Dipeptydil peptidase-4 inhibitors and HbA1c target of <7% in type 2 diabetes: meta-analysis of randomized controlled trials

Aim: We assessed the efficacy of dipeptidyl peptidase-4 (DPP-4) inhibitors vildagliptin, sitagliptin, saxagliptin and alogliptin to reach the haemoglobin HbA1c target of <7% in people with type 2 diabetes. Methods: We conducted an electronic search for randomized controlled trials (RCTs) involving DPP-4 inhibitors through September 2010. RCTs were included if they lasted at least 12 weeks, included 30 patients or more and reported the proportion of patients reaching the HbA1c target of <7%. Results: A total of 43 RCTs reporting 52 comparisons met the selection criteria, which included 19 101 study participants evaluated for the primary endpoint, 10 467 treated with a DPP-4 inhibitor and 8634 treated with placebo or a comparator drug. DPP-4 inhibitors showed a statistically significant reduction in HbA1c compared to placebo and approximately 40% of participants achieved the HbA1c goal of <7%: this was associated with weight neutrality and no greater hypoglycaemia. The reduction of the HbA1c level and the rate of HbA1c goal attainment was not different from comparator drugs, with similar hypoglycaemia, and different effect on weight owing to the nature of comparator (metformin, sulfonylurea or glitazones). Baseline HbA1c was the best predictor for achievement of A1C target (overall weighted r2 value = 0.410, p < 0.001). Conclusions: A greater proportion of type 2 diabetic patients can achieve the HbA1c goal <7% with DPP-4 inhibitors compared to placebo, with no weight gain, and no hypoglycaemic risk when used alone; DPP-4 inhibitors were not different from comparator drugs