Background: One in three adults suffers from obesity.1 Glucagon-like peptide-1 (GLP-1) receptor agonists have been associated with 15-20% weight loss, a range previously only achieved with bariatric surgery.2,3,4 This systematic review and meta-analysis compares weight loss between GLP-1 receptor agonists and bariatric surgery.

Methods: MEDLINE, Medline-in-Process, Medline EPUBS Ahead of Print, EMBASE Classic + EMBASE (OvidSP) ; and Cochrane (Wiley) databases were searched from inception to April 21, 2021. We included randomized controlled trials (RCTs) and observational studies. Two independent reviewers extracted data, reported risk of bias, and graded certainty of evidence. Risk of bias was reported using Risk of Bias 2 (RoB 2) tool for RCTs and Risk of Bias in Non-randomized Studies- of Interventions (ROBINS-I) tool for observational studies. Data were pooled separately for RCTs and observational studies using random effects models. Change in weight, body mass index (BMI) , and glycated hemoglobin (HbA1C) were summarized.

Results: Seven included studies encompassed 11patients. Among RCTs, mean difference in weight between bariatric surgery and GLP-1 receptor agonist was −22.68 (95% CI: −31.41, −13.96) , mean difference in BMI was −8.18 (95% CI: −11.59, −4.77) , and mean difference in HbA1C was −1.28 (95% CI: −1.94, −0.61) . Among observational studies, mean difference in weight was −16.56 (95% CI: −36.53, 3.42) and mean change in BMI was −10.60 (95% CI:−17.22, −3.98) . These effects all favoured bariatric surgery.

Conclusion: In adults with obesity, bariatric surgery still confers highest reductions in weight and BMI compared to GLP-1 receptor agonists, but similar effects in glycemic control.

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P. Palcu: None.


Clinician Investigator Program, University of Toronto

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