Who Enrolls in the Medicare Part D Prescription Drug Benefit Program? Medication Use Among Patients With Heart Failure

BACKGROUND Dispensing data from Medicare Part D standalone prescription drug plans are now available, but characteristics of enrollees with heart failure have not been well described. METHODS AND RESULTS We identified 81 874 patients with prevalent heart failure as of January 1, 2010, in a nationally representative 5% sample of Medicare beneficiaries. We classified patients according to enrollment in a Medicare Part D plan as of January 1, 2010. Demographic characteristics, comorbid conditions, and prescriptions were compared by enrollment status. A total of 49 252 (60.2%) were enrolled in a Medicare Part D plan as of January 1. Enrollees were more often women, black, and of lower socioeconomic status. Enrollees with heart failure more often filled prescriptions for loop diuretics than angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, β-blockers, or aldosterone antagonists. During the first 4 months of 2010, 5444 (12.3%) reached the coverage gap, and 566 (1.3%) required catastrophic coverage beyond the gap. CONCLUSIONS Medicare beneficiaries with heart failure differ significantly according to enrollment in Part D prescription drug plans and represent a population underrepresented in clinical efficacy trials. Many face the coverage gap, and few select Medicare Part D plans that provide coverage during the gap. Linking Medicare Part D event data with clinical registries could help to determine whether eligible enrollees are undertreated for heart failure.