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Original Investigation |

The Effectiveness and Risks of Bariatric Surgery:  An Updated Systematic Review and Meta-analysis, 2003-2012

Su-Hsin Chang, PhD1; Carolyn R. T. Stoll, MPH, MSW1; Jihyun Song, PhD2,4; J. Esteban Varela, MD, MPH3; Christopher J. Eagon, MD3; Graham A. Colditz, MD, DrPH1
[+] Author Affiliations
1Division of Public Health Sciences, Department of Surgery, Washington University School of Medicine, St Louis, Missouri
2Department of Statistics, Seoul National University, Seoul, South Korea
3Minimally Invasive and Bariatric Surgery, Department of Surgery, Washington University School of Medicine, St Louis, Missouri
4currently with ASAN Medical Center, Seoul, South Korea
JAMA Surg. 2014;149(3):275-287. doi:10.1001/jamasurg.2013.3654.
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Importance  The prevalence of obesity and outcomes of bariatric surgery are well established. However, analyses of the surgery impact have not been updated and comprehensively investigated since 2003.

Objective  To examine the effectiveness and risks of bariatric surgery using up-to-date, comprehensive data and appropriate meta-analytic techniques.

Data Sources  Literature searches of Medline, Embase, Scopus, Current Contents, Cochrane Library, and Clinicaltrials.gov between 2003 and 2012 were performed.

Study Selection  Exclusion criteria included publication of abstracts only, case reports, letters, comments, or reviews; animal studies; languages other than English; duplicate studies; no surgical intervention; and no population of interest. Inclusion criteria were a report of surgical procedure performed and at least 1 outcome of interest resulting from the studied surgery was reported: comorbidities, mortality, complications, reoperations, or weight loss. Of the 25 060 initially identified articles, 24 023 studies met the exclusion criteria, and 259 met the inclusion criteria.

Data Extraction and Synthesis  A review protocol was followed throughout. Three reviewers independently reviewed studies, abstracted data, and resolved disagreements by consensus. Studies were evaluated for quality.

Main Outcomes and Measures  Mortality, complications, reoperations, weight loss, and remission of obesity-related diseases.

Results  A total of 164 studies were included (37 randomized clinical trials and 127 observational studies). Analyses included 161 756 patients with a mean age of 44.56 years and body mass index of 45.62. We conducted random-effects and fixed-effect meta-analyses and meta-regression. In randomized clinical trials, the mortality rate within 30 days was 0.08% (95% CI, 0.01%-0.24%); the mortality rate after 30 days was 0.31% (95% CI, 0.01%-0.75%). Body mass index loss at 5 years postsurgery was 12 to 17. The complication rate was 17% (95% CI, 11%-23%), and the reoperation rate was 7% (95% CI, 3%-12%). Gastric bypass was more effective in weight loss but associated with more complications. Adjustable gastric banding had lower mortality and complication rates; yet, the reoperation rate was higher and weight loss was less substantial than gastric bypass. Sleeve gastrectomy appeared to be more effective in weight loss than adjustable gastric banding and comparable with gastric bypass.

Conclusions and Relevance  Bariatric surgery provides substantial and sustained effects on weight loss and ameliorates obesity-attributable comorbidities in the majority of bariatric patients, although risks of complication, reoperation, and death exist. Death rates were lower than those reported in previous meta-analyses.

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Figure 1.
Study Attrition Diagram

Remission is defined as the target comorbid condition being either resolved or improved after surgery. BMI indicates body mass index; %EWL, percentage of excess weight loss; MTC, mixed treatment comparison; OBS, observational study; RCT, randomized clinical trial; and ∆BMI, BMI change.

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Figure 2.
Meta-analysis of Body Mass Index Change (ΔBMI) After Surgery

A, Results of random-effects meta-analysis using the frequentist approach for ΔBMI for observational studies. Marker size is proportional to the number of study arms included in each analysis. B, Mixed treatment comparison meta-analysis results for ΔBMI (models 1 and 2) for randomized clinical trials. Estimates of model 1 are presented in the format of a forest plot; each estimate is the relative surgery effect compared with laparoscopic Roux-en-Y gastric bypass (LRYGB). Estimates of model 2 are presented in rhombuses; each estimate of model 2 is the relative category effect compared with gastric bypass (GB). A negative value means that the referent procedure/intervention (category) resulted in a lower ΔBMI, and vice versa. AGB indicates adjustable gastric banding; BPD-RYGB, biliopancreatic diversion with Roux-en-Y gastric bypass; Control, nonsurgical interventions; LBD-DS, laparoscopic biliopancreatic diversion with duodenal switch; LLAGB, laparoscopic adjustable gastric banding with LAP-BAND; LSAGB, laparoscopic adjustable gastric banding with Swedish band; LVBG, laparoscopic vertical banded gastroplasty; ORYGB, open Roux-en-Y gastric bypass; OVBG, open vertical banded gastroplasty; Overall, all surgery except for control; SG, sleeve gastrectomy; and VBG, vertical banded gastroplasty.

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