Abstract
OBJECTIVE: This study aimed to evaluate the effectiveness of glucagon-like peptide-1 receptor agonists (GLP-1RA) in reducing body mass index (BMI) and blood glucose levels in individuals with type 2 diabetes mellitus (T2DM) using the difference-in-differences (DID) technique. RESEARCH DESIGN AND METHODS: This retrospective cohort study included patients with T2DM, receiving GLP1-RA or other second-line antidiabetic treatments between 2010 and 2023. A linear mixed-effect regression with heterogeneous augmented inverse probability weighting DID analysis was used to compare the effectiveness of GLP-1RA and other second-line treatments in reducing BMI, fasting plasma glucose (FPG) and haemoglobin A1C (HbA1c) in patients with T2DM. An average treatment effect on the treated (ATET) for each outcome was estimated. RESULTS: 1000 patients with T2DM (GLP-1RA=220, non-GLP-1RA=880) were included. Compared with other second-line drugs, GLP-1RA significantly reduced BMI by approximately 1.02 kg/m(2) (95% CI -1.46 to -0.58) over 24 months of treatment. Additionally, GLP-1RA significantly decreased FPG and HbA1c levels, compared with other second-line treatments with overall ATETs (95% CI) of -21.34 mg/dL (-29.53 to -13.15) and -0.58% (-0.77% to -0.38%), respectively. CONCLUSIONS: Our results indicate that patients with T2DM treated with GLP-1RA had a significantly greater reduction in BMI, FPG and HbA1C levels compared with those receiving other second-line antidiabetic therapies. As such, GLP-1RA might be considered the preferred treatment for obese patients with T2DM who fail to sufficiently respond to metformin monotherapy.