Predictors and moderators of outcome for severe and enduring anorexia nervosa

Daniel Le Grange, Ellen E. Fitzsimmons-Craft, Ross D. Crosby, Phillipa Hay, Hubert Lacey, Bryony Bamford, Colleen Stiles-Shields, Stephen Touyz

Few of the limited randomized controlled trials (RCTs) for adults with anorexia nervosa (AN) have explored predictors and moderators of outcome. This study aimed to identify predictors and moderators of outcome at end of treatment (EOT) and 6- and 12-month follow-up for adults with AN (N = 63). All participants met criteria for severe and enduring AN (duration of illness ≥ 7 years) and participated in an RCT of cognitive-behavioral therapy (CBT-AN) and specialist supportive clinical management (SSCM). General linear models were utilized and included all available outcome data at all time points. Outcome was assessed across three domains: eating disorder quality of life (EDQOL), mental health (MCS), and depressive symptoms (BDI). Predictors of better outcome included: lower age, shorter duration of illness, having AN-R, being employed, not taking psychotropic medication, and better social adjustment. Four moderators of treatment outcome emerged: eating disorder psychopathology (EDE Global), depression (BDI), age, and AN subtype. Participants with higher baseline scores on these measures, older age, or binge eating/purging subtype benefited more from CBT-AN than SSCM. Older patients with more severe eating-related psychopathology and depression have better outcomes in a behaviorally targeted treatment such as CBT-AN rather than a supportive treatment such as SSCM.