[Nutritional recovery of underweight adolescents with anorexia nervosa: analysis of a hospital protocol].

Background: anorexia nervosa (AN) is a severe psychiatric pathology that has one of the highest mortality rates among mental illnesses, estimated at 5.1 deaths per 1,000 people/year, and is associated with high comorbidity, both psychiatric and somatic. Aim: to characterize hospitalized adolescents and their nutritional rehabilitation using a standardized protocol. Methods: a descriptive-retrospective study of adolescent patients hospitalized at the San Carlos of Apoquindo Clinic with a diagnosis of AN, hemodynamically stable and without refeeding syndrome criteria, between 2015 and 2021. Epidemiological, clinical, and nutritional data of the patients were analyzed. Results: of 46 patients studied, 37 were female; the average length of stay was 45.4 (SD ± 36.1) days; 53.8 % of the patients had mood disorder as psychiatric comorbidity, and the most common personality trait was obsessive-compulsive (36.9 %); the most frequent somatic comorbidity was thyroid pathology (19.2 %). The initial oral caloric intake was 1467 (SD ± 479) kcal, with an average weekly increase of 400 kcal, reaching 2430 (SD ± 457) kcal at discharge. An average body mass index (BMI%) percentage change of 7.8 % (SD ± 6.1) was obtained. Conclusions: this is the first national study that describes the nutritional rehabilitation of adolescents with AN and the length of hospitalization required to achieve it.