Preventing atherosclerotic events with aspirin

Editorial by Fitzgerald Papers p 71 On p 71 we publish the latest in a series of meta-analyses from the Antithrombotic Trialists' Collaboration. Here John Cleland argues that, despite the vast size of these meta-analyses, the evidence in support of aspirin preventing atherosclerotic events is still inconclusive. One adverse effect of the belief that aspirin is more effective than it is, he argues, is the neglect of more effective drugs for preventing heart disease and stroke. The third meta-analysis from the Antithrombotic Trialists' Collaboration, published in this issue, contains data on over 100 000 patients at high risk of atherosclerotic events, representing more than 250 000 patient years of follow up.1 This meta-analysis and its predecessors form the major argument for the current widespread fashion of prescribing aspirin to such patients. 2 3 It is an enormous body of research and the collaboration is to be congratulated for having gathered so much data. However, quality as well as quantity matters. And the quality is such that the results can only be inconclusive. ### Summary points The series of meta-analyses on the antiplatelet activity of aspirin overvalues aspirin's effectiveness and safety All the large long term trials of aspirin after myocardial infarction show no effect on mortality Aspirin may change the way vascular events present rather than prevent them This may lead to a “cosmetic” reduction in non-fatal events and an increase in sudden death Data on the safety and cost-benefit of aspirin are inadequate Advocating the use of aspirin for preventing atherosclerotic events diverts attention from other, more effective, drugs Meta-analysis is increasingly viewed either as a way of verifying that the outcome of an individual trial is consistent with the rest of the …