Regional Variation in Medicare Part D Low-Income Subsidy Enrollment: Statin Adherence and Cardiovascular Hospitalizations

Tami C. Swenson, University of Minnesota

Objective: To explore metropolitan variation of Medicare Part D Low Income Subsidy (LIS) enrollment and to examine differences in adherence to cholesterol medications and in cardiovascular hospitalizations. Methods: The observational study design will provide a statistical analysis of the individual-level Medicare claims data that tests determinants of adherence and clinically-related hospitalizations. The administrative Medicare data used to measure the enrollment estimates and clinical outcomes is combined with Census data to construct population estimates for the LIS-eligible population in metropolitan areas based on income and poverty-level. Findings: Approximately 40 percent of Part D enrollees receive premium subsidies or cost-sharing from the LIS program. Enrollment in the LIS program based on potentially eligible populations varies considerably with UT and CT having the highest eligible enrollment and WI, KY, TN, and MS having the largest gap.