A new study of gastric bypass surgery co-authored by physicians at Columbia University Medical Center has found that 49 percent of patients who have the surgery have their diabetes under control one year after surgery, compared with just 19 percent of patients who are put on an intensive medical management and lifestyle intervention program.
The findings were published June 5 in the Journal of the American Medical Association by a team of researchers from the University of Minnesota, Columbia, National Taiwan University Hospital, Mount Sinai Medical Center, Min-Sheng General Hospital in Taiwan, and the Mayo Clinic.
Gastric bypass surgery was designed to help people lose weight, but in the past decade physicians have noticed that the surgery can also improve diabetes control and, in some patients, remove the need for diabetes medications. With typical medical management, only 10 percent of type 2 diabetes patients in the United States can meet treatment targets established by the American Diabetes Association (ADA).
“Right now there are millions of people with diabetes; it is one of the leading causes of heart disease, kidney failure, and blindness. It’s very difficult to prevent these problems, so the question of bariatric surgery is coming up more and more frequently. We don’t know if we should offer surgery or medical management,” says co-author Judith Korner, MD, PhD, associate professor of medicine and director of the Weight Control Center at Columbia University Medical Center.
Though observational studies that have followed surgical patients over time suggest that 40 to 80 percent of patients are helped by bariatric surgery, randomized control trials are considered the “gold standard” of evidence.
The study by Korner and her colleagues is among the first randomized clinical trials with diabetes patients to compare the two treatments. In the trial, 60 patients with diabetes and a Body Mass Index (BMI) between 30 and 40 underwent gastric bypass. Another 60 patients followed an intensive medical management protocol that included weekly support from dietitians and medications.
After one year, the researchers measured the ADA’s three treatment targets: glucose control (HbA1c under 7 percent), low LDL cholesterol (under 100 mg/dL), and a systolic blood pressure less than 130 mm Hg. Close to half of the gastric bypass patients met the three targets, compared with 19 percent of the medical management group.
Bariatric surgery is currently offered only to diabetes patients with a BMI of 35 or above, but based on the study’s findings, says Korner, that criterion may need to be re-evaluated.
“In our study patients with lower BMIs did as well as patients with higher BMIs; that really puts into question the criteria we have for who gets the surgery and who doesn’t,” she says. “Perhaps other health criteria should be applied, rather than high BMI, which is somewhat arbitrary.”
But first, larger randomized studies should be performed and more long-term data collected.
“The big question now is, how long will the improvements last,” Korner says. “If they last only two years, we have to ask whether it’s worth having the surgery. But if it lasts 10 to 15 years—as we see in some of the observational studies—it’s worth considering.”
An editorial published in JAMA with the study also says that more safety data is needed.
Bariatric surgery does result in substantial weight loss with excellent diabetes control but is offset by initial high cost and risks of surgical complications. The optimal approach for treatment of obesity and diabetes remains unknown. The answer will only come from more well-designed, randomized trials such as that performed by Ikramuddin et al that provide definitive answers.