A Comparative Study of the Effects of a Dipeptidyl Peptidase-IV Inhibitor and Sulfonylurea on Glucose Variability in Patients with Type 2 Diabetes with Inadequate Glycemic Control on Metformin

Background: This study aimed to compare the effects of sitagliptin on glycemic change and 24-h blood glucose variability with those of the sulfonylurea glimepiride. Subjects and Methods: A 4-week randomized double blind-labeled prospective design was used. We recruited 33 patients who had been treated with metformin for at least 2 months. Each participant prescribed with metformin was randomly assigned to either the sitagliptin (100 mg) or the glimepiride (2 mg) group. Continuous glucose monitoring (CGM) was used to monitor glycemic changes for 3 successive days in both groups at baseline and at the 4-week follow-up. Glycemic changes and glucose variability were obtained using CGM, and these data were averaged over all subjects. Results: The comparison of glycated hemoglobin (HbA1c) between baseline and the 4-week follow-up showed that HbA1c was significantly reduced in the sitagliptin group (7.0 +/- 0.5% to 6.6 +/- 0.4%, P < 0.001) and the glimepiride group (7.3 +/- 0.4% to 6.9 +/- 0.4%, P < 0.001). The sitagliptin and glimepiride groups had similar HbA1c levels after 4 weeks, and there were no significant differences between the two groups. The mean amplitude of glycemic excursions (MAGE) decreased significantly in the sitagliptin group (4.9 +/- 1.0 to 3.7 +/- 0.9 mmol/L, P < 0.001), but no significant difference was observed in the glimepiride group (5.7 +/- 1.5 to 5.0 +/- 1.4 mmol/L, P = 0.175). The SD and oxidative stress markers did not differ significantly between the two groups. Conclusions: When sitagliptin was combined with metformin, the patients showed much more efficient blood glucose controlling effects, not only the three indexes of fasting blood glucose, postprandial blood glucose, and glycated hemoglobin, but also MAGE.