Efficacy and Safety of Initial Combination Therapy in Treatment-Na⟨ve Type 2 Diabetes Patients: A Systematic Review and Meta-analysis

Introduction: The aim of this study was to evaluate the efficacy and safety of initial combination therapy compared with monotherapy in drug-nai ve type 2 diabetes patients. Methods: MEDLINE, Embase and the Cochrane Central Register of Controlled Trials were searched for randomized clinical trials of initial combination therapy with hypoglycemic agents compared with monotherapy. Those which satisfied the search criteria were included in the meta-analysis. Weighted mean difference and relative risks were calculated. Results: A total of 36 studies were included in the meta-analysis. Compared with metformin monotherapy, initial combination therapy with metformin plus another anti-diabetes drug exhibited significant reductions in glycated hemoglobin (HbA1c) (p\ 0.001). Most of the combination therapies had a similar risk of hypoglycemia (p[ 0.05), with the exception of combinations of sulfonylurea/ glinide and metformin or combinations of thiazolidinedione and metformin. Compared with dipeptidyl peptidase-4 (DPP-4) inhibitor monotherapy, initial combination therapy with DPP-4 inhibitor plus another anti-diabetes drug showed a significant decrease in HbA1c (p\ 0.001) and a similar risk of hypoglycemia (p[ 0.05). Compared with monotherapy with other anti-diabetes drugs, initial combination therapies also resulted in significant HbA1c reductions, a similar risk of hypoglycemia and similar risks of other adverse events. Conclusion: Compared with monotherapy, all initial combination therapies resulted in significant HbA1c reductions. Compared with metformin monotherapy, initial combination therapies with DPP-4 inhibitors plus metformin, sodium/ glucose cotransporter 2 inhibitors and metformin, respectively, were associated with similar risks of hypoglycemia, but initial combination therapies with sulfonylurea plus metformin, thiazolidinedione and metformin, respectively, were associated with higher risks of hypoglycemia.