Low-Dose Prasugrel vs. Standard-Dose Clopidogrel for Patients Undergoing Percutaneous Coronary Intervention

Background: Low-dose prasugrel (3.75 mg) is used as maintenance therapy for percutaneous coronary intervention; however, data on long-term outcomes are scarce. Methods and Results: We analyzed 5,392 participants in the KiCS-PCI registry who were administered low-dose prasugrel or clopidogrel at discharge between 2008 and 2018 and for whom 2-year follow-up data were available. We adjusted for confounders using matching weight analyses and multiple imputations. Similarly, we used inverse probability- and propensity score-weighted analyses. We also performed instrumental variable analyses. The primary outcomes were acute coronary syndrome (ACS) and bleeding requiring readmission. Secondary outcomes were all-cause death and a composite outcome of ACS, bleeding, heart failure, stroke, coronary bypass requiring admission, and all-cause death. In this cohort, 12.2% of patients were discharged with low-dose prasugrel. Compared with clopidogrel, low-dose prasugrel was associated with a reduced risk of ACS (hazard ratio [HR] 0.58; 95% confidence interval [CI] 0.39–0.85), bleeding (HR 0.62; 95% CI 0.40–0.97), and the composite outcome (HR 0.71; 95% CI 0.59–0.86). Inverse probability-weighted analysis yielded similar results; however, matching weight analysis without multiple imputations and propensity score-matched analyses showed similar outcomes in both groups. Instrumental variable analyses showed reduced risks of ACS and composite outcome for those on low-dose prasugrel. All-cause mortality did not differ in all analyses. Conclusions: Low-dose prasugrel demonstrates comparable outcomes to clopidogrel in terms of ACS and bleeding.