Patient adherence to generic versus brand statin therapy after acute myocardial infarction: Insights from the Can Rapid Stratification of Unstable Angina Patients Suppress Adverse Outcomes with Early Implementation of the American College of Cardiology/American Heart Association Guidelines Registry

Background Statins reduce mortality after acute myocardial infarction, but up to half of patients discontinue statin use within 1 year of therapy initiation. Although cost may influence medication adherence, it is unknown whether use of generic versus brand statins influences adherence. Methods and results We linked detailed inhospital clinical data for 1421 non-ST-segment elevation myocardial infarction patients discharged on a statin in 2006 to Medicare Part D medication claims records to examine postdischarge medication use. One-year statin adherence was defined using the proportion of days covered with optimal adherence ≥80%. We examined the association of brand versus generic statin prescription and 1-year adherence after adjusting for demographics, clinical factors, predischarge lipid values, prior statin use, and socioeconomic status. Overall, 65.5% of statin fills were for brand-name statins. There were few baseline differences in demographics and clinical factors among generic versus brand users. Patient copay amounts were higher for brand versus generic statins (median = $25 vs $5, P <.001), yet the mean proportion of days covered over 1 year was similar (71.5% vs 68.9%; P =.97; unadjusted odds ratio 1.15 [95% CI 0.96-1.37]). Proportion of days covered ≥80% was low for both generic (56.2%) and brand statins (55.9%; P =.93). Statin adherence rates remained similar between generic and brand users after adjusting for demographics, clinical risk factors, lipid value, prior statin use, and socioeconomic status. Conclusions In a cohort of older non-ST-segment elevation myocardial infarction patients, we found no evidence that use of generic versus brand drug was associated with higher adherence to statins at 1 year after hospital discharge.