Pregnancy Episode Grouper: Development, Validation, and Applications

1. Pregnancy Episode Grouper: Development, Validation, and Applications Mark C. Hornbrook, PhD AcademyHealth Annual Research Meeting Washington, DC June 9, 2008

2. Reproductive Health Division, CDC Cynthia J. Berg, MD, MPH F. Carol Bruce, RN, MPHD William M. Callaghan, MD, MPH Susan Y. Chu, PhD Patricia M. Dietz, DrPH The Center for Health Research, KPNW Mark C. Hornbrook, PhD Donald J. Bachman, MS Rachel Gold, PhD, MPH Maureen C. O’Keeffe Rosetti, MS Kimberly Vesco, MD Selvi B. Williams, MD, MPH Evelyn P. Whitlock, MD, MPH Research Team

3. Contract # CDC 200-2001-00074, Task # MC2-02, “Extent of Maternal Morbidity in a Managed Care Setting,” from the Centers for Disease Control and Prevention America’s Health Insurance Plans administered this contract Contract # CDC 200-2006-17832, “Extent of Maternal Morbidity in a Managed Care Setting” Funding

4. Maternal Health • Over 6 million pregnancies in the US annually • Previously, hospitalizations used as proxy for morbidity • Today, we use a more comprehensive assessment of the incidence and prevalence of maternal morbidity • Changes in medical practice have led to more outpatient treatment for pregnancy complications • Medical informatics now frequently include computerized clinical and laboratory/pathology information systems

5. Objectives • Develop a pregnancy episode grouper algorithm using HMO electronic data warehouse • Identify all pregnancies occurring in HMO members during the study period • Identify each pregnancy’s outcome • Identify maternal morbidities occurring within pregnancy episodes • Estimate the prevalence of maternal morbidity in the study population • Develop research and quality improvement applications

6. Research Setting • Kaiser Permanente Northwest (KPNW), a non­profit, prepaid group practice HMO in the Pacific Northwest, with 475,000 members • Includes commercial, individual, Washington State Basic Health Plan, Medicare, and Medicaid enrollees • Demographically representative of the local community • Automated ambulatory medical record system linked to administrative, encounter, financial, and clinical management information systems

7. Over 2/3 of pregnancies ended in live birthand almost 1/3 in spontaneous or induced abortion Live births create inpatient delivery records, birth certificates, and health plan enrollment records

8. Episodes • Fundamental unit of measure for health care phenomena • Conceptual taxonomy • Health problem/illness episodes • Patient’s perspective on lived experience of health problem and related treatment • Disease episodes • Model of the natural course of a disease or health problem • Care Episodes • Clusters of utilization linked to a specific therapeutic problem/goal • Pregnancy • Quintessential episode—well-defined beginning and ending points and natural course

9. Episode Definition • Pregnancy = Interval between estimated date of LMP and eight weeks after delivery/pregnancy termination • Other potential specifications • Entire pregnancy episode may/may not have occurred within the observation period • Women had to be enrolled on outcome date or enrolled at any time

10. Methods • Diagnostic, treatment, laboratory, pharmacy, imaging, home health, and other databases searched for codes that could indicate pregnancy • Complex hierarchical decision rules to determine if a pregnancy occurred and, if so, the outcome and the date it began and ended

11. Hospital discharge abstracts Same-day surgery records Ambulatory encounter abstracts or electronic medical records Emergency department visits Pharmacy dispensings Outside professional & facility claims and referrals Imaging procedures Laboratory test results Home health visits Birth certificates Electronic Data Sources

12. Pregnancy End Date and Outcome • Retrospective, omniscient logic • Start at the end of the pregnancy because the data are most reliable, then work on the episodes with less data • Diagnostic and procedure codes and selected claims data, and their associated dates, indicate the outcome of pregnancy and when it ended

13. Pregnancy Episodes Identified

14. Ectopic Pregnancies • Medical termination • Rx = Methotrexate • Repeat pregnancy tests until hormone levels drop to pre­pregnancy levels • Surgical termination • Surgical procedure for removal of embryo • Repeat pregnancy tests until hormone levels drop to pre­pregnancy levels

15. Spontaneous Losses • Positive pregnancy test or diagnosis • Prenatal care encounters stop • No delivery/termination procedure • Many undetected if woman is not trying to get pregnant

16. Elective Losses • Positive pregnancy test or diagnosis • Therapeutic abortion procedure • Surgical • Medical • No evidence of delivery within expected episode window

17. Births • Live births • Delivery codes • Infant hospital discharge • Birth certificates • Addition of infant to family health plan contract • Stillbirths • Look at delivery codes, especially delivery complications • No birth certificate or infant utilization data available

18. Overlapping Episodes • Overlapping pregnancy episodes are medically impossible • Grouper algorithm has hierarchical logic to resolve implausible episode patterns • Select the most likely scenario and ignore the competing data

19. Algorithm Validation: Methods • Gold Standard = blinded medical records abstractors (MRAs) using actual electronic and hard-copy medical and billing records • Stratified sampling to obtain representation of all types of pregnancy outcomes

20. Pregnancies Missed by Algorithm (N= 24) n = 511 women, 702 pregnancies

21. Pregnancies Missed by MRAs (No. out of total of 38)

22. Obstet Gynecol 2008;111:1089­95

23. Definition:Maternal Morbidity • Any condition during a pregnancy episode that adversely affected women’s physical or psychological health • Condition are unique to, or exacerbated by, pregnancy • Used ICD-9-CM codes to classify morbidity into forty-six major categories • Clinically experienced authors reviewed all ICD-9-CM codes and developed a list of 46 major maternal morbidity disease classes

24. Results • Type of morbidity varied by pregnancy outcome • UTI common with all outcomes • Mental health conditions common with all outcomes, especially stillbirth • Anemia common with live/stillbirth • Infections common with stillbirth

25. Most Common Maternal Morbidities byPregnancy Outcome

26. Maternal Morbidities AmongLive Birth Pregnancies by Pay Source

27. Article Am J Psych 2007;164:1515-1520

28. Percent of Women with Diagnosed Depression Before, During, and After Pregnancy % of Women

29. Percent of Women Diagnosed with Depression who Received Treatment Before, During, or After Pregnancy % of Women

30. Depression before, during, or after pregnancy was common (15.4%) among women enrolled in KPNW Depression diagnosis did not vary substantially before (8.7%), during (6.9%), or after (10.4%) pregnancy, but the clinical specialty of where women were diagnosed did About 50% of women with depression before pregnancy relapsed during the postpartum period About 50% of women diagnosed with depression did not have any prior history during the study period Over 90% of women with diagnosed depression received treatment Anti-depressant use was common during pregnancy Depressed women were more likely than non-depressed women to receive Medicaid, to be unmarried, to have 3 or more children, to be white, and to have smoked during pregnancy Maternal Depression

31. New Engl J Med 2008;358:1444-53

32. Pregnancy and Obesity • Increasing maternal BMI is associated with greater utilization of health care, especially for pregnancies associated with more extreme obesity (BMI >35.0) • Almost all of this increase in utilization was related to the increased rates of cesarean delivery, gestational diabetes, diabetes mellitus, and hypertensive disorders among obese pregnant women

33. Pre-Pregnancy BMI and Hospital Days in Pregnancy

34. Pre-Pregnancy BMI and Ultrasounds in Pregnancy

35. Pre-Pregnancy BMI and MD Visits in Pregnancy

36. Pre-Pregnancy BMI and Dispensings in Pregnancy

37. Diabetes Screening • All pregnant women who receive prenatal care are screened for diabetes mellitus (DM) • DM first diagnosed in pregnancy is coded as Gestational Diabetes Mellitus (GDM) • All women with GDM should receive post-partum blood glucose screening • GDM increases risk of obesity in offspring

38. Percent of Pregnancies with Confirmed Gestational Diabetes (GDM):1999-2006 Kaiser Permanente Northwest

39. Percent of Clinician Orders and Percent of Completed Postpartum Glucose Tests among Confirmed Gestational Diabetes-affected Pregnancies

40. GDM Intervention • Adherence to GDM screening guideline varies widely by medical office within HMO • Intervention • Provider reminders to order FBS test • Patient reminders to obtain FBS test • Track noncompliant women and escalate reminders to patients and physicians

41. Missing or erroneous input data Coding errors Problems in rolling up billing records Pregnancies with little or no prenatal care Use of multiple healthcare systems Inconsistent pregnancy indicators Multiple providers: differing documentation styles Complex pregnancies with high utilization Close early losses Ectopic pregnancies and trophoblastic disease are inherently difficult to define Limitations of Pregnancy Grouper

42. Conclusions • Algorithm error rates are nearly identical to those for the MRAs (the gold standard) • Algorithm can be applied to very large datasets at low marginal cost and much below the costs of manual chart abstraction • Pregnancy-specific algorithm supports much more refined and, therefore, clinically meaningful episode classification