A randomized, parallel-group trial has demonstrated that duodenal switch induces greater weight loss than gastric bypass in patients who are severely obese.

Gastric bypass is considered the gold standard by many surgeons, but patients who are severely obese may still be morbidly obese after peak weight loss following this operation. “There are few head-to-head studies comparing different bariatric procedures,” says Torgeir T. Søvik, corresponding author for the trial. “We wanted to investigate whether the duodenal switch yielded more weight loss and more favorable improvements in cardiovascular risk and quality of life than gastric bypass.”

60 patients with a BMI of 50–60 kg/m2 were included in the study; 31 underwent gastric bypass and 29 had a duodenal switch. The primary outcome was change in BMI after 2 years. Secondary outcomes included anthropometric measures, markers of cardiovascular risk, quality of life and adverse events.

“This study shows that 2 years post-surgery, duodenal switch is more effective in reducing weight and improving lipid profiles in severely obese patients,” says Søvik. “Both operations improved other cardiovascular risk factors and quality of life, but several participants having duodenal switch experienced complications related to reduced uptake of vitamins and nutrients.” The researchers therefore recommend that patients undergoing duodenal switch should be monitored closely after surgery.