Laparoscopic bariatric surgery versus any non-surgical intervention for adolescents or adults with obesity: protocol for a systematic review with meta-analysis and trial sequential analysis of randomised clinical trials

Journal article

Introduction: The number of people living with obesity is increasing rapidly worldwide, and the WHO estimates approximately 5 million deaths yearly from non-communicable diseases related to elevated body mass index (BMI). The most effective treatment for weight loss is bariatric surgery, but due to the associated risks and the need for lifelong care, this is not a viable treatment for every patient. With the advent of gut-hormone-based medications to treat obesity, the effectiveness of non-surgical treatment is approaching that of surgical interventions. We therefore aim to investigate the beneficial and harmful effects of laparoscopic bariatric surgery versus any non-surgical treatment. Methods and analysis: We will conduct a systematic review with meta-analysis applying our eight-step procedure to assess thresholds for clinical significance and trial sequential analysis to mitigate the risk of random errors. To identify relevant trials, we will search for both published and unpublished trials, without any language restriction, in major medical databases (CENTRAL, MEDLINE, EMBASE, LILACS, SCI-EXPANDED and CPCI-S) and trial registries. The date range covered by the search is from database inception until final search date—within 3 months prior to submission of final results manuscript. Two review authors will independently screen references, extract data and perform risk-of-bias assessment using the Cochrane Risk of Bias Tool 2 and the Grading of Recommendations, Assessment, Development and Evaluations. We will include randomised clinical trials comparing laparoscopic surgery currently in use with any non-surgical comparator in adults or adolescents with BMI >30 kg/m2. Quasi-randomised studies or non-randomised studies will not be included. Our critical outcomes are all-cause mortality, serious adverse events and quality of life, and our important outcomes are major cardiovascular events, weight at follow-up, physical function and glycaemic control. In addition, we have two explorative outcomes: metabolic syndrome or Z-score and reported incident of alcohol abuse or other addictive disorder or self-inflicted harm. Ethics and dissemination: This review will collect and perform secondary analysis of data from publicly available sources and ethical approval is therefore not required. The findings will be published in peer-reviewed journals and presented at relevant scientific conferences. We will strive to publish with open access. Awareness will be made through social media platforms. This review aims to help clinicians in identifying best practices in the wide-spanning field of obesity treatment. PROSPERO registration number: CRD420251135341.

Authors: Duun, O; Dichman, M; Lindschou, J; Scragg, J; Petersen, JJ

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: BMJ Publishing Group
• Journal: BMJ Open
• Volume: 16
• Issue: 2
• Pages: e111336
• Article number: bmjopen-2025-111336
• Publication date: 2026-02-09
• Acceptance date: 2026-01-22
• DOI: 10.1136/bmjopen-2025-111336
• EISSN: 2044-6055
• ISSN: 2044-6055
• Language: English
• Keywords: Obesity; Other metabolic, e.g. iron, porphyria; Meta-Analysis; Bariatric Surgery; Systematic Review; Adolescent