Efficacy and safety of the addition of a dipeptidyl peptidase-4 inhibitor to insulin therapy in patients with type 2 diabetes: A systematic review and meta-analysis

•Effect of DPP-4 inhibitors combined with insulin therapy was evaluated by meta-analysis.•DPP-4 inhibitors decreased HbA1c and fasting plasma glucose levels.•DPP-4 inhibitors did not increase the risk of hypoglycaemia and weight gain.•DPP-4 inhibitors exhibited small but significant insulin sparing effect.