The subjects came from a cohort of nearly 29,000 men and women ages 50 to 75 years enrolled in a community health registry in Scotland. All were free of clinical cardiovascular disease at baseline, and each agreed to ankle brachial index screening. The 3350 individuals with an index of no more than 0.95 took either 100 mg of aspirin daily, or placebo, for the next 8.2 years, on average.
In the Journal of the American Medical Association for March 3, lead author Dr. F. Gerald R. Fowkes, from the University of Edinburgh and colleagues report that 357 subjects met the main endpoint (a composite of coronary events, stroke, or revascularization). Rates per 1000 person-years were similar with aspirin (13.7) and placebo (13.3).
Rates of a secondary outcome – a composite of the main endpoint plus angina, intermittent claudication, or transient ischemic attack – were also comparable: 22.8 vs. 22.9 per 1000 person-years with aspirin vs placebo, respectively.
All-cause mortality was similar as well, with 12.8 deaths per 1000 person-years in the aspirin group and 13.5 in the placebo group.
Subjects treated with aspirin were 71% more likely than those given placebo to experience major hemorrhage requiring admission to the hospital: 2.5 vs. 1.5 per 1000 person-years.
“Based on the trial conducted by Fowkes et al and other similar studies, aspirin appears to have marginal benefits for reducing initial cardiovascular events when used for patients without clinically evident cardiovascular disease and is associated with higher rates of bleeding in these patients,” Dr. Jeffrey S. Berger, from New York University School of Medicine, comments in a related editorial.
Dr. Fowkes and colleagues conclude that “given the increased level of risk among those with a low ankle brachial index, the use of alternative therapies, such as statins or more potent antiplatelet agents without attendant hemorrhagic risks may usefully be considered.”