Trends in adherence to secondary prevention medications in elderly post‐myocardial infarction patients

Abstract

BACKGROUND: Poor levels of medication adherence for patients with coronary heart disease (CHD) have been documented but it is unclear whether adherence has improved over time. METHODS: We assembled a retrospective cohort of lower-income Medicare beneficiaries who were discharged from the hospital after their first acute myocardial infarction (MI) between 1 January 1995 and 31 December 2003. For patients prescribed a statin, ACEI/ARB, beta-blocker, and all 3 of these medications after the hospital discharge, we evaluated medication adherence by determining the proportion of days covered (PDC) for each medication in the subsequent year. RESULTS: Our cohort consisted of a total of 33 646 patients. Adherence rates for statins and beta-blockers, but not ACEI/ARB, increased significantly over time but remained suboptimal. For example, among those patients that received a statin after discharge, 38.6% were fully adherent with therapy in 1995 in contrast to 56.2% in 2003 (p value for trend<0.001). Of patients prescribed all 3 of statin, beta-blocker, and ACEI/ARB, 29.1% and 46.4% were fully adherent in 1995 and 2003, respectively (p value for trend<0.001). CONCLUSIONS: Our analysis demonstrates statistically significant but modest improvements in medication adherence for statins and beta-blockers, but not ACEI/ARBs, among patients discharged from hospital after acute MI. Despite these improvements, rates of non-adherence to these highly effective therapies remain extremely high. Given the health and economic consequences of non-adherence, the development of cost-effective strategies to improve medication adherence should be a clear priority.