High triglyceride levels alter the correlation of apolipoprotein B with low- and non-high-density lipoprotein cholesterol mostly in individuals with diabetes or metabolic syndrome

Objective: To assess the correlation of Apolipoprotein B (Apo-B) with low-density (LDL-C) and non-high-density lipoprotein cholesterol (non-HDL-C) in untreated individuals attending a lipid clinic.

Methods: This was a retrospective study conducted in Greece and including 1000 dyslipidemic subjects. We included individuals not taking lipid-lowering therapy at baseline visit and divided them in 2 groups: subjects diagnosed with diabetes or fulfilling the criteria of metabolic syndrome (MetS) and hyperlipidemic subjects without diabetes or MetS. The correlations (r(2)) of Apo-B with LDL-C and non-HDL-C were assessed in these 2 groups. Further analyses were performed according to the baseline triglyceride (TG) levels (<and ≥200 mg/dL).

Results: From 821 eligible subjects, 51% were diagnosed with diabetes or MetS. The correlations between Apo-B and LDL-C or non-HDL-C were similar for the individuals with TG < 200 mg/dL. Specifically, Apo-B was significantly correlated with LDL-C (r(2) = 0.755, p < 0.01, for those with diabetes or MetS; r(2) = 0.848, p < 0.01, for non-diabetic and no MetS hyperlipidemic subjects). The corresponding correlations between Apo-B and non-HDL-C for the 2 groups were 0.743 and 0.838, respectively (p < 0.01). Although these correlations remained significant for the individuals with high TG levels (≥200 mg/dL), the correlation factor was markedly decreased mostly in those with diabetes or MetS (r(2) = 0.600, p < 0.01, for the correlation between Apo-B and LDL-C; r(2) = 0.604, p < 0.01, for the correlation between Apo-B and non-HDL-C); in contrast, the corresponding correlations were stronger in the non-diabetic and no MetS hyperlipidemic individuals (r(2) = 0.710 and 0.714, respectively, p < 0.01).

Conclusion: Apo-B correlation with both LDL-C and non-HDL-C is reduced in individuals with high TG levels and in particular for those with diabetes or MetS.