The two most common obesity surgeries—gastric bypass and gastric sleeve—have few short-term complications and are equivalent in that sense. These are the findings of a study conducted at the University of Gothenburg.

The paper is published in the journal JAMA Network Open.

Every year, around 5,000 obesity surgeries are performed in Sweden. The person undergoing surgery will normally have a BMI of at least 40, or 35 if they also have other serious medical conditions related to obesity.

The most common procedures are gastric bypass, where a large part of the stomach and part of the small intestine are bypassed, and gastric sleeve, where a large part of the stomach is surgically removed. The aim of the current study was to compare the short-term risks of the different procedures.

In this, the largest study of its kind, 1,735 adult patients planned for surgery between 2015 and 2022 agreed to participate, and they were randomly assigned to either gastric bypass or gastric sleeve. The surgeries were performed in university hospitals and other hospitals, public and private, 20 in Sweden and 3 in Norway.

Relatively few complications

The results described in the study show no significant differences between the methods. Surgical time was longer for gastric bypass, averaging 68 minutes compared to 47 minutes for gastric sleeve, but hospitalization after surgery was one day, regardless of method.

The follow-ups also gave equivalent results for the two methods. At 30 days after surgery, both groups had relatively few complications such as hemorrhage, leakage, blood clots and infections. No deaths occurred during the follow-up period of 90 total days.

"For both surgical procedures, the risk of complications is very low, especially from an international perspective, and there is no statistically significant or clinically relevant difference between the groups," says Suzanne Hedberg, first author of the study.

Many stakeholders and many opinions

"Many people have had surgery, or are on waiting lists for surgery, and there are lots of discussions and opinions about the different methods. What the study shows is that patients and doctors can now choose their surgical method without considering short-term surgical risks," she says.

Hedberg defended her thesis in surgery at Sahlgrenska Academy, University of Gothenburg in April 2023, and is a consultant at Sahlgrenska University Hospital. The study, included in her thesis, is the first publication with results from BEST (Bypass Equipoise Sleeve Trial), a Scandinavian registry-based randomized controlled multicenter study comparing the two methods of obesity surgery. The main outcome of the trial which analyzes the risk of complications and weight progression over 5 years, is expected to be completed in 2028.

"For the ongoing studies, we are off to a good start with equivalent groups, laying a good foundation for further comparisons of more long-term results," concludes Hedberg.