Participant recruitment to the Coronary Primary Prevention Trial.

This report describes participant recruitment to the Coronary Primary Prevention Trial, a long-term multicenter clinical trial sponsored by the National Heart, Lung and Blood Institute to test the effect of lowering plasma cholesterol on the incidence of coronary heart disease. The study protocol limited participation to men 35--59 yr of age with fasting plasma cholesterol of at least 265 mg/dl and in good general health. Recruitment began in July 1973, with a goal of 3550 entries within 18 months using referrals from the medical community as the primary source. The yield from this strategy proved inadequate, necessitating adoption of new recruitment sources which generally involved mass screening. These strategies led to the accrual of 3810 participants, although the pre-entry phase was extended by 19 months, i.e. through July 1976. Overall Trial recruitment experience is presented as well as results obtained from each major recruitment source and center and recommendations for conducting recruitment in future clinical trials.