Maximizing recruitment efforts in a drug lipid-lowering trial with dietary intervention to lower LDL cholesterol

Abstract

A select group of screened applicants initially disqualified from a four-center, primary prevention drug lipid-lowering trial because of borderline elevated serum low-density lipoprotein cholesterol (LDL-C) levels, as defined in National Cholesterol Education Program-Adult Treatment Panel I (NCEP-ATP I) guidelines, participated in a dietary intervention protocol that was incorporated into the screening phase of the trial. Seventy-seven screened applicants for the Asymptomatic Carotid Artery Progression Study entered the dietary program, which was overseen by an experienced registered dietitian at the central operations sites who collaborated with local staff at clinical sites during program implementation. NCEP-ATP I fat-modified step I diet specifications served as the basis for the intervention. The program, consisting of five sessions conducted over an 8-week period, primarily used written and audiovisual educational materials in combination with behavioral approaches. Of the original 77 participants, 36 responded to the intervention by achieving their LDL-C goal. Twenty-nine were nonresponders and 12 were dropouts. Responders achieved an average 11.7% drop in total cholesterol at the end of the 8-week program. Mean LDL-C decline paralleled total cholesterol change. High-density lipoprotein cholesterol also decreased significantly. These results were sustained for 24 of the responders attending the final screening visit approximately a month later, when another fasting blood lipid measurement was made. Participants who dropped out were more likely to be smokers. Pre- and postintervention nutrition data assessed by semiquantitative food frequency questionnaire for 20 screenees randomized into the study indicated significant reductions in total fat, saturated fat, polyunsaturated fat, and dietary cholesterol, all known to influence blood lipid levels. Similar programs may prove useful to other drug lipid-lowering trials to maximize recruitment efforts.