Predictors of treatment outcome in individuals with eating disorders: A systematic review and meta-analysis.

OBJECTIVE: Understanding the factors that predict a favourable outcome following specialist treatment for an eating disorder may assist in improving treatment efficacy, and in developing novel interventions. This review and meta-analysis examined predictors of treatment outcome and drop-out.
METHOD: A literature search was conducted to identify research investigating predictors of outcome in individuals treated for an eating disorder. We organized predictors first by statistical type (simple, meditational, and moderational), and then by category. Average weighted mean effect sizes (r) were calculated for each category of predictor.
RESULTS: The most robust predictor of outcome at both end of treatment (EoT) and follow-up was the meditational mechanism of greater symptom change early during treatment. Simple baseline predictors associated with better outcomes at both EoT and follow-up included higher BMI, fewer binge/purge behaviors, greater motivation to recover, lower depression, lower shape/weight concern, fewer comorbidities, better interpersonal functioning and fewer familial problems. Drop-out was predicted by more binge/purge behaviors and lower motivation to recover. For most predictors, there was large interstudy variability in effect sizes, and outcomes were operationalized in different ways. There were generally insufficient studies to allow analysis of predictors by eating disorder subtype or treatment type. DISCUSSION: To ensure that this area continues to develop with robust and clinically relevant findings, future studies should adopt a consistent definition of outcome and continue to examine complex multivariate predictor models. Growth in this area will allow for stronger conclusions to be drawn about the prediction of outcome for specific diagnoses and treatment types.