Evaluation of different formulas for LDL-C calculation

Abstract

BackgroundFriedewald's formula for the estimation of LDL-C concentration is the most often used formula in clinical practice. A recent formula by Anandaraja and colleagues for LDL-C estimation still needs to be evaluated before it is extensively applied in diagnosis. In the present study we validated existing formulas and derived a more accurate formula to determine LDL-C in a Serbian population.MethodsOur study included 2053 patients with TG ≤ 4.52 mmol/L. In an initial group of 1010 patients, Friedewald's and Anandaraja's formulas were compared to a direct homogenous method for LDL-C determination. The obtained results allowed us to modify Friedewald's formula and apply it in a second group of patients.ResultsThe mean LDL-C concentrations were 3.9 ± 1.09 mmol/L, 3.63 ± 1.06 mmol/L and 3.72 ± 1.04 mmol/L measured by a direct homogenous assay (D-LDL-C), calculated by Friedewald's formula (F-LDL-C) and calculated by Anandaraja's formula (A-LDL-C), respectively in the 1010 patients. The Student's paired t-test showed that D-LDL-C values were significantly higher than F-LDL-C and A-LDL-C values (p < 0.001). The Passing-Bablok regression analysis indicated good correlation between calculated and measured LDL-Cs (r > 0.89). Using lipoprotein values from the initial group we modified Friedewald's formula by replacing the term 2.2 with 3. The new modified formula for LDL-C estimation (S-LDL-C) showed no statistically significant difference compared to D-LDL-C. The absolute bias between these two methods was -0.06 ± 0.37 mmol/L with a high correlation coefficient (r = 0.96).ConclusionsOur modified formula for LDL-C estimation appears to be more accurate than both Friedewald's and Anandaraja's formulas when applied to a Serbian population.

Comparison of Different estimated Formulas with Direct Estimation of Low-density Lipoprotein Cholesterol

“…On calculating the mean percentage difference, it was found that MF-LDL-C differs by 3.5% from D-LDL-C, which was much lower in comparison to the other two calculated formulae (7.29 and 7.64% by F-LDL-C and A-LDL-C respectively). Similar differences were reported in the study by Kapoor 21 these differences were found to be 6.9 and 3.9% for Friedewald and Anandaraja methods respectively. Kamal et al 18 found that MF-LDL-C differs by 10.5% from D-LDL-C, which was much lower in comparison to the other two calculated formulae (16.7 and 22.35% by F-LDL-C and A-LDL-C respectively) similar to our study.…”

“…[18][19][20] The correlation between D-LDL-C and A-LDL-C in our study was found to be 0.92, which was similar to that of other studies, i.e., correlation of 0.93, 0.89, and 0.81. 18,19,21 Our study found a correlation of 0.94 between MF-LDL-C and D-LDL-C, which was higher than the one found by Kamal et al 18 (r = 0.81) and similar to Kapoor et al 17 (r = 0.95). Table 5: Summary of the measurements of TC, LDL-C (direct), LDL-C (Friedewald), and HDL-C according to TG levels, presented as mean ± SD (lowest level found -greatest level found) with Friedewald formula.…”

Low-density lipoprotein cholesterol levels in adults with type 2 diabetes: An alternative equation for accurate estimation and improved cardiovascular risk classification

“…Although a good correlation exists between calculated LDL-C and M-LDL-C, the underestimation of LDL-C according to this formula has been shown in previous studies in the general population, as well as in those with diabetes mellitus. 20,21 Attempts to derive and validate further equations for LDL-C calculation have not been widely adopted, 22,23 and the Friedewald formula remains the recommended method in clinical practice and most National Lipid Guidelines. 4,5,24 Martin et al 25 after evaluating over 1.3 million lipid samples quantified by ultracentrifugation recently recommended an adjustable factor for the TG-to-VLDL ratio, instead of using a fixed factor of 5 (when using mg/dL), based on TG and non-HDL-cholesterol levels.…”

Comparison of equations for the calculation of LDL-cholesterol in hospitalized patients

“…renal failure or diabetes) [2,11], but is widely used. Several other formulae have been developed, but these did not perform better than Friedewald's calculation [12][13][14] or had varying results in different population groups [10,[15][16][17][18][19] and including those considering TG ratios [20,21]. In the latest study validating a novel formula in comparison with Friedewald's calculation and the LDL-C reference method in 23 055 patients, the benefits over…”