CHOLESTEROL AND CORONARY HEART-DISEASE - PREDICTING RISKS BY LEVELS AND RATIOS

Objective: Comparison of four measures of cholesterol for predicting m en and women who will develop coronary heart disease within 8 to 10 ye ars. Design: Cohort study. Patients: 1898 men who received placebo (th e placebo group of the Lipid Research Clinics [LRC] Coronary Primary P revention Trial [CPPT]), 1025 men and 1442 women who participated in t he 1970-1971 Framingham Heart Study biennial examination, and 1911 men and 1767 women without coronary heart disease who were from the LRC P opulation Prevalence Study. Measurements: Total cholesterol, low-densi ty lipoprotein (LDL) cholesterol, ratio of total cholesterol to high-d ensity lipoprotein (HDL) cholesterol, and the ratio of LDL to HDL. Out comes were coronary heart disease in the CPPT and Framingham studies a nd death from coronary heart disease in the Prevalence Study. Results: independent information in the total cholesterol/HDL ratio added risk -discriminating ability to total Cholesterol and LDL cholesterol measu res (P < 0.02), but the reverse was not true. Among women, a high-risk threshold of 5.6 for the total cholesterol/HDL ratio identified a 0% to 15% larger group at 25% to 45% greater risk in the Prevalence and F ramingham studies, respectively, than did current guidelines. Among me n in the same studies, a risk threshold of 6.4 for the total cholester ol/HDL ratio identified a 69% to 95% larger group at 2% to 14% greater risk than did LDL cholesterol levels alone. Eight-year likelihood rat ios for coronary heart disease ranged from 0.32 to 3.11 in men and fro m 0.59 to 2.98 in women for total cholesterol/HDL ratios (grouped from < 3 to greater than or equal to 9). Conclusions: The total cholestero l/HDL ratio is a superior measure of risk for coronary heart disease c ompared with either total cholesterol or LDL cholesterol levels. Curre nt practice guidelines could be more efficient if risk stratification was based on this ratio rather than primarily on the LDL cholesterol l evel.