Factors associated with treatment attrition in anorexia nervosa : a systematic review

Introduction: The reasons for attrition in the therapy of anorexia nervosa are not fully understood. This systematic review provides a summary of trials focusing on factors associated with attrition; it was aimed to compare and contrast findings between different treatment settings. Materials and methods: Data were extracted from published reports sourced from online searches (till February 2013) of the following databases: SCOPUS, PubMed and PsycINFO. The search included French and English language papers, and the following search terms were used: 'anorexia nervosa' and 'attrition/drop-out/premature termination of treatment/outcome'. Results: Four hundred and twenty-one papers were identified; 34 met the inclusion criteria, four were excluded as they were reviews and three investigated outcome and not attrition. Two papers of the 27 included were qualitative studies. Factors mostly studied were the subtype of anorexia nervosa (n = 8), the personality characteristics or disorder (n = 11) and eating psychopathology (n = 10). Six studies could not find an association with attrition for demographic or other clinical characteristics. The factors associated with attrition in most studies were the subtype of anorexia nervosa, where the purging type was associated with a higher attrition rate than the restrictive type (n = 7 studies), and more frequent personality features and other psychiatric comorbidities. The majority of trials were conducted with adults and inpatient samples. Conclusion: More studies with regard to attrition in younger people and outpatient settings, and a more consistent and standardised assessment of attrition in anorexia nervosa research, are needed. Addressing the use of purging behaviours and psychological comorbidities in anorexia nervosa is likely to enhance treatment retention, but further research is required in this regard.