Predictors and moderators of treatment outcome in a randomized clinical trial for binge-eating disorder

OBJECTIVE: The current study examined predictors and moderators of two interventions for binge-eating disorder (BED).

METHOD: Participants were 112 adults with BED ( M age = 39.7 ± 13.4 years; M BMI = 35.1 ± 13.4 kg/m²; 82% female; 91% Caucasian) randomly assigned to integrative cognitive-affective therapy for BED (ICAT-BED) or guided self-help cognitive-behavioral therapy (CBTgsh). Generalized linear models examined predictors and moderators of objective binge-eating episode (OBE) frequency and OBE abstinence at end-of-treatment (EOT) and 6-month follow-up (FU).

RESULTS: Lower levels of baseline dietary restraint and emotion regulation difficulties predicted greater reductions in OBE frequency at EOT and FU, respectively. At EOT, greater pretreatment self-control predicted greater reductions in OBE frequency in ICAT-BED than CBTgsh ( ps < .05). In addition, low shape/weight overvaluation predicted greater reductions in OBE frequency in ICAT-BED than CBTgsh, whereas high shape/weight overvaluation predicted comparable reductions in OBE frequency across treatments at EOT ( ps < .02). At EOT and FU, greater baseline actual-ideal self-discrepancy predicted significantly greater reductions in OBE frequency in ICAT-BED, than CBTgsh ( ps < .02). No significant predictor or moderator effects were observed for models examining OBE abstinence.

CONCLUSION: This study identified two general predictors and four moderators of BED treatment response. However, only one predictor (actual-ideal self-discrepancy) interacted with treatment type to differentially predict OBE frequencies at both EOT and FU. Altogether, findings suggest that ICAT-BED may confer specific and durable improvements in OBE frequencies among individuals with high actual-ideal self-discrepancy. Therefore, patients demonstrating these characteristics may be more likely to benefit from ICAT-BED. (PsycInfo Database Record (c) 2020 APA, all rights reserved).