Comparative Effectiveness of Aspirin Dosing in Cardiovascular Disease and Diabetes Mellitus: A Subgroup Analysis of the ADAPTABLE Trial

OBJECTIVE: Patients with diabetes mellitus (DM) and concomitant atherosclerotic cardiovascular disease (ASCVD) must be on the most effective dose of aspirin to mitigate risk of future adverse cardiovascular events. RESEARCH DESIGN AND METHODS: ADAPTABLE, an open-label, pragmatic study, randomized patients with stable, chronic ASCVD to 81 mg or 325 mg of daily aspirin. The effects of aspirin dosing was assessed on the primary effectiveness outcome, a composite of all-cause death, hospitalization for myocardial infarction, or hospitalization for stroke, and the primary safety outcome of hospitalization for major bleeding. In this prespecified analysis, we used Cox proportional hazards models to compare aspirin dosing in patients with and without DM for the primary effectiveness and safety outcome. RESULTS: Of 15,076 patients, 5,676 (39%) had DM of whom 2,820 (49.7%) were assigned to 81 mg aspirin and 2,856 (50.3%) to 325 mg aspirin. Patients with versus without DM had higher rates of the composite cardiovascular outcome (9.6% vs. 5.9%; P < 0.001) and bleeding events (0.78% vs. 0.50%; P < 0.001). When comparing 81 mg vs. 325 mg of aspirin, patients with DM had no difference in the primary effectiveness outcome (9.3% vs. 10.0%; hazard ratio [HR] 0.98 [95% CI 0.83-1.16]; P = 0.265) or safety outcome (0.87% vs. 0.69%; subdistribution HR 1.25 [95% CI 0.72-2.16]; P = 0.772). CONCLUSIONS: This study confirms the inherently higher risk of patients with DM irrespective of aspirin dosing. Our findings suggest that a higher dose of aspirin yields no added clinical benefit, even in a more vulnerable population.