Triglyceride/low-density-lipoprotein cholesterol ratio is the most valuable predictor for increased small, dense LDL in type 2 diabetes patients

Background

Small, dense low-density lipoprotein (sd-LDL) increases in type 2 diabetes patients and causes arteriosclerosis. Non–high-density-lipoprotein cholesterol (non–HDL-C) is thought to be useful for predicting arteriosclerosis and sd-LDL elevation; however, there are no data about whether the triglyceride /low-density-lipoprotein cholesterol (TG/LDL-C) ratio is a valuable predictor for sd-LDL.

Methods

A total of 110 type 2 diabetes patients with hypertriglyceridemia were analyzed. No patients were treated with fibrates, but 47 patients were treated with statins. LDL-C was measured by the direct method. LDL-migration index (LDL-MI) using electrophoresis (polyacrylamide gel, PAG) was calculated, and a value ≥0.400 was determined to indicate an increase in sd-LDL. Simple regression analyses were carried out between LDL-MI and lipid markers. Receiver operating characteristic curves of lipid markers for predicting high LDL-MI were applied to determine the area under the curve (AUC), sensitivity, specificity, and cut-off point.

Results

LDL-MI correlated negatively with LDL-C (P = 0.0027) and PAG LDL fraction (P < 0.0001) and correlated positively with TGs, non–HDL-C, TG/LDL-C ratio, TG/HDL-C ratio, and non–HDL-C/HDL-C ratio among all study patients. Similar results were obtained for patients analyzed according to statin treatment. The AUCs (95% confidence interval) were 0.945 (0.884-1.000) for TG/LDL-C ratio and 0.614 (0.463-0.765) for non–HDL-C in patients without statins (P = 0.0002). The AUCs were 0.697 (0.507-0.887) for TG/LDL-C and 0.682 (0.500-0.863) for non–HDL-C in patients treated with statins. The optimal cut-off point for TG/LDL-C ratio for increased LDL-MI was 1.1 (molar ratio) regardless of statin treatment. The sensitivity and specificity of the TG/LDL-C ratio (90.0 and 93.9%, respectively) were higher than those of non–HDL-C (56.7 and 78.8%, respectively) in patients without statins.

Conclusions

The TG/LDL-C ratio is a reliable surrogate lipid marker of sd-LDL and superior to non–HDL-C in type 2 diabetes patients not treated with statins.

Circulating non-HDL-C levels were more relevant to atherogenic lipoprotein subfractions compared with LDL-C in patients with stable coronary artery disease

BACKGROUND

Conflicting results have been yielded as to whether low-density lipoprotein (LDL) cholesterol (LDL-C) or non-high-density lipoprotein (HDL) cholesterol (non-HDL-C) is a better marker of coronary artery disease (CAD) risk. Recently, plasma LDL and HDL subfractions have been suggested to be more accurately reflecting the lipoproteins' atherogenicity.

OBJECTIVE

We sought to compare the relationship between LDL-C or non-HDL-C and lipoprotein subfractions.

METHODS

We conducted a cross-sectional study in 351 consecutive stable CAD patients without lipid-lowering therapy. The LDL and HDL separations were performed using the Lipoprint System. The LDL-C levels were measured directly, and the non-HDL-C levels were calculated.

RESULTS

The cholesterol concentrations of LDL (large, medium, and small) and HDL (small) particles were increased (all P < .001) by non-HDL-C or LDL-C quartiles, whereas the mean LDL particle size and cholesterol concentrations of HDL (large) were decreased (both P < .001) by non-HDL-C quartiles. In age- and gender-adjusted analysis, the cholesterol in small LDL was much strongly related to non-HDL-C than to LDL-C (r = 0.539 vs 0.397, both P < .001). Meanwhile, the mean LDL particle size was more closely associated with non-HDL-C than LDL-C (r = -0.336 vs r = -0.136, both P < .05). Significantly, the cholesterol in large HDL was negatively correlated with non-HDL-C (r = -0223, P < .001) but not with LDL-C. These correlations were further confirmed by the fully adjusted multivariable linear regression analysis.

CONCLUSIONS

Non-HDL-C, in comparison to LDL-C, was more relevant to atherogenic lipoprotein subfractions in patients with stable CAD, supporting that it may be better in assessing cardiovascular risk.

Is the superiority of apoB over non-HDL-C as a marker of cardiovascular risk in the INTERHEART study due to confounding by related variables?

BACKGROUND

Patients with increased numbers of cholesterol-depleted apolipoprotein B (apoB) particles frequently have multiple other abnormalities, which might confound the comparison of apoB and non-high-density-lipoprotein-cholesterol (non-HDL-C) as markers of cardiovascular risk.

OBJECTIVE

We wanted to determine whether the superiority of apoB over non-HDL-C as a marker of cardiovascular risk in the INTERHEART study is due to such variables that act as confounders of the primary comparison.

METHODS

To test for confounding, cases and controls were first separated into 3 groups on the basis of the percentile levels within the study of non-HDL-C and apoB with discordance defined as a difference of 5 percentile points. Logistic regression was used to compute odds ratio of myocardial infarction (as an outcome) for different categories, assuming concordance as reference adjusted for other confounders.

RESULTS

Plasma triglyceride and non-HDL-C levels were highest in the discordant group with lowest risk and lowest in the discordant group with highest risk, whereas apoB was highest in the discordant group with the highest risk and lowest in the discordant group with the lowest group. Moreover, no significant change was found in the odds ratio for either discordant group when adjusted for the effect of any of the variables examined, evidence that none confounded the primary comparison.

CONCLUSION

Factors such as hypertriglyceridemia do not confound the comparison of apoB and non-HDL-C, further evidence that apoB is superior to non-HDL-C as a marker of the importance of the apoB atherogenic lipoproteins in cardiovascular risk.