More than 15,000 British patients with diabetes but no evident cardiovascular disease (CVD) were randomized to take either aspirin or placebo daily as part of the ASCEND (A Study of Cardiovascular Events in Diabetes) trial. Serious vascular events occurred in only 8.5% of the aspirin group, compared to 9.6% of the placebo group (P=0.01). However, major bleeding events occurred in 4.1% of the aspirin group and 3.2% of the placebo group, leading the study authors to conclude that the absolute benefits of aspirin were largely counterbalanced by the bleeding hazard.
The study was published in the Oct. 18, 2018, New England Journal of Medicine. The following commentary by Gaetano Santulli, MD, was published in the ACP Journal Club section of the Dec. 18, 2018, Annals of Internal Medicine.
Prevention of atherothrombotic events is a therapeutic goal for patients with diabetes. The ASCEND trial found that an increased risk for bleeding offset the reduction in CVD events and is consistent with other trials of aspirin for primary prevention. These trials challenge current guidelines and the long-held opinion of many clinicians of the net benefit of aspirin.
Aspirin use in patients with diabetes needs to be individualized after accurate assessment of risk for (athero)thrombosis and hemorrhage. Valid and precise estimators of these risks are urgently needed. For some patients, CV risk is “high enough” to warrant aspirin, especially if bleeding risk is low. Reducing risk for bleeding via gastroprotection, a cost-effective strategy in secondary prevention, could further tip the scale in favor of aspirin.
Given differences in the pathophysiology of type 1 and type 2 diabetes, aspirin could have different effects in such patients. In ASCEND, < 6% of patients had type 1 diabetes; these patients might benefit more from aspirin for primary CVD prevention. A final consideration is dosage (100 mg/d in ASCEND trial): The results could partly be attributed to dosage not tailored to bodyweight and to once- vs twice-daily administration.