Surgery for obesity
Abstract
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 methods
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.
PICOs
Plain language summary
Weight loss surgery for obesity
Obesity is associated with many health problems and a higher risk of death. Bariatric (weight loss) surgery for obesity is usually only considered when all other treatments have failed. People who are eligible for surgery have a body mass index (BMI) greater than 40 or greater than 35 with related conditions such as type 2 diabetes. Recently, it has been suggested that people with a lower BMI may benefit from surgery.
A number of different bariatric procedures are available, and these can be carried out through open (traditional) surgery or laparoscopic (keyhole) surgery. It is not clear which procedures are the most effective in reducing weight or have the least complications. The review aimed to compare these bariatric procedures with each other and with conventional treatment (such as drugs, diet and exercise).
The review found that surgery results in greater weight loss than conventional treatment in people with BMI greater than 30 as well as those with more severe obesity. Surgery also leads to some improvements in quality of life and obesity related diseases such as hypertension and diabetes. However, complications (for example pulmonary embolism), side‐effects (for example heartburn) and some deaths may occur. Although several different surgical procedures are available, not all have been compared with each other. Gastric bypass had greater weight loss 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. The evidence comparing vertical banded gastroplasty with adjustable gastric banding was not clear. Complications may occur with any bariatric procedure, but information from the included trials did not allow us to reach any conclusions about the safety of these procedures compared with each other.
Weight loss following open and laparoscopic surgery was similar. Recovery was often quicker following laparoscopic surgery, with fewer wound problems, although some studies found more reoperations were needed.
In conclusion, the review found that surgery is more effective than conventional management. Certain procedures appear to result in greater weight loss than others, but this is based on a very small number of trials. The evidence on the safety of these procedures compared with each other is even less clear. Due to the poor quality and small number of trials comparing each pair of procedures the information should be viewed with caution.
