A Novo Nordisk employee controls a machine at an insulin production line in a plant in Kalundborg (Copyright Reuters 2016)
After one year, gastric bypass surgery did a better job of bringing type 2 diabetes into remission than an intensive diet and exercise regimen, according to results of a small trial among obese patients.
Gastric bypass surgery precipitates weight loss and also triggers hormonal and metabolic mechanisms that work against diabetes specifically, beyond just weight loss, said lead author Dr. David E. Cummings of the University of Washington in Seattle.
"The new thinking is might we begin to see surgery as a way to treat diabetes primarily," Cummings told Reuters Health.
The researchers assigned 23 obese adults ages 25 to 64 years with type 2 diabetes to receive gastric bypass, in which surgeons reduce the size of the stomach and also bypass a portion of the intestines. Another 20 similar patients instead received an intensive lifestyle intervention that included at least 45 minutes of aerobic exercise five days per week, a dietitian-directed weight and blood sugar lowering diet as well as diabetes medical treatment for one year.
Eleven participants withdrew before completing the trial, so 15 in the surgery group and 17 in the lifestyle intervention group remained to be studied after one year.
Researchers measured participants' fasting blood sugar and insulin levels, sensitivity to insulin, body weight, waist circumference, body composition, blood pressure, cholesterol, aerobic fitness, medication usage and quality of life before the study began, after six months and after 12 months.
At the one year point, 60 percent of those in the gastric bypass group had lowered their blood sugar into the non-diabetic range, compared to 6 percent of those in the diet and exercise group. Less than 30 percent of participants in the gastric bypass group were using insulin after one year compared to 41 percent of the lifestyle change group, as reported in Diabetologia.
Surgical patients were also using fewer blood pressure medications after one year than lifestyle-change patients.
Body weight, waist circumference, waist-to-hip ratio and percent body fat mass decreased in both groups over time, although surgical patients lost more weight and fat mass.
Cardiorespiratory fitness, measured by peak oxygen consumption during exercise, increased for the diet and exercise group but did not change for the surgery group.
"The uniqueness of this study lies in the fact that the lifestyle intervention control group used what was considered to be the most strict program practical for such patients with diabetes that was patterned after the well-known Diabetes Prevention Program and Look Ahead trials," and patients were recruited from a broad population within a healthcare system, said Nathan D. Wong, director of the Heart Disease Prevention Program at the University of California, Irvine.
Clearly surgery is much more effective than intensive lifestyle change for causing remission of diabetes, but surgery should still be the last option, Wong told Reuters Health by email.
"Patients with pre-diabetes (and even before that) should be more conscious of their lifestyle and what they can do to prevent diabetes as the Diabetes Prevention Program and other similar studies have clearly shown modest weight loss and exercise can go a long way towards preventing diabetes," he said. "Healthcare providers (and insurers alike) need to provide better support and resources to effect intensive lifestyle intervention."
In current practice, patients are not generally given the long-term lifestyle programs that should be tried before surgery, he said.
"In those with severe or morbid obesity where multiple lifestyle intervention attempts have been unsuccessful, gastric bypass surgery is felt to be a good option by many experts," Wong said. "There are always potential risks with such surgeries such as excessive bleeding, clotting, or infections, and surgery of course is not reversible."