Intuitive Modification of the Friedewald Formula for Calculation of LDL-Cholesterol

Abstract

Background: High LDL-cholesterol (LDL-C) is an established risk factor for cardiovascular disease and is considered an important therapeutic target. It can be measured directly or calculated from the results of other lipid tests. The Friedewald formula is the most widely used formula for calculating LDL-C. We modified the Friedewald formula for a more accurate and practical estimation of LDL-C.Methods: Datasets, including measured triglyceride, total cholesterol, HDL-cholesterol, and LDL-C concentrations were collected and assigned to derivation and validation sets. The datasets were further divided into five groups based on triglyceride concentrations. In the modified formula, LDL-C was defined as total cholesterol − HDL-cholesterol − (triglyceride/adjustment factor). For each group, the adjustment factor that minimized the difference between measured LDL-C and calculated LDL-C using modified formula was obtained. For validation, measured LDL-C and LDL-C calculated using the modified formula (LDL-CM), Friedewald formula (LDL-CF), Martin-Hopkins formula (LDL-CMa), and Sampson formula (LDL-CS) were compared.Results: In the derivation set, the adjustment factors were 4.7, 5.9, 6.3, and 6.4 for the groups with triglyceride concentrations < 100, 101-200, 201-300, and > 300 mg/dL, respectively. In the validation set, the coefficient of determination (R 2 ) between measured and calculated LDL-C was higher for LDL-CM than for LDL-CF (R 2 = 0.9330 vs. 0.9206).

Associations of LDL Cholesterol, Non-HDL Cholesterol, and Apolipoprotein B With Cardiovascular Disease Occurrence in Adults: Korean Genome and Epidemiology Study

“…From an analytical viewpoint, the non-HDL-C concentration is dependent on the calculation method, and the assumed total error of total cholesterol concentration plus HDL-C concentration is larger than that of ApoB [18]. There may be a difference between LDL-C calculated by the classical Friedewald formula and directly measured LDL-C [19], which may have affected our results.…”

A novel equation for the estimation of low-density lipoprotein cholesterol in the Saudi Arabian population: a derivation and validation study

“…Moreover, they may not exhibit complete LDL-C specificity in the presence of abnormal lipoproteins, and its accuracy could sometimes be influenced by elevated TGs 56 , 57 . As shown by some studied, the homogenous assays might also be sometimes discordant with the ßQ method at low LDL-C levels 58 . Calculated VLDL-C levels can also reflect intermediate-density lipoprotein cholesterol (IDL-C) and lipoprotein (a) (Lp(a)), which constitutes a negligible amount of non-HDL-C, except in the very rare cases of elevated Lp(a) and type III dyslipidemia, which were not captured from our records, however, due to their rarity, these cases are not expected to alter our VLDL-C values and change the observed TG:VLDL-C ratio, and since our equation is independent of VLDL-C, it certainly does not impact its accuracy.…”