Endocrine Abstracts

Introduction: Long term control of glucotoxicity has been shown to increase the secretion of insulin and C-peptide (Cp) from beta cells. However, there is limited data concerning the effect of short term glycemic control and reversal of glucotoxicity on basal Cp. We aimed to investigate the change in serum Cp levels after short term glycemic control in patients with uncontrolled type 2 diabetes mellitus (DM).

Materials and methods: A total of 123 patients with type 2 DM admitted and hospitalized to our clinics with uncontrolled hyperglycemia were included. Demographic and clinical data, and basic laboratory parameters were recorded and analyzed. Basal fasting Cp levels were measured both at admission (Cp-admission) and after control of hyperglycemia just prior to discharge (Cp-discharge). Cp-difference was calculated as (Cp-discharge)-(Cp-admission). The patients were divided into 2 groups: group 1 with positive Cp-difference; group 2 with negative Cp-difference.

Results: Of the patients, 61.8% had positive Cp-difference, and Cp-differences were 0.16 (±1.59) ng/mL in all patients, 0.96 (±1.03) in group 1, and −1.11 (±1.51) in group 2 (P=0.001). Mean body weight, creatinine and Cp-discharge were significantly higher in group 1 (P=0.045, P=0.013, P=0.00; respectively). However, mean age, body mass index (BMI), diabetes duration, hospitalization duration, proteinuria, fasting and postprandial glucose, HbA1c, lipids, TSH, free T4, Cp-admission were similar in both groups. The patients were further subgrouped according to age (65< or ≥65), BMI(<30 or ≥30kg/m²), diabetes duration, use of secretagogue, diabetic ketaoacidosis history, HbA1c (<10 or ≥10%), hyperlipidemia or hypertriglyceridemia, presence of any microvascular complication. There were no significant differences between subgroups as regards to Cp-difference. Cp-admission was positively correlated with triglyceride, body weight and Cp-discharge (P=0.004, P=0.025, P=0.00; respectively); and negatively correlated with diabetes duration, HbA1c, and Cp-difference (P=0.009, P=0.043, P=0.00; respectively). Cp-discharge was positively correlated with triglyceride, body weight, Cp-admission and Cp-difference (P=0.001, P=0.00, P=0.00, P=0.00; respectively). Cp-difference was correlated positively with Cp-discharge (P=0.00), negatively with Cp-admission (P=0.00). Positive predictors of having positive Cp-difference were history of cardiovascular disease (P=0.004; Odds Ratio (OR)=3), and higher Cp-discharge (P=0.00; OR=6.42).

Conclusion: Our results indicate that short-term glycemic control has little but significant positive effect on basal Cp. Having cardiovascular disease was found as a strong predictor for positive Cp-difference. Presence or absence of microvascular complications, HbA1c level, and diabetes duration did not affect Cp-difference.