Aspirin for primary prevention of atherothrombotic vascular events: How much 'conclusive' is 'conclusive?'

摘要

Low-dose aspirin has been shown to be effective in preventing athero-thrombotic vascular events (nonfatal myocardial infarction, nonfatal stroke, or vascular death) in a meta-analysis including 9 primary prevention trials (50,868 subjects were treated with aspirin and 49,170 received placebo or control).1 Because meta-analyses aim to identify the effect of an intervention as early as possible, they are usually updated when new trials are published, so that repeated analyses are made on accumulating data. These multiple analyses induce repeated significance testing (usually with p value criterion, a = 5% for a 2-sided test), which leads to an increased risk of random error and subsequent misleading evidence in results.