[Measuring changes during the treatment of eating disorders: a comparison of two types of questionnaires].

BACKGROUND: In mental health care routine outcome monitoring (ROM) has become an important part of everyday clinical practice in the Netherlands. It is important that the questionnaires involved are sensitive to therapeutic change. The Brief Symptom Inventory (BSI) is a generic instrument that is widely used and that seems to be responsive to therapeutic change. However, in relation to patients with an eating disorder, more valuable information might be obtained from a questionnaire that is better geared to the primary symptoms of the eating disorder.<br/> AIM: To find out whether the BSI and the Eating Disorder Examination Questionnaire (EDE-Q), which is a questionnaire designed to measure eating disorder psychopathology, reveal different degrees of therapeutic change in patients with an eating disorder.<br/> METHOD: The sample consisted of 1062 patients seeking treatment for an eating disorder (DSM-IV). We performed an analysis of variance (2 x 2 design) in order to detect any difference between the two instruments regarding their sensitivity to change at the two time points. Patients were divided into four categories: recovered, improved, unchanged or deteriorated. We used a chi-squares test to determine whether the two questionnaires differed with regard to the proportions they gave for improved and recovered patients.<br/> RESULTS: The analyses revealed that in this patient group the EDE-Q was more sensitive to change than the BSI. The percentage of patients in the categories 'recovered' and 'improved' was higher in the EDE-Q than in the BSI. The same practice emerged with regards to the various subtypes of eating disorders.<br/> CONCLUSION: It does seem to matter what type of questionnaire is used to measure the course and outcome of treatment. When responsiveness to change is being measured, it is important to use an instrument that assesses the symptoms that are the primary focus of treatment. If the primary aim is to reduce eating disorder symptoms, then the best type of questionnaire to use is one that assesses eating disorder psychopathology.