Factors Affecting Insulin Resistance and Its Relation to Vitamin D Status and Clinical Nutritional Parameters in Dialysis Patients: A Single-center Indian Study

The aim of this study was to measure insulin resistance (IR) in dialysis patients and its relation to Vitamin D status and nutritional parameters. We included patients on maintenance dialysis, both hemodialysis and peritoneal dialysis (HD and PD). IR was measured by homeostatic model assessment (HOMA)-IR index defined as fasting serum insulin (μU/L) × fasting blood sugar (mmol/L)/22.5. Baseline Vitamin D levels were measured by chemiluminescence immunoassay (CLIA) method. HOMA-IR index correlated with nutritional parameters such as 7-point subjective global assessment (SGA) and anthropometric measures, for example, body fat percentage, lean body weight (LBW), mid-arm circumference (MAC), and mid-arm muscle circumference (MAMC). A total of 55 patients were studied, of them 74.55% were male with mean age of the study population being 37.44 ± 14.96 years. The prevalence values of Vitamin D deficiency <30 ngm/ml, <20 ngm/ml, and <10 ngm/ml levels were 96.36%, 70.91%, and 23.64%, respectively. Mean HOMA-IR index was 3.14 ± 3.86. The correlation of HOMA-IR with Vitamin D was negative (r = -0.140, 95% confidence interval [CI] = -0.397-0.138 and P = 0.309); however, in subgroup analysis, patients with Vitamin D level <20 ng/ml had significantly high IR compared to those with Vitamin D >20 ng/ml, i.e., 3.74 ± 4.37 and 1.67 ± 1.47, respectively (P = 0.018). The other measured parameter which had a significant positive correlation with IR was serum uric acid (r = 0.303, 95% CI = 0.021-0.534, and P = 0.025). In nutritional assessment, body mass index, MAC, and MAMC had statistically significant positive correlation with HOMA-IR index (P ≤ 0.001, 0.004, and 0.004, respectively) unlike SGA (P = 0.480). The mode of dialysis did not have a significant effect on IR (HD vs. PD, P = 0.227). The majority of the patients on maintenance dialysis are Vitamin D deficient. Low Vitamin D level, especially <20 ng/ml, muscle mass, and high serum uric acid level are likely to have more IR in dialysis-dependent patients.