Abstract
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.