Comparison of Obesity Surgeries Turns Up Surprising Results
MONDAY Sept. 17, 2012 -- Researchers who compared two types of weight-loss surgery found the less popular method -- called the duodenal switch -- results in better maintained weight loss than gastric bypass.
Gastric bypass, considered the gold standard of obesity operations, involves reducing the size of the stomach and bypassing the pyloric valve, which separates the stomach from the small intestine. In a duodenal switch, surgeons leave the pyloric valve intact. This prevents some complications associated with gastric bypass and allows for more normal digestion, which preserves vital nutrients, the researchers said.
"Surgeons are seeing ... a significant number of patients with weight gain after gastric bypass," said Dr. Alec Beekley, associate professor of surgery at Thomas Jefferson University Hospitals in Philadelphia and author of an editorial accompanying the study, which was published in the September issue of the journal Archives of Surgery. Beekley was not involved in the study.
Maintaining weight loss after gastric bypass surgery is a challenge, and over time the weight loss is not nearly as dramatic as after the initial operation, he said.
"Duodenal switch has superior weight loss and may be more appropriate as the primary bariatric operation in carefully selected patients," Beekley said.
Risks early on are higher with the duodenal switch, but the absolute risk of complications is low, the study authors said. Surgeons also have been reluctant to use duodenal switch because the nutritional requirements and need for follow-up are much higher with this procedure, he said.
"Yet, given the clear outcome advantages in terms of weight loss, perhaps it is time more U.S. surgeons considered this option," Beekley said.
For the study, a team led by Dr. Daniel Nelson of Madigan Army Medical Center in Fort Lewis, Wash., compared outcomes of more than 77,000 patients who had a traditional gastric bypass and an average body-mass index of 48 with more than 1,500 patients who had a duodenal switch and average body-mass index of 52. Body-mass index (BMI) is a measurement of body fat based on height and weight. A BMI over 40 is considered morbidly obese. More than three-quarters of the patients were women, and their average age was 45.
The duodenal switch procedure takes more than 20 minutes longer to perform on average and is associated with more blood loss and longer hospital stays -- 4.4 days vs. 2.2 days. Nearly all of the gastric bypass patients had laparoscopic surgery, while half of the duodenal switch patients underwent open surgery, which poses a longer recovery time.
The duodenal switch, however, resulted in greater sustained weight loss, the researchers found.
This result was especially noticeable among the most obese patients, called the superobese, the researchers said. Two years after surgery, 79 percent of those who had a duodenal switch still had a significant weight loss compared with 67 percent who had gastric bypass.
In addition, almost 20 percent of patients who had a gastric bypass failed to lose at least 50 percent of their body mass at the two-year follow-up, compared with 6 percent who underwent a duodenal switch, they noted.
Moreover, patients who had a duodenal switch had greater improvement in obesity-related conditions, such as diabetes, high blood pressure, high cholesterol and sleep apnea, the researchers found.
Dr. Mitchell Roslin, chief of obesity surgery at Lenox Hill Hospital in New York City, said patients gain weight after a gastric bypass because they suffer from low sugar and get instantly hungry.
"We do not see that in the duodenal switch nearly as much, because the pyloric valve is preserved," he said. "It is far better to preserve the pyloric valve and do your bypass underneath it, although it's technically more challenging than to do the gastric bypass."
"Challenge your doctor; don't believe in old wives' tales," Roslin added. "I can't think of a biologic reason why a bypass above the pyloric valve is better than a bypass beneath it."
Both procedures cost about the same -- between $25,000 and $40,000, depending on the contract a hospital has with insurance companies, Roslin said.
The authors said further research is needed to determine the ideal candidate for the duodenal switch and to assess long-term results.
For more information on weight-loss surgery, visit the U.S. National Library of Medicine.
Posted: September 2012
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