Feb. 23, 2011 -- Gastric bypass, the most commonly performed surgery for obesity in the U.S., appears to help patients lose more weight and may treat diabetes more effectively than newer techniques, two studies show.
In both studies, bypass offered more dramatic results, perhaps because the procedure reroutes digestion, bypassing a portion of the small intestine. Experts say the studies show why it’s important for people considering weight loss surgery to understand the trade-offs.
“The Lap-Band has fewer complications and is overall a safer procedure,” says Harry C. Sax, MD, a bariatric surgeon at the Warren Alpert School of Medicine at Brown University in Providence, R.I. “However, the weight loss from the Lap-Band is more modest, and we’re not clear how durable they will be long term.”
“In some cases, the riskier procedure, that is the Roux-en-Y gastric bypass, may offer greater benefits. That’s certainly some of the data that are coming out looking at the management of diabetes,” says Sax, who wrote a perspective that accompanied the studies.
Gastric Bypass vs. Lap-Band
In the first study, researchers in the bariatric surgery program at the University of California, San Francisco matched 100 patients who had chosen Lap-Band to 100 patients of the same age, sex, race, and BMI who had chosen a gastric bypass. In Lap-Band, an adjustable band is placed around the top of the stomach to create a smaller stomach pouch, leading to reduced food intake. The commercially available laparoscopic gastric banding system Lap-Band was used in the study. The Realize Adjustable Gastric Band is another commercially available system.
After one year, gastric bypass patients had lost nearly twice as much body weight as those who’d chosen Lap-Band. Of the 68 patients who had type 2 diabetes before surgery, a greater proportion who had gastric bypass saw their diabetes improve or resolve compared to those who got bands, 75% vs. 50%, respectively. Patients in the bypass group also scored better on measures of self-esteem and physical and social functioning compared to people who’d gotten Lap-Band.
“It’s very clear: Bypass is better than band, period. Bypass resolves more diabetes than band, period. And if you are diabetic with obesity, the best treatment is Roux-en-Y gastric bypass,” says study researcher Guilherme M. Campos, MD, a bariatric surgeon who is now with the University of Wisconsin School of Medicine and Public Health in Madison.
Campos notes that his study only included patients who had BMIs over 35 but that the FDA had recently approved the Lap-Band procedure for people with BMIs as low as 30 who also had at least one other obesity-related medical condition.
“I think for patients with the lower tier BMI, it may be worth considering laparoscopic banding as an option,” he says.
Lap-Band Manufacturer Responds
Cathy Taylor, senior manager of corporate communications at Allergan Inc., writes in an email to WebMD, “This is a single-center study, not a randomized, double-blind, and multi-center clinical trial, and the study’s conclusions are not in line with the vast findings from the published literature. The LAP-BAND System procedure is inherently safer than gastric bypass, given bypass is an invasive procedure... In addition, the medical literature supports that at five years, which is the measure of sustainable weight loss, weight loss achieved with the Lap-Band System is on par with weight loss achieved from gastric bypass. In terms of resolution of diabetes, a landmark study published in JAMA in 2008 found that gastric banding also helps resolve diabetes over time.”
Gastric Bypass vs. Sleeve Gastrectomy
For the second study, researchers in Taiwan recruited 60 moderately obese patients (BMIs between 25 and 35) who had poorly controlled type 2 diabetes. They randomly assigned half the patients to get a gastric bypass. The other half had a sleeve gastrectomy, which involves surgically removing a portion of the stomach, creating a small “sleeve” of stomach about as wide as a garden hose. In this procedure there is no bypass of the small intestine.
After 12 months, twice as many patients in the gastric bypass group (93%) saw their diabetes resolve compared to those who had sleeve gastrectomies (47%). The bypass group also lost more weight, had lower blood glucose levels, and had better total and LDL cholesterol levels than the gastrectomy group, a finding that surprised researchers.
“In some previous studies, sleeve gastrectomy was found to have equal efficacy in weight reduction to gastric bypass for morbidly obese patients,” says study researcher Wei-Jei Lee, MD, PhD, a surgeon at Min-Sheng General Hospital.
Lee says that in her study, rerouting food around the duodenum (a portion of small intestine) appeared to make the difference.
Choosing Weight Loss Surgery
In light of these results, doctors say it’s important for patients to go into any weight loss surgery clear-eyed and armed with information.
“What I try to explain to everybody is that a band is a diet with a seatbelt, there’s no metabolic weight loss component to it at all,” says Mitchell Roslin, MD, chief of bariatric surgery at Northern Westchester Hospital in Mount Kisco, N.Y. “You put a seatbelt around the stomach.”
Often significant weight loss, by itself, will improve diabetes.
To the extent that people lose weight with Lap-Band, Roslin says, they may see their diabetes improve. But weight loss with Lap-Band tends to be slower than it is with a bypass and in the long term may not be as substantial.
If control of diabetes is a primary concern, having an operation that bypasses the upper intestine is probably the best bet, says John G. Kral, MD, director of surgical services at SUNY Downstate Medical Center in New York.
“Adding type 2 diabetes to the equation, the evidence is fairly clear that diversionary operations are more effective. That is a powerful factor for a patient who would come requesting a bariatric operation and who has type 2 diabetes,” Kral says.
However, he adds that the gastric bypass is a complicated procedure that’s best performed by an experienced surgeon at a hospital where they are frequently performed.
Kral says surgeons need to have performed about 125 gastric bypass procedures before they can reliably and safely repeat them in patients.