A Reduction of HbA1c after 3 Months Predicts 2-year Responsiveness to Sitagliptin Treatment.

Objective: This retrospective study evaluated the long-term efficacy of sitagliptin and the factors contributing to its glucose-lowering effect.

Methods: Six hundred and sixteen dipeptidyl peptidase-4 inhibitor-naïve outpatients with type 2 diabetes who began sitagliptin treatment between December 1, 2009 and December 31, 2011 were included in this study. The inclusion criteria were that the patient had regularly visited our hospital for a period of ≥700 days from the initiation of sitagliptin treatment and the measurement of hemoglobin A1c (HbA1c) had been performed at 0, 3, 6, 12, 18, and 24 months after the initiation of treatment. From the population of 616 patients, 447 and 169 had received sitagliptin for ≥700 and <700 days, respectively. The primary endpoint was ΔHbA1c at 24 months. The factors associated with the hypoglycemic effect of sitagliptin were also investigated.

Results: Sitagliptin treatment significantly decreased the level of HbA1c, and the hypoglycemic effect was sustained for at least 2 years. The baseline HbA1c level, duration of diabetes, Δbody weight value, and ΔHbA1c value at 3 months were independently associated with the hypoglycemic effect of sitagliptin.

Conclusion: Sitagliptin has a long-term hypoglycemic effect in type 2 diabetes patients. A patient's ΔHbA1c at 3 months may be a predictor of their ΔHbA1c at 24 months.