Coronary Drug Project

The Coronary Drug Project, which was conducted during 1966 to 1974, was a randomized, double‐blind, placebo‐controlled trial of five lipid‐modifying agents—estrogens at two dosage levels, dextrothyroxine, clofibrate, and niacin—in 8341 men with previous myocardial infarction. The primary efficacy outcome was all‐cause mortality for the entire follow‐up period. The first three named regimens were terminated early because of adverse effects. Only niacin significantly reduced the risk of (1) cardiovascular events during a mean follow‐up of 6.2 years and (2) all‐cause mortality during 6.2 years with study treatment plus an additional 9 years of post‐trial follow‐up. Analyses of treatment–placebo differences with respect to all‐cause mortality, subdivided by level of adherence to the study prescription and by amount of change in serum cholesterol level, could not be properly interpreted because reasons for good/poor adherence and for cholesterol changes in the placebo group were not well defined.