Body mass index, body fat and risk factor of relapse in anorexia nervosa.

BACKGROUND/OBJECTIVES: Preliminary studies have reported an association between poor long-term outcome and lower total body fat percentage in weight-restored inpatients treated for anorexia nervosa (AN). A possible link between poor long-term outcome and higher trunk fat percentage has also been hypothesized. The aim was to assess the association between percentage and distribution of body fat at inpatient discharge and the maintenance of normal weight at 1-year follow-up in a sample of weight-restored females with AN.

SUBJECTS/METHODS: Fifty-four short-term weight-restored (body mass index (BMI; in kg/m(2)) ⩾18.5) adult females with AN treated in a specialist inpatient unit underwent dual-energy X-ray absorptiometry to determine total body fat and trunk fat percentages. Patients were contacted regularly following discharge, and at the end of the year clinical outcome was dichotomized as either 'full, good or fair' (a group that includes individuals with a BMI ⩾18.5 kg/m(2)) or 'poor' (BMI<18.5 kg/m(2)), using the modified Morgan-Russell criteria.

RESULTS: No significant differences were found between 'full, good or fair' and 'poor' outcome groups in either total body fat or trunk fat percentages. Only lower BMI at inpatient discharge was associated with poor clinical outcome in the year following inpatient treatment.

CONCLUSIONS: In short-term weight-restored adult females with AN, BMI, but not body fat percentage or distribution, at inpatient discharge is associated with long-term normal weight maintenance.