Association of Patient Enrollment in Medicare Part D With Outcomes After Acute Myocardial Infarction

Abstract

Background— Little is known about whether enrollment versus nonenrollment in Medicare’s prescription drug plan (Part D) is associated with better outcomes after acute myocardial infarction (AMI). Methods and Results— Using Medicare records linked to Acute Coronary Treatment and Intervention Outcomes Network Registry–Get With The Guidelines, we identified 59 149 Medicare beneficiaries (age ≥65 years) discharged after AMI between January 2007 and December 2010. We described trends in Medicare Part D enrollment, and compared the following 30-day and 1-year outcomes: all-cause death, all-cause readmissions, and major adverse cardiac events (a composite of all-cause death or readmission for AMI or stroke) between Part D enrollees and nonenrollees, after adjustment for patient and hospital factors. From 2007 to 2010, 29 264 (49.5%) patients with AMI enrolled in Medicare were also participating in Part D by hospital discharge. All-cause 30-day death was more common among enrollees versus nonenrollees (4.0% versus 3.3%), but this difference was not statistically significant after multivariable adjustment (adjusted hazard ratio, 1.06 [95% confidence interval, 0.97–1.17]). Enrollees also had higher unadjusted risks of 30-day all-cause readmissions or major adverse cardiac events, and 1-year mortality, all-cause readmissions, or major adverse cardiac events, but these were attenuated after multivariable adjustment. Adherence to key secondary prevention medications (statins, β-blockers, angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, and P2Y 12 antagonists) remained low (range, 55%–64%) at 1 year post discharge among Part D enrollees. Conclusions— Only half of Medicare-insured patients with AMI were enrolled in Part D by hospital discharge, and their 30-day and 1-year adjusted outcomes did not differ substantially from nonenrollees. There remain opportunities for improvement in medication adherence among patients with prescription drug coverage.