Lipid Research Clinics Coronary Primary Prevention Trial: results and implications.

The Lipid Research Clinics Coronary Primary Prevention Trial (LRC-CPPT) tested the efficacy of lowering cholesterol levels in reducing the risk of coronary heart disease (CHD) in 3,806 asymptomatic, middle-aged men with primary hypercholesterolemia. The group treated with cholestyramine had 8.5% and 12.6% greater reductions in total and low-density lipoprotein levels, respectively, than those achieved in the placebo group. The cholestyramine group had a 19% reduction in risk (p less than 0.05) of the primary endpoint of definite CHD, death or definite nonfatal myocardial infarction. Corresponding and significant reductions were also seen for angina, development of a positive exercise test, and coronary bypass surgery. All-cause mortality was only slightly, and not significantly, reduced in the cholestyramine group, reflecting more violent and accidental deaths in the cholestyramine subjects. When the cholestyramine group was analyzed separately, a 19% reduction in CHD risk was also associated with each decrement of 8% in the total cholesterol level. Moreover, CHD incidence in men in whom a decrease of 25% in total cholesterol was sustained, a typical response to the prescribed dosage (24 g/day) of cholestyramine resin, was half that of men who remained at the pretreatment level. The LRC-CPPT findings show that reducing the total cholesterol level by lowering the LDL cholesterol level can diminish the incidence of CHD morbidity and mortality in men at high risk for CHD because of increased LDL cholesterol levels. These results have considerable importance for the prevention of CHD through cholesterol lowering, at both the clinical and public health levels.