pregnancy episode grouper: development, validation, and applications mark c. hornbrook, phd...
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Pregnancy Episode Grouper: Development, Validation, and Applications
Mark C. Hornbrook, PhDAcademyHealth Annual Research MeetingWashington, DCJune 9, 2008
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Research Team
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
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Funding
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”
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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
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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
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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 communityAutomated ambulatory medical record system linked to
administrative, encounter, financial, and clinical management information systems
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Over 2/3 of pregnancies ended in live birthand almost 1/3 in spontaneous or induced abortion
Livebirthscreateinpatientdeliveryrecords,birthcertificates,andhealthplanenrollmentrecords
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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
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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
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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
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Electronic Data Sources
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
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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
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Pregnancy Episodes Identified
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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
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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
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Elective Losses
Positive pregnancy test or diagnosis Therapeutic abortion procedure
Surgical Medical
No evidence of delivery within expected episode window
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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
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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
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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
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Pregnancies Missed by Algorithm (N= 24)
n = 511 women, 702 pregnancies
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Pregnancies Missed by MRAs (No. out of total of 38)
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Obstet Gynecol 2008;111:1089 95
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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
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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
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Most Common Maternal Morbidities byPregnancy Outcome
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Maternal Morbidities AmongLive Birth Pregnancies by Pay Source
0
5
10
15
20
Anemia UTI Pelvic/PerinealComplications
Mental HealthConditions
PostpartumHemorrhage
Perc
enta
ge
0
5
10
15
20
Anemia UTI Pelvic/PerinealComplications
Mental HealthConditions
PostpartumHemorrhage
Medicaid(n=4186) BHP(n=528) Commercial(n=12104)
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Am J Psych 2007;164:1515-1520
Article
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Percent of Women with Diagnosed Depression Before, During, and After Pregnancy
% ofWomen
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Percent of Women Diagnosed with Depression who Received Treatment Before, During, or After Pregnancy
% ofWomen
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Maternal Depression
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
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New Engl J Med 2008;358:1444-53
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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
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Pre-Pregnancy BMI and Hospital Days in Pregnancy
3.5 3.6 3.74 4.1
4.4
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
<18.5 18.5-24.9 25.0-29.9 30.0-34.9 35.0-39.9 40.0+
Days
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Pre-Pregnancy BMI and Ultrasounds in Pregnancy
3.5 3.7 3.94.4
5.4
7.5
0
1
2
3
4
5
6
7
8
<18.5 18.5-24.9 25.0-29.9 30.0-34.9 35.0-39.9 40.0+
Ultrasounds
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Pre-Pregnancy BMI and MD Visits in Pregnancy
4.3 4.4 4.6 4.85.4
6
0
1
2
3
4
5
6
7
<18.5 18.5-24.9 25.0-29.9 30.0-34.9 35.0-39.9 40.0+
Visits
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Pre-Pregnancy BMI and Dispensings in Pregnancy
3.6 3.64.1
4.9
6.3
7.7
0
1
2
3
4
5
6
7
8
9
<18.5 18.5-24.9 25.0-29.9 30.0-34.9 35.0-39.9 40.0+
Dispensings
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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
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Percent of Pregnancies with Confirmed Gestational Diabetes (GDM):1999-2006 Kaiser Permanente Northwest
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Percent of Clinician Orders and Percent of Completed Postpartum Glucose Tests
among Confirmed Gestational Diabetes-affected Pregnancies
9 10.3 10.817
46.9
57.8 56.450.3
15.9 16.7
28.5
41.5
7079.3 79.2
74
0102030405060708090
100
1999 2000 2001 2002 2003 2004 2005 2006
% Completed tests
% Clinician orders
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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
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Limitations of Pregnancy Grouper
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
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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