SEATTLE – The predictive utility of a rapid response to treatment for binge eating disorder and obesity depends on the type of treatment, a randomized, controlled trial shows.
It also is important to identify predictors, because many patients with binge eating disorder do not remit from the binge eating and many fail to lose weight, lead author Carlos M. Grilo, Ph.D., reported at an international conference sponsored by the Academy for Eating Disorders.
Efforts aimed at identifying conventional predictors have met with little success. A different approach might be to look at patients' treatment response rather than at their characteristics before treatment, said Dr. Grilo, director of the Eating Disorders and Obesity Research Program at Yale University, New Haven, Conn.
In a randomized, controlled trial among 125 obese patients with binge eating disorder, the investigators compared 6 months of behavioral weight loss therapy (BWL), 6 months of cognitive-behavioral therapy (CBT), and a combination of 4 months of CBT followed by 6 months of BWL. Patients were weighed biweekly. Binge eating frequency was assessed from self-reports and from the Eating Disorders Examination Interview, administered at baseline, end of treatment, and 6 and 12 months thereafter, said Dr. Grilo, also a professor of psychiatry and psychology at Yale.
The patients were 44 years old on average, and 68% were women, Dr. Grilo reported at the conference, which was cosponsored by the University of New Mexico. Fully 70% had Axis I diagnoses, and 27% had Axis II diagnoses. The mean body mass index was 39 kg/m
Analyses focusing on the two monotherapy groups showed that 47% of patients assigned to BWL and 67% of patients assigned to CBT had a rapid response to treatment–defined as a reduction in the number of binge episodes by at least 70% during the first 4 weeks of treatment.
In the BWL group, the percentage of patients in binge remission (meaning they had no bingeing episodes in the previous month) increased in the year after treatment among rapid responders but remained unchanged among non-rapid responders. At each assessment (end of treatment, 6 months, 12 months), the remission rate was significantly higher among the former group, with a difference at 12 months of about 68% vs. 18%.
In the CBT group, the percentage of patients in remission remained stable in the year after treatment among rapid responders and increased among non-rapid responders, with about 70% and 53%, respectively, in remission at 12 months.
As a result, the remission rate was significantly higher in the rapidly responding subset only at the end of treatment, a pattern that may reflect a “catching up” among those without a rapid response, Dr. Grilo speculated.
When it came to weight loss, the change in body mass index for the BWL group was significantly greater among rapid responders than among non-rapid responders at each assessment, with a reduction of 4% vs. 0% at 12 months. Dr. Grilo characterized this as an exciting finding given the difficulty of achieving weight loss in this population.
In contrast, in the CBT group, no difference in this outcome was found according to speed of response. “Quite frankly, whether you had a rapid response to CBT or not didn't matter, because you really didn't lose much weight,” he said.
“Clinically, we think that the findings suggest that binge eating patients who respond rapidly may have the best potential outcome with behavioral weight loss, because they may be more likely to remit from binge eating plus they may actually lose weight,” Dr. Grilo asserted.
Dr. Grilo reported that he had no conflicts of interest in association with the study.
'Whether you had a rapid response to CBT or not didn't matter, because you really didn't lose much weight.' DR. GRILO