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 r(2) 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.