Patients with diabetes had a high rate of major bleeding regardless of aspirin use....

 

Among nearly 200,000 individuals, daily use of low-dose aspirin was associated with an increased risk of major gastrointestinal or cerebral bleeding, according to a study. Researchers noted that therapy with low-dose aspirin is recommended as a secondary prevention measure for individuals with moderate to high risk of cardiovascular events. "Any benefit of low-dose aspirin might be offset by the risk of major bleeding," they wrote. "It is known that aspirin is associated with gastrointestinal and intracranial hemorrhagic complications." "Randomized controlled trials have shown that these risks are relatively small," but such trials evaluate selected patient groups and do not necessarily generalize to an entire population.

In addition, low-dose aspirin use is recommended for certain patients with diabetes. Findings from a meta-analysis suggested that diabetes may increase the risk of extracranial hemorrhage. Because researchers derived these estimates from a limited number of events within randomized trials, "the risk-to-benefit ratio for the use of low-dose aspirin in the presence of diabetes mellitus remains to be clarified," the authors wrote.

Giorgia De Berardis, MSc, of Consorzio Mario Negri Sud in Italy, and colleagues conducted a study to determine the incidence of major gastrointestinal and intracranial bleeding episodes in individuals with and without diabetes who took aspirin. They used administrative data from 4.1 million citizens among 12 local health authorities in Puglia, Italy. For the study, they included 186,425 individuals being treated with low-dose aspirin and 186,425 matched controls without aspirin use.

Analysis indicated that the use of aspirin was associated with a 55% increased relative risk of gastrointestinal bleeding and 54% increased relative risk of intracranial bleeding. The authors noted that in comparison with other estimates of rates of major bleeding, their findings indicated a five-times higher incidence of major bleeding leading to hospitalization among both aspirin users and those without aspirin use.

The 55% relative increase in risk of major bleeding "translates to two excess cases per 1,000 patients treated per year," the authors wrote. "In other words, the excess number of major bleeding events associated with the use of aspirin is of the same magnitude of the number of major cardiovascular events avoided in the primary prevention setting for individuals with a 10-year risk of between 10% and 20%."

The researchers also found that the use of aspirin was associated with a greater risk of major bleeding in most of the subgroups evaluated, but not in individuals with diabetes. Diabetes was independently associated with a 36% increased relative risk of major bleeding episodes, regardless of aspirin use. Among individuals not taking aspirin, those with diabetes had increased relative risks of 59% for gastrointestinal bleeding and 64% for intracranial bleeding.

"Our study shows, for the first time to our knowledge, that aspirin therapy only marginally increases the risk of bleeding in individuals with diabetes," the authors wrote. "These results can represent indirect evidence that the efficacy of aspirin in suppressing platelet function is reduced in this population."

"Weighing the benefits of aspirin therapy against the potential harms is of particular relevance in the primary prevention setting, in which benefits seem to be lower than expected based on results in high-risk populations. In this population-based cohort, aspirin use was significantly associated with an increased risk of major bleeding, but this association was not observed for patients with diabetes.

"In conclusion, weighing the benefits of aspirin therapy against the potential harms is of particular relevance in the primary prevention setting, in which benefits seem to be lower than expected based on results in high-risk populations. In this population-based cohort, aspirin use was significantly associated with an increased risk of major bleeding, but this association was not observed for patients with diabetes. In this respect, diabetes might represent a different population in terms of both expected benefits and risks associated with antiplatelet therapy."