Efficacy, safety and impact on β-cell function of dipeptidyl peptidase-4 inhibitors plus metformin combination therapy in patients with type 2 diabetes and the difference between Asians and Caucasians: a meta-analysis

We conducted a literature search (from 1 January 2000 to 14 April 2015) for RCTs of DPP-4 inhibitors plus metformin combination therapy in T2DM.

A total of 27 RCTs were included. Compared with metformin, DPP-4 inhibitor plus metformin therapy was associated with higher reduction in HbA1c [−0.61 %, −0.69 to −0.52], FPG [−1.10 mmol/l, −1.29 to −0.92], TC [−0.11 mmol/l, −0.20 to −0.02], TG [−0.21 mmol/l, −0.33 to −0.10], HOMA-IR [−0.19, −0.36 to −0.02], gastrointestinal adverse events [OR 0.86, 0.77–0.97] and higher increment in HOMA-β [10.21, 7.73–12.69]. Comparison of HbA1c, FPG, body weight and HOMA-IR changes between Asian and Caucasian patients did not show a significant between-group difference of −0.05 % (−0.30, 0.20; P = 0.69), 0.17 mmol/l (−0.52, 0.85; P = 0.62), −0.15 kg (−0.64, 0.35; P = 0.53) and 0.27 (−0.98, 1.53; P = 0.64) compared with metformin. Comparisons of HOMA-β between Asian and Caucasian patients showed a significant between-group difference of −7.68 (−14.95, −0.42; P = 0.04).