The major randomized clinical trial, ASCEND, shows that aspirin 100 mg daily lowers the rates of cardiovascular events by 12% in patients with diabetes but increases the risk of bleeding by 30%.
A group of 15,000 participants with diabetes but without baseline CVD were followed for about 7 years.
Case by case clinical judgment would be key in evaluating CVD benefits vs. bleeding risks of aspirin use in patients with diabetes.
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Diabetes mellitus is associated with an increased risk of cardiovascular events. Aspirin use reduces the risk of occlusive vascular events but increases the risk of bleeding; the balance of benefits and hazards for the prevention of first cardiovascular events in patients with diabetes is unclear.
We randomly assigned adults who had diabetes but no evident CVD to receive aspirin at a dose of 100 mg daily or matching placebo.
Primary efficacy outcome was the first serious vascular event (i.e., myocardial infarction, stroke or transient ischemic attack, or death from any vascular cause, excluding any confirmed intracranial hemorrhage).
Primary safety outcome was the first major bleeding event (i.e., intracranial hemorrhage, sight-threatening bleeding event in the eye, gastrointestinal bleeding, or other serious bleeding).
Secondary outcomes included gastrointestinal tract cancer.
A total of 15,480 participants underwent randomization.
During a mean follow-up of 7.4 years, serious vascular events occurred in a significantly lower percentage of participants in the aspirin group than in the placebo group (658 participants [8.5%] vs. 743 [9.6%]; RR 0.88, p=0.01).
In contrast, major bleeding events occurred in 314 participants (4.1%) in the aspirin group, as compared with 245 (3.2%) in the placebo group (RR 1.29, p=0.003), with most of the excess being gastrointestinal bleeding and other extracranial bleeding.
There was no significant difference between the aspirin group and the placebo group in the incidence of gastrointestinal tract cancer (157 participants [2.0%] and 158 [2.0%], respectively) or all cancers (897 [11.6%] and 887 [11.5%]); long-term follow-up for these outcomes is planned.
Aspirin use prevented serious vascular events in persons who had diabetes and no evident cardiovascular disease at trial entry, but it also caused major bleeding events.
The absolute benefits were largely counterbalanced by the bleeding hazard.