Ability of non-high-density lipoprotein cholesterol and calculated intermediate-density lipoprotein to identify nontraditional lipoprotein subclass risk factors in dialysis patients.

BACKGROUND: Non-high-density lipoprotein cholesterol (non-HDL-C) and calculated intermediate-density lipoprotein cholesterol (IDL-C) have been proposed as surrogate markers to estimate apolipoprotein B-containing lipoproteins. The purpose of this study was to determine the validity of non-HDL-C and calculated IDL-C to predict nontraditional lipoprotein risk factors among dialysis patients and to compare the prevalence of these nontraditional risk factors between dialysis modalities.

METHODS: The authors performed a cross-sectional analysis comparing standard lipid profile with lipoprotein analysis via nuclear magnetic resonance (NMR) spectroscopy among 186 hemodialysis (HD) and peritoneal dialysis (PD) patients on modern lipid-lowering therapy.

RESULTS: The PD group had a significantly higher low-density lipoprotein (LDL) particle concentration (P < 0.005), higher large very low-density lipoprotein (VLDL; P < 0.001), greater small dense LDL (P < 0.001), and lower protective large HDL (P < 0.005). Forty-six (40%) of 118 subjects with LDL-C below goal had at least 1 nontraditional risk factor by NMR spectroscopy. The sensitivity of non-HDL-C method together with triglyceride (TG) value greater than 200 mg/dL (>2.26 mmol/L) to predict nontraditional risk was 13% and increased to 20% if TG values were excluded. A negative correlation was observed between LDL particle size and HDL-C (r2 = 0.269; P < 0.001); the sensitivity of HDL-C to predict LDL size was 92%. There was no relationship between measured IDL by NMR and calculated IDL-C (r2 = 0.005; P = 0.69).

CONCLUSION: Non-HDL-C greater than 130 mg/dL (3.4 mmol/L) independent of TG values and HDL-C lower than 40 mg/dL (1.0 mmol/L) may predict nontraditional lipoprotein risk factors among dialysis patients. This is especially applicable to patients on PD, a modality associated with a more atherogenic lipoprotein profile.