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Bariatric surgery gastric bypass tied to less weight loss and fewer complications than duodenal switch

(RxWiki News) Bariatric (weight loss) surgery can have stunning results — some patients can lose 100 pounds or more. Not all weight loss surgeries always have the same results, however.

A new study found that two common weight loss procedures had different outcomes and complication rates. Researchers in Norway compared standard gastric bypass surgery with a procedure called a duodenal switch.

The second procedure resulted in more weight loss, but patients also had more complications.

Led by Hilde Risstad, MD, of Oslo University Hospital, Norway, the authors of this study assessed outcomes in 60 patients five years after weight loss surgery.

Despite the more pronounced weight loss from duodenal switch, Dr. Risstad and colleagues wrote that “We recommend that duodenal switch be used with caution owing to a higher rate of additional surgical procedures and risk of nutritional complications.”

BMI, which stands for body mass index, is a measure of body fat based on a patient’s height and weight. A normal BMI ranges from 18.5 to 24.9, according to the Centers for Disease Control and Prevention.

All patients in this study had a BMI of 50 to 60. A patient with a BMI of 50 to 60 could weigh twice as much as the normal weight for his or her height.

The idea behind bariatric surgery is to decrease the size of the stomach and the surface area of the intestines to decrease the amount patients can eat and how much their intestines can absorb. The surgery is used for people who are severely obese and have been unable to lose weight through other means like diet and exercise.

In gastric bypass, the surgeon creates a smaller stomach pouch and shortens the small intestine. For a duodenal switch, the surgeon also creates a smaller stomach, but bypasses almost three-quarters of the small intestine.

Dr. Risstad and colleagues found that patients who had the duodenal switch reduced BMI by an average of 22.1 points — compared to 13.6 for gastric bypass.

Both groups of patients showed boosts in overall health, such as better blood pressure and lung function.

However, Dr. Risstad’s team found that patients who had the duodenal switch were more likely to have nutritional complications. These complications were likely related to decreased nutrient absorption because of the shortened small intestine, these researchers said.

Patients were also more likely to have multiple hospital admissions and more surgical procedures with duodenal switch operations. Finally, patients who had a duodenal switch were more likely to have severe diarrhea or other gastrointestinal problems.

In an editorial about this study, Oliver A. Varban, MD, and Justin B. Dimick, MD, of the University of Michigan in Ann Arbor, wrote that doctors should be more selective in offering duodenal switch to patients.

"At the very least, patients seeking this procedure should receive ample warning regarding the very high risks of adverse nutritional outcomes and the high reoperation rate," Drs. Varban and Dimick wrote. "Patients with poor compliance and poor follow-up should not be offered this procedure because they could be at risk of fatal complications if [problems after surgery] are not addressed in a timely fashion.”

The study and editorial were published Feb. 4 in JAMA Surgery.

Study authors Drs. Risstad, Søvik, and Aasheim received funding from a Norwegian research fellowship. Oslo University Hospital also funded this research. Study author Dr. Olbers received a research grant from Sahlgrenska University Hospital. Some study authors noted financial ties to pharmaceutical companies like Eli Lilly, Merck, Sanofi, Pfizer and Novartis, among others.


Review Date: 
February 10, 2015