Validation of the Friedewald formula for estimating low density lipoprotein cholesterol: the Korea National Health and Nutrition Examination Survey, 2009 to 2011

Objectives: The accurate and precise measurement of low-density lipoprotein-cholesterol (LDL-C) is important in the assessment of atherosclerotic cardiovascular disease risk (ASCVD) in people with diabetes mellitus. This study aimed at comparing directly measured LDL-C with Friedewald formula (FF)-calculated LDL-C (c-LDL-C) in people with type-2 diabetes. Methods: Fasting lipid profiles of 1905 people with type-2 diabetes, whose LDL-C was estimated by direct LDL assay, were chosen for the study. In the same group, LDL-C was calculated with FF. Correlation and agreement between these methods were analyzed at various strata of triglycerides (TGs). The possibility of misclassifying people at various levels of LDL-C targets proposed in literature was calculated. Results: The mean LDL-C levels were lower in the c-LDL-C group across various TG strata. A significant correlation was found between c-LDL-C and direct LDL-C for all the study samples ( r = 0.948, P < .001) and across all TG strata. Analysis of agreement showed a positive bias for direct LDL-C which increased at higher strata of TGs. c-LDL-C underestimated ASCVD by misclassifying people at various LDL-C target levels. Conclusion: There is a difference between direct LDL-C and c-LDL-C values in people with diabetes and this may result in misclassifying ASCVD especially at lower levels of LDL-C and higher levels of TGs.

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Applicability of Martin-Hopkins formula and comparison with Friedewald formula for estimated low-density lipoprotein cholesterol in e_COR study population

Revista Portuguesa de Cardiologia (English Edition) ◽

10.1016/j.repce.2021.07.001 ◽

2021 ◽

Author(s):

Cátia Ferrinho ◽

Ana Catarina Alves ◽

Mafalda Bourbon ◽

Sequeira Duarte

Keyword(s):

Low Density Lipoprotein ◽

Density Lipoprotein ◽

Lipoprotein Cholesterol ◽

Low Density ◽

Low Density Lipoprotein Cholesterol ◽

Study Population ◽

Friedewald Formula

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Non-HDL-C/TG ratio indicates significant underestimation of calculated low-density lipoprotein cholesterol (LDL-C) better than TG level: a study on the reliability of mathematical formulas used for LDL-C estimation

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2020-1366 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Agnieszka Ćwiklińska ◽

Ewa Wieczorek ◽

Anna Gliwińska ◽

Marta Marcinkowska ◽

Monika Czaplińska ◽

...

Keyword(s):

Total Error ◽

Low Density Lipoprotein ◽

Density Lipoprotein ◽

Lipoprotein Cholesterol ◽

Low Density ◽

Low Density Lipoprotein Cholesterol ◽

Percentage Difference ◽

Mathematical Formulas ◽

Friedewald Formula ◽

Significant Underestimation

Abstract Objectives Low-density lipoprotein cholesterol (LDL-C) is the main laboratory parameter used for the management of cardiovascular disease. The aim of this study was to compare measured LDL-C with LDL-C as calculated by the Friedewald, Martin/Hopkins, Vujovic, and Sampson formulas with regard to triglyceride (TG), LDL-C and non-high-density lipoprotein cholesterol (non-HDL-C)/TG ratio. Methods The 1,209 calculated LDL-C results were compared with LDL-C measured using ultracentrifugation-precipitation (first study) and direct (second study) methods. The Passing-Bablok regression was applied to compare the methods. The percentage difference between calculated and measured LDL-C (total error) and the number of results exceeding the total error goal of 12% were established. Results There was good correlation between the measurement and calculation methods (r 0.962–0.985). The median total error ranged from −2.7%/+1.4% (first/second study) for Vujovic formula to −6.7%/−4.3% for Friedewald formula. The numbers of underestimated results exceeding the total error goal of 12% were 67 (Vujovic), 134 (Martin/Hopkins), 157 (Samspon), and 239 (Friedewald). Less than 7% of those results were obtained for samples with TG >4.5 mmol/L. From 57% (Martin/Hopkins) to 81% (Vujovic) of underestimated results were obtained for samples with a non-HDL-C/TG ratio of <2.4. Conclusions The Martin/Hopkins, Vujovic and Sampson formulas appear to be more accurate than the Friedewald formula. To minimize the number of significantly underestimated LDL-C results, we propose the implementation of risk categories according to non-HDL-C/TG ratio and suggest that for samples with a non-HDL-C/TG ratio of <1.2, the LDL-C level should not be calculated but measured independently from TG level.

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