title: Optimal use of available claims to identify a Medicare population free of coronary heart disease.
abstract: We examined claims-based approaches for identifying a study population free of coronary heart disease (CHD) using data from 8,937 US blacks and whites enrolled during 2003-2007 in a prospective cohort study linked to Medicare claims. Our goal was to minimize the percentage of persons at study entry with self-reported CHD (previous myocardial infarction or coronary revascularization). We assembled 6 cohorts without CHD claims by requiring 6 months, 1 year, or 2 years of continuous Medicare fee-for-service insurance coverage prior to study entry and using either a fixed-window or all-available look-back period. We examined adding CHD-related claims to our "base algorithm," which included claims for myocardial infarction and coronary revascularization. Using a 6-month fixed-window look-back period, 17.8% of participants without claims in the base algorithm reported having CHD. This was reduced to 3.6% using an all-available look-back period and adding other CHD claims to the base algorithm. Among cohorts using all-available look-back periods, increasing the length of continuous coverage from 6 months to 1 or 2 years reduced the sample size available without lowering the percentage of persons with self-reported CHD. This analysis demonstrates approaches for developing a CHD-free cohort using Medicare claims.
authors.forename: Shia T
authors.initials: ST
authors.lastname: Kent
authors.forename: Monika M
authors.initials: MM
authors.lastname: Safford
authors.forename: Hong
authors.initials: H
authors.lastname: Zhao
authors.forename: Emily B
authors.initials: EB
authors.lastname: Levitan
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Curtis
authors.forename: Ryan D
authors.initials: RD
authors.lastname: Kilpatrick
authors.forename: Meredith L
authors.initials: ML
authors.lastname: Kilgore
authors.forename: Paul
authors.initials: P
authors.lastname: Muntner
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D015982:Bias; D044383:Black People / Q000706:statistics & numerical data; D003324:Coronary Artery Disease / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D006278:Medicare; D008875:Middle Aged; D011159:Population Surveillance; D011446:Prospective Studies; D014481:United States / Q000453:epidemiology; D044465:White People / Q000706:statistics & numerical data; D001741:Black or African American
keywords: Medicare; algorithms; bias (epidemiology); coronary disease; epidemiologic methods