BackgroundDipeptidyl peptidase-4 (DPP-4) inhibitors are widely used as second-option medications when metformin fails. Variance of the glycated hemoglobin (HbA1c) response to DPP-4 inhibitions in patients with type 2 diabetes mellitus (T2DM) has been observed, but the characteristics which predict the response to DPP-4 inhibitor therapy are unclear. The aim of this study was to investigate the characteristics of α- and β-cell functions which might predict the efficacy of saxagliptin and facilitate personalization of treatment.