Participant recruitment to the Lipid Research Clinics Coronary Primary Prevention Trial

The Lipid Research Clinics Coronary Primary Prevention Trial, a multicenter clinical trial sponsored by the National Heart, Lung, and Blood Institute, was undertaken in 1973 to evaluate whether lowering blood cholesterol would reduce the incidence of coronary heart disease. The study protocol limited entry into the trial to men 35-59 years of age who had type II hyperlipoproteinemia with plasma cholesterol of at least 265 mg/dl, who were free of coronary heart disease symptoms, and who were in good general health. Participants were initially recruited from physician and clinical laboratory referrals. After the first year of recruitment, yields from these sources were unacceptably low, and emphasis was directed to identifying new sources using mass screening. Six additional sources were used-blood banks, clinical studies, community screenings, mass mailings, media, and occupational (worksite) screenings. The target recruitment goal was exceeded although it required more than twice as long as originally planned. Characteristics of these eight recruitment sources and recommendations for those undertaking a similar study are presented, based on the experience gained from recruitment of participants for this trial.