Non-HDL cholesterol versus Apolipoprotein B in the identification of dyslipidemic phenotypes associated with cardiovascular risk in type 2 diabetic dyslipoproteinemia

SummaryObjectiveFew studies have compared non-HDL cholesterol (non-HDLc) and Apolipoprotein B (apoB) as markers of atherosclerotic risk. No such study has yet been undertaken in Asian-Indians who have a different lipid–lipoprotein profile than their Western counterparts. Our aim, therefore, was to evaluate the role of non-HDLc and apoB, as markers of all potentially atherogenic species, and to further assess as to which is the better index of the risk of cardiovascular disease (CVD) in type 2 diabetic subjects.Research design and methodsLipidic parameters, apoB and carotid mean intima–media thickness (IMT) were determined in the 95 diabetic subjects included in the study. Subjects were classified on the basis of apoB and triglyceride as well as non-HDLc and triglyceride levels. Agreement of the resultant phenotypes with IMT was assessed (correlation and concordance (κ) analysis), and the major contributor to the variance of IMT was determined using multistep linear regression.ResultsHyperapoB was the most prevalent lipoproteic abnormality. The correlation between apoB and non-HDLc was strong in the whole cohort (r = 0.60, p < 0.01) and better in the hypertriglyceridemic subgroup (r = 0.67, p < 0.01). There was significant concordance between IMT and apoB and non-HDLc in the whole cohort (κ = 0.490, p < 0.0001; κ = 0.403, p < 0.000); while the concordance between the apoB and non-HDLc dependent phenotypes and IMT was better in the hypertriglyceridemic subgroup (HtgHapob-κ = 0.598, p < 0.0001; HtgHnonhdl-κ = 0.481, p < 0.0001) as opposed to the normotriglyceridemic subgroup (NtgHapob-κ = 0.387, p < 0.0001; NtgHnonhdl-κ = 0.043, p = NS). Further apoB was a better predictor of IMT in all the subgroups as well as the whole cohort (R2 = 0.378, β-coefficient = 0.002) as compared to non-HDLc (R2 change = 0.030, β-coefficient = 0.0017).ConclusionsNon-HDLc and apoB are equivalent atherogenic markers of cardiovascular risk in hypertriglyceridemic diabetic subjects, but apoB is a better index of the risk of cardiovascular disease in normotriglyceridemic subjects. Thus, measurement of apoB might be helpful in identification of a subgroup of apparently normolipidemic subjects who have hyperapoB and thus stand increased cardiovascular risk.