[Importance of HDL cholesterol determination in the evaluation of coronary risk in clinical practice]

Abstract

Objective: To validate to what extent the isolated determination of total Cholesterol (TC) is effective when seeking to predict coronary risk.

Design: An observational crossover study of the analytic determinations of the clinics which systematically request TC and HDL-Cholesterol (HDL)--case-finding method.

Setting: Health Centre.

Participants: 631 analytic determinations, with samples from people who attended a Health Centre between May and November 1992, were studied.

Measurements and main results: As proof of certainty the Atherogenic Index (AI) was used for the relative risks (RR) of suffering a coronary event in line with the Framingham study. The confidence limits (CL) were calculated to 95% in order to quantify random error and permit comparison. On varying the cut-off points of TC the indicators changed, being more sensitive (S) and less specific (E) with the lower figures: 180 mg/dl, RR > 1, S = 97.5% (CL: 100-94.7) and E = 30.5% (36.8-24.2); RR > 2, S = 100%, E = 22.1% (26.9-17.3) and RR > 3, S = 100%, E = 20.8% (25.3-16.3). As values of TC increase, S diminishes and E increases: 250 mg/dl, RR > 1, S = 48.3% (57.2-39.4), E = 87.2% (91.8-82.6); RR > 2, S = 58.6% (76.5-40.7), E = 77.2% (82-72.4) and RR > 3, S = 63.6% (92-35.2), E = 75.3% (80.1-70.5).

Conclusions: HDL must be determined if TC is -200 mg/dl. If everyone with RR > 2 is to be detected, HDL-cholesterol from TC > or = 180 mg/dl must be measured.