The role of abdominal adiposity and insulin resistance in dyslipidemia of chronic renal failure.

The atherogenic profile of high triglyceride, reduced high-density lipoprotein (HDL) cholesterol, and small low-density lipoprotein particle size found in patients on chronic hemodialysis is known to be associated with insulin resistance and abdominal obesity in the general population. To assess the influence of insulin resistance and abdominal adiposity on the lipid profile in subjects on hemodialysis, intravenous glucose tolerance test and dual-energy x-ray absorptiometry were performed in 26 nondiabetic subjects on hemodialysis and compared with 22 nondiabetic control subjects matched for age, sex, and body mass index. Subjects on hemodialysis were found to have higher triglyceride (133 mg/dL [95% confidence interval, 115 to 159 mg/dL] v 97 mg/dL [95% confidence interval, 80 to 124 mg/dL]; P < 0.05), lower HDL cholesterol (36 +/- 3 mg/dL v 51 +/- 4 mg/dL [mean +/- SEM]; P < 0.01), enhanced insulin response to glucose (2.72 +/- 0.28 mUL(-1) min per mg dL(-1) v 1.67 +/- 0.22 mUL(-1) min per mg dL(-1); P < 0.01), and reduced sensitivity to the action of insulin (2.24 min(-1) per mUL(-1) min [95% confidence interval, 1.86 to 2.75 min(-1) per mUL(-1) min] v 4.17 min(-1) mUL(-1) min [95% confidence interval, 2.95 to 5.9 min(-1) per mUL(-1) min]; P < 0.01) than the control subjects. Abdominal adiposity measured by dual-energy x-ray absorptiometry (2,004 +/- 210 g v 2,163 +/- 198 g [mean +/- SEM]; P = NS) and percentage of body fat distributed to the abdomen (10.5% +/- 0.3% v 9.7% +/- 0.5% [mean +/- SEM]; P = NS) did not differ between the two groups. Subjects on hemodialysis were insulin resistant, but unlike control subjects, their lipid profile was not predicted by their insulin sensitivity. Abdominal adiposity was associated with a deteriorating lipid profile and insulin resistance in subjects on hemodialysis, as it was in control subjects. The presence of renal failure resulted in additional insulin resistance and a higher triglyceride level in the leaner subjects on hemodialysis compared with control subjects with similar levels of abdominal fat. In the more obese subjects, insulin sensitivity and triglyceride level did not differ between the two groups of subjects, although HDL cholesterol level remained low in subjects on hemodialysis. In conclusion, insulin resistance in subjects on hemodialysis did not directly account for their abnormal lipid profile. The negative impact of abdominal adiposity on the metabolic profile was preserved in subjects on hemodialysis, but the presence of renal failure itself resulted in insulin resistance in the leaner subjects and dyslipidemia in all subjects on hemodialysis compared with control subjects of comparable abdominal adiposity.