Evaluation of C-peptide and insulin resistance in nondiabetic patients with chronic kidney disease

Introduction
Chronic kidney disease (CKD) is a pathophysiologic process with several etiologies, resulting in remarkable decrease in nephron number and function. Patients with CKD have reduced life span, and a considerable proportion of these individuals die owing to cardiovascular complications. In CKD, degradation of insulin in nonrenal tissues such as liver and muscle is impaired, and the half-life of insulin is prolonged, so a state of hyperinsulinemia with increased C-peptide levels occurs in patients with CKD.
Aim
To assess serum insulin and C-peptide along with homeostasis model assessment-insulin resistance (IR) in nondiabetic patients with CKD.
Patients and methods
The study included 70 nondiabetic patients with CKD and 20 controls. Fasting serum C-peptide and insulin were done by enzyme-linked immunosorbent assay technique, and IR was calculated using the homeostasis model assessment-IR formula.
Results
Fasting serum levels of insulin and C-peptide were statistically significantly higher in nondiabetic patients with CKD compared with control individuals. Patients with stage 4 CKD had a statistically significant increase in fasting insulin levels compared with stage 3 patients, whereas there was no statistically significant difference between stage 5 and stage 4 patients. Fasting C-peptide levels show no statistically significant difference between the different stages of patients with CKD. IR levels were statistically significantly higher in the patient group compared with the controls. Patients with stage 4 CKD had statistically significantly higher levels of IR compared with stage 3 patients. There was no statistically significant difference between patients with stage 4 and stage 5 CKD.
Conclusion
The study demonstrates an increase in the IR in nondiabetic patients with CKD.