Prescribing a P2Y12 inhibitor for patients with diabetes mellitus (DM) and acute myocardial infarction (AMI) who have undergone percutaneous coronary intervention (PCI) is challenging because of the risk of bleeding and ischemia. We compared the risk of ischemia and bleeding between clopidogrel and ticagrelor in elderly East Asian patients with diabetes using the Korea Acute Myocardial Infarction Registry (KAMIR)-V data. This study included 838 patients enrolled in the KAMIR-V who were ＞75 years, had DM, AMI, and had undergone PCI. The patients were divided into two groups based on the treatment drug. After propensity score matching, 466 patients (ticagrelor: clopidogrel=233:233) were included in the Cox regression analyses to determine the risk of bleeding and ischemia. The baseline characteristics were not different. The type of antiplatelet therapy did not affect the incidence of Bleeding Academic Research Consortium type ≥2 bleeding. There was no significant difference between ticagrelor and clopidogrel treatment outcomes with respect to ischemia risk. This prospective study of a Korean patient cohort (elderly Korean patients with DM) showed no differences in bleeding and ischemia risks based on the use of either ticagrelor or clopidogrel. Large scale randomized controlled tr...