Evaluation of Recently Developed Regression Equation with Direct Measurement of Low-density Lipoprotein Cholesterol in a Bangladeshi Population

Abdul Hai Siddique,Md Aminul Haque Khan,Md Fazley Rabbi Sha,Muhammad Saiedullah

doi:10.3329/jemc.v5i2.23376

Abstract

Background: Meaningful underestimation of low-density lipoprotein (LDL) cholesterol is an important shortcoming of Friedewalds formula (FF) at higher triglyceride (TG) levels. Recently a regression equation (RE) has been developed using lipid profiles in one setting and validated externally for the calculation of LDL cholesterol. This newly developed RE requires more studies in different settings.Objective: The aim of this study was to evaluate the performance of the regression equation against direct measurement.Materials and Methods: Lipid profiles of 600 subjects attending a tertiary healthcare center were included in this study. Specimens were collected and lipid profiles were measured by standard methods. Sixty two lipid profiles with TG above 400 mg/dL were excluded. Calculated LDL cholesterol values using FF and RE were compared with measured LDL cholesterol by Pearsons correlation test, Passing & Bablok regression, accuracy within ±5% and ±12% of measured LDL cholesterol and two-tailed paired t test at various TG ranges.Results: The mean value of LDL cholesterol was 148.6 ± 37.2 mg/dL for direct measurement, 146.9 ± 42.4 mg/dL for FF and 148.6 ± 34.7 mg/dL for RE. The correlation coefficients of calculated LDL cholesterol values with measured LDL cholesterol were 0.949 (p<0.001) for FF and 0.959 (p<0.001) for RE. Passing & Bablok regression equation against measured LDL cholesterol was y = 0.897x + 16.2 for FF and y = 1.0842x 13.1 for RE. Accuracy within ±5% of measured LDL cholesterol was 45% for FF, 57% for RE and within ±12% of measured LDL cholesterol was 84% for FF, 93% for RE. When calculated LDL cholesterol was compared with measured LDL cholesterol at different TG ranges, FF significantly underestimated LDL cholesterol at TG concentrations above 200 mg/dL whereas no significant difference was observed for RE.Conclusion: This study reveals that RE equation has similar performance to direct measurement for calculation of LDL cholesterolJ Enam Med Col 2015; 5(2): 75-79

Highlights

Cardiovascular diseases, the leading cause of death worldwide, increase the global health burden
Circulating low-density lipoprotein (LDL) cholesterol is thought to be critically involved in the development of coronary heart disease (CHD)[1] and it is considered as the primary basis for accurate
In this study LDL cholesterol calculated by both Friedewald’s formula (FF) and regression equation (RE) correlated well with measured LDL cholesterol

Summary

Introduction

Cardiovascular diseases, the leading cause of death worldwide, increase the global health burden. 1. Research Fellow, Department of Applied Laboratory Sciences, Bangladesh University of Health Sciences, Dhaka, Bangladesh 2. Assistant Professor, Department of Applied Laboratory Sciences, Bangladesh University of Health Sciences, Dhaka, Bangladesh 4. A regression equation (RE) has been developed using lipid profiles in one setting and validated externally for the calculation of LDL cholesterol. This newly developed RE requires more studies in different settings. Calculated LDL cholesterol values using FF and RE were compared with measured LDL cholesterol by Pearson’s correlation test, Passing & Bablok regression, accuracy within ±5% and ±12% of measured LDL cholesterol and two-tailed paired t test at various TG ranges. Conclusion: This study reveals that RE equation has similar performance to direct measurement for calculation of LDL cholesterol.

Objectives

Methods

Conclusion