario
A1
2,106,225
1,719,135
Cost of
automated
capillary
Hob
electrophoresis
Consumables
for
Hb
electrophoresis
Transport cost of mothers
to Mulago, maintenance
plus accommodation
Transport cost of mothers
to regional hospital
Loss of productivity costs
Total cost
Cost per test
% of costs saved by using
A1 and A2
Cases which would be
detected
Lives which would be
saved
Cost per AS
57,858,750 57,858,750
Scenario
A2
57,858,750 57,858,750 57,858,750 57,858,750
1,628,055
2,106,225
Cost per SS
A1.15,133,051/=
A2. 12,364,571
1,628,055
1,719,135
16,130,400 -
21,978,000 -
18,844,800 -
-
-
-
2,288,000
3,700,000
17,032,800
48,048
48,048
62,160
62,160
50,736
50,736
75,665,253 61,,822,853 82,005,135 63,727,135 78,473,421 76,661,421
262,902
216,164
221,635
172,235
259,846
253,846
22.4%
26.7%
23.1%
50AS, 5SS
11 AS
52
A1.1,513,305/=
A2. 1,236,457/=
10
A1.=7,455,012/=
A2. 5,793,377/=
39 AS, 9 SS
45
A1.2,651,078/=
A2. 2,606,412./=
A1 8,719,269./=
A2 8,517,936./=
- 100 -
4.5.2.2 Scenarios B1 versus B2 (Automated Hb electrophoresis and sickling )
The summary of the costs in Sironko and Mbale in the east and Mbarara, Ntungamo and
Bundibugyo in the west using automated capillary Hb electrophoresis and sickling test
are as shown in Table 19. When the sickling test is used to screen children at health
centers IV and only positives cases are confirmed in Mulago hospital, using automated
Hb electrophoresis (scenario B1), the cost Ug Shs 65,991,528 would be incurred in
Mbale and Sironko in the first three months, costing Ug Shs 230,740 per test. When only
positive samples are confirmed at the regional hospital (scenario B2), Ug Shs 65,433,528
would be incurred costing Ug Shs 228,689 per test therefore saving 0.9% of the original
cost.Twenty six children with AS and 5 with SS would be detected in both B1 and B2 .
Twenty five AS would live a normal life and only one would not while 4 SS would live
to adulthood and one would not. The cost per AS detected in scenario B1 would be Ug
Shs 2,538,136 while the cost per AS case in scenario B2 would be Ug Shs 2,516,674. The
cost per SS case detected in B1 would be Ug Shs 13,198,305 and the cost in B2 would be
Ug Shs 13,086,706.
In Mbarara and Ntungamo, the cost of Ug Shs 66,633,583 would be incurred in the first
three months in B1 (costing Ug Shs 180,091 per test) and a cost of Ug Shs 65,993,583
would be incurred in B2 (costing Ug Shs 178,361 per test) therefore saving 0.96% of the
costs. Five children with AS and none with SS would be detected in both scenarios B1
and B2. All five children with AS would live normal life. The cost per AS detected in
scenario B1 would be Ug Shs 13,326,717 while the cost per AS case in scenario B2
would be Ug Shs 13,198,717.
- 101 -
In Bundibugyo districts Ug Shs 62,845,402 would be incurred when using sickling test
on 302 children in the first three months in B1 (costing Ug Shs 208,097 per test) and Ug
Shs 62,821,402 in B2 (costing Ug Shs 208,018 per test) thereby saving 0.04%/= of the
original cost. The same scenarios would detect 21 AS and 9 SS. Twenty children with AS
would live normal life and 1 would not while eight children with SS would grow to adult
hood and one would not. The cost per AS and SS case detected in scenario B1 would be
Ug Shs 2,992,638/= and Ug Shs 6,982,822 respectively. The cost per AS case detected in
scenario B2 would be Ug Shs 2,991,495 and cost per SS case would be Ug Shs
6,980,156.
- 102 -
Table 19 The costs (Ug Shs) incurred in the first three months in scenarios B1 and B2 in
Mbale and Sironko in the East and Mbarara, Ntungamo and Bundibugyo in the West
when using automated capillary Hb electrophoresis and sickling test.
Variable
Cost of automated Hb
electrophoresis
Consumables for Hob
electrophoresis
Training costs during
establishment of
suckling
screening services.
Cost of equipment,
materials and
consumables for
sickling method
Transport cost of
mothers to health
center
Loss of productivity
costs
Costs on one health
staff who delivers
positive samples to
Mulago hospital
Costs on health staff
who deliver positive
samples to regional
hospital
Total
Cost per test
% of costs saved by
using B1 and B2
Cases detected
Lives saved
Cost per AS
Sironko and Male
Scenario B1
Scenario B2
Mbarara and Ntungamo
Scenario B1
Scenario B2
Bundibugyo
Scenario B1 Scenario B2
57,858,750
57,858,750
57,858,750
57,858,750
57,858,750
204,930
204,930
51,233
51,233
155,369
155,369
2,261,000
2,261,000
2,280,000
2,280,000
1,415,000
1,415,000
3,890,800
3,890,800
4,097,440
4,097,440
2,092,515
2,092,515
858,000
858,000
1,100,000
1,100,000
906,000
906,000
48,048
48,048
62,160
62,160
33,768
33,768
870,000/=
-
1,184,000
-
384,000
-
-
312,000
544,000
-
360,000
65,991,528
230,740
0.9%
65,433,528
228,689
65,993,583
178,361
62,845,402
208,097/=
0.04%
62,821,402
208,018/=
26 AS, 5 SS
29
B1 2,538,136,
B2. 2,516,674
-
66,633,583
180,091/=
0.96%
5 AS
5
B1 13,326,717
B213,198,717
57,858,750
21 AS, 9 SS
28
B1. AS =2,992,638
B2 = 2,991,495
Cost per SS
B1. 13,198,305/=,
B2. 13,086,706
B1 SS = 6,961,463
B2 =6,980,156
- 103 -
4.5.2.3 Scenarios B1 versus B2 (Automated Hb electrophoresis and solubility )
The summary of the costs in Sironko and Mbale in the East and Mbarara, Ntungamo and
Bundibugyo in the West using automated capillary Hb electrophoresis and solubility test
are as shown in Table 20. Using the solubility test, a cost of Ug Shs 63,530,316/= would
be incurred in Mbale and Sironko districts in the first three months in B1 (costing Ug Shs
222,134 per test) and Ug Shs 62,972,316 in B2 (costing Ug Shs 220,183 per test) thereby
saving Ug Shs 0.9 of the original cost. Thirteen children with AS and 4 with SS would be
detected in both B1 and B2. Twelve children with AS would live a normal life and one
would not while three SS would live to adulthood and one would not. The cost per AS
detected in scenario B1 would be Ug Shs 4,886,947/= mean while the cost per AS case in
scenario B2 would be Ug Shs 4,844,024. The cost per SS case detected in B1 would be
Ug Shs 15,882,579 and the cost in B2 would be Ug Shs 15,743,079.
In Mbarara and Ntungamo districts, Ug Shs 64,128,213 would be incurred in B1 (costing
Ug Shs 173,321 per test) and Ug Shs 63,488,213 in B2 (costing Ug Sgs 171,590 per test)
thereby saving 1% of the costs. Three children with AS and none with SS would be
detected in both scenarios. All 3 children with AS would grow to adulthood. The cost per
AS detected in scenario B1 would be Ug Shs 21,376,071 while the cost per AS case in
scenario B2 would be Ug Shs 21,149,404.
In Bundibugyo, Ug Shs 62,019,646/= would be incurred in the first two months in B1
(costing Ug Shs 205,363 per test) and Ug Shs 61,995,646 in B2 (costing 205,284 per test)
- 104 -
therefore saving 0.04%. Eleven children with AS and 6 with SS would be detected in
both B1 and B2. Ten children with AS would live normal life and one would not mean
while 5 with SS would grow to adult hood and one would not. The cost per AS detected
in scenario B1 would be Ug Shs 6,201,965 meanwhile the cost per AS case in scenario
B2 would be Ug Shs 6,199,565. The cost per SS case detected in B1 would be Ug Shs
15,504,912 and the cost in B2 would be Ug Shs 15,498,987.
- 105 -
Table 20 The costs (Ug Shs) incurred in the first three months in scenarios B1
and B2 in Mbale and Sironko in the East and Mbarara, Ntungamo and Bundibugyo
in the West when using automated capillary Hb electrophoresis and solubility test.
Variable
Cost of automated Hb
electrophoresis
Consumables for Hob
electrophoresis
Training costs during
establishment of
sickling
screening services.
Cost of equipment,
materials and
Consumables for
solubility test
Transport cost of
mothers to health
Center
Loss of productivity
Costs
Costs on one health
staff who delivers
positive samples to
Mulago hospital
Costs on health staff
who deliver positive
samples to regional
Hospital
Total
Cost per test
% of costs saved by
using B1 and B2
Cases detected
Lives saved
Cost per AS
Cost per SS
Sironko and Mbale
Scenario B1
Scenario B2
57,858,750
57,858,750
Mbarara and Ntungamo
Scenario
Scenario B2
B1
57,858,750 57,858,750
153,698
153,698
170,775
170,775
153,698
153,698
2,261,000
2,261,000
2,280,000
2,280,000
1,415,000
1,415,000
1,480,820
1,480,820
1,592,070
1,592,070
1,251,462
1,251,462
858,000
858,000
1,100,000
1,100,000
906,000
906,000
48,048
48,048
62,160
62,160
50,736
50,736
870,000/=
-
1,184,000
-
384,000
-
-
312,000/=
-
544,000
-
360,000
63,530,316
222,134
0.9%
62,,972,316
220,183
64,128,213
173,321
1%
63,488,213
171,590
62,019,646
205,363
0.04%
61,995,646
205,284
13 AS and 4 SS
15
B1 4,886,947/=
B2 4,844,024/=
3 AS
3.
B1=21,376,071/=
B2 21,149,404=
B115,882,579,/=
B2 15,743,079/=
Bundibugyo
Scenario B1 Scenario B2
57,858,750
57,858,750
10 AS and 4 SS
14
B1. =6,201,965
B2=6,199,565
B1. 15,504,912.
B2 15,498,987
- 106 -
4.5.2.4 Automated Hb electrophoresis and peripheral blood method.
A summary of the costs in Sironko and Mbale in the East and Mbarara, Ntungamo and
Bundibugyo in the West using automated capillary Hb electrophoresis and peripheral
blood film method are as shown in Table 21. Using the peripheral blood film method, Ug
Shs 65,769,148 would be incurred in B1 in Mbale and Sironko in the first three months
(costing 229,962/= per test). In scenario B2, Ug Shs 65,211,148 would be incurred
(costing Ug Shs 228,011/= per test) thereby saving 0.8% of the original cost. Seven AS
and 2 SS would be detected in both B1 and B2. The cost per AS case detected in scenario
B1 would be Ug Shs 9,395,593 meanwhile the cost per AS case in scenario B2 would be
Ug Shs 9,315,878. The cost per SS case detected in B1 would be Ug Shs 32,879,574 and
the cost in B2 would be Ug Shs 32,914,632.
In Mbarara and Ntungamo Ug Shs 66,469,264 would be incurred in scenario B1 in the
first three months and the (costing Ug Shs 179,647 per test). In scenario B2, Ug Shs
65,829,264 would be incurred (costing Ug Shs 177,917 per test) thereby saving 0.9%.
The cost per AS detected in scenario B1 would be Ug Shs 33,234,632 meanwhile the cost
per AS case in scenario B2 would be Ug Shs 32,914,632.
In Bundibugyo, Ug Shs 62,793,883 would be incurred in the first two months in B1
(costing Ug Shs 207.927 per test) and Ug Shs 62,769,883 in B2 (costing Ug Shs 207,847
per test) therefore saving 0.04%. All 6 children with AS would live normal life while 4
children with SS would grow to adult and one would not. The cost per AS detected in
scenario B1 would be Ug Shs 10,465,639 meanwhile the cost per AS case in scenario B2
- 107 -
would be Ug Shs 10,461,647. The cost per SS case detected in B1 would be 12,558,777/=
and the cost in B2 would be 12,553,977/=.
- 108 -
Table 21: The costs (Ug Shs) incurred in the first three months in scenarios B1
and B2 in Mbale and Sironko in the East and Mbarara, Ntungamo and
Bundibugyo in the West when using automated capillary Hb electrophoresis
and peripheral test.
Sironko and Male
Mbarara
and
Bundibugyo
Ntungamo
Variable
Scenario
Scenario
B1
B2
Cost of automated Hb 57,858,750
57,858,750
electrophoresis
Consumables for
79,695
79,695
Hb electrophoresis
Training costs
2,261,000
2,261,000
during establishment of
sickling screening
services.
Cost of equipment,
3,793,655
3,793,655
materials and
consumables for
peripheral method
Transport cost of mothers 858,000
858,000
to health center
Loss of productivity costs 48,048
48,048
Costs on one health staff 870,000
who delivers positive
samples
to
Mulago
hospital
Costs on health staff who 312,000
deliver positive samples
to regional hospital
Total
65,769,148
65,211,148
Cost per test
229,962
228,011
% of costs saved by using 0.8%
B1 and B2
Cases detected
7 AS and 2 SS
Lives saved
9
Cost per AS
B1=9,395,593/=
B2=9,315,878/=
Cost per SS
Scenario
B1
57,858,750
Scenario
B2
57,858,750
Scenario
B1
57,858,750
Scenario
B2
57,858,750
39,848
39,848
96,773
96,773
2,280,000
2,280,000
1,415,000
1,415,000
3,944,506
3,944,506
2,082,624
2,082,624
1,100,000
1,100,000
906,000
906,000
62,160
1,184,000
62,160
-
50,736
384,000
50,736
-
-
544,000
-
360,000
66,469,264
179,647
0.9%
65,829,264
177,917
62,793,883
207,927
0.04%
62,769,883
207,847
2 AS
2
B133,234,632/=
B2.32,914,632/
B1 32,879,574
B232,605,574/=
6 AS and 5 SS
10
B110,465,647/=
B210,461,647 /=
B112,558,777/=
B2 12,553,977./=
- 109 -
4.5.2.5 Scenarios A1 and A2 (cellulose acetate Hb electrophoresis)
A summary of the costs in Sironko and Mbale in the East and Mbarara, Ntungamo and
Bundibugyo in the West using only cellulose acetate Hb electrophoresis are as shown in
Table 22. When cellulose acetate Hb electrophoresis is used for sickle cell screening at
Mulago National referral hospital, Ug Shs 20,060,448/= would be incurred in A1 on
screening 286 children in Mbale and Sironko, in the first three months, (costing Ug Shs
70,141/= per test). In A2, six million, two hundred eighteen thousand and fourty eight
shillings (Ug Shs 6,218,048). would be incurred when cellulose acetate is used at the
regional hospital (costing Ug Shs 21,714 per test) thereby saving 69% of the original
cost. Fifty children with AS and 5 with SS would be detected in both scenarios B1 and
B2. In all these scenarios, 48 AS children would live a normal life and 2 would not,
while 4 children with SS would live to adulthood and only one would. In A1, the cost per
AS case detected would be Ug Shs 401,209, while cost per SS case detected would be Ug
Shs 4,012,090. In scenario A2 the cost per AS case detected would be Ug Shs 130,361
meanwhile the cost per SS case detected would be Ug Shs 1,303,610.
In Mbarara and Ntungamo Ug Shs 26,165,160 would be incurred in scenario A1 (costing
Ug Shs 70,717/= per test) and Ug Shs 7,887,160 in scenario A2 costing Ug Shs 70,717
per test therefore saving 69.9% of the original cost. Ten AS children would live normal
life and 1 would not. The cost per AS case detected in scenario A1 would be Ug Shs
2,378,650 while the cost per AS case detected in scenario A2 would be Ug Shs 717,015.
- 110 -
In Bundibugyo district 22,826,878/= would be incurred in scenario A1 on screening 302
children in the first three months (costing Ug Shs 75,586 per test) and Ug Shs 21,014,878
in scenario A2 (costing Ug Shs 69,586 per test) therefore saving 7.9% of the original
cost. In all these scenarios, 39 AS and 9 SS children would be detected and 37 children
would live a normal life and two would not, meanwhile 8 children with SS would grow to
adulthood and only one would. In scenario A1 the cost per AS case detected would be Ug
Shs 585,305/=, while cost per AS cace detected in A2 would be Ug Shs 555,186/=. The
cost per SS case detected in A1 would be Ug Shs 2,536,320 while in scenario A2, the
cost per SS case detected would be Ug Shs 2,368,320/=. /=.
- 111 -
Table 22: The costs (Ug Shs) incurred in the first three months in scenarios A1 and A2 in
Mbale and Sironko in the East and Mbarara, Ntungamo and Bundibugyo in the West when
using only cellulose acetate Hb electrophoresis.
Sironko and Male
Mbarara and Ntungamo
Vraibale
Scenario A1
Scenario A2
Scenario A1
Cost of cellulose
acetate Hb
Electrophoresis
Consumables for Hb
electrophoresis
Transport cost of
mothers to Mulago,
maintenance plus
accommodation
Transport cost of
mothers to regional
hospital
Loss of productivity
costs
Total cost
Cost per test
% of costs saved by
using A1 and A2
Cases which would
be detected
Lives which would
be saved
Cost per AS
3,000,000
3,000,000
3,000,000
882,000
882,000
1,125,000
1,125,000
16,130,400
-
21,978,000
-
-
2,288,000
48,048
48,048
62,160
20,060,448
70,141
69%
6,218,048
21,714
26,165,160
70,717
69.9%
Scenario A2
3,000,000
3,000,000
931,342
931,342
18,844,800
-
3,700,000
-
17,032,800
62,160
50,736
50,736
22,826,878
75,586/=
7.9%
21,014,878
69,586/=
Cost per SS
A1 4,012,090/=
A2. 1,303,610/=
7,887,160
21,317
11 SS
52
Scenario A1
3,000,000
-
50AS, 5SS
A1 401,090/=
A2. 130,361/=
Scenario A2
10
A1.=2,373,650/=
A2. =717,015
Bundibugyo
39 AS, 9 SS
45
A1.585,305/=
A2. 555,186./=
A12,536,320./=
A2 2,368,320./=
- 112 -
4.5.2.6 .
Comparative analysis of of scenarios B1 versus B2 using cellulose
acetate Hb electrophoresis and sickling tests
A summary of the costs in Sironko and Mbale in the East and Mbarara, Ntungamo and
Bundibugyo in the West using cellulose acetate Hb electrophoresis and sickling test are
as shown in Table 23. When the sickling test is used at district health centers IV and only
positives are confirmed at the regional hospital using cellulose acetate Hb
electrophoresis, Ug Shs 11,119,848 would be incurred in Mbale and Sironko in the first
three months in scenario B1 (costing Ug Shs 38,880 per test) and Ug Shs 10,561,848 in
B2 costing Ug Shs 36,930 per test) thereby saving 5% of the initial cost. Twenty six
children with AS and 5 with SS would be detected in both B1 and B2. In both scenarios,
twenty five AS would live normal life and only 1 would not while 4 SS would live to
adulthood and 1 would not. The cost per AS case detected in scenario B1 would be Ug
Shs 444,794 while the cost per AS case detected in B2 would be Ug Shs 406,225. The
cost per SS case detected in B1 would be Ug Shs 2,223,970 while the cost per AS
detected in B2 would be Ug Shs 2,112,370.
In Mbarara and Ntungamo, Ug Shs 11,855,600 would be incurred in the first three
months in B1 (costing Ug Shs 32,042 per test) and Ug Shs 11,215,600 in B2 (costing
30,312 per test) thereby saving 5.4% of the original cost. Five children with AS and none
with SS would be detected in both scenarios B1 and B2. All five children with AS would
live a normal life. The cost per AS case detected in scenario B1 would be Ug Shs
2,371,120 while the cost per AS case detected in scenario B2 would be Ug Shs 2,243,120
- 113 -
In Bundibugyo, Ug Shs 7,973,921 would be incurred in the first three months in B1
(costing Ug Shs 26,404 per test) and Ug Shs 7,949,921 in B2 (costing Ug Shs 26,324 per
test) therefore saving 3.0% of the original cost. Twenty one children with AS and nine
with SS would be detected in both scenarios B1 and B2. Twenty children with AS would
live a normal life and one would not meanwhile eight children with SS would grow to
adult hood and one would not. The cost per AS detected in scenario B1 would be Ug Shs
379,711 while the cost per AS case in scenario B2 would be Ug Shs 378,568. The cost
per SS case detected in B1 would be Ug Shs 885,911 and the cost in B2 would be Ug Shs
883,325.
- 114 -
Table 23: The costs (Ug Shs) incurred in the first three months in scenarios B1 and B2
in Mbale and Sironko in the east and Mbarara, Ntungamo and Bundibugyo
in the west when using cellulose acetate Hb electrophoresis and sickling test.
Sironko and Mbale
Mbarara and Ntungamo
Variable
Scenario B1
Scenario B2
Scenario B1
Scenario B2
Cost of cellulose
acetate Hb
electrophoresis
Consumables for
Hb electrophoresis
and cost of other
materials
Training costs
during
establishment of
sickling screening
services.
Cost of equipment,
materials and
consumables for
sickling method
Transport cost of
mothers to health
center
Loss of
productivity costs
Costs on one health
staff who delivers
positive samples to
Mulago hospital
Costs on health
staff who deliver
positive samples to
regional hospital
Total
Cost per test
% of costs saved by
using B1 and B2
Cases detected
Lives saved
Cost per AS
3,000,000
3,000,000
3,000,000
3,000,000
3,000,000
3,000,000
192,000
192,000
132,000
132,000
192,199
192,199
2,261,000
2,261,000
2,280,000
2,280,000
1,415,000
1,415,000
3,890,800
3,890,800
4,097,440
4,097,440
2.025,986
2,025,986
858,000
858,000
1,100,000
1,100,000
906,000
906,000
48,048
48,048
62,160
62,160
50,736
60,736
870,000/=
-
1,184,000
-
384,000/=
-
-
312,000
544,000
-
360,000
11,215,600
30,312
5.4%
7,973,921
26,404
11,119.848
38,881
10,561,848
36,930
5%
26 AS and 5 SS
29
B1.427,686 /=
B2 406,225 /=
Scenario B1
-
11,855,600
32,042
Scenario B2
Bundibugyo
5 AS
5
B1 = 2,371,120 /=
B2.t= 2,243,120/=
21 AS and 9 SS
28
B1.379,711./=
B2. 378,568/=
Cost per SS
B1.2,223,970/=
B2 2,112,370 /=
B1 885,991/=
B2 883,325/=
- 115 -
7,949,921
26,324
0.3%
4.5.2.7.
Comparative analysis of scenarios B1 versus B2
using cellulose
acetate Hb electrophoresis and solubility tests
A summary of the costs in Sironko and Mbale in the East and Mbarara, Ntungamo and
Bundibugyo in the West using cellulose acetate Hb electrophoresis and solubility test are
as shown in Table 24. Using the solubility test, Ug Shs 8,585,368 would be incurred in
Mbale and Sironko in the first three months in B1 (costing Ug Shs 30,019 per test) and
Ug Shs 8,027,368 in B2 (costing Ug Shs 28,067 per test) thereby saving 6.5% of the
original cost. Thirteen children with AS and 4 with SS would be detected in both
scenarios B1 and B2. In both scenarios twelve children with AS would live a normal life
and one would not while 3 SS would grow to adulthood and one would not. The cost per
AS case detected in scenario B1 would be Ug Shs 660,413, meanwhile the cost per SS
case detected would be Ug Shs 2,146,342. The cost per AS case detected in scenario B2
would be Ug Shs 617,490 while the cost per SS case detected would be Ug Shs
2,006,842.
In the districts of Mbarara and Ntungamo, Ug Shs 9,389,230/= would be incurred in B1
(costing Ug Shs 25,376 per test and Ug Shs 8,749,230 in B2 (costing Ug Shs 23,647 per
test) thereby saving 6.8% of the original cost. Three children with AS and none with SS
would be detected in both scenarios B1 and B2. All three children with AS would grow
to adulthood. The cost per AS case detected in scenario B1 would be Ug Shs 3,129,743
while the cost per AS detected in scenario B2 would be Ug Shs 2,916,410.
- 116 -
In Bundibugyo district, Ug Shs 6,861,556/= would be incurred in the first three months
in B1 (costing Ug Shs 22,,720 per test) and Ug Shs 6,837,556 in B2 (costing Ug Shs
22,641 per test) therefore saving 3.4% of the original cost. Eleven children AS and 6
with SS would be detected in both scenarios. Ten children with AS would live a normal
life and one would not, while five children with SS would grow to adulthood and one
would not. The cost per AS detected in scenario B1 would be Ug Shs 623,778 while the
cost per AS case in scenario B2 would beUg Shs 621,596. The cost per SS case detected
in B1 would be Ug Shs 1,143,593/= and the cost in B2 would be Ug Shs 1,139,592 /=
- 117 -
Table 24: The costs (Ug Shs) incurred in the first three months in scenarios B1 and B2 in
Mbale and Sironko in the east and Mbarara, Ntungamo and Bundibugyo in the west when
using cellulose acetate Hb electrophoresis and solubility test.
Sironko and Mbale
Mbarara and Ntungamo
Variable
Scenario B1
Scenario B2
Scenario B1
Cost of cellulose
acetate Hb
electrophoresis
Consumables for
Hb electrophoresis
Cost of other
Materials
Training costs
during
establishment of
sickling screening
services.
Cost of equipment,
materials and
consumables for
solubility test
Transport cost of
mothers to health
center
Loss of
Productivity costs
Costs on one health
staff who delivers
positive samples to
Mulago hospital
Costs on health
staff who deliver
positive samples to
regional hospital
Total
Cost per test
% of costs saved by
using B1 and B2
Cases detected
Lives saved
Cost per AS
Cost per SS
3,000,000
3,000,000
3,000,000
67,500
67,500
2,261,000
Scenario B1
Scenario B2
3,000,000
3,000,000
3,000,000
171,000
171,000
144,000
144,000
2,261,000
2,280,000
2,280,000
1,415,000
1,415,000
1,480,820
1,480,820
1,592,070
1,592,070
961,671
961,671
858,000
858,000
1,100,000
1,100,000
906,000
906,000
48,048
48,048
62,160
62,160
50,736
50,736
870,000/=
-
1,184,000
-
384,000/=
-
312,000/=
-
544,000
-
8,585,368
30,019
8,027,368
28,067
6.5%
13 AS and 4 SS
15
B1. 660,413 /=
B2 617,484/=
B1. 2,146,342/=
B2 2,006,842 /=
9,389,230
25,376
Scenario B2
Bundibugyo
8,398,230
23,647
10.6%
3 AS
3
B1Cost per AS = 3,129,743/=
B2.Cost per AS=2,916,410/=
- 118 -
6,861,556
22,720
360,000
6,837,556
22,641
0.3%
11 AS and 6 SS
15
B1. 623,778./=
B2. 621,596/=
B1 1,143,592/=
B2 1,139,592 /=
4.5.2.8 Comparative analysis of scenarios B1 versus B2 using cellulose acetate Hb
electrophoresis and peripheral blood film method
The summary of the costs in Sironko and Mbale in the East and Mbarara, Ntungamo and
Bundibugyo in the West using cellulose acetate Hb electrophoresis and peripheral blood
film method are as shown in Table 25. Using the peripheral blood film method, Ug Shs
10,968,703 would be incurred in B1 the East in the first three months (costing Ug Shs
38,352 per test). In scenario B2, Ug Shs 10,410,703 would be incurred (costing Ug Shs
36,401 per test) therefore saving 5.1% of the original cost). Seven children with AS and 2
with SS would be detected in both scenarios B1 and B2. In both scenarios, all seven
children with AS would live a normal life and all two with SS would grow to adulthood.
The cost per AS detected in scenario B1 would be Ug Shs 1,566,958 and the cost per SS
detected would be Ug Shs 5,484,352. In scenario B2, the cost per AS detected would be
Ug Shs 1,487,243 and the cost per SS detected would be Ug Shs 5,205,352.
In Mbarara and Ntungamo districts, Ug Shs 11,679,666 would be incurred in scenario
B1 in the first three months (costing Ug Shs 31,567 per test). In scenario B2, Ug Shs
10,989,666 would be incurred (costing Ug Shs 29,702 per test) therefore saving 5.5% of
the original cost. Two children with AS and none with SS would be detected in both
scenarios A1 and A2. The cost per AS detected in scenario B1 would be Ug Shs
5,839,833 while the cost per AS detected in scenario B2 would be Ug Shs 5,494,833.
- 119 -
In Bundibugyo, Ug Shs 7,927,452 would be incurred in the first three months in B1
(costing Ug Shs 26,250 per test) and Ug Shs 7,903,452 in B2 (costing Ug Shs 26,170 per
test therefore saving 3.7%. Six children with AS and 5 with SS would be detected in
both scenarios B1 and B2. All six children with AS would live a normal life, while four
children with SS would grow to adulthood and one would not. The cost per AS detected
in scenario B1 would be Ug Shs 1,321,242 while the cost per AS case in scenario B2
would be Ug Shs 1,317,242. The cost per SS case detected in B1 would be Ug Shs
1,580,690/= and the cost in B2 would be Ug Shs 1,580,690.
- 120 -
Table 25: The costs (Ug Shs) incurred in the first three months in scenarios B1 and B2 in
Male and Sironko in the east and Mbarara, Ntungamo and Bundibugyo in the west when
using cellulose acetate Hb electrophoresis and peripheral blood film.
Sironko and Male
Mbarara and Ntungamo
Variable
Scenario B1
Scenario B2
Scenario B1
Cost of cellulose
acetate Hb
electrophoresis
Consumables for Hb
electrophoresis
Cost of other
Materials
Training costs during
establishment of
sickling screening
services.
Cost of equipment,
materials and
consumables for
peripheral method
Transport cost of
mothers to health
center
Loss of productivity
Costs
Costs on one health
staff who delivers
positive samples to
Mulago hospital
Costs on health staff
who deliver positive
samples to regional
hospital
Total
Cost per test
% of costs saved by
using B1 and B2
Cases detected
Lives saved
Cost per AS
3,000,000
3,000,000
3,000,000
28,000
28,000
110,000
Scenario B1
Scenario B2
3,000,000
3,000,000
3,000,000
14,000
14,000
34,000
34,000
110,000
95,000
95,000
55,092/=
55,092
2,261,000
2,261,000
2,280,000
2,280,000
1,415,000
1,415,000
3,793,655
3,793,655
3,944,506
3,944,506
2,082,624
2,082,624
858,000
858,000
1,100,000
1,100,000
906,000
906,000
48,048
48,048
62,160
62,160
50,736
50,736
870,000
-
1,184,000
-
384,000
-
-
312,000
-
544,000
-
360,000
Cost per SS
B1. 5,484,352/=
B2 5,205,352/=
10,968,703
38,352
10,410,703
36,401
5.1%
7 AS and 2 SS
9
B1. 1,566,958/=
B2. 1,487,243/=
11,679,666
31,567
Scenario B2
Bundibugyo
11,039,666
29,837
5.5%
2 AS
2
B1 = 5,839,833/=
B2.=5,579,833/=
7,927,452
26,250
7,903,452
26,170
0.3%
6AS and 5 SS
10
B1. 1,321,242/=
B2. 1,317,242/=
B1 1,585,490/=
B2 1,580,690 /=
- 121 -
4.5.2.9 Analysis of establishment of the screening services in Bundibugyo hospital
using the automated and Cellulose acetate Hb electrophoresis as sickle cell
disease screening methods
The summary of the costs (Ug Shs) incurred in the first three months when automated
capillary and cellulose acetate Hb electrophoresis methods are used in Bundibugyo
hospital are as shown in Table 26. When the screening services are established at
Bundibugyo district hospital using automated Hb electrophoresis, a cost 62,195,621/=
would be incurred on 302 children in the the first three months costing 205,946/= per test.
Using cellulose acetate, it would cost 6,549,078 costing 21,686 per test and therefore
saving 89.5% of the original cost. Thirty nine children with AS and nine with SS would
be detected in both scenarios.
The cost per AS case detected by automated Hb
electrophoresis would be Ug Shs 1,594,760 and cellulose acetate Hb electrophoresis Ug
Shs 167,927.
- 122 -
Table 26: The costs (Ug Shs) incurred in the first three months when automate capillary
and cellulose acetate Hb electrophoresis methods are used in Bundibugyo hospital.
Variable
Automated
Cellulose acetate
Cost of automated Hb
electrophoresis
Consumables
for
electrophoresis
57,858,750
-
Hb 1,719,135
Cost of cellulose acetate
Consumables for cellulose acetate Cost of consumables for Hb
electrophoresis
and other materials
Transport cost of mothers
Bundibugyo hospital
Lunch
Loss of productivity costs
Total
Cost per test
% of costs saved by using
Automated and cellulose
Cases detected
Lives saved
Cost per AS
to 2,114,000
Cost per SS
453,000
50,736
62,195,621
205,946
-
3,000,000
604,000
327,342
2,114,000
453,000
50,736
6,549,078
21,686
89.5%
39 AS and 9 SS
45
Automated 1,594,760/=
Cellulose 167,925 /=
Automated 6,910,625
Cellulose 729,673/=
- 123 -
4.5.2.10 Analysis of establishment of the screening services in Bundibugyo hospital
using the automated and Cellulose acetate Hb electrophoresis and sickling
tests
The summary of the costs (Ug Shs) incurred in the first three months when automated
capillary and cellulose acetate Hb electrophoresis methods are used in Bundibugyo
hospital together with sickling test are as shown in Table 27. When the automated Hb
electrophoresis service is established in Bundibugyo hospital for confirmation of positive
cases generated by the sickling test established at district health center IV, a cost of
62,569,402/= would be incurred on 302 children in the first three months costing
207,183/= per test. When cellulose acetate Hb electrophoresis is used, cost of 7,597,722
would be incurred on these children in the first three months costing 25,158 per test
thereby saving 87.9% of the original cost. Twenty one children with AS and nine children
with SS would be detected by both automated and cellulose. The cost per AS case
detected by automated would be Ug Shs 2,979,495 and cellulose Ug Shs 461,796. The
cost per SS case detected by automated and cellulose acetate would be Ug Shs 6,952,156
and 844,191. Twenty one children with AS and nine with SS would be detected by both
services. The summary of the costs were as shown in Table 27
- 124 -
Table 27: The costs (Ug Shs) incurred in the first three months when automated
and cellulose acetate Hb electrophoresis methods are used with sickling test in
Bundibugyo hospital.
Variable
Automated and sickling
Cellulose and sickling
Cost of automated Hob
electrophoresis
Consumables for automated Hb
electrophoresis
Cost of cellulose acetate
Hb
electrophoresis
consumables for cellulose Hb
electrophoresis
Other costs
Training costs during
establishment of
sickling screening services.
Cost of equipment,
materials and consumables for
sickling method
Transport cost of mothers to
health center
Loss of productivity costs
Costs on one health staff who
delivers positive samples to
Bundibugyo
Hospital
Total
Cost per test
% of costs saved by using
Automated and cellulose
Cases detected
Lives saved
Cost per AS
Cost per SS
57,858,750
-
204,930
-
-
3,000,000
1,415,000
72,000
327,342
1,415,000
2,025,986
2,025,986
906,000
906,000
50,736
108,000
50,736
108,000
62,569,402
207,183
7,597,722
25,158
87.9%
21 AS, 9 SS
28
Automated 2,979,495/=
Cellulose 361,796 /=
Automated 6,952,156
Cellulose 844,191/=
- 125 -
4.5.2.11.
Projections of the costs (Ug Shs) of establishing the automated Hb
electrophoresis screening service with time
The summary of the accumulative costs, number of children detected, money saved in
Sironko and Mbale in the East and Mbarara, Ntungamo and Bundibugyo in the West
using Automated cellulose acetate Hb electrophoresis method are as shown in Table 28.
The costs of the screening services were projected forward for a period of five years. In
one year, 1,144 children would be screened in Mbale and Sironko and 1480 children in
Mbarara and Ntungmao districts. One thousand two hundred eight children would be
screened in Bundibugyo district.
When the automated Hb electrophoresis screening method is used, a cost of Ug Shs
71,226,012 would be incurred in year 1 in scenario A1, in Eastern Uganda, (costing Ug
Shs 62,261 per test). In A2, Ug Shs 15,856,412 in A2 would be incurred (costing Ug Shs
13,861 per test) therefore saving 77.7% of the original cost. Two hundred AS and 20 SS
children would be detected in both scenarios, (costing Ug Shs 356,130 and 79,282 per AS
case detected in A1 and A2 respectively. The cost per SS case detected in A1 would be
Ug Shs 3,561,301 and in A2 Ug Shs 792,821 respectively.
In Mbarara and Ntungamo, Ug Shs 96,585,540 would be incurred on scenario A1 in year
1 (costing Ug Shs 65,261 per test) and Ug Shs 23,473,540 in A2 (costing Ug Shs 15,861
per test) therefore saving 75.7% of the original cost. Forty four children with AS would
- 126 -
be detected in both scenarios costing Ug Shs 2,195,126 per AS case detected in A1 and
costing Ug Shs 533,490/= per AS detected in A2.
In Bundibugyo district, a cost of Ug Shs 82,458,684 would be incurred in year1 in
scenario A1 (costing Ug Shs 68,261 per test) and Ug Shs 75,210,684 in scenario A2
(costing 62,261 per test) therefore saving 8.8% of the original cost. One hundred and fifty
six AS and 36 SS would be detected in both A1and A2. A cost per AS case detected in A1
would be Ug Shs 528,581 and cost per AS case detected in A2 would be Ug Shs 482,120.
The cost per SS cases detected in A1 and A2 would be Ug Shs 2,290,519/= and Ug Shs
2,089,186 respectively.
- 127 -
Table 28: The reflection of the accumulative costs (Ug Shs) with time in
scenarios A1 and A2 using Automated Hb electrophoresis screening method
in Mbale and Sironko in the East and Mbarara, Ntungamo and Bundibugyo
in the West.
Variable
A1
A2
AS
SS
Money saved
A1
A2
AS
SS
Money saved
A1
A2
AS
SS
Money saved
A1
A2
AS
SS
Money saved
A1
A2
AS
SS
Money saved
Sironko / Mbale
Mbarara/ Ntungamo
Bundibugyo
Year 1
71,226,012
15,856,412
200
20
77.7%
Year2
144,588,804
32,188,516
406
41
155.4%
Year 3
220,152,480
49,010,583
618
63
233%
Year 4
297,983,066
66,337,312
837
86
310.8%
Year 5
378,148,570
84,183,843
1,063
110
388.5%
Year 1
96,585,540
23,473,540
44
0
75.7%
Year 2
196,068,646
47,651,286
85
0
151.4%
Year 3
298,536,245
72,554,364
131
0
227.1%
Year 4
404,077,872
98,204,534
181
0
302.8%
Year 5
512,785,748
124,624,209
230
0
398.9
Year 1
82,458,684
75,210,684
156
36
8.8%
Year 2
167,391,129
152,677,689
317
73
17.6%
Year 3
254,871,547
232,468,705
483
111
26.4%
Year 4
344,976,378
314,653,451
654
150
35.2%
Year 5
437,984,354
399,303,739
830
190
44%
- 128 -
4.5.2.12.
Projections of the costs (Ug Shs) of establishing cellulose acetate Hb
electrophoresis screening service with time
A summary of the calculations of the accumulative costs and the children detected and
money saved when using cellulose acetate Hb electrophoresis as a screening method in
the districts of Male and Sironko in the East and Mbarara /Ntungamo and Bundibugyo in
the West are as shown in Table 29. When cellulose acetate Hb electrophoresis screening
method is used, a cost of 67,844,792/= would be incurred in Mbale and Sironko in year1
(costing Ug Shs 59,305 per test), in scenario A1 and 12,475,192/= in scenario A2
(costing Ug Shs 10.905 per test) therefore saving 81.6% of the original cost. Two
hundred AS and 20 SS children would be detected in both A1and A2. The cost per AS
case detected in A1 would be Ug Shs 339,224 and in A2 Ug Shs 62,376 respectively.
The cost per SS case detected in A1 and A2 would be Ug Shs 3,392,240 and Ug Shs
623,760 respectively.
In Mbarara and Ntungamo, Ug Shs 92,240,640 would be incurred on scenario A1 and Ug
Shs 19,128,640/= in A2 in year 1 thereby saving Ug Shs 79.3%. The cost per test in A1
would be Ug Shs 62,325 and Ug Shs 12,925 in A2. Fourty four AS cases would be
detected in both A1 and A2. Ther cost per AS in A1 would be Ug Shs 2,096,378 while
the cost per AS case deteced in A2 would be Ug Shs 434,742. More children with sickle
disease would be identified and more money would be saved in the subsequent years by
both interventions.
- 129 -
In Bundibugyo district, a cost of 79,307,512/= would be incurred in year 1 in scenario A1
and (costing Ug Shs 65,652 per test) and Ug Shs 72,059,512 in scenario A2 (costing Ug
Shs 59,652 per test) therefore saving Ug Shs 9.1% of the original cost. One hundred and
fifty six AS and 36 SS children would be detected in both A1 and A2. A cost per AS
case detected in A1 would be Ug Shs 508,381 and cost per AS case detected in A2 would
be Ug Shs 461,920. The cost per SS cases detected in A1 and A2 would be Ug Shs
2,202,986 and 2,001,653 respectively. In year 2 and subsequent years, more children
- 130 -
Table 29: The reflection of the accumulative costs (Ug Shs) with time in
scenarios A1 and A2 using cellulose acetate Hb electrophoresis screening
method in Mbale and Sironko in the East and Mbarara, Ntungamo and
Bundibugyo in the West.
A1
A2
AS
SS
Money saved
A1
A2
AS
SS
Money saved
A1
A2
AS
SS
Money saved
A1
A2
AS
SS
Money saved
A1
A2
AS
SS
Money saved
Sironko / Mbale
Mbarara/ Ntungamo
Bundibugyo
Year 1
67,844,792
12,475,192
200
20
81.6%
Year2
132,368,032
25,324,640
406
41
163.2%
Year 3
206,796,969
38,559,571
618
63
244.8%
Year 4
279,338,774
52,191,550
837
86
326.4%
Year 5
354,056,833
66,232,488
1,063
110
408%
Year 1
92,240,640
19,128,640
44
0
79.3%
Year 2
187,248,499
38,831,139
85
0
158.6%
Year 3
285,106,594
59,124,713
131
0
237.9%
Year 4
385,900,434
80,027,094
181
0
317.2%
Year 5
489,718,089
101,556,546
230
0
396.5%
Year 1
79,307,512
72,059,512
156
36
9.1%
Year 2
160,994,249
146,280,791
317
73
18.2%
Year 3
245,131,588
222,728,708
483
111
36.4%
Year 4
331,793,047
301,470,062
654
150
45.5%
Year 5
421,054,350
382,573, 656
830
190
54.6%
- 131 -
4.5.2.13.
Projections of the costs (Ug Shs) of establishing sickling test and
automated Hb electrophoresis screening service with time.
A summary of the accumulative costs, number of children detected and money saved in
Sironko and Mbale in the East and Mbarara, Ntungamo and Bundibugyo in the West
using Automaated Hb electrophoresis method with sickling test are as shown in Table 30.
When the sickling test is used together with the automated capillary Hb electrophoresis
method, Ug Shs 9,565,912 would be incurred in the East in B1 and Ug Shs 7,147,912 in
B2 in year 1, therefore saving 25% of the original cost. The cost per test in scenario B1
and B2 would be Ug Shs 8,362 and Ug Shs 6,248 respectively. One hundred and four AS
and 20 SS children would be detected in both scenarios B1 and B2. The cost per AS case
detected in B1would be Ug Shs 91,980 and in B2 Ug Shs 68,780. The cost per SS case
detected in B1 and B2 would be Ug Shs 478,296 and Ug Shs 357,396 respectively.
In Mbarara and Ntungamo Ug Shs 10,920,130 would be incurred in B1 and Ug Shs
8,840,130 in B2 thereby saving 19% of the cost. The cost per test in scenario B1 and B2
would be Ug Shs 7,378 and 5,973 respectively. Twenty AS 0 SS children would be
detected in both B1 and B2. The cost per AS case detected in B1would be Ug Shs
546,007 and Ug Shs 442,007 in B2.
In Bundibugyo, when the sickling test is used, a cost of Ug Shs 7,949,008 would be
incurred in B1 and Ug Shs 7,805,008 in B2 therefore saving 1.8% of the original cost. The
cost per test in scenario B1 and B2 would be Ug Shs 6,580 and Ug Shs 6,461 respectively.
- 132 -
Eighty four AS and 36 SS children would be detected in both B1 and B2. The cost per
AS case detected in B1 would be Ug Shs 94,631 and in B2 Ug Shs 92,917. The cost per
SS case detected in B1 and B2 would be Ug Shs 220,806 and 216,806 respectively.
- 133 -
Table 30: The reflection of the accumulative costs (Ug Shs) with time in scenarios B1
and B2 using Automated Hb electrophoresis screening method with sickling in Mbale
and Sironko in the East and Mbarara, Ntungamo and Bundibugyo in the West.
B1
B2
AS
SS
Money saved
B1
B2
AS
SS
Money saved
B1
B2
AS
SS
Money saved
B1
B2
AS
SS
Money saved
B1
B2
AS
SS
Money saved
Sironko / Mbale
Mbarara/ Ntungamo
Bundibugyo
Year 1
9,565,912
7,147,912
104
20
25%
Year2
19,418,801
14, 510,261
211
41
50%
Year 3
29,567,277
22,093,480
321
63
75%
Year 4
40,020,207
29,904,196
434
86
100.8%
Year 5
50,786,725
37,947,233
550
110
388.5%
Year 1
10,920,130
8,840,130
20
0
19%
Year 2
22,167,864
17,945,464
41
0
38%
Year 3
33,753,030
27,323,9 58
63
0
57%
Year 4
44,685,751
36,938,807
86
0
76%
Year 5
42,202,361
41,653,242
110
0
95%
Year 1
7,9 49,008
7,805,008
84
36
1.8%
Year 2
16,136,486
15,844,166
169
73
3.6%
Year 3
24,569,683
24,124,499
257
111
5.4%
Year 4
33.255,683
32,653,242
348
150
7.2%
Year 5
42,202,361
41,653,242
442
190
9.0%
- 134 -
4.5.2.14. Projections of the costs (Ug Shs) of establishing solubility test and
automated Hb Hb electrophoresis test screening service with time
A summary of the accumulative costs, number of children detected and money saved in
Sironko and Mbale in the east and Mbarara, Ntungamo and Bundibugyo in the west using
automaated Hb electrophoresis method with solubility test are as shown in Table 31.
Using the solubility method, a cost of Ug sh 11,766,602 would be incurred in year 1 in
scenario B1 and Ug Shs 9,348,602 in B2 in Mbale and Sironko therefore saving 20.5% of
the original cost. The cost per test in scenario B1 and B2 would be Ug Shs 10,285 and
8,172 respectively. Fifty two AS and 16 SS cases would be detected in both B1 and B2.
The cost per AS case detected in B1would be Ug Shs 226,280 and in B2 Ug Shs 179,780.
The cost per SS case detected in B1 and B2 would be Ug Shs 735,413/= and 584,288/=
respectively.
In Mbarara and Ntungamo, a cost of Ug Shs 13,376,820 and Ug Shs 11,296,820 would
be incurred in B1 and B2 respectively therefore saving 15.5% of the original cost. Twelve
AS and 0 SS cases would be detected. The cost per test in scenario B1 and B2 would be
Ug Shs 9,038 and 7,633 respectively. The cost per AS case detected in B1 would be Ug
Shs 1,114,735 and in B2 Ug Shs 941,402.
Using the solubility test, a cost of Ug Shs 10,645,982/= would be incurred in B1 and Ug
Shs 10,501,982 in B2 in Bundibugyo district therefore saving 1.4% of the original cost..
The cost per test in scenario B1 and B2 would be Ug Shs 8,813 and Ug Shs 8,694
- 135 -
respectively. Fourty four AS and 24 SS cases would be detected in both scenarios. The
cost per AS case detected in B1 would be 241,954/= and in B2 Ug Shs 238,681. The cost
per SS case detected in B1 and B2 would be Ug Shs 443,583 and 437,583 respectively.
- 136 -
Table 31: The reflection of the accumulative costs (Ug Shs) with time in scenarios B1
and B2 using Automated Hb electrophoresis screening method with solubility in Mbale
and Sironko in the East and Mbarara, Ntungamo and Bundibugyo in the West.
B1
B2
AS
SS
Money saved
B1
B2
AS
SS
Money saved
B1
B2
AS
SS
Money saved
B1
B2
AS
SS
Money saved
B1
B2
AS
SS
Money saved
Sironko / Mbale
Mbarara/ Ntungamo
Bundibugyo
Year 1
11,766,602
9,348,602
52
16
20.5%
Year2
23,886,202
18,977,662
106
33
41%
Year 3
36,369,390
28,895,594
162
51
61%
Year 4
49,227,074
39,111,064
220
70
82%
Year 5
62,470,489
49,632,998
280
90
102.5%
Year 1
13,376,820
11,296,820
12
0
15.5%
Year 2
27,154,945
22,932,545
24
0
31%
Year 3
41,346,414
34,917,342
37
0
46.5%
Year 4
55,963,627
47,261,683
50
0
62%
Year 5
71,019,356
59,976,354
64,
0
77.5%
Year 1
10,645,982
10,501,982
44
24
1.4%
Year 2
21,611,343
21,319,023
89
49
2.8%
Year 3
32,905,665
32,460,575
135
75
4.2%
Year 4
44,538,817
43,936,374
182
102
5.6%
Year 5
56,520,964
55,756,447
230
130
7.0%
- 137 -
4.5.2.15. Projections of the costs (Ug Shs) of establishing peripheral blood film
method and automated Hb electrophoresis screening service with time.
A summary of the accumulative costs, number of children detected and money saved in
Sironko and Mbale in the East and Mbarara, Ntungamo and Bundibugyo in the West
using automated Hb electrophoresis method with solubility test are as shown in Table 32.
When the peripheral blood film method is used together with Hb electrophoresis, Ug Shs
8,876,392 would be incurred in year 1 in scenario B1 and Ug Shs 6,458,392 in B2 in
Eastern Uganda therefore saving 27%. The cost per test in scenario B1 and B2 would be
Ug Shs 7,759 and 5,645 respectively. Twenty four AS and 12 SS children would be
detected in both B1 and B2. The cost per AS case detected in B1 would be Ug Shs
369,850 and in B2 Ug Shs 269,100. The cost per SS case detected in B1 and B2 would be
Ug Shs 739,699 and 538,199 respectively.
In Mbarara and Ntungamo, a cost of Ug Shs 10,262,854 would be incurred in B1 and Ug
Shs 8,182,854 in B2 therefore saving 20% of the original cost. The cost per test in
scenario B1 and B2 would be Ug Shs 6,934 and 5,529 respectively. Eight AS and 0 SS
children would be detected in both B1 and B2. The cost per AS case detected in B1would
be Ug Shs 1,282,857 and in B2 Ug Shs 1,022,85 respectively.
When the peripheral blood film is used in Bundibugyo district, a cost of Ug Shs
7,742,930 would be incurred in B1 and Ug Shs 7,598,930 in B2 therefore saving 1.9 % of
the original cost. The cost per test in scenario B1 and B2 would be Ug Shs 6,410 and
- 138 -
6,291 respectively. Twenty four AS and 20 SS children would be detected in both A1
and A2. The cost per AS case detected in B1 would be Ug Shs 322,622 and in B2 Ug Shs
316,622. The cost per SS case detected in B1 and B2 would be Ug Shs 387,147 and
379,947 respectively. More money will be saved and more children with AS and SS will
be detected by these methods in the subsequent years.
- 139 -
Table 32: The reflection of the accumulative costs (Ug Shs) with time in scenarios B1
and B2 using Automated Hb electrophoresis screening method with peripheral blood
method in Mbale and Sironko in the East and Mbarara, Ntungamo and Bundibugyo in
the West.
Sironko / Mbale
Mbarara/ Ntungamo
Bundibugyo
Year 1
Year 1
Year 1
B1
B2
AS
SS
Money saved
8,876,392
6,458,392
10,262,854
8,182,854
7,742,930
7,598,930
24
12
27%
Year2
8
0
20%
Year 2
24
20
1.9%
Year 2
B1
B2
AS
SS
Money saved
18,019,076
13,110,536
20,833,324
16,611,194
15,485,860
15,425,828
49
24
54%
Year 3
16
0
40%
Year 3
49
41
3.8%
Year 3
B1
B2
AS
SS
Money saved
27,436,041
19,962,244
31,721,186
25,292,384
23,700,335
23,487,533
62
37
81%
Year 4
24
0
60%
Year 4
75
62
5.7%
Year 4
B1
B2
AS
SS
Money saved
37,135,515
27,019,503
42,935,684
34,234,010
32,161,244
31,791,089
87
50
109%
Year 5
33
0
80%
Year 5
102
85
7.6%
Year 5
B1
B2
AS
SS
Money saved
47,125,973
34,288,480
54,486,617
43,443,885
40,879,980
40,343,752
113
64
136%
42
0
100%
130
109
9.5%
- 140 -
4.5.2.16. Projections of the costs (Ug Shs) of establishing sickling and cellulose
acetate Hb electrophoresis screening service with time
A summary of the accumulative costs, number of children detected and money saved in
Sironko and Mbale in the East and Mbarara, Ntungamo and Bundibugyo in the West
using cellulose acetate Hb electrophoresis method with sickling test are as shown in
Table 33. When the sickling test is used together with cellulose acetate Hb
electrophoresis, Ug Shs 9,131,192 would be incurred in the Mbale and Sironko in B1 and
Ug Shs 6,713,192 in B2 in year 1, thereby saving 27% of the original cost. The cost per
test in scenario B1 and B2 would be Ug Shs 7,982 and 5,868 respectively. One hundred
and four AS and 20 SS children would be detected in both A1 and A2. The cost per AS
case detected in B1 would be Ug Shs 87,800 and in B2 Ug Shs 64,650 respectively. The
cost per SS case detected in B1 and B2 would be Ug Shs 456,560 and 335,660
respectively.
In Mbarara and Ntungamo Ug Shs 10,812,200 would be incurred in B1 and Ug Shs
8,732,200 in B2 therefore saving 19% of the original cost. The cost per test in scenario B1
and B2 would be Ug Shs 7,305 and 5,900 respectively. Twenty AS and 0 SS would be
detected in both B1 and B2. The cost per AS case detected in B1would be Ug Shs
540,610 and 436,610 in B2.
In Bundibugyo, when the sickling test is used, a cost of Ug Shs 7,898,084 would be
incurred in B1 and Ug Shs 7,754,084 in B2 therefore saving 1.8% of the original cost. The
cost per test in scenario B1 and B2 would be Ug Shs 6,538 and 6,419 respectively. Eighty
- 141 -
four AS and 36 SS children would be detected in both B1 and B2. The cost per AS case
detected in B1 would be Ug Shs 94,025 and in B2 92,311. The cost per SS case detected in
B1 and B2 would be Ug Shs 219,391 and Ug Shs 215,391 respectively.
- 142 -
Table 33: The reflection of the accumulative costs (Ug Shs) with time in scenarios B1
and B2 using cellulose acetate Hb electrophoresis screening method with sickling test in
Mbale and Sironko in the East and Mbarara, Ntungamo and Bundibugyo in the West.
Sironko / Mbale
Mbarara/ Ntungamo
Bundibugyo
Year 1
Year 1
Year 1
B1
B2
AS
SS
Money saved
9,131,192
6,713,192
10,812,200
8,732,200
7,898,084
7,754,084
104
20
27%
Year2
20
0
19%
Year 2
84
36
1.8%
Year 2
B1
B2
AS
SS
Money saved
18,536,320
13,627,780
21,948,766
17,726,366
16,033.111
15,740,791
211
41
54%
Year 3
41
0
38%
Year 3
169
73
3.6%
Year 3
B1
B2
AS
SS
Money saved
28,223,602
20,749,806
33,419,429
26,990,357
24,412,189
23,967,099
321
63
81%
Year 4
63
0
57%
Year 4
257
111
5.4%
Year 4
B1
B2
AS
SS
Money saved
38,201502
28,085.493
45,234,212
36,532,268
33,042,639
32,440,196
434
86
109%
Year 5
86
0
76%
Year 5
348
150
7.2%
Year 5
B1
B2
AS
SS
Money saved
48,478,739
35,641,251
57,403,439
46,360,436
41,932,003
41,167,486
550
110
136%
110
0
95%
442
190
9.0%
- 143 -
4.5.2.17. Projections of the costs (Ug Shs) of establishing solubility and cellulose
acetate Hb electrophoresis screening services with time
A summary of the accumulative costs, number of children detected and money saved in
Sironko and Mbale in the East and Mbarara, Ntungamo and Bundibugyo in the West
using automated Hb electrophoresis method with solubility test are as shown in Table 34.
Using the solubility test, a cost of Ug Shs 11,381,272 would be incurred in year 1 in
scenario B1 and Ug Shs 8,963,272 in B2 in Mbale and Sironko therefore saving 21% of
the original cost. The cost per test in scenario B1 and B2 would be Ug Shs 9,947 and Ug
Shs 7,835 respectively. Fifty two AS and 16 SS children would be detected in both B1
and B2. The cost per AS case detected in B1 would be Ug Shs Ug Shs 218,871 and Ug
Shs 172,371 in B2 . The cost per SS case detected in B1 and B2 would be Ug Shs 569,060
and 560,205.
In Mbarara and Ntungamo, a cost of Ug Shs 13,122,720 and Ug Shs 11,042,720 would
be incurred in B1 and B2 respectively therefore saving 16% of the original cost. The cost
per test in scenario B1 and B2 would be Ug Shs 8,867 and 7,461 respectively. Twelve AS
and 0 SS children would be detected in both B1 and B2. The cost per AS case detected in
B1would be Ug Shs 1,093,560 and Ug Shs 920,227 in B2 respectively.
When the solubility test is used in Bundibugyo district, a cost of Ug Shs 10,391,788
would be incurred in B1 and Ug Shs 10,247,788 in B2 therefore saving 1.4% of the cost.
The cost per test in scenario B1 and B2 would be Ug Shs 8,602 and 8,483 respectively.
- 144 -
Fourty four AS and 24 SS children would be detected in both B1 and B2. The cost per
AS case detected in B1 would be Ug Shs 236,177 and in B2 Ug Shs 232,904 The cost per
SS case detected in B1 and B2 would be Ug Shs 432,991 and Ug Shs 426,991
respectively.
- 145 -
Table 34: The reflection of the accumulative costs (Ug Shs) with time in scenarios B1
and B2 using cellulose acetate Hb electrophoresis screening method with solubility in
Mbale and Sironko in the East and Mbarara, Ntungamo and Bundibugyo in the West.
Sironko / Mbale
Mbarara/ Ntungamo
Bundibugyo
Year 1
Year 1
Year 1
B1
B2
AS
SS
Money saved
11,381,272
8,963,272
13,122,720
11,042,720
10,391,788
10,247,788
52
16
21%
Year2
12
0
16%
Year 2
44
24
1.4%
Year 2
B1
B2
AS
SS
Money saved
23,103,982
18,195,442
26,639,122
22,416,722
21,095,533
20,803,010
106
33
42%
Year 3
24
0
32%
Year 3
89
49
2.8%
Year 3
B1
B2
AS
SS
Money saved
35,178,373
27,704,577
40,561,016
32,120,181
31,674,889
162
51
63%
Year 4
34,917,342
37
0
48%
Year 4
B1
B2
AS
SS
Money saved
47,614,996
37,498,986
54,900,567
46,198,622
43,475,568
42,872,924
220
70
84%
Year 5
50
0
64%
Year 5
182
102
5.6%
Year 5
B1
B2
AS
SS
Money saved
60,424,718
47,542,227
72,670,302
58,627,300
54,830,955
54,406,900
280
90
105%
64,
0
80%
230
130
7.0%
- 146 -
135
75
4.2%
Year 4
4.5.2.18. Projections of the costs (Ug Shs) of establishing peripheral blood and
cellulose acetate Hb electrophoresis screening services with time
A summary of the accumulative costs, number of children detected and money saved in
Sironko and Mbale in the East and Mbarara, Ntungamo and Bundibugyo in the West
using automated Hb electrophoresis method with solubility test are as shown in Table 35.
When the peripheral blood film method is used together with Hb electrophoresis, Ug Shs
8,823,812 would be incurred in year 1 in scenario B1 and Ug Shs 6,405,812 in B2 in
Eastern Uganda therefore saving 27.4% of the original cost. The cost per test in scenario
B1 and B2 would be Ug Shs 7,713 and 5,599 respectively. Twenty four AS and 12 SS
children would be detected in both B1 and B2. The cost per AS case detected in B1would
be Ug Shs 367,659 and Ug Shs 266,909 in B2. The cost per SS case detected in B1 and
B2 would be Ug Shs 735,318 and 533,818.
In Mbarara and Ntungamo, a cost of Ug Shs 10,198,464 would be incurred in B1 and Ug
Shs 8,118,464 in B2 therefore saving 20.4% of the original cost. The cost per test in
scenario B1 and B2 would be Ug Shs 6,890 and 5,485 respectively. Eight AS and 0 SS
children would be detected in both B1 and B2. The cost per AS case detected in B1would
be Ug Shs 1,274,808 and Ug Shs 1,014,808 in B2.
When the peripheral blood film method, is used in Bundibugyo, a cost of Ug Shs
8,327,335 would be incurred in B1 and Ug Shs 8,183,335 in B2 therefore saving 1.7% of
the original cost. The cost per test in scenario B1 and B2 would be Ug Shs 6,927 and
- 147 -
6,807 respectively. Twenty four AS and 20 SS children would be detected in both B1 and
B2. The cost per AS case detected in B1 would be Ug Shs 346,639 and in B2 Ug Shs
342,639. The cost per SS case detected in B1 and B2 would be Ug Shs 4,18,367 and
411,168 respectively.
- 148 -
Table 35: The reflection of the accumulative costs (Ug Shs) with time in scenarios B1
and B2 using cellulose acetate Hb electrophoresis screening method with peripheral
blood method in Mbale and
Sironko in the East and Mbarara, Ntungamo and
Bundibugyo in the West.
Sironko / Mbale
Mbarara/ Ntungamo
Bundibugyo
Year 1
Year 1
Year 1
B1
B2
AS
SS
Money saved
8,823,812
6,405,812
10,198,464
8,118,464
8,327,335
8,183,335
24
12
27%
Year2
8
0
20.4%
Year 2
24
20
1.9%
Year 2
B1
B2
AS
SS
Money saved
17,912,335
13,993,798
20,833,324
16,611,194
16,904,490
16,612,170
49
24
54%
Year 3
16
0
40.8%
Year 3
49
41
3.8%
Year 3
B1
B2
AS
SS
Money saved
27,273,517
19,799,724
31,522,433
25,093,361
25,738,960
25,293,870
62
37
81%
Year 4
24
0
61.2%
Year 4
75
62
5.7%
Year 4
B1
B2
AS
SS
Money saved
36,915,564
26,799,528
42,666,570
33,964,625
34,834,464
34,236,021
87
50
109%
Year 5
33
0
80.6%
Year 5
102
85
7.6%
Year 5
B1
B2
AS
SS
Money saved
46,846,842
34,009,326
54,145,032
43,102,029
44,206,951
40,343,752
113
64
136%
42
0
101%
130
109
9.5%
- 149 -
4.5.2.19.
Projections of the costs (Ug Shs) of establishing automated
and
cellulose acetate Hb electrophoresis screening services with time in
Bundibugyo hospital
A summary of the accumulative costs, number of children detected and money saved
when screening is done in Bundibugyo hospital in the west using either automated or
cellulose acetate Hb electrophoresis methods with sickling test are as shown in Table 36.
Using the automated Hb electrophoresis in Bundibugyo hospital, a cost of Ug Shs
17,347,484 would be incurred on 1,208 children in year one at Ug. Shs 14,361 per test.
One hundred and fifty six AS and 36 SS would be detected. Using cellulose acetate Hb
elecetrophoresis, Ug Shs 14,196,912 would be incurred on these children in year one at
Ug Shs 11,752 per test. Eighty four AS and 36 SS would be detected therefore saving
18%. When the automated is used together with sickling test, a cost of Ug Shs 6,113,022
would be incurred on these children in year one at Ug Shs 5,060 per test. The same
number of AS and SS would be detected. When cellulose acetate is used together with
sickling test, Ug Shs 6,602,656 would be incurred on these children in year one at Ug Shs
5,466 per test. The same number of AS and SS would be detected, therefore saving Ug
Shs 7% of the original cost.
- 150 -
Table 36: The reflection of the accumulative costs (Ug Shs) with time of establishing
either automated or cellulose acetate Hb electrophoresis alone or with sickling test in
Bundibugyo hospital.
Period
Money incurred
AS
SS
Money Saved
Period
Money incurred
AS
SS
Money saved
Period
Money incurred
AS
SS
Money saved
Period
Money incurred
AS
SS
Money saved
Period
Money incurred
AS
SS
Money saved
Automated
Cellulose
alone
alone
Year 1
Year 1
17,347,484
14,196,912
156
156
36
36
18.2%
Year 2
Year 2
35,215,393
28,819,731
317
317
73
73
36.4%
Year 3
Year 3
Automated with
sickling
Year 1
6,113,022
84
36
53,619,339
18,894,740
482
111
Year 4
72,575,403
652
150
Year 5
92,100,149
827
190
43,881,235
482
111
54.6%
Year 4
Year 2
12,409,431
169
73
Year 3
257
111
Year 4
59,394,584
652
150
72.8%
Year 5
25,574,604
348
150
Year 5
75,373,334
827
190
91%
32,454,864
442
190
- 151 -
Cellulose with
sickling
Year 1
6,602,656
84
36
7.4%
Year 2
13,403,392
169
73
15.4%
Year 3
20,408,150
257
111
22.8%
Year 4
27,623,051
348
150
30.2%
Year 5
35,054,399
442
190
37.6%
4.6 Methodological issues
4.6.1 Logistics
Although I wanted to sample more districts, it was not possible because of financial
constraints.
4.6.2 Knowledge, attitudes and beliefs of the communities in Eastern and Western
Uganda about sickle cell disease and its detection (KAP).
The estimated sample size might have been under estimated because in the analysis I did
not take into consideration or account of the possible design effect by multistage
sampling. Since the study sampled only the households with children, the findings were
therefore not representative of all the households. The fact that the selection of the study
districts was done using convenient sampling, the rest of the districts in Eastern and
Western Uganda were therefore not given equal chance to be represented. So the results
on knowledge, attitudes and beliefs about SCD can not be generalized as representative
of the whole Eastern and Western Uganda.
4.6.3 Current prevalence of sickle cell disease in Eastern, Mbarara/Ntungamo and
Bundibugyo in the West.
Since our study sampled only children and not adults, our findings could have biased the
statistical comparison between these findings and findings of Lehmann and Raper study
which used all ages including adults. Just like KAP study, the current results on
- 152 -
prevalence can not be generalized as representative of the whole Eastern and Western
Uganda.
3.6.3. Reliability study
It was not possible to differentiate between haemoglobin AS and SS using sickling and
solubility tests and peripheral blood film method. They only demonstrated the presence
of sickle cells in the samples which were then confirmed by Hb electrophoresis as either
AS or SS. Although Hb electrophoresis was used as “a gold standard”, better screening
methods such as automated capillary Hb electrophoresis, iso-electric focusing (IEF) and
high liquid chromatography (HPLC) are today available.
3.6.4 Cost benefit analysis study
Some of the costs in cost benefit analysis were estimated and were therefore not accurate
costs.
- 153 -
CHAPTER FIVE
DISCUSSION
5.1.
Knowledge gaps attitudes and beliefs about sickle cell disease
This study was undertaken with the main aim of establishing sickle cell screening
services at health centers IV in the districts of Uganda so that cases of SCD can be
detected as early as possible to enable optimal management of the disease. It focused on
finding out about knowledge gaps, attitudes and beliefs of the communities in some
districts about sickle cell disease as one of its specific objectives.
Whereas there was increased awareness about SCD among household communities in the
Eastern region compared to those from the West
142,
(see appendix ix) as expected, these
findings could have been influenced by differences in the prevalence SCD in these study
populations 7,. These results were similar to those presented by Armeli in which it was
noted that persons from areas of high prevalence of SCD were more likely to be more
aware of it than those from areas of low prevalence89.
This observation was further augmented by the fact that although the urban respondents
who had secondary, tertiary and university education, watched televisions and read news
papers (Table 11) were more aware of SCD than their rural counterparts ((Table 7) who
- 154 -
mostly had primary education and whose main sources of information about health were
health visitors and radio (Table 11), the difference was statistically not significant. The
likely reason for this finding was that the awareness of SCD was probably sensitve to the
prevalence of SCD other than location and education back ground.
The beliefs about SCD were diverse among the respondents in these communities.
Whilst the majority believed SCD was acquired from parents, a few believed that it was
acquired as “a curse from GOD”, and was due to witchcraft (Table 8). These observations
are in agreement with the study by Ohaeri and Shokunbi which indicated that whilst the
majority of the respondents believed that SCD was a natural or genetic phenomenon, a
few believed it was acquired as a curse from God and witchcraft42. These findings are
also similar to those of Treadwell and colleagues which noted that although the majority
of the respondents correctly believed that sickle was inherited from parents, a few
believed that it was acquired through blood transfusion and was contagious90. These
imaginations at times degenerate into witch-hunting, leading to unnecessary deaths of
innocent people within the communities. Sensitization and community education is
therefore of paramount importance in areas with high prevalence of such diseases.
Whereas certain studies have found high positive attitude towards sickle cell disease
screening to be linked to improved management of SCD143, this study showed that
although the majority of the respondents who included health workers were positive
towards sickle cell screening, the screening services were lacking at the health centers in
the district of Uganda. This probably explains why most of the district health centers
- 155 -
were not screening for SCD and highlights why many children are probably dying from
sickle cell disease undected and why most of these respondents did not know their sickle
cell status. This finding is in conformity with the study by Rahimy, which found that lack
of skills among the medical staff and limited health care facilities were probably
responsible for high morbidity and mortality among children with sickle cell anemia in
sub-Saharan Africa 144.
These findings are similar to reports in the study by Okwi et al;145 which found that
whilst a majority of the health staff at the health centers were aware about cervical
cancer, they lacked skills on cervical cancer screening procedures and were therefore not
screening for it. Besides, most of the respondents who included female health staff had
not been screened for cervical cancer. These findings are also in conformity with the
study by Odunybum et al;143 who found that although the majority of the respondents
were willing to have their babies screened for SCD, most of them did not know their
sickle cell status. This observation was equally noted by Cynthia and Wonkam who
found that although the majority of health workers considered sickle cell screening as
acceptable, absence of such screening services at health centers was associated with lack
of familiarity of health service providers to SCD screening methods and poor decision
making.
Whereas other studies have linked lack of skills on SCD screening tests among health
staff to low prevalence of SCD in the community 97, on the contrary, this study noted that
the health workers in the districts of Mbale and Sironko, with high prevalence of sickle
- 156 -
cell disease, had low skills on sickle cell screening methods just like health workers from
Mbarara and Ntungamo with low prevalence of SCD.
5.2.
Prevalence of sickle cell disease
The observed prevalence of sickle cell trait of 17.5% in the districts of Sironko and
Mbale was found to be slightly lower than the 20-28% reported by Raper and Lehamn7
(Table 13). The most likely reason for this low observed prevalence is that since Lehman
and Raper study sampled adults which is a stable population, our study sampled only
children between 6 months to 5 years who are vulnerable to several infant mortality
causes such as malaria, pneumonia and so forth thereby reducing their number in the
population.
Surprisingly the observed prevalence of sickle cell trait in the district of Bundibugyo of
13.4% was found to be much lower than that estimated by Lehman and Raper (45%)
(Table 12). One hypothesis may be used to explain this finding. Based on the first survey
of 1949, which was 60 years ago, the Baamba were one of the exclusively preserved
tribes in Uganda which practiced high level of endogenous marriages. However, due to
the movement of the people, probably as a result of wars, hunger and trade, the Baamba
people may have intermarried other tribes leading to a sickle cell gene dilution.. Although
this hypothesis does explain for a decline of the sickle cell trait in Bundibugyo, it is
possible that the Lehman and Raper studies could have correctly estimated the impact of
sickle cell disease in Bundubugyo. The fact that this study found the higher prevalence of
3% of sickle cell anemia among the Baamba children than the 1-2% reported by Serjeant
- 157 -
and Marsden9,146, it could possibly be reflecting a higher prevalence of sickle cell trait
among the Baamba adult population
147
(see appendix x.). This hypothesis is supported
by the fact that this study sampled only children as compared to Lehman and Raper study
which sampled adults.
Generally the prevalence of sickle cell trait of 3% had remained low in the districts of
Mbarara and Ntungamo and was in conformity with the 1-4% noted by Raper. The
probable reason is that the level of intermarriage between these communities and other
tribes could still be very low and as a result, emergence of new cases of sickle cell
disease due to gene admixture may have been curtailed.
Although the prevalence of 1-2% of SS reported by Serjeant and Marsden was lower than
3% found in Bundibugyo and was within 1.7% seen in Mbale and Sironko, the observed
prevalence of SS in all these districts may actually be much lower than expected (Table
13). The question is, what happened to these missing children?. It is possible that many
children could have succumbed to the disease before reaching their fifth birth day
because of the absence of comprehensive sickle cell screening and management
programmes in these districts. Serjeant and Ndugwa alluded to this in their advocacy
paper9. This hypothesis appeared to have been supported by the fact that 10 out of 11
children detected with SS in Mbale and Sironko in Eastern and Bundibugyo in the West
were less than <4 years old (Table 14). It is not surprising then that SS cases are rarely
detectable at 5 years since affected children would have died before their fifth birth day.
- 158 -
This would also explain why the data on median survival times of persons with sickle cell
anemia in many developing countries including Uganda is scarce.
The fact that no children with SS were detected in Mbarara and Ntungamo (Figure 11 )
does not mean that these children do not exist. The reason for this observation may be
that since the AS prevalence was very low in these districts, establishment of new
effective malaria intervention progammes could probably have kept AS numbers further
low by natural law of selection, as they are no longer selected for against malaria by the
sickle cell gene. Therefore this could have had influence on the occurrence of SS cases in
these districts. Another possible reason for this could be that the detectability power
(precision) or study design used was probably not sensitive enough such that if some
body today repeated the study using a more sensitive power, he/she could probably detect
children with SS in Mbarara and Ntungamo and in Bundibugyo and Mbale and Sironko.
Although the study did not cover all the districts of Uganda, it is quite clear that sickle
cell disease is still a public health problem in Uganda which requires un urgent medical
attention.
- 159 -
5.3.
Reliability of the different methods for sickle cell disease
screening
Despite the availability of SCD screening methods such as the solubility and sickling
tests and peripheral blood film method, their reliability for SCD screening at district
health centers in Uganda has, hitherto, not been ascertained. This was the first study to
determine the reliability of these methods using Hb electrophoresis as gold standard
Whilst all these methods could reliably demonstrate haemoglobin S gene, they showed
variability in their ability to demonstrate the carrier state of haemoglobin (AS) (Table
15). The solubility test in particular was found to have low sensitivity for Hb AS. This
finding is in agreement with a study by Chasen and others
148
in which it was found that
the solubility test was not sensitive for the detection of carriers and was therefore
unsuitable for screening purposes. Besides, the solubility test could lead to stigmatization
and unnecessary referrals because it is associated with high false positive rate which is
characteristic of a test with low diagnostic accuracy and low positive likehood ratio
(Table 16). The probable reason for this high false positive rate was that some of the
samples might have shown erythrocytosis, highly marked leucocytosis and/or
hyperlipidemia149. Unfortunately, none of these parameters were measured in this study.
However, this observation was noted by other workers who found that erythrocytosis,
highly marked leucocytosis and hyperlipidemia were responsible for high false positivity
by this method 150.
- 160 -
Although the solubility test was easier to perform, it had a high turn around time because
of reagent preparation (Table 17). The sickling test was the most reliable for the detection
of haemoglobin AS because it had high sensitivity, specificity, positive and negative
predictive values and Cohen’s kappa than the rest of the methods
151,
( see appendix xi)
although it also had some false positive cases (Tables 15 and 16). The false positivity of
the sickling test was probably due to anemia. Unfortunately, this study did not estimated
hemoglobin levels in these blood samples because of inadequate funds. However, the
study by Scheneider et al;152 found that the presence of anemia was associated with a
false positive result when using the sickling test.
While the peripheral blood film method was found reliable in detecting normal
haemoglobin AA, it was found un-reliable for the detection of haemoglobin AS (Table
15). The probable reason for this was that most of the children who had been recruited
into the study with hemoglobin AS, were looking normal (asymptomatic) and probably
had very few circulating sickle cells in their blood at that time.
5.4.
Cost benefit analysis of establishing sickle cell disease screening
tests
This study found that the cost benefit of screening for SCD was sensitive to various
variables. As expected, the cost effectiviness of the screening programme was found to
be sensitive to prevalence, the cost, reliability of the screening tools, number of cases
screened and the distance to the screening center125,129,. Whilst automated capillary Hb
- 161 -
electrophoresis153 would initially incur over 75 million Ug Shs, when children are
referred to Mulago hospital from Mbale and Sironko districts (scenario A1) and more
than Ug Shs 61 million when they are referred to the regional hospital (scenario A2), 50
children with AS and 5 with SS would be detected by both scenarios respectively (Table
18). On the contrary, whilst an expenditure of more than Ug Shs 82 million would be
incurred on scenario A1 in Mbarara and Ntungamo districts and more than Ug Shs 63
million on scenario A2, only eleven children with AS would be identified by both
scenarios (Table 18). The most likely reason for this difference would be that Mbarara
and Ntungamo had a low prevalence of SCD as was found by this study and by Lehman
and Raper7. In addition, screening costs in Mbarara and Ntungamo would be higher than
Sironko and Mbale in both scenarios A1 and A2 because as expected, more children
would have to be screened in Ntungamo and Mbarara in order to detect those with the
disease.
Although operational costs of automated capillary and cellulose acetate Hb
electrophoresis would drop in year one and subsequent years, in both scenarios A1 and
A2, these costs would remain particularly high in scenario A1 (Tables 28 and 29) because
the mothers would have to travel a greater distance from Mbale and Sironko and Mbarara
and Ntungamo to Mulago hospital. Whereas the initial operational costs of cellulose
acetate Hb electrophoresis54 would be much lower than automated capillary Hb
electrophoresis in both scenarios A1 and A2 because of high cost of establishing
automated Hb electrophoresis (Tables 21 and 22), operational costs of cellulose acetate
would drastically increase in year one and in subsequent years in scenario A1 (Table 29)
- 162 -
because of the same reason cited above. Although the screening costs of cellulose acetate
Hb electrophoresis in A2 would be increasing in year one and subsequent years, they
would comparatively remain cheaper than automated Hb electrophoresis (Tables 28 and
29) because of its’ low maintenance cost..
Notably, when scenarios A1 and A2 are used in Bundibugyo district, operational costs in
the subsequent years would remain very high instead of decreasing (Table 28 and 29)
because of the long distance from Bundibugyo to Mulago National referral hospital
and/or Hoima regional hospital. This would therefore render both A1 and A2 screening
interventions less cost effective since they would be associated with minimal savings.
When children are screened first at health centres IV using sickling test, and positives are
confirmed at either Mulago hospital (scenario B1) or regional hospital (scenario B2)
using either automated Hb electrophoresis or cellulose acetate (Tables 19 and 23), the
same cases of SS would be detected as with scenarios A1 and A2 (Tables 18 and 22) at
very low cost Using sickling test would therefore both cheaply and reliability detect
children with haemoglobin SS 154.(see appendix xii). Notably the solubility test would be
associated with high operational and maintenance costs and less savings. The probable
reason for this is that solubility test would be associated with high maintenance costs
since it has many reagents and chemicals as compared to both sickling and peripheral
blood film methods.
Surprisingly, just like scenarios A1 and A2, the scenarios B1 and B2 would have
minimal savings in initial and subsequent years when used in Bundibugyo district. This is
- 163 -
probably because the mothers would have to travel a greater distance from Bundibugyo
district to either Mulago hospital or Hoima regional hospital.
When the children are screened in Bundibugyo hospital using either cellulose acetate or
automated Hb lectrophoresis, initial screening costs of cellulose acetate would seemingly
look cheaper than automated capillary Hb electrophoresis because of high purchasing
costs of automated Hb system (Table 26). However, these costs would decrease in the
subsequent years rendering automated fairly as cheap as cellulose acetate Hb
electrophoresis. However, cellulose acetate would still remain the cheapest probably
because of its low maintenance costs (Table 36).
Notably when either automated capillary or cellulose acetate Hb electrophoresis is used
in Bundibugyo hospital as confirmatory method and sickling test is used at the district
health centers IV, their operational costs would drastically reduce in year one and
subsequent years (Table 36), making automated Hb electrophoresis slightly cheaper than
cellulose acetate Hb electrophoersis in terms of average cost per test. This is probably
due to the reduction in travel distance since Bundibugyo hospital is very near to the
health center. However, initial establishment costs of the automated screening service
would still remain inhibitory because of the high purchasing cost of the system.
Therefore, using cellulose acetate Hb electrophoresis as a screening method in the district
hospitals for districts which are far from the regional hospitals, would remain the most
affordable and non-inhibitory intervention for low resource countries like Uganda.
- 164 -
Besides, establishment of these screening programmes in most of the regions of Uganda,
would be feasible, thus allowing wider utilization of the service.
Although Lane and Eckman believe that universal screening of children in areas with low
prevalence would be more effective and less costly155, the findings of this study seemed
to agree with the studies by Tsevat and Macintyre et al; which found that screening all
persons in a population with low prevalence or risk of the disease was associated with
very high costs122,123. It is therefore logical to say that screening all the population in
Mbarara and Ntungamo with low prevalence of AS and worse still with rarely detectable
SS using Hb electrophoresis method, would not be cost effective because a lot of money
would be required to identify these children as compared with Mbale, Sironko and
Bundibugyo where using the same programme would cost effectively identify many of
these children
121.
However, having no screening and intervention at all would mean
denying medical services to these vulnerable groups which is not ethically acceptable.
The argument, therefore, would be to carry out targeted screening in the populations of
Mbarara and Ntungmo for the identification of only those children who are at high risk of
having SCD. In this case, clinically identifying children at health centers IV with
symptoms of SCD and referring them to the regional hospital for screening using
cellulose acetate would therefore be the most cost effective intervention.
- 165 -
CHAPTER SIX
Conclusions and Recommendations
6.1.
Conclusions
1.
People from Mbale and Sironko were more aware of SCD than those from the
Mbarara and Ntungamo. Few believed it was a ‘curse from God’ or that it was
due to witch craft. Only 12% of health workers claimed to have participated in
screening. The majority of the respondents did no know their sickle cell status.
2.
The prevalence of both sickle cell trait and sickle cell anemia was higher in Mbale
and Sironko in Eastern Uganda,and Bundibugyo than in Mbarara and Ntungamo
districts in the West. The Bundibugyo, Mbale and Sironko had the highest
prevalence of SS. No cases of SS were detected in Mbarara and Ntungamo
districts.
3.
The sickling test was the most reliable and easiest to perform. It had a high
specificity, sensitivity and kappa score and low turn around time of 38 minutes.
The solubility test was found unreliable for sickle cell screening because it had
both low sensitivity and kappa score and had high turn around time of 44 minutes.
The peripheral film method was the most unreliable among all methods because it
had lowest sensitivity and kappa score and highest turn around time of 70
minutes.
- 166 -
4.
Screening all the children in Mulago hospital using both cellulose acetate and
automated capillary Hb electrophoresis would not be cost beneficial although it
would be sensitive. The cost of identifying a child with sickle cell disease in an
area with low prevalence would be higher than that in an area with high
prevalence. Screening all the children at health centers IVs or IIIs using the
sickling test and confirming the positive samples at the regional hospital using
cellulose acetate Hb electrophoresis would be cheaper for the districts with high
prevalence and are nearer to the regional hospitals. Confirming positive samples
at a district hospital using cellulose acetate Hb electrophoresis would be cost
effective for the districts distant from a regional hospital.
6.2.
Recommendations
1.
Given the magnitude of SCD and the non-availablity of neonatal screening, there
is a need to sensitise the communities and policy makers about prevention,
screening and management of SCD. As a matter of urgency, there is need to carry
out an update survey of SCD prevalence in all other districts of Uganda. The
information generated should be used as a basis for the planning of a
comprehensive intervention management programme for SCD in Uganda.
2.
Intervention programmes for management and detection of SCD should be
established in health centers in order to save infants with SCD. Sickling test
should be used for screening SCD at health centers and then confirming positives
using cellulose acetate Hb electrophoresis at either:- (i) regional hospitals for
- 167 -
districts nearer regional hospital or (ii) district hospitals for districts distant from
regional hospital.
3.
Programmes targeting the screening of children who are at high risk of disease at
regional hospitals using cellulose acetate Hb electrophoresis should be adopted
for areas with low prevalence of SCD.
4.
The above SCD screening services should be augmented by the establishment of
tracking programmes at district hospital for children detected with the disease so
that they can be registered. Importantly, comprehensive clinical health care and
counseling programmes should be established at district hospitals for management
of patients with SS and the counseling of families of children detected with this
disease respectively.
5.
Pre-marital screening of adults, especially in areas with high prevalence of SCD,
should also be encouraged.
- 168 -
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Appendices
Appendix (i)
Questionnaire
ATTITUDE AND KNOWLEDGE GAP OF THE RURAL AND URBAN PEOPLE
ABOUT SICKLE CELL DISEASE AND ITS’ DETECTION IN THE DISTRICTS
OF NTUNGAMO, MBARARA , SIRONKO AND MBALE.
(To be filled by secondary school students and heads of families or care takers). Circle
and Tick where appropriate.
Questionnaire No:…………………….
Date…………………………………...
District……………………………………………………………
Sub-county………………………………………………………..
Respondent:
Interview No……………………………
1) Sex
(i) Male
(ii) Female
2) Age (i) 10-17 years
(ii) > 18 years
3) Marrital status (i) Married
(ii) Unmarried
4) Education background
(i)
Primary
(ii)
Secondary
(iii)
Tertiary
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(iv)
University
(v)
No formal education
5) Occupation
(i)
Employed
(ii)
Student
(iii)
Peasant
(iv)
Other(s) Specify…………………………………………………………
……………………………………………………………………………………
6) Religion
(i)
Catholic
(ii)
Protestant
(iii)
Moslem
(iv)
Orthodox
(v)
Redeemed Church
(vi)
Other(s)
Specify……………………………………………………………………
…………………………………………………………………………………….
7) Tribe………………………………………………………………………………
8) Number of pregnancies………………………………………….
9) Number of live children………………………………………….
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10) Number of marriages……………………………………………
11) What is the relationship between you and your sexual partner(s)?
(i)
Niece
(ii)
Cousin
(iii)
Nephew
(iv)
Aunt
(v)
None
12) Has any member of your family had any serious sickness in the last one year?
(i)
YES
(ii)
NO
13) Do you have an idea of what might have been the cause of the illness?
(i)
YES
(ii)
NO
14) If (YES) What might have been the cause of the illness ?.
……………………………………………………………………………………………
……………………………………………………………………………………………
……………………………………………………………………………………………
…………………………………………………………………………………………
15) Has any relative of yours had any member of the family who has had serious
sickness in the last one year?
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16) If (YES) what might have been the cause?
…………………………………………………………………………………………..
……………………………………………………………………………………………
……………………………………………………………………………………………
17) How did you handle this illness or sickness?
(i)
Treated the patient at home using herbs
(ii)
Treated the patient at home using the drugs bought from the drug shop
(iii)
Took the patient to a witch-doctor
(iv)
Took the patient to clinic, dispensary or hospital.
(v)
Did nothing
18) If it is number (iv) above, how far is the health center from your home?
(i)
<3 km
(ii)
3-10 km
(iii)
>10 km
19) How soon did you take the patient to the health center?
(i)
Immediately
(ii)
After 2 days
(iii)
After 1 week
(iv)
After 1 month
20) How do you feel about the patients’ illness?
(i)
Angry
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(ii)
Embarrassed
(iii)
Depressed
(iv)
Sympathetic
(v)
Not affected
21) Is there any history of serious illness among members in your family tree?
(i)
YES
(ii)
NO
22) Have you heard about sickle cell disease?
(i) YES
(ii) NO
23) If (YES) , What do you think the cause(s) is (are)?
(i)
Natural
(ii)
Punishment from God
(iii)
Witchcraft
(iv)
Acquired from parents
24) Has any body been detected with sickle cell disease in your family or community?
(vi)
YES
(vii)
NO
25) If (YES) Where was it detected?
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(i)
(ii)
(iii)
(iv)
In the hospital
At the clinic
At home by the health worker
By the witch doctor
26) Would you like your family to be tested for
sickle cell disease?
(viii) YES
(ix)
NO
27) If (NO) Why?
(i)
Our custom does not allow
(ii)
Our religion prohibits
(iii)
We fear to know the results
(iv)
I don’t want it
(v)
Any other(s) Specify
………………………………………………………………………………….
………………………………………………………………………………….
………………………………………………………………………………….
28) Do you think this disease can be prevented by early screening before marriage?
(i)
YES
(ii)
NO
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29) Did you and your spouse think that you could have children with sickle cell disease
before marriage?
(i)
YES
(ii)
NO
30) Have you been screened for sickle cell disease?
(i)
YES
(ii)
NO
31) Where do you get your information concerning health?
(i)
From the community.
(ii)
Health visitors
(iii)
Radio
(iv)
TV
(v)
News papers
(vi)
Any other(s) specify
………………………………………………………………………………..
………………………………………………………………………………..
………………………………………………………………………………..
31) Is your area having high cases of malaria?
(i)
YES
(ii)
NO
Thank you for your participation
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Appendix (ii)
ATTITUDE AND KNOWLEDGE GAP OF HEALTH WORKERS ABOUT
SICKLE CELL DISEASE AND ITS DETECTION IN THE DISTRICTS OF
NTUNGAMO, MBARARA, SIRONKO AND MBALE.
To be filled by health workers
(Circle and Tick where appropriate)
Questionnaire No:…………………….
Date…………………………………...
District……………………………………………………………
Sub-county………………………………………………………..
Name of health center……………………………………………………………
Respondent:…………………………………………………………………..
Interviewee No………………………
1) Sex
(i) Male
(ii) Female
2) Age (i) 10-17 years
(ii) > 18 years
3) Marrital status (i) Married
(ii) Unmarried
4) Education background
(i)
Primary
(ii)
Secondary
(iii) Tertiary
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(iv)
University
(v)
No formal education
5) Occupation
(i)
Employed
(ii)
Student
(iii) Peasant
(x)
Other(s) Specify…………………………………………………………
……………………………………………………………………………………
6) Religion
(i)
Catholic
(ii)
Protestant
(iii) Moslem
(iv)
Orthodox
(v)
Redeemed Church
(vi) Other(s)
Specify……………………………………………………………………
…………………………………………………………………………………….
7) Has any member of your family had any serious illness in the last one year?
i)
YES
ii)
NO
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8) Do you have an idea of what the illness was?
i)
YES
ii)
NO
9) If (YES) What might have been the cause of the illness ?.
……………………………………………………………………………………………
……………………………………………………………………………………………
……………………………………………………………………………………………
…………………………………………………………………………………………
10) Has any relative of yours had serious sickness in the last one year?.
(i)
YES
(ii)
NO
11) If (YES) what the disease?.
…………………………………………………………………………………………..
……………………………………………………………………………………………
……………………………………………………………………………………………
12) Is there any history of serious illness among members in your family tree?
(iii)
YES
(iv)
NO
13) Have you heard about sickle cell disease?
(i) YES
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(ii)NO
14) Have you been screened for sickle cell disease?
(i) YES
(ii) NO
14) Have you ever come across persons with sickle cell disease ?.
(i) YES
(ii) NO
15) If (YES) how often do they present ………………………………………..
………………………………………………………………………………
………………………………………………………………………………
16) What age are they ?………………………………………………………..
17) Do you think sickle cell disease can be prevented by early screening before
marriage?.
(i)
YES
(ii)
NO
18) Are you aware that complications due to sickle cell disease can be managed if
diagnosed early?
(i)
YES
(ii)
NO
19) Do you know of any technique (s) involved in early diagnosis of sickle cell
disease?
(i)
YES
(ii)
NO
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20) If yes, which one?.………………………………………………………..
…………………………………………………………………………..
21)
Do you perform this/ these technique or techniques here?.
(i) YES
( ii) NO
22)
If (ii) Would you be willing to have these protocols introduced at your
health center?
(i)
(ii)
YES
NO
Thank you for your participation
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Appendix (iii)
CONSENT TO PARTICIPATE IN THE STUDY
Study title:
To study the feasibility of the establishment of sickle cell screening
services at health centers in Uganda.
Purpose:
Andrew Livex Okwi of Makerere University is the Principal Researcher in the study of
“The feasibility of establishing sickle cell anemia screening services at health centers in
Uganda”.
The study aims at finding out the knowledge gaps, attitudes and practices of community
about sickle cell anemia and its detection, determining the current prevalence of SCA in
the districts and establishing the most cost effective sickle cell screening method among
infants.
The results obtained therefrom may help in the introduction sickle cell screening services
at district health centers for the control and management of sickle cell disease.
I am being requested to participate because I and my family members may be carrying
sickle cell gene and I am aware that if I chose to participate I or my infant/s may be asked
to donate a sample of blood.
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Procedures
I have understood that if I choose to participate in this study, I will be subjected to any of
the following procedures according to the state of my health.
I will be asked a few personal questions related to my health or my infants.
I am free to ask any relevant questions to the investigator.
My child or I may be examined physically
Blood sample may be taken from me or my infant/s.
I may be involved in a later part of the study for assessment
Risks and disorders.
I am aware that asking questions and examining me or my child physically will cause no
harm or discomfort to me or them.
When drawing blood from me or my child, I or my child may feel pain at site of puncture
but I have appreciated that pain will be slight and the risk of bleeding is negligible.
In the unlikely invent of any complications directly related to taking blood, the local
medical officer in charge of health center shall be available for assistance and shall
inform the researcher.
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I have understood that the findings from the study may help establish sickle cell disease
screening services at health centers in the districts of Uganda. I am participating at my
own free will and I will not ask for payment
Consent
I have been asked to participate in the above study and I give my free consent by signing
this form. I understand that:
1) My consent to participate is voluntary and I may withdraw from the study any
time I wish to do so.
2) I have understood the information that has been given to me about the study in my
vernacular and I have had all my questions answered to my satisfaction.
3) I am further aware that information I give will be treated in a confidential manner
and I will not be personally identified with the information.
4) A member of the team may examine me or my infant/s physically and I am aware
that examining me or my infant/s physically will cause no harm or discomfort to
me or them.
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5) Blood samples may be taken from me or my infant/s, I or my infant/s may feel
pain at the site of puncture but I will appreciate that the pain will be slight and the
risk of bleeding will be negligible.
6) In the unlikely event of any complications directly related to taking of blood, the
local medical officer in charge of health center unit will be available for
assistance.
………………………………………
………………………………….
Thumb/Signature of the participant
Signature of interviewer (Researcher)
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Appendix (iv)
LABORATORY RESULT FORM
Date…………………District…………………….……Sub-county……………………………..
Village…….………………………………..Health center………………………………………..
Study No…………….. Sex……….Age………Time of taking blood sample………….….……..
Sample taken by……………………………….
Received by ………………………………
I/C Health center
Researcher
Received in Laboratory: Time………………………..Date…………………………………..
Lab No:………………………………………….
Results:
Sickling
Solubility
Peripheral blood film
Hb Electrophoresis
.
The results were recorded in the columns as either positive (+ve) or negative (-ve).
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Appendix (v)
Sickling method (Metabisulphite protocol) adopted after Barbara and colleagues 54.
Requirements
Sodium-metabisulphite, slides, wet chamber and microscope. The sodium metabisulphie
was prepared as described by the manufacturer.
Principle
When a drop of blood is mixed with Sodium metabisulphite, the oxygen will be removed
from the red blood cells resulting into their sickling if the person is a sickler or sickle cell
trait.
Protocol
1). 20 micro liters of blood was placed at the center of the of a slide
2). 20 micro litres of sodium-metabisulphite was added without allowing
air bubbles to form.
3. The coverslip was lowered on to the glass slide and ringed around using
condle wax.
4). The slide was then supported by two sticks or glass rods on a wet
chamber ( petri-dish with wet filter paper or soaked cotton wool placed
inside) and left to stand at R/T for 15 min and examined under the
microcope using x 40.
5). The slide was re-examined after 1 hr and 2 hours respectively.
6). The results were interpreted as positive when sickle cell count was
more than 2% of the total cell count.
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Appendix (vi)
Solubility test method adopted after Barbara et al;.54.
Requirements: Buffer, Sodium dithionite, slides and microscope.
The buffer pH 7.1 and working solution of sodium dithionite were prepared as described
by the manufacturer
Principle
This is a qualitative method which determines the presence of haemoglobin S by turbidity
formation. Its principle is based on the immediate lysis of the red blood cells by saponin
and deoxygenation of the haemoglobin tetramers by diothinate resulting into lateral
displacement of the beta S globin chains. This leads to the interaction of tetramers to
form microfilaments which form microcables which finally form nematic liquid crystals
characteristic of turbidity. These crystals disperse light and obscure the black lines during
examination. Where as the normal heamoglobin AA and AF remain un affected.
Protocol
1). 0.02 mls of blood was added to 2 ml of 0.01% Na dithionate in a test tube and mixed.
2). The mixture was left to stand at room temperature (R/T) for 3-5 minutes and
examined using good light against background of dark lines.
3). The turbidity was suggestive of either As or SS when the dark lines were not clearly
seen and the clearity was suggestive of Hb AA, A2 or AF.
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Appendix (vii)
Peripheral blood film method adopted after Barbara et al;129.
Requirements:
Giemsa stain, paateur pipette (droper), buffer pH 6.8. The Giemsa stain and buffer were
prepared according to manufactures instructions.
Principle
When the blood film is fixed in methanol and stained by Romanowisky stain, the red
blood cells stain pinkish. If sickled red cells are present, then they will be seen as pinkish
stained sickled cells under the microscope at high power magnification (x100 objective).
Preparation and fixation of blood film.
a) The thin film was quickly made by evenly spreading a small drop of blood on a
clean (grease free) slide and left to dry.
b) The film was then fixed in methanol or ethanol alcohol for 2-3 minutes.
Staining protocol
1) The blood film was immersed in Giemsa stain diluted with two parts of buffered
water at Ph 6.8 to one part of stain and left to stain for 10-15 minutes.
2) It was then washed in buffered water and left to dry.
3) The film was finally examined under the microscope using oil immersion
objective
The results were interpreted as positive when sickle cell count was more than 2% of
the total cell count.
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Appendix (viii)
Hb electrophoresis cellulose acetate method adopted after Junius et al;130.
Requirements
Titan Power supply, Electrophoresis tank, Sample plates and applicators, plastic holder
for CAM, Plastic pots for soaking CAM and fixing bands, test tubes preferably 3 x 0.5
inch, plastic pasteur pipettes with bulbous ends, what man No 1 filter paper sheet for
blotting, plastic peg racks for tubes, scissors, small forceps. 5% Ponceau Red, Barbital
Tris Buffer buffer pH 9.2, 5% acetic acid, distilled water and normal saline.
Preparation of the reagents
Some of the reagents were prepared according to manufactures guidelines.
a) Barbital Tris Buffer pH 9.2 : Weigh 10.3 grams of Sodium Barbita, 1.84 grams of
Barbital and 7.2 gramms of Tris. Dissolve all of them in 1000 L of distilled water.
b)
5% Ponceau Red : Was made by weighing 50 grams of Ponceau Red powder and
dissolved in 1000 ml of distilled water.
c) Colour contrast: 5% acetic acid, which was made by adding 5mls of acetic acid to 95
mls of distilled water.
Principle
The principle of the method is based on the fact that proteins normally have either
positive or negative charge that is determined by the charged amino acid they contain. If
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the electric field is applied to a solution containing protein molecules, positively charged
proteins will move to the cathode and negatively charged proteins will migrate to the
anode. Using this principle, different haemoglobins will separate and migrate at different
rates depending on their size and shape. They are then stained and their bands compared
with the known controls.
Protocol
1) First the cellulose acetate strip was soaked in Tris buffer for a minimum of 15
minutes to soften it.
2) The blood was span at 4000 revolutions per min (rpm) for 5 min to separate the
plasma from red blood cells (The samples whose plasma had already separated, were
not centrifuged).
3) The plasma was pooled and the red blood cells were then washed by adding 1 ml of
normal saline to the cells and centrifuged as per above for two times.
4) Red blood cells were haemolysed to get haemoglobin by adding a few mls of distilled
water to the tubes and then shaken.
5) 20 micro mls of haemoglobin were placed in each well.
6) The cellulose acetate membrane strip (CAM) was removed from buffer, blotted
using filter paper.
7) The strip was then made securely firm on strip stand or aligning base.
8) Using sample applicators, the test samples which included positive control were
lined up into cellulose strip.
9) The CAM was then lowered down into an electrophoretic tank and power supply was
adjusted to 200 volts and switched on and left to run until the bands had clearly
- 215 -
separated (Excess running was avoided to minimize over running and destroying the
bands)
10) The bands were then stained in Poncaeu Red for 5 min.
12) Excess Poncaeu Red was washed off with 5% acetic acid until the bands were
distinctively clear red against unstained background.
13) The Hb bands of the test samples were then compared with control bands.
The results were interpreted according to the marching of the test bands and control
bands.
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