Comparison of direct versus Friedewald estimation of LDL cholesterol: Experience in Indian hyperlipidemic patients

Author(s): Harshad Malve

Background and Objectives: LDL cholesterol is routinely calculated by the Friedewald equation to guide the treatment of dyslipidemia; however, Friedewald equation has certain limitations especiallywith high triglyceride levels. Direct methods are available for LDL estimation but have received relatively little scrutiny in India.Very limited data is available on comparison of these 2 methods in Indian patients. This study was aimed at comparing the calculative and directmethods of LDL Cholesterol estimation in Indian hyperlipidemic patients.Materials andMethods: In this observational study, data from380 consecutive lipid profileswas analysed. CHOD PAPMethod was used to estimate Total Cholesterol. Enzymatic Colorimetric Method was used to estimate Triglycerides, Enzyme selective protection method was used to estimate HDL, Homogenous Enzymatic Colorimetric Assay was used to estimate direct LDL and VLDL was calculated whereas Friedewald’s formula was used to derive calculated LDL. Results: Total Cholesterol values correlated positively with LDL values measured by both themethods. However, a statistically significant difference (p=0.0418) was noted between the correlation coefficients of both the methods. Triglyceride values correlated weakly with LDL levels measured by both themethods.Aweak negative correlationwas observedwithLDL-Cwhereas a weak positive correlation existed between TG and LDL-D values. The difference between the correlation coefficientswas statistically significant. Conclusion: Both the direct and calculated methods of LDL estimation have their limitations. Need a robust studywith larger sample size to further investigate whether the differences in LDL estimation methods are translated into “clinical relevance” in Indian settings.

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