Inpatient target discharge weight for early-onset anorexia nervosa: Restoring premorbid BMI percentile to improve height prognosis

Early-onset anorexia nervosa (EO-AN) is characterized by restricted food intake leading to low body weight, emerging before 14 years old. Most patients reaching a target body mass index (BMI) around the 25th percentile at hospitalization discharge display an incomplete prospective height catch-up. A better understanding of height prognosis determinants is required. In 74 children with an EO-AN, we collected height and weight premorbidly, at hospitalization, and at discharge, 6 months, 12 months, and at longer-term follow-up of 36 months. We defined a height prognosis parameter (HPP) as the difference between the height percentile at follow-up times and the premorbid height percentile. We explored the relationship between weight parameters and height catch-up at follow-up with linear regression analyses. A higher weight suppression (WS) - i.e., difference between premorbid and current BMI - at admission and discharge was associated with lower HPP - i.e., a greater loss of height - at 12 months and 36 months follow-up. Similarly, a higher premorbid BMI percentile was associated with a lower HPP at 12 and 36 months. Target discharge weight for EO-AN patients should be tailored and based on premorbid BMI trajectory to improve height prognosis. •High premorbid BMI and persistent weight suppression at discharge are associated with less favorable height prognosis.•The weight restoration target at treatment should be based on premorbid BMI trajectory to improve height prognosis.