Disability, race/ethnicity, and medication adherence among Medicare myocardial infarction survivors.

Background: Long-term medication therapy for patients with post-myocardial infarction (MI) can prolong life. However, recent data on long-term adherence are limited, particularly among some subpopulations. We compared medication adherence among Medicare MI survivors by disability status, race/ethnicity, and income.

Methods: We examined 100% of Medicare fee-for-service beneficiaries discharged post-MI in 2008. The outcomes were adherence to β-blockers, statins, and angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers, for 1-year and 6-month postdischarge. Adherence was defined as having prescriptions in possession for ≥75% of days.

Results: Among aged beneficiaries who survived 1-year adherence to β-blockers were 68%, 66%, 61%, 58%, and 57% for whites, Asians, Hispanics, Native Americans, and blacks, respectively; among persons with disability, 1-year adherence was worse for each group: 59%, 54%, 52%, 47%, and 43%, respectively. The racial/ethnic difference persisted after adjustment for age, gender, income, drug coverage, location, and health status. Patterns of adherence to statins and angiotensin-converting enzymes/angiotensin II receptor blockers were similar. Among beneficiaries with close-to-full drug coverage, minorities were still less likely to adhere relative to whites: odds ratio 0.70 (95% CI 0.65-0.75) for blacks and odds ratio 0.70 (95% CI 0.55-0.90) for Native Americans.

Conclusions: Although β-blockers at discharge has improved since the National Committee for Quality Assurance implemented quality measures, long-term adherence remains problematic, especially among persons with disability and minority beneficiaries. Quality measures for long-term adherence should be created to improve outcomes in patients with post-MI. Even among those with close-to-full drug coverage, racial differences remain, suggesting that policies simply relying on cost reduction cannot eliminate racial differences.