Comparative efficacy and safety of antidiabetic drug regimens added to stable and inadequate metformin and thiazolidinedione therapy in type 2 diabetes.

AIMS: Determine the efficacy and safety of antidiabetic agents added-on to metformin and a thiazolidinedione (TZD) in patients with inadequately controlled type 2 diabetes (T2D). METHODS: MEDLINE and CENTRAL were searched for randomised controlled trials (RCTs) evaluating the addition of an antidiabetic agent in patients with T2D inadequately controlled on stable, optimised metformin and TZD therapy (≥ 1500 mg metformin and ≥ 50% maximum TZD dose for ≥ 4 weeks). Frequentist network meta-analysis was performed on identified studies. RESULTS: Eleven RCTs evaluating dipeptidyl peptidase-4 inhibitors (linagliptin, sitagliptin), sulfonylureas (SUs) (glibenclamide, glimepiride), glucagon-like peptide-1 (GLP-1) analogues (exenatide, liraglutide, dulaglutide, taspoglutide) and sodium-glucose cotransporter2 (SGLT2) inhibitors (canagliflozin, empagliflozin) were identified. The mean reduction in HbA1c from baseline was significant for all agents (range, 0.55-1.17%) vs. placebo. SUs were associated with weight gain (range, 3.31-7.29 kg), while weight loss was seen with all GLP-1 analogues (range, 1.53-2.20 kg) and SGLT2 inhibitors (range, 2.08-2.95 kg) vs. placebo. Relative risk of hypoglycaemia was increased with dulaglutide, exenatide and glimepiride vs. placebo (RR range, 2.65-6.17); and trended higher with all other agents except linagliptin. GLP-1 analogues and canagliflozin reduced systolic blood pressure vs. placebo (range, 2.39-5.05 mmHg). No agent with available data increased the risk of urinary or genital tract infection vs. placebo. CONCLUSION: When added to stable, optimised metformin and TZD, all evaluated antidiabetic agents reduced HbA1c; albeit not to the same degree. Moreover, agents differed in their effects on body weight, hypoglycaemia and systolic blood pressure.