Group CBT Does Not Maintain Weight Loss in Obese With Diabetes

Becky McCall

September 13, 2017

LISBON, PORTUGAL — Cognitive behavioral group therapy (CBGT) does not prevent people with obesity and type 2 diabetes from putting back on weight they have lost, according to results of a new randomized controlled trial.

Participants had previously adhered to an 8-week very low-calorie diet and lost around 10% of their body weight. However, adding the CBGT to usual care over the following 2 years had no effect on preventing weight regain nor in controlling cardiovascular risk factors and indicators of psychological well-being.

Presenting the results in a poster at this year's European Association for the Study of Diabetes (EASD) 2017 Annual Meeting was Kirsten Berk, DRS, a dietician from the Erasmus Medical Center, Rotterdam, the Netherlands.

"Based on these findings, there is no scientific justification to offer group CBT to optimize the effect of weight-loss dieting in obese patients with type 2 diabetes," she told Medscape Medical News, adding that negative trials like this matter because they indicate what does not work, which is as important as what does. 

"This is different from findings in patients who are healthy obese, as seen in other studies. Obese patients with diabetes are more challenged than the healthy obese, and it is more difficult [for them to] both lose weight and maintain it. This needs to be acknowledged, and findings in the healthy obese cannot be automatically transferred to patients with both diabetes and obesity," she explained.

Commenting on the work, Naveed Sattar, MD, visiting professor at the Institute of Cardiovascular and Medical Sciences, University of Glasgow, Scotland, remarked that the study broadly supports other research suggesting that weight-loss strategies work slightly less well in patients with diabetes.

"It is no surprise....The rationale for why this may be the case includes diabetes patients being on several other drugs, some of which can cause weight gain, but also that they tend to have lower exercise capacity and complications that may limit activity levels," he told Medscape Medical News.

"We need to do different lifestyle studies in diabetes to find ways to help [patients] attenuate weight regain after weight loss, since any such successful strategies could have tremendous and long-term clinical benefits," he added.

Prevention of Weight Regain (POWER) Is First RCT in Obese Diabetics

Prior work on weight regain in patients with both obesity and type 2 diabetes comprises two observational studies, so this is the first randomized controlled trial to investigate the issue, said Ms Berk, who is soon to complete her PhD.

"We see a lot of people who lose weight only to regain it, and this is especially unfortunate in those with diabetes — many of whom are obese — because weight loss is associated with so many health benefits, including cardiovascular ones," she asserted. "Upon regaining weight we know these beneficial effects are unfortunately lost."

She and her colleagues set out to investigate whether group CBT would prevent weight regain in patients with both obesity and type 2 diabetes, who had lost weight by following a very low-calorie diet, in the Prevention of Weight Regain (POWER) trial.

The initial 8-week very low-calorie diet (750 kcal/day based on meal replacements) resulted in 158 patients losing at least 5% of initial body weight, and these individuals were included in the randomization stage.

All patients had a body mass index of greater than 27 kg/m2 (mean around 36 kg/m2), and just over half were female.

Participants were randomized to the active group CBT (n = 83) or usual care (n = 75). They underwent regular checkups with a medical doctor, diabetic nurse, and dietitian, and five group meetings for measurements. The intervention arm comprised an additional 17 group CBT sessions over one and a half years, with patients considered compliant when they attended at least nine out of 17 group sessions. Diet during the follow-up period involved slow reintroduction of healthy normal eating habits.

"We did therapy in groups of 10 because it was more efficient…but also because the literature suggests that this is more effective than individual CBT," Ms Berk pointed out.

Explaining the benefits of group CBT, she said it "aims to help patients take a more realistic attitude toward their eating behavior, so for example, having one cookie will not ruin your whole diet for the day."

Follow-up was 2 years, and primary outcomes comprised body weight at 2 years, and weight regain from randomization over the follow-up period. Secondary outcomes were waist circumference, HbA1c, insulin dose, lipids, depression, and anxiety.

What Difference Is Diabetes Making to Weight Regain?

"We actually found that during the initial very low-calorie diet, patients lost around 10% of their body weight, but unfortunately after 2 years we saw no difference in weight regain between the control and the intervention groups," reported Ms Berk. In the group CBT arm, weight regain was 4.0 kg vs 4.7 kg in the control arm; between-group difference was only -0.7 kg (CI 95%, -3.1 to  1.6).

Ms Berk and colleagues also looked at a subgroup of compliant patients who had attended nine or more sessions. "Again, this…still showed no difference between groups, which is odd because they had many more sessions, on top of usual care, so we expected to see some difference."

In contrast to the findings in this study, group CBT was provided to obese patients without type 2 diabetes in a separate study run at Maastricht University, the Netherlands and was found to be effective.

Of particular interest is the difference between these two sets of patients in relation to having diabetes or not, remarked Ms Berk.

She agreed with Dr Sattar that the patients with diabetes may be "more challenged metabolically, they also have more comorbidities. [And] maybe their disease means they are less active, and indeed we saw that they did not exercise more in our study."

And "perhaps medication has a role here. Of our patients with type 2 diabetes, two-thirds used insulin, a therapy known for weight gain. Maybe these patients have too many other challenges for group CBT to work."

In an effort to provide some clarification of the results, the researchers also looked at whether there was any variance in approach to group CBT between the two psychologists who implemented the intervention, but no difference was found.

Likewise, no difference was seen between the genders among patients.

There were no differences seen in secondary outcomes either, Ms Berk reported.

"However, when you look at the group as a whole, after 2 years we found that they had all still lost 5% of their weight [initial weight loss was 10%] and had a lower waist circumference and depression score.

"We will need to find other ways to tackle this problem, and future research should focus on other treatment strategies in the battle against weight regain," she concluded. She suggested that research exploring how to intervene in automatic behavior might be beneficial.

The work has been submitted to a medical journal for publication.

Ms Berk has no relevant financial relationships. Dr Sattar has consulted for Boehringer Ingelheim, Novo Nordisk, Janssen, and Eli Lilly and had research grants from AstraZeneca and Boehringer Ingelheim.

Berk K et al. Cognitive behavioural group therapy to prevent weight regain in type 2 diabetes: A randomised controlled trial. European Association for the Study of Diabetes 2017 Annual Meeting. September 11-15, 2017, Lisbon, Portugal. ePoster 606.

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