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The Perinatal Periods of Risk

The Perinatal Periods of Risk. CityMatCH http://www.citymatch.org/. Maternal Health/ Prematurity. Maternal Care. Newborn Care. Infant Health. PPOR Maps Fetal & Infant Deaths. Age at Death. Fetal Death. Post- neonatal. Neonatal. Birthweight. 500-1499 g. 1500+ g.

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The Perinatal Periods of Risk

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  1. The Perinatal Periods of Risk CityMatCH http://www.citymatch.org/

  2. Maternal Health/ Prematurity Maternal Care Newborn Care Infant Health PPOR MapsFetal & Infant Deaths Age at Death Fetal Death Post- neonatal Neonatal Birthweight 500-1499 g 1500+ g

  3. PPOR analytic methods Analytic Preparation http://www.citymatch.org/PPOR/HowTo/Content/AnalyticReadinessWKSHOP.ppt • Acquire access to three required vital records computer files • Prepare vital records files and required data elements • Assess data quality • Assess study sample size

  4. PPOR analytic methodsPhase I:THE MAPShttp://www.citymatch.org/PPOR/HowTo/HowToDo.htm • Define study population • Restrict study population by birthweight and gestational age • Calculate numbers and rates for the feto-infant mortality map • Compare different time periods, subpopulations and geographic areas

  5. PPOR analytic methodsPhase I, continued: THE GAPS • Select reference population • Calculate excess mortality rates and numbers of deaths • Identify excess mortality gaps

  6. PPOR Analytic Methods— Phase 2 Analysis Explains why the excess deaths occurred so that appropriate action can be taken.

  7. Maternal Health/ Prematurity Preconception Health Health Behaviors Perinatal Care Prenatal Care High Risk Referral Obstetric Care Maternal Care Perinatal Management Neonatal Care Pediatric Surgery Newborn Care Sleep Position Breast Feeding Injury Prevention Infant Health PPOR is aboutACTION

  8. PPOR Analytic Methods — Three Phase 2 Directions • Community health and health systems assessment • Fetal Infant Mortality Reviews (FIMR) • Further epidemiologic study

  9. PPOR Analytic Methods— Phase 2 Analysis The third direction is the focus of this presentation: Epidemiologically investigate the reasons for excess mortality

  10. PPOR Analytic Methods— Steps of Phase 2 Analysis : • Identify causal pathways or biologic mechanisms for excess mortality • Estimate prevalence of risk and preventive factors by type of mechanism • Estimate the impactof the risk and preventive factors.

  11. PPOR Phase 2 AnalysesLimitations • Large number of deaths needed to obtain statistically significant because models are complex and effect sizes are small. • Unlikely to identify new causes because an observational study using vital records and existing data. • Unlikely to find a single cause for excess mortalitybecause the feto-infant mortality it is a multifactorial problem

  12. How can we most effectively determine the likely causes of excess deaths in our community?

  13. PPOR Phase 2 AnalysesStrategy • Eliminate factors unlikely to be contributing • Find and target factors likely to be contributing

  14. PPOR Phase 2 AnalysesStrategy A factor is a likely contributor if: • KNOWN cause of death based on scientific literature. • MORE PREVALENT among the population with excess deaths Impact analysis helps prioritize among likely contributors

  15. Phase 2 Analysis Plan Depends on: • Phase 1 Analysis results • Availability of data • Community priorities

  16. Phase 2 Analysis Plan Guidelines Developed for : • Infant Health • Maternal Health/Prematurity Recommendations for : • Maternal Care

  17. Phase 2 Analyses Preparation The DEATH CERTIFICATE is the source of • Age at death • Cause of death The BIRTH CERTIFICATE is the source for • Maternal characteristics & risk factors • Circumstances of the birth • Infant risk factors & conditions • Geo-coding (mother’s residence)

  18. Phase 2 Analyses Preparation of data for impact estimation • Use a birth cohort file of live births and fetal deaths with linked deaths. • Convert death cohort files to a single birth cohort file Combine linked • Add fetal deaths for the same year with a variable indicating the outcome.

  19. Preparation of data for impact estimationConverting 2000 and 2001 Period Files to a 2000 Birth Cohort File

  20. Preparation of data for impact estimationPortion of birth cohort data file

  21. Phase 2 Data Preparation • Other files can be also now be linked to the combined study file • If geocoded according to street address, census tract or zip code (e.g.), GIS analysis including neighborhood and community factors, census, crime, housing, etc.

  22. Phase 2 Analyses Preparation OTHER DATA SETS to consider: • Hospital discharge system • PRAMS • Birth defects surveillance • Pregnancy/Pediatric Nutrition Surveillance • Injury surveillance • STD reports • Child abuse reporting systems • Program files (Medicaid, WIC, etc) • Linked program files

  23. When linked to birth certificates,other datasets can be used to estimate the impact of risk factors on mortality.

  24. INFANT HEALTH PERIOD Protocol is on the web at http://www.citymatch.org/PPOR/HowTo/Content/PHAS2IH.doc

  25. Phase 2 Analyses-Infant Health PeriodIdentify causal pathways or biologic mechanisms for excess mortality • Use Underlying Cause of Death • Categorize by CDC’s Postneonatal Mortality Surveillance System • birth defects • infections • injuries • perinatal conditions • SIDS • other causes

  26. Phase 2 Analyses-Infant Health PeriodIdentify causal pathways or biologic mechanisms for excess mortality Infant Health Each category has its own set of risk factors SIDS Injury Infection Anomalies Perinatal

  27. Phase 2 Analyses-Infant Health PeriodIdentify causal pathways or biologic mechanisms for excess mortality Cause-specific mortality rate (CSMR) the number of deaths in each category number of live births>=1500g Excess Cause-specific mortality rate = Study Pop. CSMR – Ref. Pop. CSMR

  28. Phase 2 Analyses-Infant Health PeriodIdentify causal pathways or biologic mechanisms for excess mortality

  29. Example City Excess Infant Health Mortality Rate=0.712 per 1000 live births

  30. Passive smoke Sleep position Breast-feeding Bedding Co-sleep Maternal age Death scene investigation Folic acid intake Alpha-feto protein Alcohol Drug abuse Diabetes Ultrasound Delivery site Phase 2 Analyses-Infant Health PeriodEstimate prevalence of risk and preventive factors by type of mechanism SIDS Anomalies

  31. Medical home Immunizations Breast-feeding Passive smoke Prenatal care Maternal age Infection type Bedding Supervision Environment Injury type Phase 2 Analyses-Infant Health PeriodEstimate prevalence of risk and preventive factors by type of mechanism Infection Injury

  32. Estimate prevalence of risk and preventive factors by type of mechanism • SIDS—major contributor to excess deaths • Examine risk factor disparity for SIDS • Compare prevalence between study population to reference population • Denominator is all live births

  33. Phase 2 Analyses-Infant Health Period OTHER DATA SETS to consider: • Hospital discharge system • PRAMS • Birth defects surveillance • Pregnancy/Pediatric Nutrition Surveillance • Injury surveillance • STD reports • Child abuse reporting systems • Program files (Medicaid, WIC, etc) • Linked program files

  34. Phase 2 Analyses-Infant Health PeriodExample CityPrevalence of SIDS Risk Factors Among Live Births Study versus Reference Populations

  35. Phase 2 Analyses-Infant Health PeriodEstimate the impact of the risk and preventive factors Risk Ratio or Relative Risk • Probability of disease in the exposed population divided by the probability of disease in the unexposed population A/(A+B) RR= C/(C+D)

  36. Phase 2 Analyses-Infant Health PeriodEstimate the impact of the risk and preventive factors Population Attributable Risk Percent • Compares the rate for the whole population to the rate for those WITHOUT the risk factor • Based on the relative risk and the prevalence of the exposure for the whole population. • Has a meaningful interpretation: “Percent of the population that would be prevented from the poor outcome if the risk factor were eliminated from the entire population.” • Relevant to overall impact and cost.

  37. Phase 2 Analyses-Infant Health PeriodEstimate the impact of the risk and preventive factors Population Attributable Risk Deb Rosenberg recommends using the formula PAR = P0 – P2 Where P0 is the proportion of the whole population that have the bad outcome P2 is the proportion of those without the risk factor that have the bad outcome. The difference is interpreted as the proportion of bad outcomes that would be eliminated if no-one in the population had the risk factor. This is the proportion of bad outcomes that can be “attributed” to the factor.

  38. Phase 2 Analyses-Infant Health PeriodEstimate the impact of the risk and preventive factors Population Attributable Risk Percent (PAR%) PAR% = {P (RR-1) /1+P (RR-1)} x 100 • Where P = proportion of the population with a particular risk factor, and • RR = Risk Ratio(can substitute Adjusted Odds Ratio or RR from logistic regression or published literature)

  39. PAR Resources • http://www.soph.uab.edu/mch-imrm/stats.htm, • LEVIN 1953, Fleiss 1981 p76 • Calculator at : http://www.urmc.rochester.edu/cpm/education/mach/PARC.xls

  40. Phase 2 Analyses-Infant Health PeriodPAR% EXAMPLE: EXAMPLE INFANT MORTALITY ATTRIBUTABLE TO TEEN MATERNAL AGE • Example: • RR=1.998 • PAR%=8.94 If no teen births occurred, 8.94% fewer babies would die in Example. This translates to 17 fewer deaths, or a reduction in IMR from 6.2 to 5.7 per thousand live births.

  41. MATERNAL HEALTH / PREMATURITY PERIOD Protocol is on the web athttp://www.citymatch.org/PPOR/HowTo/Content/PHAS2MH.doc

  42. Phase 2 Analyses-Mat. Health/Prem. Identify causal pathways or biologic mechanisms for excess mortality Causes for 500-1,499g are • Multifactorial • Complex • Inconsistent • Varies by training

  43. Phase 2 Analyses-Mat. Health/Prem. Identify causal pathways or biologic mechanisms for excess mortality Kitagawa’s formula algebraically partitions excess mortality into 2 strata • portion to birthweight distribution • portion to birthweight specific mortality

  44. Phase 2 Analyses-Mat. Health/Prem. Identify causal pathways or biologic mechanisms for excess mortality Kitagawa Maternal Health/ Prematurity Birthweight Distribution Birthweight- Specific Mortality

  45. Phase 2 Analyses-Mat. Health/Prem. Identify causal pathways or biologic mechanisms for excess mortality • The Kitagawa Formula Where “P” stands for birthweight distribution (proportion of births in stratum n) And “M” stands for specific mortality (the mortality rate in stratum n) http://www.citymatch.org/PPOR/HowTo/Content/kitgawa_updated_98_00.xls (save the spreadsheet on your own computer)

  46. Contribution to Mortality Difference Pinellas County National Reference Group

  47. Contribution to Mortality DifferencePinellas County vs National Reference Group

  48. Feto-Infant Mortality Contribution to MortalityPinellas County vs National Reference Group Total Fetal Infant Mortality Maternal Health/ Prematurity Mortality

  49. Presenting kitagawa resultsKitagawa: Most Common Conclusion • “The predominant cause of death for VLBW babies is birthweight distribution: too many babies are born at very low weights. Our community will benefit most by preventing prematurity” • “Birthweight-specific mortality nearly matches that of the reference group. Babies born too small are surviving nearly as well as babies in the reference group.”

  50. Presenting kitagawa resultsKitagawa: Some cities have up to 40% of excess deaths in the MH/P period of risk due to birthweight specific mortality. • “Birthweight-specific mortality in our target group is not as good as it is in the reference group. Babies in that group that are born too small are not surviving as well as can be expected.”

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