Importance of low-density lipoprotein cholesterol dosage

Abstract

The Friedewald equation assumes that the plasma concentration of very low-density lipoprotein cholesterol (VLDL-C) is one fifth of the plasma level of triglycerides (TG). The present work proposes a more refined method to estimate low-density lipoprotein cholesterol (LDL-C), but recommends also evaluating the VLDL composition because its triglyceride content would constitute a biomarker of atherogenic benefit. One hundred patients attending routine health control were randomly selected. No selection criteria were applied. Standardized analytical methods and classic statistical techniques were used. A new calculation method, based on the Friedewald equation with the addition of a logarithmic term, was proposed to estimate LDL-C concentration. This formula allowed improving the estimation by 2.8 %. Also, the decrease in VLDL triglycerides, estimated by the VLDL-C/TG index, was positively associated with VLDL-C (r = 0.370) and high-density lipoprotein cholesterol (HDL-C) (r = 0.438), and negatively with LDL-C (r = -0.421) and TG (r = -0.578); p < 0.001 in all cases. These results highlight the importance of measuring LDL-C, calculating VLDL-C as the difference between total cholesterol and the sum of HDL-C and LDL-C, and evaluating VLDL composition through the VLDL-C/TG index. Although it may be assumed that cholesterol enriched in VLDL particles would be more atherogenic, its presence is associated with better lipid profiles.