Weight-Loss Surgery to Treat Diabetes
The ideal type of surgery to use for treating diabetes is also not yet known—and there are different variations being developed all the time. The JAMA study looked at laparoscopic adjustable gastric banding, a procedure that uses minimally invasive surgery to put in place a band to cordon off part of the stomach, effectively making it smaller. The more complex gastric bypass procedure Stanford had, which surgically shrinks the stomach and reroutes the digestive tract so that food reaches the lower regions more quickly and less is absorbed, carries greater risk but also potentially higher rewards. While the banding surgery treats diabetes through the gradual beneficial effect of weight loss alone, there's evidence that doing an end run around parts of the digestive tract can send diabetes into remission within days of surgery and promote greater weight loss over the long run.
No one knows exactly why. Theories include the idea that shunting food directly to lower in the intestine stimulates a substance called glucagon-like peptide 1, which can increase insulin production, and that hormones that prompt hunger are damped by rearranging the anatomy. "You may be dramatically changing the release patterns of hormones that are important to controlling appetite and weight," says Garth Ballantyne, director of minimally invasive and telerobotic surgery at Hackensack University Medical Center in New Jersey. Other surgeries are also being studied, including one pioneered by Rubino that keeps the stomach intact but bypasses the uppermost part of the small intestine, thus bringing the hormonal benefits without producing such drastic weight loss. "We can find new operations that might be similar to the most effective operations but maybe cut back on the complexity, particularly for patients who are not morbidly obese," says Rubino.
The ideal time window for treatment is also up for debate. The JAMA study focused on people who had been diagnosed within the past two years and had no major complications. It's not so clear how long it takes for the disease to set in and destroy the pancreas' beta cells, which make insulin. "The later you intervene, the lesser the likelihood of having complete remission," says Rubino. He says there are exceptions—he's seen longtime diabetics achieve remission—but it's ideal to operate early rather than after pancreatic function has severely deteriorated. And no surgery will consistently reverse the secondary effects of diabetes, like diabetic retinopathy, says Sasha Stiles, medical director of the bariatric surgery program at Kaiser Permanente. "For the superobese, who need to lose 50 percent of their body weight, maybe we say, 'Let's go right to bypass,'" says Cummings.
Until more extensive trials are done, researchers and clinicians say that surgery should at least be more fully included as part of the regular menu of care for diabetics who meet the current guidelines. Cummings noted that more than 90 percent of the type 2 diabetics eligible for surgery don't have the procedure, and most probably aren't even informed of the option. Vickie Klubek from Murphysboro, Ill., is a 56-year-old type 2 diabetic whose height and weight put her BMI at more than 37. She's tried everything to lose weight and says she eats well and exercises. No one has told her about gastric bypass, though her doctor has told her to skip doughnuts for breakfast (a food she says she doesn't even like). "Probably, in routine clinical practice, we aren't offering this as a therapeutic option for patients as often as we should," says Martin Abrahamson, medical director at the Harvard-affiliated Joslin Diabetes Center in Boston. Part of that may be due to cost; private insurers won't always cover the surgery and the necessary follow-up, which can run tens of thousands of dollars.
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