Concordance between LDL Cholesterol estimated by various formulas and directly measured LDL cholesterol

Background: Low density lipoprotein cholesterol (LDL C) has been established as a major risk factor for cardiovascular diseases. Numerous algorithms have been developed for LDL C calculation; nonetheless, the precision of these equations varies across different ethnicities. This study aimed to quantify the discordance in LDL-C levels between (the DeLong’s, Friedewald, Sampson and Martin/Hopkins equations) and compare them with direct LDL-C (dLDL-C). Materials and Methods: A total of 1020 patients, aged between 18-65 years were included in the study. LDL-C measured by friedewald’s formula, deLong’s formula, sampson’s formula, de Cordova’s formula, anandaraja formula and martin’s formula were compared with directly measured LDL-C. Comparison of calculated LDL-C with directly measured LDL-C was done at Triglyceride (TG) range of 400 mg/dL. Statistical analysis was done utilizing Lin's concordance coefficient (CCC) and two paired t-test. Results: Of the total 1020 samples, there were 619 males and 401 females. The mean age observed was 40.9±8.0 years. The formulas with the best CCC were DeLong (0.962) and Sampson (0.960) with no relevant differences. The extended Martin/Hopkins formula (0.935) and the Friedewald formula (0.949) also executed well. The Anandaraja (0.887) and de Cordova (0.924) equations exhibited inferior performance. The mean differences observed was in the range of 1.6 to 9.68 mmol/L. Conclusion: In the present study, DeLong’s and Sampson formula showed highest concordance and low percentage of errors compared to Frieldwald’s, Martin/Hopkins, Anandaraja and de Cordova’s formula.