Efficacy of Adding Once-Daily Insulin Glulisine in Japanese Type 2 Diabetes Patients Treated with Insulin Glargine and Sitagliptin

Background: Glucose fluctuation often remains to be corrected under basal-supported oral therapy. We investigated the efficacy of adding once-daily rapid-acting insulin in Japanese diabetes patients treated with basal-supported oral therapy. Subjects and Methods: In this 8-week, parallel-group, randomized, open-label trial, 62 Japanese adults with type 2 diabetes treated with insulin glargine and 50 mg of sitagliptin were randomized into the following two arms: the single-bolus group, in which once-daily insulin glulisine was initiated at a main meal at a fifth (i.e., 20%) the dose of insulin glargine, and the control group, in which the dose of sitagliptin was maximized to 100 mg. The primary end point was the change of glycemic fluctuation assessed with the M-value. Results: Baseline hemoglobin A1c levels, mean blood glucose profiles, and M-value were 7.2 +/- 0.6%, 9.3 +/- 1.7 mmol/L, and 21 +/- 13 units, respectively. At the end of the study, the single-bolus group had a greater reduction of M-value than the control group (P=0.02); the difference was 6.5 units (95% confidence interval, 1.1-11.9 units). The single-bolus group also had a greater reduction of mean blood glucose levels (P=0.01). There were no significant differences in the incidence of hypoglycemia or the weight change between the two groups (P>0.05). Conclusions: Adding once-daily insulin glulisine was more effective in controlling the glycemic fluctuation in Japanese type 2 diabetes patients treated with insulin glargine together with sitagliptin.