It's Not Too Late to Improve Statin Adherence: Association Between Changes in Statin Adherence from Before to After Acute Myocardial Infarction and All‐Cause Mortality

BACKGROUND: Many older patients have a change in statin adherence—either an increase or a decrease—from before to after an acute myocardial infarction (AMI), but its association with mortality is unknown. METHODS AND RESULTS: Using Medicare administrative claims, a cohort of patients ≥66 years old with an AMI hospitalization from 2008 to 2010 was assembled. Statin adherence was measured for 180 days pre‐AMI and 180 days post‐AMI and categorized as severely nonadherent, moderately nonadherent, or adherent. Categorical change in statin adherence from pre‐ to post‐AMI was assessed. Patients were then followed for up to 18 months for all‐cause mortality. A Cox proportional hazards model was applied to estimate the effects of statin adherence change on all‐cause mortality, adjusted for patient baseline characteristics. Of 101 011 eligible patients, 20% had a categorical increase in adherence, 16% decreased, and 14% remained nonadherent both pre‐ and post‐AMI. Compared with patients who were always severely nonadherent (both pre‐ and post‐AMI), patients whose adherence increased from severely nonadherent to adherent (hazard ratio=0.83; 95% CI: 0.75–0.92) and patients who were always adherent (hazard ratio=0.88; 95% CI: 0.82–0.94) were less likely to die; patients whose adherence decreased from moderately nonadherent to severely nonadherent were more likely to die (hazard ratio=1.11; 95% CI: 1.01–1.22). CONCLUSIONS: After an AMI, patients with decreased statin adherence had the worst mortality outcomes. However, patients with increased statin adherence had a similar risk of mortality compared with continuously adherent patients, suggesting that, even after an AMI, it is not too late to improve statin adherence.