A new study suggests that weight-loss surgery combined with low-level lifestyle interventions may be a more effective way to treat diabetes in obese patients than lifestyle interventions alone. In some patients, the surgery can even lead to a complete reversal of diabetes, the researchers reported this week in JAMA Surgery.
Excess weight is the primary risk factor for type 2 diabetes; more than 90% of people who have type 2 diabetes are overweight or obese. Given that an estimated one in every three adults in the United States is obese, health experts developed the term “diabesity” to talk about this epidemic. According to the American Diabetes Association, as many as one in three American adults will have diabetes in 2050 if present trends continue.
It is recommended that obese patients with type 2 diabetes adopt lifestyle changes, such as a healthy diet and regular exercise, to help manage or treat their condition. Recently, however, research has suggested that weight-loss surgery, also known as bariatric surgery, may be just as effective as lifestyle interventions and medical therapy for obese patients with type 2 diabetes. For example, in a 2014 study published in the New England Journal of Medicine, researchers at the Cleveland Clinic concluded that “bariatric surgery is a highly effective and durable treatment for type 2 diabetes in obese patients, enabling nearly all surgical patients to be free of insulin and many to be free of all diabetic medications three years after surgery.”
But the surgery is risky and “questions remain” about the efficacy of such treatment, said Dr. Anita P. Courcoulas, who led the new research along with her colleagues at the University of Pittsburgh Medical Center. “More information is needed about the longer-term effectiveness and risks of all types of bariatric surgical procedures compared with lifestyle and medical management for those with [type 2 diabetes] and obesity.”
For the study, the team tracked the outcomes of 61 obese patients aged 25-55 with type 2 diabetes who were randomly assigned to receive either weight-loss surgery in the first year followed by a low-level lifestyle intervention for 2 years, or an intense lifestyle intervention for 1 year followed by a low-level lifestyle intervention for 2 years.
Subjects who underwent weight-loss surgery received one of two procedures: roux-en-Y gastric bypass (RYGB) or laparoscopic adjustable gastric banding (LAGB). RYGB involves the creation of a small stomach pouch from a portion of the stomach, which is then connected to the small intestine, bypassing the rest of the stomach and the duodenum. LAGB involves the placement of a band around the upper part of the stomach to create a smaller stomach pouch. The band can be adjusted after the procedure to make food pass more slowly or quickly through the stomach. Both of these procedures limit the amount of food a person can eat, making them feel full faster.
Weight-loss surgery led to complete type 2 diabetes remission for some obese patients
Three years after the study began, the researchers took follow-up measurements from all participants to assess the incidence of partial or complete type 2 diabetes remission, as well as other outcomes such as body weight.
Bariatric surgery was found to be significantly more effective for weight loss than lifestyle interventions. During the three-year follow-up period, participants who underwent RYGB lost an average of 25 percent of their body weight and LAGB subjects lost an average of 15 percent of their body weight, while lifestyle intervention-only participants lost an average of just 5.7 percent.
Notably, more than a third of participants who underwent weight-loss surgery were found to have experienced partial or complete type 2 diabetes remission, while none of those who engaged in lifestyle interventions alone experienced remission at all. Of the subjects who underwent RYGB, 40 percent had partial or complete type 2 diabetes remission, along with 29 percent of subjects who underwent LAGB. Additionally, three subjects treated with RYGB and one treated with LAGB had complete remission.
The results also showed that patients who underwent weight-loss surgery were more likely to achieve and maintain blood glucose control and less likely to need medication to control their type 2 diabetes, compared with those in the lifestyle intervention-only group. “More than two thirds of those in the RYGB group and nearly half of the LAGB group did not require any medications for [type 2 diabetes] at 3 years,” the researchers wrote.
These findings are particularly noteworthy in light of the fact that many participants — about 40 percent — fell into the category of class 1, or mild obesity, defined as having a body mass index (BMI) of between 30 and 35. Since weight-loss surgery is typically carried out on patients with a BMI of 40 or more, there is very limited evidence of the effectiveness of weight-loss surgery for obese patients with a lower BMI.
“This study provides further important evidence that [surgical treatments] are superior to lifestyle intervention alone for the remission of [type 2 diabetes] in obese individuals, including those with a BMI between 30 and 35,” the researchers conclude. “While this trial provides valuable insights, unanswered questions remain such as the impact of these treatments on long-term microvascular and macrovascular complications and the precise mechanisms by which bariatric surgical procedures induce their effects.”
In an editorial linked to the study, bariatrics expert Dr. Michel Gagner said the findings provide strong support for increasing the use of weight-loss surgery to treat more obese individuals with type 2 diabetes. He explains that bariatric surgery not only stimulates weight loss — a key tactic in fighting type 2 diabetes — but also alters hormones produced in the stomach, including ghrelin, known to stimulate hunger. Regulating these hormones helps patients achieve lasting improvements in both body weight and diabetes control, said Dr. Gagner, who performed the world’s first laparoscopic duodenal switch in 1999 and the first laparoscopic sleeve gastrectomy in the U.S. in 2000.
“We should consider the use of bariatric surgery in all severely obese patients with [type 2 diabetes] and start a mass treatment,” he wrote, “similar to what was done with coronary artery bypass graft more than 50 years ago.”
Dr. Gagner joins a growing number of experts calling for a more comprehensive approach to treating obesity and its metabolic effects — one that goes beyond just diet and exercise. In February, a leading group of obesity researchers published a report in The Lancet Diabetes & Endocrinology journal arguing that obesity is a chronic disease with largely biological causes that cannot be cured with diet and exercise alone, but rather through addressing the underlying physiological mechanisms.