The effect of icodextrin and glucose-containing solutions on insulin resistance in CAPD patients

Peritoneal dialysis patients have particular risks with respect to their lipid status and hyperinsulinemia. The aim of this study was to investigate the relation between insulin resistance and the type of the peritoneal dialysis solution.

41 randomly selected non-diabetic patient cohort who were already under treatment with continuous ambulatory peritoneal dialysis (CAPD) and 10 healthy controls participated in the study. 24 of the 41 patients were using 3 standard 1.36% glucose solutions during the day and 1 hypertonic solution with 2.27% glucose dwell during the night (glucose group: mean age 45.54 +/- 16.67 years and median CAPD duration 16.5 months). The remaining 17 patients were using 3 standard 1.36% glucose solutions during the day and 1 icodextrin dwell during the night for 8-10 hours (icodextrin group: mean age 47.47 +/- 13.15 years, median duration of icodextrin use 6 months (range 2-20 months), and median CAPD duration 30 months). Insulin resistance (IR) was calculated according to the homeostasis model assesment (HOMA) formula: HOMA-IR = fasting glucose (mmol/l) x fasting insulin (microU/1/22.5. The HOMA cutoff point for diagnosis of insulin resistance was established with receiver-operating characteristic (ROC) curves. The patients were called HOMA-IR(+) if their HOMA scores were higher than cutoff value.

There were no significant differences between age, BMI, triglyceride, total and high-density lipoprotein (HDL) cholesterol, iron and ferritin, alanine aminotransferase, fibrinogen, intact parathyroid hormone, magnesium, hemoglobin and hematocrit levels of the 2 groups. The mean glucose levels of the groups were not different but fasting insulin levels and HOMA scores of the icodextrin group were significantly lower than the glucose group (10.15 +/- 6.87 vs. 18.11 +/- 13.15, p = 0.028, and 2.28 +/- 1.67 vs. 4.26 +/- 3.27, p = 0.027, respectively). The ratio of patients with low HOMA scores (cutoff = 2.511) were significantly higher in the icodextrin group than in the glucose group (71% vs 38%, p = 0.037). Other than fasting insulin and glucose levels, significantly positive correlation was found between HOMA score and BMI in both groups. With regression analysis, we found that the main parameters effecting HOMA score were BMI (p = 0.008) and triglyceride (p = 0.029) in the glucose group, but no parameters were found to affect HOMA score in icodextrin group.

These results suggest that insulin resistance is reduced in peritoneal dialysis patients using icodextrin-based dialysis fluid instead of glucose-based dialysis fluid.