Weight Loss Outcomes Between GLP ‐1 Receptor Agonists and Bariatric Surgery in Adults With Obesity: A Systematic Review, Meta‐Analysis and Meta‐Regression

ABSTRACT Background The comparative effectiveness of bariatric surgery (BS) and glucagon‐like peptide‐1 receptor agonists (GLP‐1 RAs) for weight loss among patients with obesity remains uncertain. Methods MEDLINE, EMBASE and CENTRAL were searched to 5 October 2025. Pooled mean differences (MDs) for change in weight, body mass index (BMI), glycaemic indices, lipid profile and blood pressure were calculated using random‐effects models with heterogeneity quantified by I 2 . Outcomes were assessed separately according to time duration. Meta‐regression was performed for the primary outcome of change in BMI. Results Fifteen studies (20 594 participants) were included. Weight loss did not differ significantly at 6 months (MD –12.19 kg; p = 0.13), but favoured BS at ≤ 1 year (MD −16.97 kg; p = 0.02) and > 1 year (MD −19.78 kg; p < 0.001). BMI reduction consistently favoured BS at 6 months (MD −6.77 kg/m 2 ; p = 0.02), ≤ 1 year (MD −5.10 kg/m 2 ; p < 0.001) and > 1 year (MD −6.61 kg/m 2 ; p < 0.001). HbA1c reduction was greater with BS beyond one year (MD −1.69%; p < 0.001), and fasting glucose was lower overall with BS (MD −1.22 mmol/L; p = 0.03). Serum lipids and blood pressure showed no significant between‐group differences. Meta‐regression demonstrated larger BMI reductions with BS in older patients, male patients and those with higher baseline BMI. Conclusion Although substantial heterogeneity was present, BS was associated with greater and sustained reductions observed over multi‐year follow up in weight, BMI and glycaemic indices compared to GLP‐1 RAs, with similar effects on serum lipids and blood pressure, supporting its use in appropriately selected adults with obesity.