Weight loss from bariatric surgery compared to nonsurgical care for people with severe obesity

Researchers found that bariatric surgical procedures, including gastric bypass surgery and sleeve gastrectomy, led to significantly more weight loss than nonsurgical care for people with severe obesity—information that could help with treatment decisions. Although past research demonstrated that bariatric surgery leads to substantial weight loss, only a few long-term studies compared weight loss from nonsurgical care to that from surgery, and there has been less information on sleeve gastrectomy, though it is currently the most common bariatric procedure.

To better understand the effects of surgery, researchers analyzed electronic medical records and other data from women and men of diverse race and ethnicity with severe obesity in a large health care system, including 13,900 people who had sleeve gastrectomy (SG), 17,258 who had Roux-en-Y gastric bypass (RYGB), and 87,965 people who did not have surgery. Those in the nonsurgical group received usual medical care, which in general did not include specific obesity treatment. On average, 1 year after surgery, people in the RYGB group had lost 28 percent of their weight, and those who had SG lost 23 percent of their weight. At a similar time point, those in the nonsurgical group had lost 0.2 percent of their weight. Longer-term follow-up data were available for a majority of the people. At 5 years, the people who had surgery regained some weight, but those who had RYGB still maintained an average 22 percent weight loss, and those in the SG group still maintained 16 percent weight loss, or approximately 60 pounds and 43 pounds lost, respectively. Some regained enough weight to be within 5 percent of their initial weight, however, including 1 of every 10 people who had SG and 1 in 27 who had RYGB. Those who didn’t have surgery had lost approximately 2 percent of their weight, or about 6 pounds. At 10 years, those who had RYGB were still on average 20 percent below their pre-surgical weight, and those in the nonsurgical group had lost approximately 5 percent of their weight. (There were not enough data to analyze weight loss 10 years after SG.)

This study provides important information that people with severe obesity and their health care providers can use when considering bariatric surgery. The findings also suggest a need for additional care for people who experience weight regain after surgery. Future research could explore other long-term effects of bariatric surgery on health.