Comparing surgical treatment and non-surgical care for long-term weight loss

Researchers have found that people with severe obesity who underwent bariatric surgery had significantly more short- and long-term weight loss compared to those who did not have surgery. Bariatric surgery can be an effective tool for treating severe obesity, leading to significant weight loss and improved health outcomes. However, few people with severe obesity opt to undergo bariatric surgery. This suggests that more data are needed about the long-term outcomes in people who have undergone bariatric surgery compared to those who have not had surgery, to help inform clinical decision making.

To help fill this knowledge gap, scientists analyzed data from the health records of women and men with severe obesity enrolled in a managed health care system. The study sample included over 31,000 people who had undergone a bariatric surgery procedure—either Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG)—as well as nearly 88,000 people who did not have bariatric surgery. Those who did not have surgery received usual medical care, which typically did not include treatment specifically for obesity. The scientists examined the level of total weight loss at 1, 5, and 10 years post-surgery, and at similar timepoints for those in the non-surgical group. After 1 year, people who had RYGB or SG lost about 28 and 23 percent of their body weight, respectively, which was much higher than the 0.2 percent weight loss observed in the non-surgical group. After 5 years, there was some weight regain in the people who had bariatric surgery, so the total weight loss decreased to about 22 percent in the RYGB group and 16 percent in the SG group. However, those levels still exceeded the 2.2 percent weight loss seen in the non-surgical group after 5 years. After 10 years, significant differences persisted: 20 percent weight loss in the RYGB group and 4.8 percent in the non-surgical group. The 10-year data could not be assessed for the SG group because it is a more recent procedure, though it is now the most common form of bariatric surgery. Although the data showed that people who underwent bariatric surgery regained weight over time, regain to within 5 percent of their pre-surgical weight was rare.

Overall, the researchers found that, for people with severe obesity, both RYGB and SG resulted in much more short- and long-term weight loss compared to non-surgical care. Bariatric surgery has serious surgical risks, and lifetime risk remains unknown; however, severe obesity also increases risks for serious diseases. Thus, this study contributes important new information for people with severe obesity and their health care providers as they consider both the risks and benefits of different treatment approaches.