Background: Bariatric (weight loss) surgery for obesity is considered when other treatments have failed. The effects of the available bariatric procedures compared with medical management and with each other are uncertain. This is an update of a Cochrane review first published in 2003 and previously updated in 2005.
Objectives: To assess the effects of bariatric surgery for obesity.
Search strategy: Studies were obtained from computerized searches of multiple electronic bibliographic databases, supplemented with searches of reference lists and consultation with experts in obesity research.
Selection criteria: Randomised controlled trials (RCTs) comparing different surgical procedures, and RCTs, controlled clinical trials and prospective cohort studies comparing surgery with non-surgical management for obesity.
Data collection and analysis: Data were extracted by one reviewer and checked independently by two reviewers. Two reviewers independently assessed trial quality.
Main results: Twenty six studies were included. Three RCTs and three prospective cohort studies compared surgery with non-surgical management, and 20 RCTs compared different bariatric procedures. The risk of bias of many trials was uncertain; just five had adequate allocation concealment. A meta-analysis was not appropriate.Surgery results in greater weight loss than conventional treatment in moderate (body mass index greater than 30) as well as severe obesity. Reductions in comorbidities, such as diabetes and hypertension, also occur. Improvements in health-related quality of life occurred after two years, but effects at ten years are less clear.Surgery is associated with complications, such as pulmonary embolism, and some postoperative deaths occurred.Five different bariatric procedures were assessed, but some comparisons were assessed by just one trial. The limited evidence suggests that weight loss following gastric bypass is greater than vertical banded gastroplasty or adjustable gastric banding, but similar to isolated sleeve gastrectomy and banded gastric bypass. Isolated sleeve gastrectomy appears to result in greater weight loss than adjustable gastric banding. Evidence comparing vertical banded gastroplasty with adjustable gastric banding is inconclusive. Data on the comparative safety of the bariatric procedures was limited.Weight loss and quality of life were similar between open and laparoscopic surgery. Conversion from laparoscopic to open surgery may occur.
Authors' conclusions: Surgery is more effective than conventional management. Certain procedures produce greater weight loss, but data are limited. The evidence on safety is even less clear. Due to limited evidence and poor quality of the trials, caution is required when interpreting comparative safety and effectiveness.