Context: The benefit of aspirin for the primary prevention of cardiovascular events is relatively small for individuals with and without diabetes. This benefit could easily be offset by the risk of hemorrhage.
Objective: To determine the incidence of major gastrointestinal and intracranial bleeding episodes in individuals with and without diabetes taking aspirin.
Design, setting, and participants: A population-based cohort study, using administrative data from 4.1 million citizens in 12 local health authorities in Puglia, Italy. Individuals with new prescriptions for low-dose aspirin (≤300 mg) were identified during the index period from January 1, 2003, to December 31, 2008, and were propensity-matched on a 1-to-1 basis with individuals who did not take aspirin during this period.
Main outcome measures: Hospitalizations for major gastrointestinal bleeding or cerebral hemorrhage occurring after the initiation of antiplatelet therapy.
Results: There were 186,425 individuals being treated with low-dose aspirin and 186,425 matched controls without aspirin use. During a median follow-up of 5.7 years, the overall incidence rate of hemorrhagic events was 5.58 (95% CI, 5.39-5.77) per 1000 person-years for aspirin users and 3.60 (95% CI, 3.48-3.72) per 1000 person-years for those without aspirin use (incidence rate ratio [IRR], 1.55; 95% CI, 1.48-1.63). The use of aspirin was associated with a greater risk of major bleeding in most of the subgroups investigated but not in individuals with diabetes (IRR, 1.09; 95% CI, 0.97-1.22). Irrespective of aspirin use, diabetes was independently associated with an increased risk of major bleeding episodes (IRR, 1.36; 95% CI, 1.28-1.44).
Conclusions: In a population-based cohort, aspirin use was significantly associated with an increased risk of major gastrointestinal or cerebral bleeding episodes. Patients with diabetes had a high rate of bleeding that was not independently associated with aspirin use.