This research project is in progress. PCORI will post its findings here within 90 days after our final review is complete. In the meantime, results have been published in peer-reviewed journals, as listed below.
What is the research about?
Adults and adolescents affected by obesity are more likely to develop conditions such as diabetes, heart disease, and arthritis than are people without obesity. Some people with severe obesity can’t lose enough weight with diet and exercise to improve their health. Weight loss surgery, also known as bariatric surgery, can help with weight loss. It can also improve some diseases related to obesity, like diabetes.
People usually get one of three types of weight loss surgery. In Roux-en-Y gastric bypass, a surgeon uses part of the stomach to create a small pouch that can hold only a small amount of food. Patients feel full after eating only a little. The surgeon bypasses the rest of the stomach and attaches this small pouch to the middle portion of the small intestine. This bypass means the body absorbs fewer calories. In adjustable gastric banding, a doctor places a band around the upper part of the stomach. This band helps limit the amount of food a person can eat because the person feels full after eating a small amount. In sleeve gastrectomy, a surgeon removes a large part of the stomach, which also limits the amount of food a person can eat.
Not many studies have looked at patients’ weight losses and health several years after these surgeries. This study compares the long-term benefits and harms of these three common types of weight loss surgery.
Who can this research help?
This research can help individuals and their doctors decide if weight loss surgery is an option for treating their obesity. The research can also help in deciding whether one type of weight loss surgery is better than another for a person.
What is the research team doing?
The research team is following more than 65,000 patients who have had bariatric surgery at one of more than 42 healthcare systems across the United States. More than 700 of these patients are adolescents ages 12–19. More than 10,000 of these patients have diabetes.
The team is using medical record information to see how each type of weight loss surgery compares to the other two types. Team members are checking records at 1, 3, and 5 years after surgery to see
- How much weight people have lost compared with their weight before surgery
- Whether people who have diabetes at the time of surgery still have diabetes afterward
- How often people have new surgeries, go back to the hospital, or die
Because of the large number of people included in the study, the researchers can look at whether the benefits and harms of each type of surgery differ depending on a person’s characteristics. For example, the researchers can look at whether people with diabetes lost more or less weight than did people without diabetes. Researchers can also look to see if people who are one race lost more or less weight than did people of other races.
The researchers are holding focus groups with adults and adolescents affected by obesity to learn whether they would have bariatric surgery, what type of bariatric surgery they might have, and what kind of follow-up care they would want after surgery. Researchers are also holding focus groups with people who have already had bariatric surgery to get their opinions on the same topics. They are interviewing bariatric surgeons around the United States to hear how those surgeons choose weight loss surgeries and how they care for people after surgery.
The research team is working with people who have had bariatric surgery and with other partners, such as obesity advocacy groups, to design and carry out the study.
The study is a demonstration project of the National Patient-Centered Clinical Research Network, PCORnet.
Research methods at a glance
|Design||Observational: cohort study|
|Population||Adolescents and adults ages 12 to 79 years who underwent an eligible type of bariatric surgery between 1/1/2005 and 9/30/2015|
Primary: change in body mass index, whether and for how long remission from diabetes occurs; adverse events, including reoperation and rehospitalization and death
Secondary: weight regain, change in hemoglobin A1c
|5-year follow-up for most primary outcomes|
^Kaiser Permanente acquired Group Health Cooperative in February 2017.