The Perinatal Periods
of Risk Approach
Phase 1 Analytic Methods
CityMatCH Training
August 25, 2007
Denver, Colorado
Workshop Objectives
During this session, participants will have the opportunity to:
•
•
•
•
Recognize and understand the PPOR approach
and its six stages
Learn how to assess “community readiness”
Learn how to assess “analytic readiness”
Understand what it takes to conduct the
first phase of analysis
Six Stages:
Perinatal Periods of Risk Approach
Stage 1: Assure Analytic and Community Readiness
Stage 2: Conduct Analytic Phases of PPOR
Stage 3: Develop Strategic Actions for Targeted
Prevention
Stage 4: Strengthen Existing and/or Launch New
Prevention Initiatives
Stage 5: Monitor and Evaluate Approach
Stage 6: Sustain Stakeholder Investment and
Political Will
DEFINITIONS
Traditional Infant Mortality Rate “IMR” is
deaths before first birthday, per thousand
live births
=deaths x 1,000 ÷ births
This can be done for any subpopulation, for
example, the White IMR would be white
deaths before first birthday, per thousand
white live births
Definitions
Ideally, we use a BIRTH COHORT,
count births in one year, and watch those babies until
they reach their first birthday (must wait until the end of
the following year ) to count deaths.
Often, we use a DEATH COHORT
count births
in one year, count deaths IN THE SAME YEAR. This is
an easy way to approximate the true mortality rate.
Infant Mortality Rate,
Urban County, 1990-2001
30.0
25.0
20.0
15.0
Black
10.0
White
5.0
0.0
0
9
19
2
9
19
4
9
19
6
9
19
8
9
19
0
0
20
2
0
20
4
0
20
Source: DHHS
What do PPOR analytic methods
bring “to the table”
The Importance of Fetal Deaths
One difference between PPOR and traditional analysis is that
PPOR includes fetal deaths, an important part of the picture.
Fetal and Infant Mortality Rates, 5 Urban Counties
7.9
Urban A
7.2
9.9
Urban B
6.1
7.1
Urban C
8.3
9.2
Urban D
5.7
8.5
Urban E
0
Fetal
Infant
8.9
5
10
15
20
PPOR Uses a Reference Group
• A subpopulation with optimal outcomes or
an external population
• Comparison of target population with
reference group helps target deaths that
could be prevented.
PPOR Examines Deaths in TWO
dimensions simultaneously:
• Age at death
• Weight at birth
The First Dimension Of PPOR Analysis:
Age at Death
Fetal
4 wks
Infancy
20 wks 28 wks
Spontaneous
Abortion
Early
Fetal
Late
Fetal
Postneonatal
Infant
Feto-Infant
Second Dimension: Birthweight
Birthweight
• Very Low Birthweight (PPOR limit)
= less than 1500 grams (3.3 pounds)
• Low Birthweight
= less than 2500 grams (5.5 pounds)
• Normal Birthweight
e.g., a 7.5-pound baby weighs 3,400 grams
PPOR ANALYTIC METHODS
Steps of Analytic Preparation
Acquire access to three required vital
records computer files
Prepare vital records files and required data
elements
Assess data quality
Assess study sample size
PPOR Analytic Preparation
• Fetal death certificate files (24+ wks, 500+ grams)
• Infant death certificate files (500+ grams)
• Live birth files (500 + grams)
• Linked birth—infant death certificate files are
needed to find birth information for the infants who
died
• Spontaneous and induced abortions are NOT
included (they are not given certificates)
Analytic Preparation—Number of Deaths
• At least sixty deaths overall and at least ten
deaths in each period of risk, for each
population being studied
• May combine UP TO 5 years to reach
adequate number of deaths (no more, due
to changes in medical practice)
• Phase 2 analyses require even more
deaths.
Analytic Preparation – Data Quality
• Serious bias is introduced if more than 5-10% of
births, deaths, and fetal deaths are missing key
data items such as birthweight, age at death,
and maternal characteristics.
• Imputation (educated guessing) can help when
key data are missing: e.g. if gestational age
>=31 weeks we impute birthweight >=1500
grams
Relationship Between Gestational Age
and Median Birthweight
3500
Infant Deaths
Fetal Deaths
3000
2500
2000
1500
1000
500
Gestational Age (Weeks)
39
37
35
33
31
29
27
25
23
21
19
17
0
Imputation I: Fetal Deaths
GA Unknown
BW Unknown
GA>=32
Y
BW>=1500
N
GA>=24
BW>=500
Y
500<=BW<1500
N
<500
<24
Y
GA >=24
Imputation II: Infant Deaths
GA Unknown
BW Unknown
GA>=31
Y
BW>=1500
N
GA>=22
N
<500
Y
N/A
500<=BW<1500
What is PPOR Analysis?
Analytic Phases of PPOR
Phase 1: Identifies populations
and periods of risk with the
largest excess mortality.
Phase 2: Explains why the excess
deaths occurred.
PPOR Maps Fetal & Infant Deaths
Age at Death
Birthweight
500-1499 g
1
2
3
1500+ g
4
5
6
PPOR Maps Fetal & Infant Deaths
Age at Death
Birthweight
Fetal
Death
500-1499
g
1500+ g
Neonatal
Postneonatal
Maternal Health/
Prematurity
Maternal Newborn
Care
Care
Infant
Health
PPOR is about ACTION
(each period of risk is associated with a set of possible areas for action)
Maternal
Health/
Prematurity
Preconception Health
Health Behaviors
Perinatal Care
Maternal
Care
Prenatal Care High
Risk Referral
Obstetric Care
Newborn
Care
Perinatal Management
Neonatal Care
Pediatric Surgery
Infant
Health
Sleep Position
Breast Feeding
Injury Prevention
PPOR Map of Feto-Infant Deaths
Urban County, All Races
2000-2002
35 Fetal Deaths
Maternal Health/ Prematurity
48
Maternal
Care
(fetal deaths)
83 Fetal
Deaths are
sorted into
two periods of
risk
PPOR Map of Feto-Infant Deaths
Urban County, All Races
2000-2002
62 Infant Deaths
Maternal Health/ Prematurity
(live births)
44
47
Newborn
Care
Infant
Health
(live births)
(live births)
Of the 23,199
Infants born
alive, 153
died. These
are sorted into
three periods
of risk
PPOR Map of Feto-Infant Deaths
Urban County, All Races
2000-2002
97
Maternal Health/ Prematurity
(35 fetal deaths, 62 live births)
48
44
47
Maternal
Care
Newborn
Care
Infant
Health
(fetal deaths)
(live births)
(live births)
236 FetoInfant Deaths
PPOR ANALYTIC METHODS
Steps of Phase 1
Define study population
Restrict study population by birthweight
and gestational age
Calculate numbers and rates for the fetoinfant mortality map
Compare different time periods,
subpopulations and geographic areas
Steps of Phase 1
Defining the Study Population
 Include mothers who are RESIDENTS
of the target area at the time of the
baby’s birth.
 Define the baby’s race/ethnicity
according to the mother’s.
 Include multiple gestations.
 Include congenital anomalies.
PPOR Map of Feto-Infant Deaths
Urban County, All Races
2000-2002
23,199 live
births
97
Maternal Health/ Prematurity
(35 fetal deaths, 62 live births)
48
44
47
Maternal
Care
Newborn
Care
Infant
Health
(fetal deaths)
(live births)
(live births)
153 died as
infants
83 fetal
deaths
Denominator
is 23,199 + 83
= 23,282
Calculating Feto-Infant Mortality Rate
Urban County, All Races
2000-2002
Maternal Health/ Prematurity
Rate=deaths x 1,000 ÷ births
=97 deaths x 1,000 ÷ 23,282
= 4.2
2.1
1.9
2.0
Maternal
Care
Newborn
Care
Infant
Health
4.2 + 2.1 + 1.9 + 2.0
= 10.1
Period rates
add up to
overall rate
(except for round-off
error)
PPOR Map of FetoInfant Mortality
Urban County, By Race, 2000-2002
(N=number of live births and fetal deaths)
White Fetal-Infant
8.6
Black Fetal-Infant
Rate =17.6
(N=3,291)
Rate =
(N=16,045)
8.8
3.1
2.0
1.9
1.6
White non-Hispanic
2.4
2.4
4.0
Black non-Hispanic
STOP HERE ANALYTIC EXERCISE
CALCULATE RATES
PPOR ANALYTIC METHODS
More Phase 1 Steps:
“THE GAPS”
 Select reference population
 Calculate excess mortality rates and
numbers of deaths
 Identify excess mortality gaps
PPOR Redefines Disparities,
Estimates “Opportunity” Gap
 ASK: Which women/infants have the "best" outcomes?
 ASSUME: all infants can have similar “best” outcomes
 CHOOSE: a comparison group(s) (‘reference group’)
who already has achieved “best” outcomes
 COMPARE: fetal-infant mortality rates in your target
group with those of the comparison group(s)
 CALCULATE: excess deaths (= target – comparison
groups). This is your community’s “Opportunity Gap.”
Reference Groups
Choose an easily defined optimal group
•At least 15% of the population
•At least 60 deaths
•Acceptable to the community
U.S. National Reference Group:
•20 or more years of age
•13 or more years of education
•Non-Hispanic white women
USA Reference Group 1998-2000
• Defined by maternal characteristics
– 20 or more years of age
– 13 or more years of education
– Non-Hispanic white women
– residents of the US at the time of baby’s
birth
2.2
1.5
1.1
1.0
Total FetalInfant
Mortality
Rate = 5.9
Calculating Excess Rates
Overall population Urban County, 2000-2002
(external reference group)
Urban
County
all
USA
Reference
Group
Maternal
Health/
Prematurity
Maternal
Care
Newborn
Care
Infant
Health
Fetal-Infant
Mortality
4.2
2.1
1.9
2.0
10.1
Maternal
Health/
Prematurity
Maternal
Care
Newborn
Care
Infant
Health
Fetal-Infant
Mortality
2.2
1.5
1.1
1.0
5.9
____________________________________________________________
Excess
Mortality
Rate
Maternal
Health/
Prematurity
Maternal
Care
Newborn
Care
Infant
Health
Fetal-Infant
Mortality
By Subtraction
2.0
0.6
0.8
1.0
4.3
Feto-Infant Mortality Rates
Racial/Ethnic subgroups of Urban County, 2000-2002
(external reference group)
Racial
Groups
Maternal
Health/
Prematurity
Maternal
Care
Newborn
Care
Infant
Health
Overall FetoInfant
Mortality
White,
nonHispanic
3.1
2.0
1.9
1.6
8.6
Black,
nonHispanic
8.8
2.4
2.4
4.0
17.6
Hispanic
and other
races
4.6
2.0
1.3
2.3
10.2
External
Reference
Group
2.2
1.5
1.1
1.0
5.9
Excess Feto-Infant Mortality Rates
Based on USA 1998-2000 reference group
Racial
/Ethnic
Groups
Maternal
Health/
Prematurity
Maternal
Care
Newborn
Care
Infant
Health
Feto-Infant
Mortality
White, nonHispanic
0.9
0.5
0.8
0.6
2.8
Black, nonHispanic
6.6
0.9
1.3
3.0
11.8
Other
Races
2.4
0.5
0.2
1.3
4.4
All
2.0
0.6
0.8
1.0
4.3
CALCULATING EXCESS NUMBER OF DEATHS
FROM Fetal-Infant Mortality Rates
using External Comparison Group
Urban County, 2000-2002
Racial/ Ethnic Group
Excess
Mortality
Rate
Live Births
and Fetal
deaths
Multiply
Number of
Excess
Deaths
White Non-Hispanic
2.8
16,045
2.8*16,045
1,000
=45
Black Non-Hispanic
11.8
3,291
11.8*3,291
1,000
=39
4.4*3,947
1,000
=17
4.3*23,282
1,000
=101
Other Race
All
4.4
4.3
3,947
23,282
Urban County by Race
2000-2002 estimated Excess Number of Deaths
based on external comparison group
Racial
/Ethnic
Groups
Maternal
Health/
Prematurity
Maternal
Care
Newborn
Care
Infant
Health
Feto-Infant
Mortality
White, nonHispanic
14
8
13
10
45
Black, nonHispanic
22
3
4
10
39
Other Races
9
2
1
5
17
46
13
18
25
101
All
ANALYTIC EXERCISE
CALCULATE EXCESS MORTALITY AND
ESTIMATE EXCESS NUMBER OF DEATHS
Feto-Infant Mortality Rates in the
Internal Comparison Group
(Best Outcomes in Urban County)
Urban County, 2000-2002
• Defined by maternal characteristics
–
–
–
–
20 or more years of age
13 or more years of education
Non-Hispanic White women
Residents of Urban County at time of
baby’s birth
2.4
2.2
1.8
1.0
Total Fetal-Infant
Mortality Rate = 7.4
Excess (Internal) Fetal-Infant Mortality
Rates
Overall population Urban County, 2000-2002
Urban
County
Internal
Reference
Group
Maternal
Health/
Prematurity
Maternal
Care
Newborn
Care
Infant
Health
Fetal-Infant
Mortality
4.2
2.1
1.9
2.0
10.1
Maternal
Health/
Prematurity
Maternal
Care
Newborn
Care
Infant
Health
Fetal-Infant
Mortality
2.4
2.2
1.8
1.0
7.4
____________________________________________________________
Excess
Mortality
Rate
Maternal
Health/
Prematurity
Maternal
Care
Newborn
Care
Infant
Health
Fetal-Infant
Mortality
By Subtraction
1.7
-0.1
0.1
1.0
2.7
Fetal-Infant Mortality Rates
Urban County, by Race,
Internal Comparison Group 2000-2002
Racial
Groups
Maternal
Health/
Prematurity
Maternal
Care
Newborn
Care
Infant
Health
Overall FetoInfant
Mortality
White,
nonHispanic
3.1
2.0
1.9
1.6
8.6
Black,
nonHispanic
8.8
2.4
2.4
4.0
17.6
Hispanic
and other
races
4.6
2.0
1.3
2.3
10.2
2.4
2.2
1.8
1.0
7.4
Internal
Reference
Group
Urban County by Race
2000-2002 Excess Fetal-Infant Mortality Rates
based on internal comparison group
Racial
/Ethnic
Groups
Maternal
Health/
Prematurity
Maternal
Care
Newborn
Care
Infant
Health
Feto-Infant
Mortality
White, nonHispanic
0.7
-0.2
0.1
0.6
1.2
Black, nonHispanic
6.4
0.2
0.6
3.0
10.2
Other
Races
2.2
-0.2
-0.5
1.3
2.8
All
1.7
-0.1
0.1
1.0
2.7
Urban County by Race
2000-2002 Estimated Excess Number of Deaths
based on internal comparison group
Racial
/Ethnic
Groups
Maternal
Health/
Prematurity
Maternal
Care
Newborn
Care
Infant
Health
Feto-Infant
Mortality
White, nonHispanic
10
-3
1
10
19
Black, nonHispanic
21
1
2
10
33
8
-1
-2
5
11
40
-3
2
24
63
Other
Races
All
PPOR is about impact and results:
•
•
•
•
•
•
•
Builds data and epi capacity
Promotes effective data use
Strengthens essential partnerships
Fosters integration with other key efforts
Encourages evidence-based interventions
Helps leverage resources
Enables systems change for perinatal
health
• Please remember to turn in your
evaluations !
Perinatal Periods of Risk:
For More Information:
www.citymatch.org
By looking at the numbers in a
new way, we can finally
understand fetal/infant mortality
and its common causes. Only
through understanding can we
take steps to ensure every child
gets a chance at life.
The Perinatal Periods
of Risk Approach
Phase 1 Analytic Methods
CityMatCH Training
August 25, 2007
Denver, Colorado
www.citymatch.org