Weight loss surgery effective, but risk remains

Bariatric surgery is effective at helping patients lose weight and improve obesity-related conditions like diabetes, high blood pressure and sleep apnea, according to a review of published studies. Complications are possible following these procedures, but death rates generally are low, according to researchers at Washington University School of Medicine in St. Louis who performed the analysis.

Their study appeared Dec. 18 in JAMA Surgery.

“We found that death rates were lower than those reported in previous meta-analyses,” said first author Su-Hsin Chang, PhD, instructor in surgery in the Division of Public Health Sciences. “Possibly, this is because we only included more recent studies published from 2003 to 2012, capturing the fact that the technology of bariatric surgery and the experience of surgeons have advanced.”

According to the investigators, the outcomes of bariatric surgery have not been systematically evaluated in a large number of trials since 2003. They looked at 164 randomized clinical trials and observational studies that included, but were not limited to, the three most common bariatric procedures: gastric bypass, adjustable gastric banding and sleeve gastrectomy.

Across all procedures, the mortality was eight deaths out of 10,000 patients within 30 days of surgery. This mortality increased to 31 deaths out of 10,000 patients after 30 days, based on the data from the randomized clinical trials.

The rate of any type of complication ranged from 10 to 17 percent, with gastric bypass having more complications but also more effective weight loss. Patients who underwent adjustable gastric banding lost comparatively less weight and were more likely to require another operation to fix problems such as band erosion. Despite requiring more follow-up operations, gastric banding had lower death and complication rates.

Looking at the 11 studies that reported data five years after surgery, the researchers calculated that study participants maintained a 12 to 17 point reduction in body mass index.

Sleeve gastrectomy appeared comparable to gastric bypass in terms of weight loss and therefore was more effective than adjustable gastric banding.

In addition to the weight loss benefit, the studies showed substantial improvement in conditions associated with obesity. Looking at the studies providing information about diabetes, rates of disease remission — a return to normal blood sugar levels — ranged from 86 to 92 percent. Among the studies reporting blood pressure data, 75 percent of patients returned to normal blood pressure readings following surgery.

This work was funded by the National Cancer Institute at the National Institutes of Health (NIH), grant numbers KM1CA156708 and U54 CA155496 and by the Agency for Healthcare Research and Quality, grant number K01 HS022330, by the Foundation for Barnes-Jewish Hospital and by an American Cancer Society Clinical Research Professorship.

Chang SH, Stoll CRT, Song J, Varela JE, Eagon CJ, Colditz GA. The effectiveness and risks of bariatric surgery, an updated systematic review and meta-analysis, 2003-2012. JAMA Surgery. Dec. 18, 2013.

Washington University School of Medicine’s 2,100 employed and volunteer faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Children’s hospitals. The School of Medicine is one of the leading medical research, teaching and patient-care institutions in the nation, currently ranked sixth in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Children’s hospitals, the School of Medicine is linked to BJC HealthCare.