Comparison of Calculated LDL-Cholesterol Using Various Formulae with Directly Measured LDL-Cholesterol: A Retrospective Study

Background: Among the various risk factors for developing dyslipidemia and Cardiovascular Disease (CVD), elevated Low-Density Lipoprotein Cholesterol (LDL-C) has been recognized as an independent and widely accepted risk factor for CVD. Therefore the objective of the study was to calculate LDL-C using various formulae and to compare the various formulae to calculate LDL-C with direct LDL-C measurement. Materials and methods: It was a retrospective observational study and study was conducted for a period of 3 Months. During this period, 400 consecutive serum samples were included, out of which 37 had TG value more than 400 mg/dl and were excluded from the study. Finally 363 samples data were included for analysis and data were obtained from the investigation ledger of clinical Biochemistry section and same sample Triglyceride, Total Cholesterol and High Density Lipoprotein Cholesterol was used for calculating LDL-C using various formulae. Results: A total of 400 lipid profile reports were collected, of these, 37 reports had triglyceride level ≥ 400 mg/dl and hence 363 samples were included. There is no statistical difference between the direct LDL-C (131.64± 29.34mg/dl) and LDL-C level calculated by Friedewald formula (133.85±35.97mg/dl, p>0.05). There is a highly significant statistical difference between the direct LDL-C and the LDL-C level calculated using all other formulae (p=0.0001) Cordova and Cordova formula (88.06 ± 28.40mg/dl), Vujovic formula (80.44 ± 15.52mg/dl), Ahmadi formula (186.34 ± 63.26mg/dl), Anandaraja formula (92.46 ± 32.37mg/dl), Puavillai formula (88.54 ± 32.78mg/dl) and Hattori formula (77.45 ± 30.31mg/dl). Conclusion: The study established Friedewald formula as the most suitable method for calculating LDL-C in the absence of direct LDL-C measurement facilities. A large sample size and multicentric study is warranted to confirm which formula is most suitable for measuring the LDL-C in the absence of direct LDL-C measurement.