The most frequently performed weight-loss surgery, the gastric bypass, may not be the most effective in producing weight loss, according to a preliminary study by physician-scientists at NewYork-Presbyterian Hospital/Weill Cornell Medical Center.
The study finds that a more complex procedure, the duodenal switch, was more effective at promoting loss of body weight and body fat than gastric bypass.
The study followed 13 patients who underwent duodenal switch and 33 patients who underwent gastric bypass, all with comparable pre-surgery body mass index (BMI) and body composition. One to two years after surgery, duodenal-switch patients lost 50 percent more weight than gastric-bypass patients (22.3 BMI units lost vs. 15.1 BMI units lost). Furthermore, duodenal-switch patients reduced their body fat to 25.7 percent, compared to 34.0 percent for gastric bypass patients (25 percent body fat is within the normal range for most people). These findings will be presented at the 2005 North American Association for the Study of Obesity (NAASO) meeting in Vancouver on October 16.
"Overall, we found that patients who elect to have duodenal switch end up slimmer than those who choose gastric bypass," says Dr. Gladys W. Strain, director of research for bariatric surgery at NewYork-Presbyterian/Weill Cornell and associate research professor of nutrition in surgery at Weill Medical College of Cornell University. "Previous research has shown that significant weight loss reduces cardiac risk and early mortality."
In the duodenal-switch procedure (also know by its formal name, the biliopancreatic diversion with the duodenal-switch, or BPD/DS), the stomach is reshaped and somewhat reduced in size, creating a sleeve-like or banana shape. Approximately half of the small intestine is bypassed, and the stomach is reconnected to the shortened small intestine. This forms a short channel in which food and digestive juices are mixed. In a gastric bypass, a small gastric pouch is formed from the upper part of the stomach. A section of the upper intestine is then connected to the small gastric pouch through a Y-shaped connection.