Cases and Rates in 1991
•
•
•
•
Table 6
Population: ?
New SM +: N = 8,507
All Cases: N = 10,903
Table 8
Population: ?
New SM +: N = 8,835
All cases: N = 10,872
Table 7
Population: 8,904,395
• New SM +: N = 8,103
• Rate = 91/100,000
• All Cases: N =11,036
• Rate = 123/100,000
Rate SM + : 220 - 20
Rate All
: 276 - 26
Cases and Rates in 2009
•
•
•
•
•
N SM +: N = 17,863
Rate N SM + = 133/100,000
All forms: N = 38,770
Rate All forms: 289/100,000
Source cases: Page 9 R10 proposal
45000
NOTIFICATIONS ASIAM 1982-2008
40000
35000
30000
ALL FORMS
25000
20000
15000
10000
SMEAR POSITIVE (N+R)
5000
0
1
3
5
7
9
11
13
15
17
19
21
23
25
27
300
NOTIFICATIONS/100,000 ASIAM 1982-2006
NOTIFICATIONS/100,000 ASIAM 1982-2008
250
ALL FORMS
200
ALL FORMS
150
100
SMEAR POSITIVE (N+R)
SMEAR POSITIVE (N+R)
50
0
1
3
5
7
9
11
13
15
17
19
21
23
25
27
Average Prevalence 1981-1989
Table 5:
• Survey population: N = 71,398
• Smear-positive cases: N = 374
• Prevalence smear-positive cases
= 520/ 100,000 population
Note:
Table 4: ARI in 1970 between 4.7 and 2.7 !!
Prevalence in 2001
•
•
•
•
SM+: 270/100,000
Cult+: 902/100,000
CDR SM +: 124/270 = 46%
Trend of prevalence:
520 (81-89) > 270 (01)
True decline or unreliable survey data?
Conclusions
•
•
•
•
•
The TB problem is still serious as:
Notification rate SM+ = 91/100,000 in 1991
(74% of all cases are new smear-positive)
Notification rate SM+ = 141/100,000 in 2000
Prevalence rate of SM+ 81-89 = 520/100,000
Prevalence rate of SM+ 2001 = 270/100,000
HIV + TB: 2.5% in 95 > 8.9% in 2000 > 10.3 in
2001
Observations
• Trend of notifications 82-91 is inconclusive
• New SM+ notification rate in 1991< 20% of
SM + prevalence rate (1981-1989)
• Rate SM+ ranges from 220/100,000 in
province 1 to 17/100,000 in province 17
• 20% of cases are registered in the capital
• 36% of cases in the capital are > 54
Observations
• Trend of notifications 92-2004 steady
increase
• DOTS introduced in 1994
• In 2004 ~ 50% of prevalent cases detected
• Still considerable differences between
provinces
• TB problem increasing due to HIV
Final Conclusions
• The TB problem in Asiam is serious
• The NTP in Asiam detects only 50% of the
prevalent cases
• Case-detection in a number of provinces is
very low
• How to increase coverage and detection?
Problem description and Situational analysis
• TB prevalence survey data
• Tuberculin survey data: prevalence of
infection with M.tuberculosis
• Case notifications recent and past years
• Age, Gender, Area differences
• Rates and trend
• Drug resistance survey data
• HIV prevalence, incidence and trend
Conclude:
• Size of TB problem: High, medium, low?
High: > 50 new sm+ cases/100,000 per yr.
Low: < 10 new sm+ cases/100,000 per yr.
• Trend: Increase, decrease, stable?
• Program coverage: % of districts?
Estimate number of expected TB notifications
for each year during plan period! (3 to 5years)
Block 5
1. 8,507/38,868 = 22% (see table 6, set I)
3. 93/171 centers = 53% (see table 10, set I)
4. 38,868 x 3 = 116,604 : 260 = 448 : 93 = ~ 5
(4.8)
5. 9,000,000 : 100,000 = 90 x 520 = 46,800 x 35%
= 16,380 x 30 = 491,400 : 260 = 1,890 : 93 =
20,3
Yes the number is sufficient
Block 5
6. Positive suspects 33.6% (2002 review, 18)
7. 141 microscopy centers (2002 review, 14)
8. 15,640 : 33.6 x 100 = 46,548 x 3 =
139,642 : 260 = 537 : 141 = ~ 4 (3.8)
9. 12,014,000 : 100,000 x 270 = 32,438 x
70% = 22,706 x 30 = 681,194 : 260 =
2,620 : 141 = 18,6
160,000
30
suspects
140,000
25
120,000
20
100,000
80,000
15
sputum positivity rate
60,000
10
40,000
smear positive cases
20,000
5
% population examined
0
0
1
2
3
4
5
6
7
8
100
sputum positivity rate
10
1
1
2
3
4
5
6
7
proportion of population examined
by direct microscopy
0.1
8
Population examined and positiv e suspects
1980-1991 (table 6, data set I)
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
25
20
15
10
5
0
1980
1982
1984
1986
% of population examined
1988
1990
% of suspects positiv e
RESULTS OF DIRECT MICROSCOPY
IN DISTRICT X FROM 1997 TILL 2001
year Suspects Positive
%
% of
examined suspects positive population
suspects examined
1997
1998
1999
2000
2001
80
172
230
580
393
22
32
24
20
24
27.5
18.6
10.4
3.5
6.1
0.12
0.27
0.35
0.82
0.56
Positive
suspects
per
100,000
population
33.8
50.2
36.4
28.2
34.2
Relation between positivity rate and %
population examined
1000
100
suspects examined
positive suspects
10
positivity rate
1
0.1
% population examined
PARAMETERS FOR PLANNING THE MICROSCOPY
NETWORK
• Expected number of smear-positive cases
• As a rule one centre per 100,000 population
if case-notification rate of smear + cases =
50/100,000
• 3 smears per suspect
• Number of smears per technician per day:
Not more than 20
• Minimum requirement one positive case per
week per reader in view of proficiency
PARAMETERS FOR PLANNING THE MICROSCOPY NETWORK
• Workload and smear-positivity rate (SPR):
SPR 20% = 1 positive case per 5 suspects =
15 smears to diagnose one sm+ case
SPR 5% = 1 positive case per 20 suspects =
60 smears to diagnose one sm+ case
• Screening of suspects by X-ray?
• Number of existing microscopy centres
• Available technicians and available time for
direct microscopy per centre
Conclude:
• Number of microscopy centres sufficient or
not? If not how many more needed?
• Available technicians and time sufficient or
not? If not train and employ more or ensure
more time of available technicians
• Calculate need for microscopes, slides,
cups, reagents, slide boxes, laboratory
equipment, immersion oil, etc.
External Factors Influencing
Smear-Positivity Rate
• Prevalence of Tuberculosis in community
• Prevalence of other conditions causing a
chronic cough
• Patients delay/doctors delay
• Selection of suspects
• Active CF surveys
Duration of cough as criteria
Screening of suspects by X-ray
Laboratory Factors Influencing
Smear-Positivity Rate
False Positive Results
Acid Fast Particles other than TB bacilli
Food particles
Precipitated stains (filter, use fresh stains)
Saprophytic acid-fast bacilli (distilled water)
Spores, fibers, pollen
Scratches on slide (always use new slides)
Contamination
Laboratory Factors Influencing
Smear-Positivity Rate
False Negative Results
Inadequate sputum collection
Selection of particles from sputum
Inadequate storage of sputum specimens and
stained smears
Inadequate preparation of smears or staining
of slides
Inadequate examination of the smear
Laboratory Factors Influencing
Smear-Positivity Rate
False Negative Results
Administrative errors
Reading errors
Time spend on reading
Work load
Lab
Diagnosis Follow up
serial
number
x
x
x
1
2
+
+
3
Neg Neg Neg
x
Neg
x
+
Neg
+
+
Indicators to evaluate microscopy
using the laboratory register
• % of population in the district examined per
year by direct microscopy =
suspects in the register (one year)
-------------------------------------------- x 100
population of the district in that year
• Value: 0.6 to 0.9 (Note:Vietnam data)
Indicators to evaluate microscopy
using the laboratory register
• Distribution of positive smear results
80-85% of positive cases show positive in the
first smear
Few (~ 5%) positive cases show positive in
the third smear only
This distribution should normally appear in
the laboratory register, if not this should be
investigated
Indicators to evaluate microscopy
using the laboratory register
• Smear-positivity rate:
N suspects with positive smear
result(s) during a quarter or year
--------------------------------------- x 100
N suspects examined during
a quarter or year
• Value usually observed: 5 to 15%
Indicators to evaluate microscopy
using the laboratory register
• % of suspects with three smear results
N suspects with 3 smear
result(s) during a quarter or year
--------------------------------------- x 100
N suspects examined during
a quarter or year
• Value: Target 100%.
Observed in good programs 85-90%
Further use of laboratory register
• Calculation of proportions of suspects by
Gender
Age-groups
Distance to microscopy centre
• Time between first examination and
diagnosis
• Number of examinations per day/ month
• Requirements of slides and materials
Link with TB register
• Serial number of laboratory book in TB
register and TB registration number in
laboratory register
• Are all diagnosed SM + cases (new and
previously treated) put on treatment?
• Average time between diagnosis and start of
treatment
• % of negative suspects put on treatment
Case of tuberculosis
• A definite case of TB, or one in which a
clinician has diagnosed TB and has decided
to treat the patient with a full course of TB
treatment
• Note: Any person given treatment for
tuberculosis should be recorded
A definite case of tuberculosis
• Patient with positive culture or positive
LPA test for the Mycobacterium
tuberculosis complex
• In countries where culture is not routinely
available a patient with one or more initial
sputum smears positive for acid fast bacilli
(AFB+) is also considered a definite case
Smear positive pulmonary case
• At least one initial sputum smear
examination (direct smear microscopy)
with at least one AFB provided that
there is a functional EQA system with
blind rechecking
STAG 2007
New definition of smear-positive PTB
One smear
with at least
one AFB
in 100 fields
Smear-negative pulmonary case
Sputum smear-negative, but culture positive
At least 2 sputum specimens at the start of
treatment with functional EQA, high
workload and limited human resources
Sputum culture should be performed in
settings where HIV > 1% in pregnant
women or > 5% in TB patients
Smear-negative PTB case (B)
Decision by a clinician to treat with a full
course of anti-TB therapy
X-ray suggestive for active TB and patient is
HIV+ (laboratory or clinical evidence)
X-ray suggestive for active TB and no
improvement after antibiotics in HIVnegative patients
STAG 2007
New definition of smear-negative PTB
When two smears are negative
follow algorithm
for the diagnosis of
smear-negative tuberculosis
Extra-pulmonary case
• Patient with tuberculosis of organs other
than the lungs e.g. pleura, lymph nodes,
abdomen, genito-urinary tract, skin, joint
and bones, meninges
• Note: a patient diagnosed with both
pulmonary and extra-pulmonary
tuberculosis should be classified as a case of
pulmonary tuberculosis
EPTB
• Diagnosis of EPTB should be based on one
culture positive specimen, or histological or
strong clinical evidence consistent with
active extra-pulmonary disease, followed by
a decision by a clinician to treat with a full
course of anti-tuberculosis chemotherapy
New Case
• Patient who has never had treatment for
tuberculosis, or who has taken antituberculosis drugs for less than one month
Previously treated case
•
•
•
•
•
•
Received 1 month or more anti-TB drugs
May be smear-positive or –negative
May have TB at any site
Further defined by treatment outcome:
Relapse, Failure and Default
Note: classification “Chronic” stopped
Indicators for quality of Diagnosis
• Proportions of New SM +, SM - and EPTB
depend on efficiency of CF and diagnostic
methods used
• Proportions reported by well organised
NTP’s are:
60-70% New smear-positive PTB
20-30% New smear-negative PTB
10-20% New EPTB
Indicators for quality of Diagnosis
• Ratio New SM +/New SM- PTB
N new smear-positive TB cases
--------------------------------------N new smear-negative TB cases
• Value: normally 2 to 2.5, but often lower in
high HIV prevalence countries
• Minimum acceptable level 1 to 1.5
Indicators for quality of Diagnosis
• In high HIV-prevalence countries the
proportion of EPTB may be higher due to a
higher frequency of Pleural Effusions and
miliary TB
• Diagnosis of EPTB depends further on
clinical capacity, preferences of clinicians
and focus on childhood TB
Indicators for quality of Diagnosis
• A SM+/SM- PTB ratio of <1 may indicate
that SM- cases are diagnosed without
microscopy (X-ray and clinical diagnosis)
• The proportion of relapses: should be < 57% of all cases reported or less than <10%
of new smear-positive cases reported
• A high proportion of previously treated
cases is an indication of poor program
and/or poor private sector performance
Block 8: Strategies for DOT
•
•
•
•
•
Population 2000: 12,014,000 (table 3. set II)
Cases detected: 18,892 (table 3. set II)
HC’s: 90% x 632 = 569 (table 7. set II)
Area Asiam: 181,035 sq.km. (table 1. Set II)
Area 5 km radius = 3.14 (π) x 5 km² = 78,5
x 569 = 44,667 : 181,035 x 100 = 25%
(30% if 115 hospitals also provide A-Dots)
• Beds: 18,892 x 75% = 14,169 : 6 = 2,362
• (19 to 21 beds per hospital: 2,362 : 115)
Advantages of SCC
•
•
•
•
Lower case-fatality (high sterilising effect)
Lower relapse rate (role of pyrazinamide)
Lower default rate (shorter duration)
Intermittent (3 x per week or on alternating
days) as effective as daily treatment
• Effective in HIV+ TB cases (only daily!)
• DOT is essential to prevent R resistance
Intensive phase
• Sterilizing phase to reduce the bacillary
load as quick as possible
• Always treat with combination of at least 3
drugs to prevent development of resistance
• Recommended by WHO: 2EHRZ
• EHRZ FDC tablets have been developed in
recent years
Continuation phase
• Maintenance phase to take care of dormant
bacilli (persisters)
• Always treat with at least 2 drugs
• Duration defined by relapse rate in sensitive
patients
• 2RH > 15% relapse rate
• 4RH < 5% relapse rate
Consider how to ensure DOT
• Hospitalise patients during intensive phase?
Consider costs for health service, patients
and availability of beds
• Ambulatory treatment at PHC facilities?
Consider feasibility in view of access
• Community based DOT?
Consider presence of volunteers and costs
of training and supervision of volunteers
Decide:
• Using Fixed Dose Combination tablets
(ERHZ) or (RHZ) instead of loose
formulations?
• Using blister packs?
• Consider costs, logistics, training of staff
and revision of guidelines
What is cohort analysis?
• A cohort: A group of patients diagnosed and
registered for treatment during a given time
period usually one quarter of a year
• Cohorts are defined by: period, type of TB,
type of treatment, age, gender, income, etc
• Cohort analysis: Evaluation of treatment
outcome when all patients in the cohort
have finished treatment and results are
collected
Treatment outcome: Cure rate
• Initially smear-positive patient who has a
smear negative result in the last month of
treatment, and on at least one previous
occasion
• Value: > 85% in low HIV prevalence
countries, > 80% in high HIV prevalence
countries
• A high cure rate is the result of a
combination of low other outcome rates!!
Treatment outcome:
Treatment completion rate
• Patient who completed treatment but does
not meet the criteria for cure or failure
• Depends essentially on the proportion of
patients producing sputum during the last
month of treatment and the efficiency of
sputum collection.
• Value: Not well established!
• Observed: 5-15% of patients, which finish
treatment
Treatment outcome:
Treatment success rate
• Total of cure and treatment completion rate
• WHO: “Successfully treated”: Essentially a
rate showing the effectiveness of caseholding
• Operational indicator: At least 85-90% of
cases, which complete treatment should
have a final smear result shown in the
register (Indicate no sputum obtained in
cases which can not produce sputum!)
Treatment outcome: Death rate
• Proportion of patients who die while on
treatment, irrespective of the cause
• Factors: Severity of disease at time of
diagnosis (diagnostic delay!), initial
resistance, type of regimen, age, immunity,
HIV status, adherence to treatment.
• Value: with SCC 1-3% , but in high HIV
prevalence countries 5-15%!!
Treatment outcome: Failure rate
• Smear-positive patient who remained
smear-positive, or became smear-positive
again, at least 5 months after the start of
treatment
• Factors: Initial resistance, type of regimen,
treatment adherence
• Value: In new patients on SCC < 1-2%. In
relapse case on retreatment < 3-5%. Other
previously treated cases on retreatment?
Treatment outcome:Default rate
• Interrupted treatment rate: Patient who did
not collect drugs for 2 months or more at
any time after registration
• Most important case-holding indicator!
• Influenced by multiple factors!
Accessibility and acceptability of DOT
services: distance, clinic hours, attitude of
staff, waiting time, privacy, support, control
Treatment outcome: Default rate
• Patient perspective: convenience, costs, loss
of income, side effects, well being after
initial treatment, awareness about treatment,
availability of drugs, duration of treatment,
support, attitude of community, intercurrent
events
• Value: Target 0%!
• Good performance < 5%
Treatment outcome:
Transferred out rate
• Patient who was transferred to another
reporting unit and from whom treatment
results are not know
• Depends essentially on mobility of patients
and capacity of NTP to retrieve results of
transferred patients
• Value: Not defined! Preferably < 5%
• Future: Electronic register?