Aspirin and secondary mortality after myocardial infarction.

Three randomized controlled trials of aspirin and secondary mortality have been conducted in patients who had had a myocardial infarction. One trial was based on 1239 men followed for 1-2 years; the second was based on 1468 men and 257 women followed for 1 year after infarction. Although the results are not statistically significant in either trial, they are consistent with a reduction in mortality during the year after infarction of about 24% and 17%. Detailed analyses, in which allowance is made for small imbalances between the groups on aspirin and on placebo, indicate that the estimate of benefit of 17% in one of the trials is almost certainly an underestimation. The third trial, in which we analyzed only very early mortality based on 2530 patients, did not show evidence of benefit from aspirin given during the acute phase of infarction.