Safety and Effectiveness of Contemporary P2Y12 Inhibitors in an East Asian Population With Acute Coronary Syndrome: A Nationwide Population-Based Cohort Study.

Background Prior reports indicate that the effect of P2Y12 inhibitors may be different in East Asian patients ("East Asian paradox"); therefore, understanding the outcomes associated with potent P2Y12 inhibitors in different populations is clinically important. Methods and Results In this observational cohort study using administrative healthcare data sets, we compared safety and effectiveness of contemporary P2Y12 inhibitors in patients with acute coronary syndrome. The primary safety outcomes were major and any bleeding, and the primary effectiveness outcomes were major cardiovascular events (a composite of cardiovascular death, myocardial infarction, or stroke) and all-cause mortality. Among 70 715 patients with acute coronary syndrome, 56 216 (79.5%) used clopidogrel, 11 402 (16.1%) used ticagrelor, and 3097 (4.4%) used prasugrel. The median follow-up period was 18.0 months (interquartile range: 9.6-26.4 months). In a propensity-matched cohort, compared with clopidogrel, ticagrelor was associated with a higher risk of any bleeding (hazard ratio: 1.23; 95% CI, 1.14-1.33) but a lower risk of mortality (hazard ratio: 0.76; 95% CI, 0.63-0.91). Prasugrel, compared with clopidogrel, was associated with higher risks of any bleeding (hazard ratio: 1.23; 95% CI, 1.06-1.43) and major bleeding (hazard ratio: 1.50; 95% CI, 1.01-2.21) but a similar risk of effectiveness outcomes. No significant difference was noted between ticagrelor and prasugrel with respect to key safety or effectiveness outcomes. Several sensitivity analyses showed similar results. Conclusions In East Asian patients with acute coronary syndrome, compared with clopidogrel, ticagrelor was associated with an increased risk of bleeding but a decreased risk of mortality. Prasugrel was associated with an increase of any bleeding without difference in effectiveness outcomes. The risks of bleeding and ischemic events were similar between ticagrelor and prasugrel.