DURHAM, N.C. -- Gastric bypass surgery is more effective for weight loss and long-term weight maintenance than are other surgical procedures and non-surgical treatment, according to a study led by researchers at Duke Health and the Durham VA Medical Center.

The study’s findings, published Aug. 31 in the journal JAMA Surgery, are based on the analysis of ten years of medical records for veterans who underwent one of three different weight-loss surgery procedures at VA medical centers or community hospitals reimbursed by the VA.

“Very few studies have shown how weight-loss surgery patients change over the long term, which we consider a period of five years or more,” said lead author Matthew Maciejewski, Ph.D, a professor of medicine at Duke and director of the Health Economics and Policy Unit at the Durham VA Medical Center.

“We also wanted to contribute to filling the evidence gap about the comparative outcomes of the different forms of weight-loss surgery,” Maciejewski said.

In the study’s first part, Maciejewski and co-investigators compared the records of 1,787 veterans who underwent gastric bypass to the records of 5,305 veterans who did not have any form of weight loss surgery. These non-surgical patients were included in the study based on several criteria -- including age, sex, race, chronic conditions, and body mass index (BMI) -- to compare their experiences with weight to those of the bariatric surgery patients.

After one year, patients undergoing Roux-en-Y gastric bypass lost 31 percent of their baseline weight, while the non-surgical patients lost 1.1 percent of their baseline weight, making for a nearly 30 percent greater weight loss among surgical patients. The study team also found that the gastric bypass patients had maintained a nearly 21 percent greater weight loss then their non-surgical counterparts after 10 years.

In the second part of the study, the study team compared weight change four years after surgery for 246 patients who underwent adjustable gastric banding (AGB); 1,785 who underwent gastric bypass; and 379 who underwent sleeve gastrectomy (SG). The latter two procedures have become common forms of bariatric surgery in recent years and sleeve gastrectomy is a relatively new procedure, so the study team could only examine outcomes for a four-year period.

The study team found that the gastric bypass patients saw the most weight loss in each year. At year four, gastric bypass patients had lost 27.5 percent of their baseline weight, while AGB patients lost 10.6 percent and SG patients lost 17.8 percent.

“The results indicate that bariatric surgery, especially gastric bypass, provides significant long-term health benefits in terms of dramatic and sustained weight loss up to ten years after surgery,” Maciejewski said.

“Patients, clinicians and policymakers should feel confident that gastric bypass can induce sustainable weight loss,” he added.

The authors note that the patients in the study were predominantly male and about five years older than the typical bariatric surgery patient seen outside of VA hospitals. Additionally, in the absence of standardized weight measurements for patients, researchers used model-estimated predictions for certain time points.

In addition to Maciejewski, study authors from Duke include Maren K. Olsen, Valerie A. Smith and William S. Yancy. They were joined by David E. Arterburn, Lynn Van Scoyoc, Hollis J. Weidenbacher, and Edward H. Livingston.

The study was supported by the Department of Veterans Affairs (IIR 10-159 and RCS 10-39).

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