In a study led by Dr. Shia T. Kent, postdoctoral fellow in the department of epidemiology at the University of Alabama at Birmingham, claims-based approaches for identifying individuals without coronary heart disease (CHD) were examined, using data from 8,937 American Blacks and Whites who were enrolled from 2003 to 2007 in a the REasons for Geographic and Racial Differences in Stroke (REGARDS) study linked to Medicare claims.
“Our goal was to minimize the percentage of persons with self-reported CHD at entry into a Medicare study, namely previous myocardial infarction or coronary revascularization,” says Dr. Kent. “We assembled six cohorts without CHD claims by requiring six months, one year, or two years of continuous Medicare fee-for-service insurance coverage prior to study entry and using either a fixed-window of Medicare claims prior to study entry or all-available claims. We examined using only claims for myocardial infarction and coronary revascularization, as well as additionally including other CHD-related claims.”
Using a six-month fixed-window of Medicare claims, 17.8 percent of study participants who did not have myocardial infarction or coronary revascularization claims reported having CHD; using all-available claims and additionally including other CHD claims, this was reduced to 3.6 percent. When using all available Medicare claims, increasing the required Medicare coverage length from six months to one or two years decreased the available sample size without reducing the percentage of subjects with self-reported CHD. The researchers determined that “[t]his analysis demonstrates approaches for developing a CHD-free cohort using Medicare claims.”
UAB co-investigators include department colleagues Mr. Hong Zhao, statistician; Dr. Emily B. Levitan, associate professor; and Dr. Paul Muntner, professor and vice chair; as well as Dr. Monika M. Safford, professor in the division of preventive medicine; Dr. Jeffrey R. Curtis, professor in the division of immunology and rheumatology; and Dr. Meredith Kilgore, professor and chair in the department of health care organization and policy.
“Optimal Use of Available Claims to Identify a Medicare Population Free of Coronary Heart Disease” was published online in October in the American Journal of Epidemiology.