Definitions
- For the purpose of this study, we considered three scenarios in the timeline treatment of a total of 30 sessions (1 individual + 29 group sessions).
- 33% of presence, corresponding to 10 sessions with no other requirement.
- 60% of presence, corresponding to 18 sessions with no other requirement.
- 75% of presence, i.e., (i) completed the treatment until the final session and missed less than 4 sessions in a sequence, and/or (ii) completed at least 22 out of 30 sessions.
- Frequency of binge eating episodes was considered when the participant reported at least one episode per week during the last 3 months.
- Purging was defined as any current use of self-induced vomiting, laxatives, and/or diuretics as a method of weight and/or shape control within the past 3 months. It could be compensatory or non-compensatory.
Participants
This secondary analysis study comprised a sample of 98 participants, adults, both genders, with BMI ≥ 27 and < 40 kg/m², recruited from clinical and community sources, with threshold or subthreshold BN or BED diagnoses, according to the Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5) [6]. The exclusion criteria were: use of weight loss medication; clinical conditions that could interfere with appetite regulation; history of bariatric surgery; current diagnosis of psychosis or bipolar disorder; high level of suicide risk; and, current participation in psychotherapy for eating disorders. This RCT was conducted by specialists at a university centre for treatment of eating disorders (PROATA) in the Universidade Federal de São Paulo, Brazil. Participants were recruited from July 2015 to November 2017, via waiting list, advertisements in the internet, printed and oral media.
All participants were evaluated in three stages (see trial protocol for details) [4]. The third stage comprised the assessment with a semi-structured interview that confirmed the eating disorder diagnosis and detailed eating disorders symptoms and behaviour. In total, ten groups were organized, with 5 groups receiving the experimental intervention (HAPIFED) and the other 5 groups receiving the control intervention (CBT-E). An investigator (PH) external to the site conducted the allocation through a website www.sealedenvelope.com. The randomisation process was concealed from the statistician involved in the analysis, and only the therapists of the Brazilian research team knew it until the finalization of the 12-month follow-up after the end of the active treatment. See the flow chart (Figure 1).
Four female therapists were guided in agreement with CBT-E and HAPIFED manuals. They were trained by experienced therapists (PH and Jessica Swinbourne) receiving monthly telephone supervision during the 2 pilot groups, and monthly telephone supervision during the trial by PH who visited Brazil 6 times in 3 years for face-to-face supervisions with the Brazilian therapists and other members of the HAPIFED project. Each pair of therapists conducted both CBT and HAPIFED groups to administer the non-specific therapists’ effect.
For both interventions were offered an initial individual session and more 29-group sessions, being twice weekly for the first four weeks and weekly after that until the end of active treatment comprising a total of 6 months. HAPIFED is a multidisciplinary program including four sessions with dietician and/or occupational therapist accompanied by the psychological therapists. Differently from CBT-E, HAPIFED emphasizes a nutritional counselling gave by the nutritionist, the behavioural monitoring including appetite cues directed to the hunger and satiety perception, the behavioural activation, e.g. stimulate the remission of body avoidance, healthy exercise encouragement, and emotion regulation skills mainly focusing in mood intolerance. Despite CBT-E originally be offered in 20 sessions, in this protocol the number of sessions were extended in number of sessions and duration to equate to HAPIFED. Besides that, both interventions received four group follow-up sessions during the first 6 months’ follow-up after the end of the active treatment, and a final assessment was conducted in 12-month follow-up.
We did not adjust for treatment group in our analysis as there were no significant differences in completion of 10, 18 or 22 sessions between groups (p>0.05).
Measures
For the purpose of this study, the following instruments were used:
- For the evaluation of frequency of binge eating episodes, purging behaviour and eating disorder symptom severity: the semi-structured Eating Disorder Examination Edition 17.0D (EDE) [7] interview was used. The EDE generates eating disorder diagnoses and assesses the symptom severity using four subscales, which are averaged for a global score. The version 16.0 was translated to Brazilian/Portuguese with a satisfactory reliability (80% inter-interviewer agreement and 0.69 Kappa were evaluated with considering the diagnosis using the EDE interview) and concurrent validity (77.3% agreement and 0.68 kappa). For a consistency with the most recent edition - EDE 17.0D – small modifications were made in the previous Portuguese version, in order to derive DSM-5 diagnoses.
- For the measurement of weight: a calibrated scale was used.
- For the evaluation of mental health-related quality of life: the 12-Item Short Form Survey (SF-12) [8] was applied. The SF-12 is a self-report instrument that measures physical and mental health-related quality of life.
- For the measurement of eating disorder illness duration: the participants fulfilled a self-report questionnaire where they were asked about the illness duration.
Participant Flow
As we aimed to study early, middle and late treatment attrition three time points, 33%, 60% and 75%, were analysed. Seventy-one participants (72.4%) completed at least 10 (33%) sessions, 51 (52.0%) completed at least 18 sessions (60%); and 45 (45.9%) completed at least 22 (75%) sessions and/or completed the treatment until the final session and missed fewer than 4 sessions. These were chosen based on previous studies by the authors as previous reviews have not identified a consensus across the RCT treatment literature for psychological therapies in eating disorders [1, 9]. However late attrition is usually 75% or more of therapy sessions and has been applied in previous studies of the authors [9]. As shown on Figure 1, first, 71 (72.4%) completed at least 10 (33%) sessions, second, 51 (52.0%) completed at least 18 sessions (60%); and, last, 45 (45.9%) completed at least 22 (75%) sessions and/or completed the treatment until the last session and missed fewer than 4 sessions. The last was the most stringent assessment of treatment completion.
Statistical analyses
Data were cleaned including correcting for coding errors. Descriptive statistics such as mean for a continuous covariate and its standard error, as well as proportion for a categorical covariate and its standard deviation were estimated for completers and non-completers of sessions. Logistic regression analysis was performed to determine the significant predictors of treatment completion. The maximum likelihood estimation was not used to fit the logistic models for predicting the odds of completing at least 18 and 22 sessions as they did not satisfy the widely used criterion of having at least 10 events per predictor for using maximum likelihood in logistic regression. For these models the penalised likelihood with Firth’s correction [10] was used as it should perform much better in estimating unbiased regression coefficients. The missing data were estimated in the analysis by multiple imputation using multivariate normal imputation. All analyses were performed using SAS version 9.4 [11].