A less usual and common type of obesity surgery may spur more weight loss than its far more popular cousin, gastric bypass - but at the price of greater long-term risks, researchers reported.
The study, published in the Annals of Internal Medicine, followed 60 severely obese patients who were randomly assigned to either gastric bypass surgery or a more extensive procedure known as duodenal switch.
Two years after surgery, duodenal switch patients had lost more weight: about 50 pounds more, on average. People shed a substantial amount of weight with either type of surgery. Gastric bypass patients cut an average of 111 pounds, while duodenal switch patients dropped about 162.
But those extra pounds came with nearly double the complication rate. Of the 29 duodenal switch patients, 62 percent had problems like abdominal pain, vomiting, diarrhea and intestinal obstruction. And several suffered long-term malnutrition - something not seen in the gastric bypass group.
In a 2008 study duodenal switch accounted for just 1 percent of weight-loss, or bariatric, surgeries done in the U.S., and 5 percent in Europe. The technique is often reserved for “super-obese” patients with a body mass index (BMI) of 50 or higher -- though some surgeons perform it with less severely obese patients too, explained Dr. Torgeir T. Sovik of Oslo University in Norway, the lead researcher on the new study. “As duodenal switch can be associated with more adverse events, this procedure should only be performed in carefully selected patients by a dedicated bariatric team… And a closer follow-up after surgery is required after such procedures,” he said.
“This is an operation that should probably go away,”" said Dr. Edward H. Livingston, a professor and surgeon at the University of Texas Southwestern Medical Center in Dallas who was not involved in the study.
The average weight loss seen with either gastric bypass or duodenal switch will improve or reverse obesity-related ills like diabetes, sleep apnea and knee arthritis, according to Livingston, who wrote an editorial published with the study.
In the U.S., where about 220,000 people underwent weight-loss surgery in 2009, gastric bypass is the most common form chosen.
During gastric bypass, the upper portion of the stomach is stapled off to create a smaller pouch that restricts the amount of food a person can eat at one time. The surgeon also creates a bypass around the rest of the stomach and a portion of the small intestine, which limits the body's absorption of food. Duodenal switch is more extensive. The surgeon removes part of the stomach, and the remaining “sleeve-like” stomach is attached to the final section of the small intestine; that puts even greater limits on the body's absorption of calories and nutrients.
In a study recently published in the Journal of the American Medical Association, Livingston and his colleagues found no survival advantage among severely obese patients who'd undergone weight-loss surgery versus those who hadn't.
The study involved 850 U.S. veterans who underwent some form of weight-loss surgery, at an average age of about 50, and more than 41,000 vets who had only non-surgical care. There was no evidence that surgery improved longevity over the next seven years. “We really don't even know if there's a survival benefit,” Livingston said.
But according to Sovik, duodenal switch might be appropriate for some super-obese patients. In the U.S., he said, about one in three weight-loss surgery candidates have a BMI of 50 or higher. And studies suggest that a sizable percentage of those people will still have a BMI higher than 40 after gastric bypass. In this study, one-quarter of gastric bypass patients still had a BMI that high two years after surgery - versus none of the duodenal switch patients.
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