Long-term Medication Adherence after Myocardial Infarction: Experience of a Community

Abstract

Background Adherence to evidence-based medications after myocardial infarction is associated with improved outcomes. However, long-term data on factors affecting medication adherence after myocardial infarction are lacking. Methods Olmsted County residents hospitalized with myocardial infarction from 1997-2006 were identified. Adherence to HMG-CoA reductase inhibitors (statins), beta blockers, angiotensin-converting enzyme inhibitors, and angiotensin II receptor blockers, were examined. Cox proportional hazard regression was used to determine the factors associated with medication adherence over time. Results Among 292 subjects with incident myocardial infarction (63% men, mean age 65 years), patients were followed for an average of 52 ± 31 months. Adherence to guideline-recommended medications decreased over time, with 3-year medication continuation rates of 44%, 48%, and 43% for statins, beta-blockers, and angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers, respectively. Enrollment in a cardiac rehabilitation program was associated with an improved likelihood of continuing medications, with adjusted hazard ratio (95% confidence interval) for discontinuation of statins and beta-blockers among cardiac rehabilitation participants of 0.66 (0.45-0.92) and 0.70 (0.49-0.98), respectively. Smoking at the time of myocardial infarction was associated with a decreased likelihood of continuing medications, although results did not reach statistical significance. There were no observed associations between demographic characteristics, clinical characteristics of the myocardial infarction, and medication adherence. Conclusions After myocardial infarction, a large proportion of patients discontinue use of medications over time. Enrollment in cardiac rehabilitation after myocardial infarction is associated with improved medication adherence.