Newswise — A study published this month in the Annals of Internal Medicine found that adults with severe obesity had greater initial and sustained weight loss with gastric bypass surgery compared to sleeve gastrectomy or adjustable gastric banding surgery.
The largest, long-term national study of bariatric surgery to date was led by Kaiser Permanente and involved two University of Nebraska Medical Center physician/researchers.
The findings are important because severe obesity affects more than 15 percent of U.S. adults.
The study, which compared the three most common operations, included more than 46,000 patients at 41 health systems in 11 Clinical Data Research Networks nationwide. thanks to its use of a large new resource called PCORnet®, the National Patient-Centered Clinical Research Network.
Bariatric surgeons can use various operations to help people lose weight by making changes to their digestive system. The study compared 1-, 3- and 5-year results from the three most commonly performed weight-loss operations: gastric bypass, sleeve gastrectomy and adjustable gastric banding.
James McClay, M.D., UNMC associate professor of emergency medicine and chair of the UNMC Biomedical Informatics Program, and Corrigan McBride, M.D., UNMC professor of surgery, were participants in the study. Both see patients at Nebraska Medicine, UNMC’s clinical partner.
"The Bariatric Center at Nebraska Medicine and the researchers of UNMC are very proud participants in this collaborative study," Dr. McBride said. "The study is very important for patients considering bariatric surgery because it shows that both laparoscopic gastric bypass and laparoscopic sleeve surgeries have durable long-term weight loss and give us good predictions of weight loss."
The new results are among the first to be produced using the resources of PCORnet®, an innovative initiative funded by the Patient-Centered Outcomes Research Institute (or PCORI). PCORnet® is designed to produce clinical insights faster and less expensively than traditional clinical studies. It involves multiple individual networks that together represent more than 100 million patients.
The network securely collects health information during routine care to produce real-world evidence with outcomes that matter to patients, who are full partners in this research. Patient identity is not identified in the data.
"This study showcases the power of PCORnet® to deliver on its goal to produce faster, less costly, and more meaningful research results than traditional clinical trials," Dr. McClay, co-leader of the Greater Plains Collaborative, one of PCORnet’s partner networks. "Working together we were able to securely assess de-identified health information collected during routine care to compare the outcomes of each weight loss procedure."
This PCORnet® study, registered at (NCT02741674), was funded by PCORI through PCORI Award OBS-1505-30683.
What the investigators found:

  • People who had gastric bypass surgery had lost 31 percent of their weight at the first year and maintained 26 percent of their loss at 5 years. 
  • People who had sleeve gastrectomy had lost 25 percent of their pre-surgery body weight at one year and maintained 19 percent weight loss at five years.
  • That translates into a 19-pound difference in weight loss between gastric bypass and sleeve gastrectomy at five years for the average person in this study, who weighed 277 pounds before surgery.
  • By contrast, adjustable gastric banding was much less effective for losing weight and keeping it off, with 14 percent and 12 percent of weight lost at one and five years, respectively. Gastric banding used to be the most commonly performed bariatric procedure, but it now represents just 10 percent of bariatric procedures.
  • Members of the same PCORnet® Bariatric Study Collaborative found similar results in teenagers.

Kaiser Permanente is committed to helping shape the future of health care. We are recognized as one of America’s leading health care providers and not-for-profit health plans. Founded in 1945, Kaiser Permanente has a mission to provide high-quality, affordable health care services and to improve the health of our members and the communities we serve. We currently serve more than 12.2 million members in eight states and the District of Columbia. Care for members and patients is focused on their total health and guided by their personal Permanente Medical Group physicians, specialists and team of caregivers. Our expert and caring medical teams are empowered and supported by industry-leading technology advances and tools for health promotion, disease prevention, state-of-the-art care delivery and world-class chronic disease management. Kaiser Permanente is dedicated to care innovations, clinical research, health education and the support of community health. For more information, go to:
We are Nebraska Medicine and UNMC. Our mission is to lead the world in transforming lives to create a healthy future for all individuals and communities through premier educational programs, innovative research and extraordinary patient care.

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Newswise: National Study Finds Gastric Bypass Most Effective Weight Loss Surgery


Caption: James McClay, M.D.

Newswise: National Study Finds Gastric Bypass Most Effective Weight Loss Surgery


Caption: Corrigan McBride, M.D.


Annals of Internal Medicine