In a consecutive adolescent anorexia nervosa cohort, structured inpatient nutritional rehabilitation was associated with substantial cardiovascular and nutritional improvement, lower admission BMI z-score predicted longer hospitalization, and systematic electrolyte monitoring documented no hypophosphatemia requiring intervention and no refeeding syndrome.
Mean supine heart rate increased significantly from admission to discharge following structured nutritional rehabilitation.
Lower admission BMI z-score was independently associated with longer length of stay.
No refeeding syndrome or hypophosphatemia requiring intervention was documented under the structured protocol with systematic electrolyte monitoring.
Exploratory analyses suggested that the magnitude of heart rate recovery was more closely associated with baseline nutritional status and baseline heart rate than with caloric escalation.
Documented mental health comorbidities or clinically significant symptom clusters were present in the large majority of patients.
This research examined 68 adolescents (mostly girls, average age 14) hospitalized for anorexia nervosa at a national specialty center over an eight-year period. Patients followed a structured feeding protocol that started with modest calorie amounts and gradually increased to higher levels, while medical staff monitored blood electrolytes daily. The study found that heart rates improved dramatically during hospitalization — on average increasing by more than 28 beats per minute — and the proportion of patients with dangerously slow heart rates (below 50 beats per minute) fell from about 40% to just 1.5%. No patients developed refeeding syndrome, a potentially dangerous complication of rapid nutritional rehabilitation, suggesting the gradual, monitored approach was medically safe in this setting. The study also found that how malnourished a patient was at admission — measured by their BMI z-score, which compares their weight-to-height ratio to peers — was the strongest predictor of how long they stayed in the hospital. Each unit improvement in admission BMI z-score was associated with an approximately 19% shorter hospital stay. Interestingly, how much a patient's heart rate recovered during hospitalization appeared to be linked more to how sick they were at the start (their baseline BMI and heart rate) than to how quickly calories were increased. Additionally, more than 80% of patients had documented mental health conditions alongside their eating disorder, highlighting the complex psychiatric needs of this population. This research suggests that the severity of malnutrition at the time of hospital admission plays a central role in shaping both the medical trajectory and the length of hospitalization for adolescents with anorexia nervosa. The findings also reinforce that a carefully monitored, stepwise nutritional rehabilitation approach can help patients recover cardiovascular function without triggering dangerous metabolic complications. The high rate of psychiatric comorbidities underscores that effective care for this population requires attention to mental health needs in addition to medical and nutritional stabilization.
Elhag S, Fahmi A, Alansari A, Al-Kuwari S, Al-Kuwari A, Ahmed A, et al.. (2026). Nutritional Rehabilitation and Medical Stabilization of Adolescents with Anorexia Nervosa: Length-of-Stay Predictors, Cardiovascular Recovery, Refeeding Safety, and Psychiatric Comorbidity Burden.. Nutrients. https://doi.org/10.3390/nu18172789