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

Objective: 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. Methods: 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. Results: 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. Conclusion: Target discharge weight for EO-AN patients should be tailored and based on premorbid BMI trajectory to improve height prognosis.