Bariatric surgery: a systematic review and network meta-analysis of randomized trials


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  • Marcello Tonelli, the Corresponding Author and Guarantor, has the right to grant on behalf of all authors and does grant on behalf of all authors, a worldwide licence to the Publishers and its licensees in perpetuity, in all forms, formats and media (whether known now or created in the future), to (i) publish, reproduce, distribute, display and store the Contribution, (ii) translate the Contribution into other languages, create adaptations, reprints, include within collections and create summaries, extracts and/or, abstracts of the Contribution, (iii) create any other derivative work(s) based on the Contribution, (iv) to exploit all subsidiary rights in the Contribution, (v) the inclusion of electronic links from the Contribution to third party material where-ever it may be located; and, (vi) licence any third party to do any or all of the above.

  • Sources of funding: This project was primarily funded by the Canadian Agency for Drugs and Technology in Health. Additional support for this work was provided through an Interdisciplinary Team Grant from the Alberta Heritage Foundation for Medical Research. Dr Tonelli was supported by a New Investigator Award from the Canadian Institutes of Health Research. Dr Tonelli and Dr Klarenbach were supported by salary awards from the Alberta Heritage Foundation for Medical Research. Dr Tonelli, Dr Padwal, and Dr Klarenbach were supported through an alternative funding plan from the Government of Alberta and the University of Alberta.

M Tonelli, 7-129 CSB, University of Alberta, 8440 112 St NW, Edmonton, Alberta, Canada, T6B 2B7. E-mail:


The clinical efficacy and safety of bariatric surgery trials were systematically reviewed. MEDLINE, EMBASE, CENTRAL were searched to February 2009. A basic PubCrawler alert was run until March 2010. Trial registries, HTA websites and systematic reviews were searched. Manufacturers were contacted. Randomized trials comparing bariatric surgeries and/or standard care were selected. Evidence-based items potentially indicating risk of bias were assessed. Network meta-analysis was performed using Bayesian techniques. Of 1838 citations, 31 RCTs involving 2619 patients (mean age 30–48 y; mean BMI levels 42–58 kg/m2) met eligibility criteria. As compared with standard care, differences in BMI levels from baseline at year 1 (15 trials; 1103 participants) were as follows: jejunoileal bypass [MD: −11.4 kg/m2], mini-gastric bypass [−11.3 kg/m2], biliopancreatic diversion [−11.2 kg/m2], sleeve gastrectomy [−10.1 kg/m2], Roux-en-Y gastric bypass [−9.0 kg/m2], horizontal gastroplasty [−5.0 kg/m2], vertical banded gastroplasty [−6.4 kg/m2], and adjustable gastric banding [−2.4 kg/m2]. Bariatric surgery appears efficacious compared to standard care in reducing BMI. Weight losses are greatest with diversionary procedures, intermediate with diversionary/restrictive procedures, and lowest with those that are purely restrictive. Compared with Roux-en-Y gastric bypass, adjustable gastric banding has lower weight loss efficacy, but also leads to fewer serious adverse effects.