Clinical outcomes of adjusted-dose versus standard-dose prasugrel in East Asian patients with acute myocardial infarction

Background: The comparative efficacy and safety of adjusted- and standard-dose prasugrel in East Asian patients with acute myocardial infarction (AMI) undergoing percutaneous coronary intervention (PCI) remain unclear. This study aimed to comparatively assess the ischaemic and bleeding outcomes of adjusted-dose (maintenance dose: 3.75 mg) and standard-dose (maintenance dose: 10 mg) prasugrel in East Asian patients with AMI undergoing PCI. Methods: From a combined dataset sourced from nationwide AMI registries in Japan and South Korea (n = 17,118), patients treated with either adjusted- or standard-dose prasugrel were identified. Patients who did not undergo emergent PCI, those on oral anticoagulants, and those meeting the criteria of contraindication of prasugrel in South Korea (age ≥ 75 years, body weight < 60 kg, or history of stroke) were excluded. Major adverse cardiovascular events (MACE) and Thrombolysis in Myocardial Infarction (TIMI) major bleeding events were compared between the adjusted-dose (n = 1160) and standard-dose (n = 1086) prasugrel groups. Results: Within the propensity-matched cohort (n = 702 in each group), no significant difference was observed in the in-hospital MACE between the adjusted- and standard-dose prasugrel groups (1.85% vs. 2.71%, odds ratio [OR] 0.68, 95% confidence interval [CI] 0.33–1.38, p = 0.286). However, the incidence of in-hospital major bleeding was significantly lower in the adjusted-dose prasugrel group than in the standard-dose group (0.43% vs. 1.71%, OR 0.25, 95% CI 0.07–0.88, p = 0.031). The cumulative 12-month incidence of MACE was equivalent in both groups (4.70% vs. 4.70%, OR 1.00, 95% CI 0.61–1.64, p = 1.000). Conclusions: Among East Asian patients with AMI undergoing PCI, those administered adjusted-dose prasugrel exhibited a lower risk of in-hospital bleeding events than those administered standard-dose prasugrel, while maintaining a comparable 1-year incidence of MACE.