Long-term Study of Bariatric Surgery for Obesity: LABS
The NIDDK funded the Longitudinal Assessment of Bariatric Surgery (LABS) observational study to research the risks and benefits of certain types of weight-loss (bariatric) surgery in adults—including gastric band and open or laparoscopic gastric bypass—and its impact on the health and well-being of people who have obesity with a body mass index (BMI) of 35 or higher. LABS played a major role in shaping clinical recommendations by identifying the types of people who are most likely to benefit from bariatric surgery. Data from the LABS study also helped the research community advance research and helped clinicians and patients understand the long-term risks and benefits of bariatric surgery.
More than 40 percent of U.S. adults have obesity and more than 9 percent have severe obesity,1 which may raise the risk of developing certain health problems such as type 2 diabetes, heart disease, liver disease, and kidney disease. People can lower their risk of developing these health problems through weight loss. However, some people, especially people who have severe obesity, may have a hard time losing weight or keeping weight off over the long term with diet and exercise alone, and they may benefit from bariatric surgery.
Over the years, bariatric surgery has become less invasive, safer, and more common. More than 250,000 bariatric surgery operations were performed in the United States in 2018, according to the American Society for Metabolic and Bariatric Surgery, or ASMBS.2 However, the surgery still involves risks.
Thirty days after bariatric surgery, LABS researchers found that
- Death rates were low. Only 2.1 percent of participants who had open gastric bypass and 0.2 percent of participants who had laparoscopic gastric bypass died. No participants who had gastric band surgery died.
- Only 4.1 percent of participants had at least one major bad outcome, such as death, development of blood clots, repeat surgeries, or failure to be released from the hospital.
- No significant differences in complication risk were found based on the type of gastric bypass procedure.
- Participants with the highest BMI values had the greatest risk of complications.
- Participants with a history of deep vein blood clots or sleep apnea had a higher risk of complications.
At the 7-year follow-up, LABS researchers found that
- Participants lost an average of 28.4 percent of their body weight after gastric bypass surgery and 14.9 percent of their body weight after laparoscopic gastric band surgery.
- Most participants maintained their weight loss. Three to 7 years after surgery, participants who had gastric bypass surgery regained an average of 3.9 percent of their body weight, and participants who had gastric band surgery regained on average of 1.4 percent of their body weight.
- High cholesterol was less common after gastric bypass and gastric band surgery.
- Diabetes and high blood pressure were less common after gastric bypass surgery. Over time, diabetes reoccurred in some patients, but numbers of new cases were low.
- Alcohol use disorders increased after gastric bypass surgery but not after gastric band surgery.
- Pain and physical function improved after bariatric surgery.
Although gastric sleeve is now the most common type of bariatric surgery, it was less common when the LABS study took place. Outcomes for gastric sleeve surgeries are not included in the results.
Study Size, Participant Demographics, and Study Design
LABS started in 2003. During the first 18 months of the study, LABS researchers developed a database at the University of Pittsburgh to collect standardized information from participants. Between 2005 and 2009, LABS participants had bariatric surgery at six participating clinical centers
- Columbia University, New York
- East Carolina University, North Carolina
- Oregon Health & Science University, Oregon
- University of North Dakota, North Dakota
- University of Pittsburgh, Pennsylvania
- University of Washington, Washington
LABS was divided into three parts: LABS 1, LABS 2, and LABS 3.
LABS 1 looked at the short-term safety of bariatric surgery. Researchers followed 4,776 participants with an average BMI of 46.5 who had bariatric surgery between 2005 and 2007. Researchers measured complications and death rates within 30 days after surgery.
LABS 2 looked at the long-term safety and effectiveness of bariatric surgery. Researchers followed more than 2,400 people who had bariatric surgery between 2006 and 2009. Researchers collected detailed data about the surgical procedure and the care provided before and after surgery. In addition, they measured changes in the patient’s clinical, metabolic, and psychosocial characteristics, and the patient’s use of health care services following surgery. Researchers met with participants before surgery, at 6 months after surgery, at 1 year after surgery, and then annually through 2015.
LABS 3 looked more closely into specific effects of bariatric surgery. Researchers followed some LABS 1 and 2 participants through two follow-up studies.
- Diabetes study. Researchers followed 63 participants who had type 2 diabetes to see how bariatric surgery affected their blood sugar levels.
- Psychosocial study. Researchers followed up with 202 participants to see how bariatric surgery affected their mental well-being and eating behaviors.
Researchers met with participants one time per year.
Related Health Information
- Diabetes Prevention Program (DPP) and DPP Outcomes Study (DPPOS). These studies showed that people who are at high risk for type 2 diabetes can prevent or delay the disease by losing a modest amount of weight through lifestyle changes (dietary changes and increased physical activity).
- Bariatric Surgery for Teens with Severe Obesity Study: Teen-LABS. Teen-LABS was the first large-scale study of bariatric surgery in teens who have severe obesity and serious weight-related health problems.
- Long-term Lifestyle Change for Type 2 Diabetes Study: Look AHEAD. Look AHEAD studied whether weight loss lowered the risk for cardiovascular disease events, such as heart attack, stroke, and other health problems in people who were overweight or had obesity and had type 2 diabetes.
News Releases and Reports
- Study shows adults had significant weight loss three years after bariatric surgery
- Understanding the health benefits and risks of bariatric surgery
Scientific Publications and Resources
- LABS 1, Longitudinal Assessment of Bariatric Surgery on ClinicalTrials.gov
- LABS 2, Long-term Effects of Bariatric Surgery on ClinicalTrials.gov
- LABS 3, Improving Diabetes After Bariatric Surgery on ClinicalTrials.gov
- LABS 3, Psychosocial Issues and Bariatric Surgery on ClinicalTrials.gov
- LABS from the NIDDK Central Repository
- LABS from dkNET
- Courcoulas A, Coley RY, Clark JM, et al. Interventions and operations 5 years after bariatric surgery in a cohort from the US National Patient-Centered Clinical Research Network Bariatric Study. JAMA Surgery. 2020;155(3):194–204. doi: 10.1001/jamasurg.2019.5470
- Courcoulas AP, King WC, Belle SH, et al. Seven-year weight trajectories and health outcomes in the Longitudinal Assessment of Bariatric Surgery (LABS) Study. JAMA Surgery. 2018;153(5):427–434. doi:10.1001/jamasurg.2017
- Purnell JQ, Johnson GS, Wahed AS, et al. Prospective evaluation of insulin and incretin dynamics in obese adults with and without diabetes for 2 years after Roux-en-Y gastric bypass. Diabetologia. 2018;61(5):1142–1154. doi:10.1007/s00125-018-4553-y
- King WC, Chen JY, Courcoulas AP, et al. Alcohol and other substance use after bariatric surgery: prospective evidence from a US multicenter cohort study. Surgery for Obesity and Related Diseases. 2017;13(8):1392–1402. doi: 10.1016/j.soard.2017.03.021
- King WC, Chen JY, Belle SH, et al. Change in pain and physical function following bariatric surgery for severe obesity. JAMA. 2016;315(13):1362–1371. doi: 10.1001/jama.2016.3010
- Courcoulas AP, Christian NJ, Belle SH, et al. Weight change and health outcomes at 3 years after bariatric surgery among individuals with severe obesity. JAMA. 2013;310(22):2416–2425. doi: 10.1001/jama.2013.280928
- Longitudinal Assessment of Bariatric Surgery (LABS) Consortium; Flum DR, Belle SH, King WC, et al. Perioperative safety in the longitudinal assessment of bariatric surgery. New England Journal of Medicine. 2009;361(5):445–454. doi: 10.1056/NEJMoa0901836
This content is provided as a service of the National Institute of Diabetes and Digestive and Kidney Diseases
(NIDDK), part of the National Institutes of Health. The NIDDK translates and disseminates research findings to increase knowledge and understanding about health and disease among patients, health professionals, and the public. Content produced by the NIDDK is carefully reviewed by NIDDK scientists and other experts.