Validation of the Estimation of Low-density Lipoprotein Cholesterol by the Modified Friedewald Equation in Ethnic Chinese Adults Living in Taiwan

Abstract

Objective The Friedewald equation has been used as the standard formula for the estimation of very low-density lipoprotein cholesterol (VLDL-C) to calculate the serum levels of low-density lipoprotein cholesterol (LDL-C). However, the usefulness of this formula in non-Caucasians has been challenged in recent years. The aim of this study was to assess the validity of the conventional and modified Friedewald equation in an ethnic Chinese adult population.
Methods We prospectively recruited 938 subjects from the Lipid Clinic of the National Taiwan University Hospital. The fasting lipids, including cholesterol, high-density lipoprotein cholesterol, LDL-C, VLDL-C, and triglycerides (TGs), of each participant were measured and we constructed a prediction model for the estimation of LDL-C by the modified Friedewald equation.
Results The constant values, used to estimate the VLDL-C concentration, were different in the Friedewald equation in the subgroups exhibiting different cardiovascular characteristics, ranging from 4.45 to 6.63, if we calculated the equation by a direct LDL-C measurement. According to the results of a stepwise multiple linear regression analysis excluding the TG levels ≥400 mg/dL, an equation for the individual constant Y estimation was as follows: Constant Y = 4.39 + (-0.59) if the age ≥50 years + 0.98 if men + TG group (2.06 if the TG levels were between 150-399 mg/dL; 1.07 if the TG levels were between 100-149 mg/dL) + (-0.49) if the cholesterol levels ≥240 mg/dL + the body mass index (BMI) group (0.8 if BMI ≥27 kg/m²; 0.48 if BMI =24-27 kg/m²).
Conclusion This modified Friedewald formula provides a new and simple equation for calculating the LDL-C levels in ethnic Chinese people.