Medication adherence after myocardial infarction: Predictors, mortality and cardiovascular outcomes

BACKGROUND AND AIMS: Secondary prevention medications after myocardial infarction (MI) are crucial for reducing mortality and cardiovascular events, however, adherence is often suboptimal. This study aimed to investigate predictors of adherence, and clinical outcomes among STEMI and NSTEMI survivors in Sweden. METHODS: This nationwide cohort study included patients hospitalized with MI between 2017 and 2020 who completed a 2-month follow-up, with medication adherence assessed over the following 12 months, and outcome follow-up beginning thereafter. Data were obtained from the SWEDEHEART registry and linked to other national registers. Medication adherence was defined as filling ≥4 prescriptions for each prescribed secondary prevention drug class during the 12 months following the 2-month visit. Logistic regression identified adherence predictors, and Cox models assessed associations with all-cause mortality, ischemic heart disease, and stroke. RESULTS: The cohort included 26,592 patients (mean age 65.5 years; 25.9% female), of whom 56.6% with STEMI and 53.0% with NSTEMI were adherent. Higher income and physical activity were associated with adherence, while atrial fibrillation with non-adherence. Adherence was associated with reduced all-cause mortality among NSTEMI patients (HR 0.71, 95% CI 0.59-0.86), and reduced risk of ischemic heart disease in both STEMI (HR 0.69, 95% CI 0.53-0.90) and NSTEMI (HR 0.76, 95% CI 0.61-0.94). No association was found between adherence and stroke. CONCLUSIONS: Just over half of MI survivors adhered to prescribed secondary prevention medications based on dispensation data from 2 to 14 months post-MI. Adherence was influenced by sociodemographic and clinical factors and was associated with improved outcomes.