Jones WS, Mulder H, Wruck LM, et al. - This study sought to explore the comparative effectiveness of aspirin dosing in cardiovascular disease. Researchers randomized patients with established atherosclerotic cardiovascular disease to a strategy of 81 mg or 325 mg of aspirin per day using an open-label, pragmatic design. A composite of death from any cause, hospitalization for myocardial infarction, or hospitalization for stroke, assessed in a time-to-event analysis was the primary effectiveness outcome. Hospitalization for major bleeding also assessed in a time-to-event analysis was the primary safety outcome. The study enrolled a total of 15,076 patients, followed for a median of 26.2 months (interquartile range [IQR], 19.0 to 34.9). There was substantial dose switching to 81 mg of daily aspirin and no significant differences in cardiovascular events or major bleeding between patients assigned to 81 mg and those assigned to 325 mg of aspirin daily in this pragmatic trial involving patients with established cardiovascular disease.