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.