Free and fixed-ratio combinations of basal insulin and GLP-1 receptor agonists versus basal insulin intensification in type 2 diabetes: A systematic review and meta-analysis of randomized controlled trials

A meta-analysis is presented of randomized controlled trials (RCTs) comparing free or fixed combinations of a glucagon-like peptide-1 receptor agonist plus basal insulin versus insulin intensification on metabolic control in patients with type 2 diabetes. Electronic databases were searched for RCTs assessing changes in HbA1c, proportion of patients at HbA1c target of < 7% (53 mmol/mol), hypoglycaemia and body weight. A random-effect model was used to calculate the weighted mean difference (WMD) or relative risk (RR) with 95% CI. Eleven RCTs were identified, lasting 24-30 weeks and involving 6176 patients. In the overall analysis, the combination therapy led to a mean HbA1c decrease significantly greater than insulin up-titration (WMD -0.53%, 95% CI, -0.66, -0.40%, P < 0.001), more patients at HbA1c target (RR 1.69, 95% CI, 1.42, 2.00, P < 0.001), similar hypoglycaemic events (RR 0.97, 95% CI, 0.84, 1.12, P = 0.114), and reduction in body weight (WMD -1.9, 95% CI -2.3, -1.4, P < 0.001), with heterogeneity (I-2 > 71%, P < 0.001). Results did not differ in either the free or fixed combination subgroups. Combination strategies, either free or fixed, represent a good option for intensifying basal insulin therapy in patients with type 2 diabetes who need amelioration of glycaemic control.