Prediction of coronary risk for primary prevention of coronary heart disease: a comparison of methods

Most recent guidelines advise targeting of lipid lowering for primary preve ntion at those at high absolute coronary (CHD) risk. We compared the accura cy of five CHD risk assessment methods in identifying such patients: one ba sed on total cholesterol greater than or equal to 6.5 mmol/l plus two risk factors, and four based on the Framingham risk function (the European Task Force chart and Sheffield table, both using total cholesterol and the New Z ealand chart and modified Sheffield table, both using total:HDL cholesterol ratio) for predicting CHD event risk greater than or equal to 2% per year, calculated by an independent risk function, PROCAM, in 126 treated hyperte nsive men. Cholesterol threshold plus two risk factors had sensitivity 59% and specificity 63%, did not identify some very high-risk patients, and ide ntified very low-risk patients. Framingham-based methods using total choles terol alone had sensitivity 90-98% and specificity 37-43%, and identified h igh-risk patients well, but identified some patients at very low risk. Meth ods based on total:HDL cholesterol ratio had sensitivity 90-98% and specifi city 60-63%, and did not identify incorrectly patients at very low CHD risk . Methods based on cholesterol threshold and counting of risk factors are t oo inaccurate for targeting drug therapy for primary prevention of CHD. Fra mingham-based methods should incorporate HDL-cholesterol as the total:HDL c holesterol ratio.