Low-Density Lipoprotein Estimated by Various Equations in Patients With Obesity

Reducing atherogenic lipoproteins to lower cardiovascular risk is a key objective in obesity treatment. Accurate lipoprotein measurements are essential for determining the need for therapy and guiding its management. To identify the best equation for estimating LDL cholesterol, LDL measured directly (LDL-D) is compared to LDL calculated using equations developed by Friedewald (LDL-F), Martin (LDL-M) and Sampson/NIH (LDL-S). This study also examines the change of LDL and apolipoprotein B levels during a multidisciplinary obesity treatment programme.

This retrospective observational study included 308 adult patients with obesity who participated in a single-centre, multidisciplinary treatment programme using meal replacement (Optifast-professional). This study employed Pearson's correlations, repeated-measures analyses of variance (ANOVA) and a paired t-test and also compared calculated values against desirable bias and total allowable error.

The absolute values of LDL-M and LDL-S showed less bias and correlated better with LDL-D than LDL-F. All equations significantly underestimated absolute LDL values: LDL-F (mean -12.43 mg/dL, p < 0.001), LDL-M (mean -10.05 mg/dL, p < 0.001) and LDL-S (mean -9.49 mg/dL, p < 0.001). LDL-F also underestimated the change occurring during the programme (3.81 mg/dL; p = 0.017). All equations performed poorly against desirable bias and total allowable error. LDL-D, LDL-F, LDL-M, LDL-S and ApoB levels all decreased significantly, and these decreases remained significant after excluding patients taking lipid-lowering medications.

LDL estimation equations systematically underestimated LDL in individuals with obesity. Among these, the Martin equation most accurately captured changes in LDL. Consequently, it appears to be the most suitable estimation method. However, direct measurement should remain the preferred method. The multidisciplinary meal replacement programme significantly reduced LDL cholesterol and ApoB.