Patient-Oriented Evidence That Matters
Benefits and Harms for Low-Dose Aspirin in Patients with Diabetes Mellitus
Am Fam Physician. 2019 Jun 1;99(11):718.
Related Editorial: Rethinking Aspirin for the Primary Prevention of Cardiovascular Disease
What are the benefits and harms of low-dose aspirin in adults with diabetes mellitus?
The 7,740 patients who took low-dose aspirin experienced 51 fewer vascular deaths, nonfatal myocardial infarctions (MIs), or nonfatal ischemic strokes; 29 fewer transient ischemic attacks (TIAs); and 44 fewer revascularizations than patients who took placebo over a mean of 7.4 years. This is balanced by an additional 69 major bleeding episodes during that period, with no effect on vascular or all-cause deaths, and no difference in the incidence of cancer. (Level of Evidence = 1b)
This British study recruited adults 40 years and older with diabetes, no known cardiovascular disease, no contraindications to aspirin, and no major comorbidity that would keep them from participating in the study for at least five years. After a placebo run-in period to assure adherence, 15,480 participants were randomized to receive aspirin 100 mg once daily or matching placebo. They were also randomized to receive an omega-3 fatty acid capsule or placebo; those results are reported separately. The groups were balanced at the start of the study: the patients had a mean age of 63 years, 63% were men, and 96% were white. Almost all (94%) had type 2 diabetes. A validated risk score determined that approximately 40% of participants were at low risk of vascular events (less than 5% at five years), 40% had a five-year risk of 5% to 10%, and the remainder were at high risk. Because the trial was ongoing, the authors added TIA to the original primary composite efficacy outcome of vascular death, nonfatal MI, or nonfatal stroke (excluding intracranial hemorrhage). The primary safety outcome was a composite of intracranial hemorrhage, intraocular hemorrhage that threatens sight, gastrointestinal bleeding, or any other serious bleeding event. After a mean follow-up of 7.4 years, 99% of patients had complete follow-up data, with outcomes adjudicated for more than 90% by a committee masked to treatment
Editor's Note: Dr. Ebell is Deputy Editor for Evidence-Based Medicine for AFP and cofounder and Editor-in-Chief of Essential Evidence Plus, published by Wiley-Blackwell.
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