Children with Prepubertal Anorexia Nervosa: assessing the sex hormone profile and prognostic factors for inpatient treatment outcomes.

Background: Even though Anorexia Nervosa (AN) is an emerging research topic, scarce literature data are available on children with prepubertal AN. To date, no specific study has assessed the potential prognostic factors on treatment outcomes in this population.

Methods: Observational, retrospective study of 39 children (12.5±1.8 years) hospitalized for AN, with primary amenorrhea and absence of pubertal development at clinical examination. Sexual hormonal profile: plasma levels luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol (E2), progesterone (P4), and prolactin (PRL) were assessed at admission. Clinical (age, duration of illness, comorbidity, admission body-mass index - BMI), treatment (psychopharmacological therapies) and outcome (BMI improvement, length of hospital stay - LOS) variables were assessed. Multiple linear regressions were conducted to assess potential predictors of outcomes.

Results: A predictive model of BMI improvement (F(4, 32)=8.713; Adjusted R2=0.491; p<0.001) was documented, with longer LOS (B=0.010; p<0.001), lower plasma levels of E2 (B=-0.043; p=0.002) and lower plasma levels of LH (B=-0.292, p=0.043) predicting a greater BMI improvement. A predictive model of LOS (F(2, 38)=9.527; Adjusted R2=0.310; p<0.001) was documented as well, with younger age (B=17.835; p<0.001), and reduced BMI improvement (B=22.656; p=0.012) predicting a shorter LOS. No predictive value of comorbidity, FSH, P4 or PRL was found.

Conclusions: This is the first study to investigate the prognostic value of sex hormones on the treatment of children with prepubertal AN. Low E2, LH, and age, but not FSH, P4 or PRL, were associated with better outcomes. These data should be investigated in wider populations and controlled studies.