A double-blind, randomized multi-hospital study is in progress to investigate, among patients with unstable angina, the efficacy of aspirin (1300 mg daily) and sulfinpyrazone (800 mg daily), both singly and in combination, in reducing mortality, both overall and cause-specific; myocardial infarction; recurrence of unstable angina; and the frequency of aorto-coronary bypass surgery. It is proposed to enroll approximately 600 patients from six coronary care units and to follow each patient for up to two years.
An outline of the study design and execution will be presented and some of the specific methodological problems associated with this study will be discussed. In particular, attention will be drawn to the difficulty of recruiting patients to this type of trial (8000 patients screened to produce the first 200 patients actually entered into the study) and to the confounding created by other interventions among these patients, including both medication and coronary bypass surgery. An interim assessment of efficacy will not be presented but some overall descriptive data relating to patient characteristics, protocol adherance, and outcome measures will be summarized.