Biomarker potential of C-peptide for screening of insulin resistance in diabetic and non-diabetic individuals

Abstract

Insulin resistance is a hallmark feature of type-2 diabetes mellitus (T2DM). We determined the homeostatic model assessment insulin resistance (HOMA-IR) and evaluated its association with C-peptide, insulin, fasting blood glucose (FBG) and glycated hemoglobin (HbA1c) in T2DM patients and non-diabetic subjects. This study comprised a total of 47 T2DM patients and 38 non-diabetic controls. Venous blood samples from all the subjects were collected and sera were analyzed for FBG, HbA1c, insulin and C-peptide using an autoanalyzer. HOMA-IR was calculated using the following equation: HOMA-IR = fasting insulin (µU/ml) × fasting glucose (mmol/L)/22.5. There was a significant increase in the levels of FBG and HbA1c in diabetic patients. Although the levels of C-peptide and insulin did not differ significantly between the two groups, a significant increase in HOMA-IR was observed in T2DM patients. Both insulin and C-peptide were significantly correlated with HOMA-IR. In conclusion, C-peptide may serve as a simple and convenient predictor of HOMA-IR.

Keywords: Biomarker; C-peptide; Diabetes; Fasting blood glucose; HbA1c; Insulin resistance.

Fig. 1

Levels of (a) fasting blood glucose and (b) HbA1c in controls and diabetic patients. ^*P < 0.001 versus control group, t-test.

Fig. 2

Levels of (a) serum insulin and (b) insulin resistance in controls and diabetic patients. ^*P < 0.01 versus control group, t-test.

Fig. 3

Serum C-peptide levels in controls and diabetic patients.