Comparative effectiveness and safety of antiplatelet drugs in patients with diabetes mellitus and acute coronary syndrome.

PURPOSE: Comparative outcomes of treatment with antiplatelet drugs in patients with acute coronary syndrome (ACS) and co-morbid diabetes mellitus (DM) are not well studied. METHODS: We performed a cohort study using US commercial claims data (2009-2015) and conducted the following pairwise comparisons in ACS patients with DM: prasugrel vs clopidogrel, ticagrelor vs clopidogrel, and prasugrel vs ticagrelor. Outcomes of interest included (1) a composite effectiveness endpoint including myocardial infarction, ischemic stroke, or inpatient mortality; (2) a composite safety endpoint including major bleeding events requiring hospitalization; and (3) pneumonia hospitalizations as a negative control endpoint. We used calendar time-specific propensity score matching to account for confounding and applied Cox proportional hazard models to calculate hazard ratios (HR) with 95% confidence intervals (CI). RESULTS: Comparative risk of the effectiveness endpoint was lower among prasugrel initiators compared to clopidogrel initiators (HR 0.82, 95% CI 0.68-0.99, N = 7011 matched pairs), but no different between ticagrelor and clopidogrel (HR 1.02, 95% CI 0.76-1.37, N = 3013 pairs) or prasugrel and ticagrelor (HR 0.83, 95% CI 0.58-1.18, N = 2207 pairs). Bleeding risk was higher among prasugrel initiators when compared to clopidogrel initiators within the first month of treatment (HR 1.85, 95% CI 1.03-3.35); no other comparison indicated any difference. No differences in the negative control outcomes were noted after PS matching for all comparisons, indicating adequate confounding control. CONCLUSIONS: Prasugrel was associated with superior cardiovascular outcomes and a higher risk of short-term bleeding compared to clopidogrel in patients with ACS and DM. Comparative outcomes were similar between ticagrelor and clopidogrel or prasugrel and ticagrelor.