Comparison of Regression Equation and Friedewald’s Formula with Direct Measurement of Low-density Lipoprotein Cholesterol in Bangladeshi Population

Abstract

Friedewald's formula (FF) is the most widely used formula in clinical practice to calculate low-density lipoprotein cholesterol (LDLC) from total cholesterol (TC), triglyceride (TG) and high-density lipoprotein cholesterol (HDLC). But this formula frequently underestimates LDLC. The aim of this study was to derive a regression equation (RE) to abolish the underestimation and to compare the performance of RE and FF in Bangladeshi population. RE was derived from 531 lipid profiles (equation derivation group) for the calculation of LDLC by multiple linear regression analysis. The RE was then used to calculate LDLC in another 952 subjects (equation validation group). LDLC calculated by RE and FF were compared with measured LDLC by appropriate statistical analyses. In equation validation group, measured LDLC, LDLC calculated by RE and FF were 2.97±0.81, 2.91±0.80 and 2.72±0.93 mmol/L respectively. Precision (r) was 0.9525 for RE and 0.9193 for FF. Passing & Bablok linear regression equations against measured LDLC were y = 0.9792x + 0.007 for RE and y = 1.1412x -0.6781 for FF. Accuracy within ±12% of measured LDLC was 79% and 57% for RE and FF, respectively. The derived RE is more accurate than FF for the calculation of LDLC in Bangladeshi population.

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

“…This is consistent with a previous study done in this population. 24 Passing & Bablok regression of calculated LDL cholesterol with measured LDL cholesterol also revealed better agreement of RE with direct measurement compared with that of FF. In this study, though accuracy within ±12% of measured LDL cholesterol was higher compared to previous study 24 (84% vs 57%) for FF, better accuracy within ±5% (57% vs 45%) and ±12% (93% vs 84%) of measured LDL cholesterol was observed for RE compared to FF.…”

“…24 Passing & Bablok regression of calculated LDL cholesterol with measured LDL cholesterol also revealed better agreement of RE with direct measurement compared with that of FF. In this study, though accuracy within ±12% of measured LDL cholesterol was higher compared to previous study 24 (84% vs 57%) for FF, better accuracy within ±5% (57% vs 45%) and ±12% (93% vs 84%) of measured LDL cholesterol was observed for RE compared to FF. Differences of mean values of calculated LDL cholesterol using FF with measured LDL cholesterol in the total study subjects were minimal; but it was high and statistically significant at TG concentrations above 200 mg/dL.…”

“…Like the underestimation reported in different population, the underestimation of LDL cholesterol calculated by FF is also common in Bangladeshi population [18][19][20][21][22][23][24][25] and there is no evidence of systematic overestimation of LDL cholesterol by FF in this population. [18][19][20][21][22][23][24] In 2014 Saiedullah et al published a regression equation by analyzing lipid profiles of 531 adult Bangladeshi subjects which was validated externally using lipid profiles of 952 Bangladeshi subjects using linear regression. 24 Subsequently it has been evaluated using another set of lipid profiles collected from the setting of external validation group of the previous study.…”

“…[18][19][20][21][22][23][24] In 2014 Saiedullah et al published a regression equation by analyzing lipid profiles of 531 adult Bangladeshi subjects which was validated externally using lipid profiles of 952 Bangladeshi subjects using linear regression. 24 Subsequently it has been evaluated using another set of lipid profiles collected from the setting of external validation group of the previous study. 25 However, it requires external validation using lipid profiles collected from a setting other than equation development and equation validation.…”

Derivación y validación de una ecuación para estimar el colesterol ligado a lipoproteínas de baja densidad en una población de Lima, Perú

“…En el total de sujetos del estudio, la fórmula de Friedewald y la nueva ecuación infraestimaron el LDLc, obtenién-dose sesgos absolutos de 14,01 mg/dL y 5,52 mg/dL, respectivamente, resultados que coinciden con otros estudios que también utilizaron el análisis de regresión múltiple para derivar su ecuación, pero validado en otra población (22,23) .…”