While lifestyle interventions alone appear to have no effect on type 2 diabetes remission, researchers found these combined with weight-loss surgery led to remission for many obese patients with the condition.
Dr. Anita P. Courcoulas, of the University of Pittsburgh Medical Center, PA, and colleagues publish their findings in JAMA Surgery.
Excess weight is a major risk factor for type 2 diabetes; more than 90% of people who have type 2 diabetes are overweight or obese.
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. But recently, studies have suggested weight-loss surgery, or bariatric surgery, may be just as effective as lifestyle interventions and medical therapy for obese patients with type 2 diabetes
In April 2014, for example, Medical News Today reported on a study published in the New England Journal of Medicine that found obese patients who underwent bariatric surgery were able to control their type 2 diabetes without the use of medical therapy in the 3 years following the procedure.
But Dr. Courcoulas and colleagues say "questions remain" about the efficacy of such treatment. "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 T2DM [type 2 diabetes mellitus] and obesity," they note.
As such, the team assessed 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.
Dr. Courcoulas and colleagues assessed the incidence of partial or complete type 2 diabetes remission among all subjects after 3 years.
Weight-loss surgery led to complete type 2 diabetes remission for some obese patients
Bariatric surgery was found to be most effective for weight loss among study participants. Those who underwent RYGB lost around 25% of their body weight during follow-up, LAGB subjects lost around 15% of their body weight, while lifestyle intervention-only participants lost around 5.7%.
The team found that many participants who underwent weight-loss surgery followed by lifestyle interventions experienced partial or complete type 2 diabetes remission, while those who engaged in lifestyle interventions alone experienced no remission at all.
Of the subjects who underwent RYGB, 40% experienced partial or complete type 2 diabetes remission, while this was the case for 29% of subjects who underwent LAGB. Three subjects treated with RYGB and one treated with LAGB had complete remission.
In addition, the team found that patients who underwent weight-loss surgery were more likely to have better blood glucose control and less likely to need medication for their type 2 diabetes, compared with those who engaged in lifestyle interventions alone.
"More than two thirds of those in the RYGB group and nearly half of the LAGB group did not require any medications for T2DM treatment at 3 years," say the researchers.
One strength of this study, according to the team, is that around 40% of participants fell into the category of class 1 obesity - defined as having a body mass index (BMI) of between 30 and 35. The researchers note that weight-loss surgery is normally carried out on patients with a BMI of 40 or more, so data is lacking on the effects of weight-loss surgery for obese patients with a lower BMI.
Commenting on their findings, the team says:
"This study provides further important evidence that at longer-term follow-up of 3 years, surgical treatments, including RYGB and LAGB, are superior to lifestyle intervention alone for the remission of T2DM in obese individuals including those with a BMI between 30 and 35.
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, Dr. Michel Gagner, of Florida International University in Miami, says the findings indicate the use of weight-loss surgery should be increased for obese individuals with type 2 diabetes.
"We should consider the use of bariatric (metabolic) surgery in all severely obese patients with T2DM and start a mass treatment, similar to what was done with coronary artery bypass graft more than 50 years ago," he says.
In November 2014, MNT reported on a study suggesting that weight-loss surgery may also be effective for prevention of type 2 diabetes among obese patients.
Published in The Lancet Diabetes & Endocrinology, the study found that obese patients who underwent bariatric surgery were 80% less likely to develop type 2 diabetes than those who received no obesity-related treatment.