Comparative evaluation of liraglutide plus metformin combination therapy versus metformin monotherapy in patients with type 2 diabetes mellitus: A retrospective clinical study

Durable glycemic control remains challenging in patients with type 2 diabetes mellitus inadequately controlled with metformin alone. Liraglutide, a glucagon-like peptide-1 receptor agonist, has been proposed as a beneficial add-on therapeutic option. This retrospective study included adults with type 2 diabetes mellitus treated between March 2021 and March 2025. Patients were divided into a combination group receiving liraglutide plus metformin and a control group receiving metformin alone. Glycemic parameters and safety outcomes were assessed at baseline and after 6 months of treatment. Statistical comparisons were conducted using Welch t test and Chi-square or Fisher exact test. A total of 207 patients were analyzed. Compared with metformin monotherapy, combination therapy achieved greater reductions in glycated hemoglobin (-1.8 ± 0.9% vs -1.3 ± 0.8%; P < .001), fasting and postprandial plasma glucose, fasting insulin, and homeostasis model assessment of insulin resistance. The proportion achieving composite glycemic targets was higher in the combination group (76.5% vs 57.9%; P = .006). Adverse event incidence and treatment discontinuation did not differ significantly between groups. Liraglutide add-on therapy provided superior glycemic improvement compared with metformin alone and demonstrated acceptable safety and tolerability.