Comparison of adherence, persistence, and clinical outcome of generic and brand-name statin users: A retrospective cohort study using the Japanese claims database

Abstract

BackgroundNon-adherence to statin treatment results in an increased risk of cardiovascular events and all-cause mortality. This study compared adherence, persistence, and clinical outcomes of patients who initiated brand-name and generic statins in the Japanese population. MethodsThe retrospective cohort study included adult patients who initiated statins between 2014 and 2016. Primary adherence was measured as the proportion of days covered (PDC) within 1 year. Persistence was assessed using the proportion of non-persistent users. Any major adverse cardiac and cerebrovascular event (MACCE) was assessed as a clinical outcome. Propensity score matching was performed to adjust for confounding factors. ResultsAmong 47,770 patients who met inclusion criteria in the study, 32,130 (67.3%) initiated generic statins. The median age of the patients was 53 (interquartile range: 46-59) years and 60.2% were male. A higher proportion of patients with PDC ≥80% [60.2% vs. 57.1%; odds ratio, 1.14; 95% confidence interval (CI), 1.09–1.19; p<0.001] and a higher PDC value (median, 90.2% vs. 87.9%; difference, 2.3%; p<0.001) were observed in the generic group. Similarly, fewer patients discontinued statins in the generic group [24.2% vs. 27.7%; hazard ratio (HR), 0.91; 95% CI, 0.87–0.95; p<0.001]. Differences in MACCE occurrence were not significant between the groups (4.3% vs. 4.2%; HR, 1.04; 95% CI, 0.93–1.17; p=0.99). ConclusionsAdherence and persistence were higher among generic statin recipients; nevertheless, no significant differences in clinical outcomes were noted between the two groups, suggesting that generic medication did not impair treatment benefits and may improve patient adherence.