By Amy Norton
WEDNESDAY, Jan. 15, 2020 (HealthDay News) -- People considering obesity surgery have a lot to think about, including the specific procedure they want. Now a large study finds that one surgery is tied to a higher rates of hospitalization in the years afterward.
Looking at medical records from more than 33,000 U.S. patients, researchers found that those who underwent gastric bypass surgery had higher rates of hospitalization in the next five years, versus patients who underwent sleeve gastrectomy.
Bypass patients also tended to need more abdominal surgeries and other invasive procedures.
But compared with the "explosion" of research on the effectiveness of weight-loss surgery, relatively little has dug into the downsides, said Dr. Anita Courcoulas, who led the new study.
"It's just as important to publish studies on the adverse outcomes," said Courcoulas, a professor of surgery at the University of Pittsburgh School of Medicine. "We want to give patients information on both sides of the risk-benefit equation."
So when it comes to deciding on a procedure, patients' values and preferences are key, she said.
In the United States, gastric bypass and sleeve gastrectomy are the two most common surgeries used to treat severe obesity. Both change the anatomy of the digestive system and limit the amount of food a person can eat before feeling full.
During gastric bypass, surgeons divide the top portion of the stomach from the rest, creating a small pouch that is then attached to the small intestine -- bypassing most of the stomach. As a result, people eat less, and the body absorbs fewer calories. That rerouted traffic also changes the function of the gut's hunger hormones, according to the American Society for Metabolic and Bariatric Surgery (ASMBS).
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.
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.
So it's not clear whether having bariatric surgery actually increased patients' need for procedures.
But what's important, Courcoulas said, is that patients have an idea of what their medical care might look like in the years after weight-loss surgery. More studies are needed, she added, to follow the outlook beyond five years.