BACKGROUND:

Correlation of high levels of serum cholesterol with an increased incidence and prevalence of coronary heart disease (CHD) was demonstrated--prior to the inception of the Coronary Drug Project--repeatedly in prospective and cross-sectional epidemiological surveys (e.g., the Tecumseh Study, the Framingham Heart Disease Study). These findings led to the question of whether long-term lowering of serum lipids in individuals both with and without CHD would have a beneficial effect on morbidity and mortality.

The Coronary Drug Project was designed to answer the question of secondary prevention. In 1961, Dr. Robert Wilkins (Boston University School of Medicine) chaired an ad hoc committee which determined the desirability and feasibility of the conduct of this study. Following National Heart Advisory Council (NHAC) support, a study Policy Board, Steering Committee, and Coordinating Center were established and a detailed protocol was written.

In 1964, NHAC approved the project and the NHI recommendation for implementation; the study was begun in 1965. Supported by the grant mechanism, the trial involved 53 participating clinics, a coordinating center, central laboratory, ECG center, drug procurement and distribution center, and NHI medical liaison office, and a policy board, steering committee, and 12 other committees (e.g., a data and safety monitoring committee).

The first patient was randomly allocated to treatment in March 1966 and the last in October 1969. Each patient reported to the clinic every 4 months for a follow-up visit.

DESIGN NARRATIVE:

Randomized, double-blind, fixed sample. A total of 8,341 patients were randomly assigned to six treatment groups consisting of 2.5 mg/day of conjugated estrogens, 5.0 mg/day of conjugated estrogens, 1.8 gm/day of clofibrate, 6.0 mg/day of dextrothyroxine sodium, 3.0 gm/day of niacin, or 3.8 gm/day of lactose placebo.