Effect of vildagliptin on glucose and insulin concentrations during a 24-hour period in type 2 diabetes patients with different ranges of baseline hemoglobin A1c levels

Currently, it is still unknown whether differences in glycemic control have any effect on glucose and insulin kinetics after vildagliptin administration. The aim of this study was to evaluate the effect of vildagliptin on glucose and insulin concentrations during a 24-h period in type 2 diabetes patients with different ranges of baseline hemoglobin A1c (A1C) levels. A randomized, double-blind, crossover, placebo-controlled clinical trial was carried out in 12 drug-naive adult volunteers with type 2 diabetes and overweight or obesity. Subjects had fasting glucose values between 7.2 and 13.3 mmol/L. Six patients had A1C between 7.0% and 8.4% (Group A), and the remaining subjects had A1C between 8.5% and 10.0% (Group B). Patients received oral administration of vildagliptin (50 mg twice daily) or placebo in a crossover manner for two consecutive days. Until the second day of the interventions, glucose and insulin concentrations were measured every hour during a 24-h period, and areas under the curve (AUCs) were calculated. Statistical analyses were evaluated with Wilcoxon and Mann-Whitney U tests. There were significant decreases in glucose concentrations after vildagliptin administration in both groups when comparing placebo in all measurements throughout the 24-h period and in the AUC. There were no significant changes in insulin concentration in both groups after vildagliptin administration when comparing placebo in all measurements throughout the 24-h period and in the AUC. Vildagliptin administration improved glucose control during a 24-h period in type 2 diabetes patients, independent of the basal A1C level, without changes in insulin levels.