Application of the Sampson equation to estimate LDL-C in children: Comparison with LDL direct measurement and Friedewald equation in the BLIP study.

Background and aims: In epidemiological trials and in clinical practices, it is relevant to have affordable and reliable methods to measure the main lipid cardiovascular risk factors, and in particular low-density lipoprotein cholesterol (LDL-C) plasma level. In this context, we aimed to compare the reliability of the Friedewald's (LDL-Cf) and Sampson's (LDL-Cs) equations with the LDL-value dosed by a validated dosage method (LDL-Cd) in a large cohort of children. Methods and results: We considered the lipid values of 145 infants, 278 preschoolers, 810 scholar children, and 1372 adolescents (Total N. 2605, 1291 males, 1314 females), with mean total cholesterol (TC) = 169.8 ± 39.7 mg/dL, HDL-Cholesterol = 50.8 ± 12.7 mg/dL, non HDL-Cholesterol = 118.9 ± 35.9 mg/dL, Triglycerides (TG) = 90.3 ± 77.9 mg/dL, LDL-Cd = 106.2 ± 29.9 mg/dL, LDL-Cf = 100.9 ± 33.8 mg/dL, and LDL-Cs = 102.2 ± 33.4 mg/dL. Comparing the distance to the LDL-Cd, Friedewald's equation mildly but significantly underestimated in infants (3.4 ± 5.3 mg/dL), preschoolers (1.5 ± 7.1 mg/dL). Children (1.2 ± 2.2 mg/dL) and adolescents (1.1 ± 5.9 mg/dL) compared to Sampson's equation (all comparisons, p < 0.001). Conclusions: Our analysis, being carried out on a large population sample, shows that Sampson's equation is more reliable than Friedewald's one at each considered age class and even for extreme TG values.