Determinants of the HbA1c-lowering effect of sitagliptin when added to ongoing insulin therapy in Japanese patients with type 2 diabetes

Adding of Sitagliptin on Insulin Therapy Effectively and Safely Reduces a Hemoglobin A1c Level and Glucose Fluctuation in Japanese Patients with Type 2 Diabetes

Aims. Efficacy and safety of DPP-4 inhibitor, sitagliptin, add-on therapy to insulin were investigated in Japanese patients with type 2 diabetes. Subjects and Methods. Two hundred and sixteen patients (126 men, 65 ± 12 years old, BMI 24.9 ± 4.5, means ± S.D.) who had been treated by insulin alone or insulin combined with other oral hypoglycemic agents (OHAs) were recruited, and sitagliptin was added for 3 months. Results. HbA1c was significantly decreased after 3 months of add-on therapy as a whole (8.56 ± 1.50% to 7.88 ± 1.25%, P < 0.0001). Body weight did not change and insulin dosage was significantly (P < 0.0001) decreased for 3 months. Furthermore, day-to-day glucose variability was significantly reduced (18.3 ± 9.1 to 16.1 ± 8.1%, P < 0.05). In stepwise multiple regression analysis on ΔHbA1c as an outcome variable, the higher baseline HbA1c value and a preserved CPR were selected as significant predictive variables. Fifteen patients complained of mild hypoglycemia without any assistance during 3 months of sitagliptin add-on, while no severe hypoglycemic episode was reported. Conclusions. Add-on of sitagliptin to ongoing insulin therapy effectively reduced either HbA1c level or glucose fluctuation and could be a practical and well-tolerated alternative to treat Japanese patients with type 2 diabetes who had been inadequately controlled by insulin with or without other OHAs.