Assessment of the relative effectiveness and tolerability of treatments of type 2 diabetes mellitus: a network meta-analysis

Abstract

Purpose: The relative effectiveness and tolerability of treatments for type 2 diabetes mellitus (T2DM) is not well understood because few randomized, controlled trials (RCTs) have compared these treatments directly. The purpose of the present study was to evaluate the relative effectiveness and tolerability of treatments of T2DM.

Methods: We performed a network meta-analysis of available RCTs with pharmacologic interventions in T2DM and compared antidiabetic drugs and combination regimens with metformin (the reference drug). Glycemic control (proportion achieving HbA1c goal) and tolerability (risk of hypoglycemia) were the primary outcomes of interest. Direct and indirect relative effects (unadjusted) were expressed as odds ratios and 95% CIs.

Findings: Eight treatments (glucagon-like peptide-1 [GLP-1] agonists plus metformin, sulfonylureas plus metformin, dipeptidyl peptidase-4 [DPP-4] inhibitors] plus metformin, colesevelan plus metformin, thiazolidinediones plus metformin, meglitinides plus metformin, α-glucosidase inhibitor plus metformin, and rosiglitazone monotherapy) outperformed metformin (direct effects). Triple combinations of GLP-1, thiazolinedione, insulin, metiglinide, or sulfonylureas added to a metformin backbone improved glycemic control (indirect effects). Higher risk of hypoglycemia was noted for sulfonylureas, α-glycosidases, and metiglinides when added to metformin (direct effects). Across indirect effects, only 17% of comparisons yielded less risk of hypoglycemia (70% were worse and 13% were comparable).

Implications: Our results point out the relative superiority of 2- and 3-drug combination regimens over metformin and summarize treatment effects and tolerability in a comprehensive manner, which adds to our knowledge regarding T2DM treatment options.

Keywords: diabetes type 2; effectiveness; network meta-analysis; tolerability; treatment.