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

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 Stalin 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. Copyright (C) 2008 John Wiley & Sons, Ltd.