Percent body fat is a risk factor for relapse in anorexia nervosa: a replication study

We aimed to replicate and extend our previous findings of an association between percent body fat in recently weight-restored patients with Anorexia Nervosa (AN) and clinical outcome in the year following treatment.

Twenty-two hospitalized, weight-restored women with AN underwent whole body MRI to determine percent adipose tissue. Following hospital discharge, patients were contacted regularly, and at the end of the year, clinical outcome was determined using modified Morgan-Russell (MR) criteria: full, good, fair or poor. Identical to our previous study, outcome was dichotomized into "full, good or fair" and "poor" groups.

Data from 21 subjects were available for analysis. Percent body fat was significantly lower in the poor outcome group (22% ± 5%) compared to the "full, good or fair" outcome group (27 % ± 4%)(p < 0.035). To further examine the relationship, we combined data from the current study with data from the 26 subjects on whom we had previously reported. Univariate analysis of variance (ANOVA) demonstrated a significant difference in percent adipose tissue across the four MR outcome groups (F = 3.416, df = 3, p<0.03).

Lower percent adipose tissue after short-term weight normalization is associated with poor clinical outcome in the year following inpatient treatment. These findings may be important in the assessment of risk for relapse in patients with AN.