Aspirin Not Beneficial for Reducing Vascular Events in Healthy People With a Low Ankle Brachial Index
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Data from the Aspirin for Asymptomatic Atherosclerosis trial have cast additional doubt on the value of aspirin therapy for people without clinical cardiovascular disease. In that trial, the administration of aspirin (compared with placebo) did not result in a significant reduction in vascular events among healthy people deemed to be at increased risk because of a low ankle brachial index (ABI).
The Aspirin for Asymptomatic Atherosclerosis trial was conducted from April 1998 to October 2008. Trial participants were recruited from a group of more than 29,000 men and women in Scotland who were between 50 and 75 years of age at baseline and agreed to undergo ABI screening. A total of 3,350 people with a low ABI ( 0.95) were enrolled in the trial and randomized to receive 100 mg of enteric-coated aspirin daily or placebo. The primary end point was a composite of initial fatal or nonfatal coronary event or stroke or revascularization; secondary end points were all initial vascular events (a composite of a primary end point event or angina, intermittent claudication, or transient ischemic attack) and all-cause mortality.
A primary end point event occurred in 357 participants over a mean follow-up period of 8.2 years. The event rate over time in the aspirin group (13.7 events per 1,000 person-years) was not significantly different from the event rate in the placebo group (13.3 events per 1,000 person-years). The occurrence of secondary end points also did not differ significantly between the two groups. However, more participants in the aspirin group (34 people) than in the placebo group (20 people) had an initial event of major hemorrhage that required admission to a hospital.
The authors concluded that using ABI in the community to screen healthy individuals—with a goal of identifying a higher-risk subgroup potentially amenable to preventive treatments—is unlikely to be beneficial if aspirin is the intervention of choice.
JAMA. 2010;303:841-8.