Bariatric surgery is more effective than is conventional weight loss management in terms of weight lost, improved quality of life, and decreased comorbidities, according to an updated review by the Cochrane Collaboration.
The goal of the review, according to the authors, was twofold.
First, they set out to evaluate the effectiveness of surgery compared with nonsurgical weight loss methods.
Second, they compared the different types of weight loss surgery to each other, including gastric bypass surgery, vertical banded gastroplasty, adjustable gastric banding, and isolated sleevegastrectomy.
Unfortunately, only 26 trials met the researchers' qualifications for inclusion, according to the authors, led by Prof. Jill L. Colquitt of the University of Southampton, England (Cochrane Database Syst. Rev. 2009 April 15 [doi: 10.1002/14651858.CD003641.pub3]).
Furthermore, even among those trials, “The risk of bias of many trials was uncertain; just five had adequate allocation concealment,” wrote the authors, adding that they were unable to conduct a meta-analysis for that reason.
Also, because of the limited data, they could not assess the safety of the various procedures.
Among the review's other notable findings:
▸ Surgical intervention led to greater improvements in comorbidities such as diabetes, metabolic syndrome, and hypertension than did nonsurgical intervention at follow-up periods between 2 and 10 years. In the most definitive example of this, one study that specifically enrolled type 2 diabetes patients found that 2 years after laparoscopic adjustable gastric banding surgery there was significantly higher remission of the disease compared with conventional therapy (73% versus 13%) (JAMA 2008;299:316-23).
▸ Although there is limited good-quality evidence comparing types of surgery, the data suggest 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,” according to the authors. They added, however, that few, if any, trials examined this or any procedure in young people, adults with either class I or class II obesity (body mass index 30-34.9 and 35-39.9 kg/m
▸ There is a lack of data comparing the safety of each procedure. “All procedures were associated with adverse events, but few trials compared data statistically and none were powered to do so,” the authors wrote. Overall, the proportion of deaths reported in the surgery cohorts of the studies ranged from 0.25% to 10%.
The authors recommended that, for the sake of future studies, a core set of important adverse outcomes in this type of surgery should be identified.
They also recommended that future studies be undertaken to assess the effects of presurgery counseling and education on outcomes, and to “identify providers at different stages of the learning curve and to document the impact of experience on the safety, effectiveness, and efficiency of surgery.”
The analysis is the second update of bariatric surgery by the Cochrane Collaboration. The first review was published in 2003, and a previous update was published in 2005.
The authors indicated that they did not have any conflicts of interest with regard to this review.
The study was sponsored by the United Kingdom's National Institute for Health Research.