Gastric bypass surgery has better outcomes than gastric banding for long-term weight loss, controlling type 2 diabetes and high blood pressure, and lowering cholesterol levels, according to a new review by UT Southwestern Medical Center surgeons of nearly 30 long-term studies comparing the two types of bariatric procedures.
The review, appearing in JAMA, found that those undergoing gastric bypass operations lost more weight - an average of 66 percent of their excess weight, compared to 45 percent average excess weight loss for those undergoing gastric banding procedures.
"We know gastric bypass brings more weight loss success and relief of commonly associated illness versus gastric band at one year after surgery. We now have the best evidence available telling us this outcome continues to be true even up to five years after surgery. We also know these procedures maintain their safety profile long-term," said Dr. Nancy Puzziferri, Assistant Professor of Surgery and part of the bariatric surgery team at UT Southwestern.
According to a 2011 estimate, some 120,000 bariatric procedures are performed annually in the U.S. Worldwide, gastric bypass accounts for about 47 percent of weight loss procedures, while gastric bands account for about 18 percent.
Researchers found dramatic differences between the two procedures in controlling diabetes. More than two-thirds of gastric bypass patients with Type 2 diabetes saw remission of the disease, compared to less than a third of gastric band patients.
Gastric bypass surgery also lowered hypertension better than gastric banding. Nearly half of patients (48 percent) with hypertension reported remission after two years with gastric bypass, compared to less than a fifth (17 percent) for those undergoing gastric band procedures.
Gastric bypass also improved hyperlipidemia, characterized by high levels of cholesterol, triglycerides, and lipoproteins in the blood. About 60 percent of gastric bypass patients reported remission in the studies, compared to about 23 percent of gastric band patients.
"The review underscores the importance of thinking about durable treatments, as obesity, type 2 diabetes, hypertension, and elevated cholesterol are chronic illnesses, rather than focusing on short-term results," Dr. Puzziferri said.
Long-term complication rates for the two procedures also favored gastric bypass, through both were relatively low - less than 3 percent for bypass surgery and less than 5 percent for banding procedures.
The review focused only on studies that followed patients for at least two years and in which more than 80 percent of patients were successfully tracked during that time; 29 studies total. Most - 97 percent - of weight-loss surgery studies track only a small percent of patients and/or only for up to one year. The researchers suggested more studies are needed to look at long-term outcomes - at least two years past the initial surgery - while maintaining follow-up of at least 80 percent to be considered reliable. They also concluded there were not a sufficient number of studies meeting these criteria to accurately assess gastric sleeve procedures.
"It is also very important to understand sleeve gastrectomy, which with the evidence we have so far, appears to perform as well as gastric bypass for weight loss. We just don't have as much evidence, in quantity or quality, as we have for the other procedures. The evidence will come in time," Dr. Puzziferri said. "We have not been doing sleeve gastrectomies for as many years as we have been performing gastric bypass or gastric band surgeries."
Gastric bypass, known as Roux-en-Y (pronounced "roo-n-why") gastric bypass, is considered the gold standard and one of the most commonly performed weight-loss procedures. Surgeons create a smaller stomach pouch and reroute food to bypass part of the small intestine. Gastric band procedures install an inflatable band around a portion of the stomach that can be adjusted to limit food intake. With both procedures, patients feel fuller more quickly, and therefore eat less and consume fewer calories.