Should you take a daily aspirin?

After a recent physical, where my LDL was determined to be slightly high, my physician suggested I take a low dose of a statin. Since I am not convinced that taking statins is beneficial for low to medium risk asymptomatic people, (please see our review on taking statins), I declined. She then suggested that "at least" I should take a baby aspirin (81 mg aspirin) daily. So before commiting to doing this, I thought it would be worthwhile to review the evidence.

Reference 1 presents results of "The Physicians' Health Sudy" completed in 1989. It tracked 22,071 U.S. male physicians 40 to 84 years of age for 5 years, comparing low dose aspirin (325 mg taken every other day) to a placebo. The physicians taking the aspirin has a Relative Risk of myocardial infarction ("heart attack") of 0.56, with a Margin of Error between 0.45 to 0.70. The reduction was apparent for those who were 50 years of age and older. However, there was no significant reduction in mortality from cardiovascular causes - a Relative Risk of 0.96, with a Margin of Error between 0.60 to 1.54. Of course, given the large Margin of Error, it is possible that mortality is reduced, but there is no conclusive evidence that it is. Simultaneously, there is an increased risk of ulcers (RR=1.22, Margin of Error between 0.98 and 1.53) that is also borderline significant.

These conclusions are updated in reference 2. This is a metastudy, that combines results from several previous studies. The metastudy has a total of 55,580 randomized participants, now including 11,466 women. The new Relative Risk for non-fatal heart attacks is determined to be 0.68 (Margin of Error between 0.59 and 0.79). There is no significant impact of aspirin on ischemic strokes (strokes resulting from a blood clot, decreasing the flow of blood to the brain), and a borderline significant increase in the number of hemorrhagic strokes (strokes in which a blood vessel in the brain ruptures) - RR=1.56, Margin of Error is 0.99 to 2.46. As in the first study, there is no significant reduction in risks for vascular deaths (RR = 0.98. Margin of Error between 0.85 and 1.12). As similar metastudy (reference 3) adds that the odds for major gastrointestinal bleeding are RR=1.7, with a Margin of Error between 1.4 and 2.1, and also concludes that all-cause mortality was not significantly affected.

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Last Modification - April 2, 2005