By comparison, sleeve gastrectomy is simpler: Surgeons remove a large portion of the stomach, turning it into a tubular pouch that holds much less food. Like bypass, it alters gut hormone activity.
On average, people shed more pounds with bypass. A 2018 study of 46,000 patients found that bypass patients lost, on average, one-quarter of their starting weight over five years. That compared with 19% among sleeve gastrectomy patients.
Dr. Matthew Hutter is president of the ASMBS and an assistant professor of surgery at Harvard Medical School.
He said that both procedures are generally safe. And by spurring substantial weight loss, both can improve medical conditions like type 2 diabetes, high blood pressure and sleep apnea.
To Hutter, the results were “not surprising.” But he said they offer useful information for doctors and patients to discuss. In the end, he stressed, the choice of surgery has to be individual.
“It should be an informed decision, based on a detailed discussion with your doctor,” Hutter said.
The findings were published Jan. 15 in JAMA Surgery. They’re based on 33,560 patients who had surgery at any of 10 U.S. centers. Just over half had gastric bypass, and the rest had sleeve gastrectomy.
Over five years, 38% of bypass patients were hospitalized, versus 33% of sleeve patients. Similarly, about 12% of bypass patients needed an abdominal operation or an invasive (but not surgical) procedure. That compared with 9% of sleeve patients, the findings showed.
In addition, almost 16% of bypass patients underwent an endoscopy — where doctors thread a tube into the body in order to study internal tissue in detail. Only half as many gastric sleeve patients needed an endoscopy.
There are questions, however. The researchers had no information on the reasons for those hospitalizations and procedures. And, Courcoulas said, they were not necessarily related to surgery issues.
Some people, she noted, may have had hernia repairs, or knee replacements due to long-standing arthritis, for example.
Hutter made another point. “There was no comparison against [severely obese] people who did not have bariatric surgery,” he said.