In two recent head-to-head year-long trials, one testing gastric bypass surgery versus lap band surgery and another pitting gastric bypass surgery against sleeve gastrectomy, gastric bypass came out ahead with regard to resolving the symptoms of type 2 diabetes. Both studies were published in the February issue of the Archives of Surgery.
Lap-band surgery and sleeve gastrectomy are both “restrictive” procedures, which reduce the amount of food that can be taken into the stomach. In sleeve gastrectomy, the stomach is cut and sewn to form a narrow sleeve that is not much thicker than the intestine into which it empties. A lap band is a silicon belt that is tightened around the top portion of the stomach. The band creates a small pouch that holds only about a half-cup of food, much less than the six cups that an unobstructed stomach can hold.
Gastric bypass is known as a “malabsorptive” procedure, as opposed to a restrictive procedure, because it reduces the amount of nutrients absorbed by the small intestine. A small stomach pouch is created, to which a Y-shaped section of the small intestine is attached. This causes food to bypass the lower stomach and the first sections of the small intestine. Skipping those two feet of small intestine not only reduces the amount of nutrients the body absorbs, but also causes hormonal and metabolic changes that have been theorized to have a salutary effect on type 2 diabetes. According to this theory, known as the “foregut hypothesis,” eliminating the movement of food through the first part of the small intestine normalizes blood glucose levels by altering metabolic signaling.
In the first study, led by Dr. Guilherme Campos while at the University of California at San Francisco, 100 patients who chose bypass surgery were compared to 100 who decided on lap band surgery. All were morbidly obese, and 34 patients in each group had type 2 diabetes. After a year, the bypass patients had lost an average of 64 percent of their excess weight, while the lap-banders had lost an average of 36 percent. Of the 34 patients with diabetes, 76 percent of the gastric bypass patients experienced improved or resolved diabetes, versus 50 percent of the lap-banders.
The second study, led by Dr. Lee-Ming Chung of Taiwan, was specifically designed to test bariatric procedures as treatments for diabetes. In the study, 60 obese patients with type 2 were randomized to receive either sleeve gastrectomy or gastric bypass. Of the gastric bypass group, 93 percent experienced a resolution of their diabetes, versus only half of the sleeve gastrectomy group. These numbers dropped to 57 percent and 0 percent, respectively, after a year.
Dr. Chung and his colleagues indicated that although their findings support the foregut hypothesis, they do not disprove other theories, especially because patients in the sleeve gastrectomy group initially experienced improvement in their diabetes.
Because patients tend to regain weight for several years after these procedures, some experts commented that a year is not sufficient to establish the superiority of one procedure over the others. A five-year or ten-year follow-up, they said, would be more revealing.
Sources: HealthDay News