Increase in C-peptide levels after resolution of hyperglycemia in patients with type 2 diabetes mellitus: Myths or facts?

Abstract

Aim: Long term control of glucotoxicity was shown to increase the secretion of insulin and C-peptide (Cp). We aimed to investigatethe change in Cp levels after short term glycemic control in patients with uncontrolled type 2 diabetes mellitus (DM).Material and Methods: Patients with type 2 DM with uncontrolled hyperglycemia were included. Basal fasting Cp levels weremeasured both at admission (Cp-admission) and after control of hyperglycemia prior to discharge (Cp-discharge). Cp-differencewas calculated as (Cp-discharge)-(Cp-admission). The patients were divided as group 1 (positive Cp-difference) and group 2(negative Cp-difference), and group A (Cp-difference ≥+0.5) and group B (Cp-difference ≤-0.5).Results: Of the patients (n=123), 61.8% had positive Cp-difference, and mean Cp-differences were 0.16 (±1.59), 0.96 (±1.03), and-1.11 (±1.51) in all patients, group1 and 2; respectively (p=0.001). Mean body weight, creatinine and Cp-discharge were higher ingroup 1(p=0.045, p=0.013, p=0.001; respectively). Mean age, body mass index(BMI), diabetes duration, hospitalization, proteinuria,fasting and postprandial glucose, glucose-discharge, HbA1c, lipids, TSH, free T4, Cp-admission were similar in group 1 and 2.Cpdifference was correlated positively with Cp-discharge(p=0.001), negatively with Cp-admission (p=0.001). There were no significantdifferences between subgroups (age, BMI, diabetes duration, use of secretagogue, diabetic ketaoacidosis history, HbA1c (