Baseline Predictors of Attrition in a Randomised Controlled Trial of a New Group Psychological Intervention for People with Recurrent Binge Eating Episodes Associated to Overweight or Obesity

Abstract

Purpose: Understanding the high rate of treatment attrition in trials of people with eating disorders is important as it can compromise the quality of the trials. In clinical practice, it may also contribute to illness chronicity, relapse, and costs. Thus, we investigated factors associated with treatment attrition to a new manualised psychotherapy HAPIFED compared to CBT-E, for individuals with Bulimia Nervosa or Binge Eating Disorder comorbid with overweight or obesity.Methods: In total, 98 participants were recruited with 50 randomised to HAPIFED and 48 to the control intervention CBT-E, all administered in groups of up to 10 participants. An investigator external to the site conducted the random allocation, which was concealed from the statistician involved in the analysis, and known only to the therapists until the finalization of the 12-month follow-up after the end of active treatment. Three scenarios in the timeline treatment of a total of 30 sessions were assessed: 33% or 60% or 75% of presence. Logistic regression analysis was performed to find the correlates of attrition.Results: None of the six variables - frequency of binge eating episodes, purging, eating disorder symptom severity, weight, illness duration and mental health-related quality of life - significantly predicted attrition at 33%, but longer illness duration predicted lower treatment attrition at both 60% and 75% presence of the interventions. Also for 75% presence, lower body weight predicted lower treatment attrition. Conclusions: Lower attrition due to late treatment completion was associated with longer binge eating illness length and a lower body weight. More research is needed to recognize factors that may interfere with engagement in treatments aiming to avoid early dropout.Trial registration: US National Institutes of Health clinical trial registration number NCT02464345, date of registration 1 June 2015.