We performed a randomized, double-blind, placebo-controlled trial in 555 patients with
unstable angina who were hospitalized in coronary care units. Patients received one of four possible treatment regimens:
aspirin (325 mg four times daily),
sulfinpyrazone (200 mg four times daily), both, or neither. They were entered into the trial within eight days of hospitalization and were treated and followed for up to two years (mean, 18 months). The incidence of
cardiac death and nonfatal
myocardial infarction, considered together, was 8.6 per cent in the groups given
aspirin and 17.0 per cent in the other groups, representing a risk reduction with
aspirin of 51 per cent (P = 0.008). The corresponding figures for either
cardiac death alone or death from any cause were 3.0 per cent in the groups given
aspirin and 11.7 per cent in the other groups, representing a risk reduction of 71 per cent (P = 0.004). Analysis by intention to treat yielded smaller risk reductions with
aspirin of 30 per cent (P = 0.072), 56 per cent (P = 0.009), and 43 per cent (P = 0.035) for the outcomes of
cardiac death or nonfatal acute
myocardial infarction,
cardiac death alone, and all deaths, respectively. There was no observed benefit of
sulfinpyrazone for any outcome event, and there was no evidence of an interaction between
sulfinpyrazone and
aspirin. Considered together with the results of a previous clinical trial, these findings provide strong evidence for a beneficial effect of
aspirin in patients with
unstable angina.