Hypercarbia in Hospitalized Children and Adolescents with Anorexia Nervosa as a Predictive Marker for Readmission: A Prospective Study

Abstract

Background Readmissions in anorexia nervosa (AN) are a common though understudied outcome. No organic alterations have been related to the likeliness of readmission to date. This study evaluated clinical and laboratory alterations associated to the risk of AN-related hospital readmissions in children and adolescents. Methods A prospective study was performed with every person ≤18 years old admitted due to AN destabilization to the Eating Disorder Ward of a freestanding children's hospital in Madrid (Spain) from November 2018 to October 2019. Both subtypes of AN were included. The participants were evaluated upon admission, at discharge and six months after discharge. T-tests or Mann-Whitney U tests were used for means comparison. Pearson or Spearman correlations were used for measuring the association between two variables. Logistic regression models were developed to evaluate the relationship between scoring methods and readmission. Results 154 persons were admitted during the study period. 131 met the inclusion criteria. Median age was 15.1 years (interquartile range 13.5-16.4). 71% of participants were malnourished at admission. 33 participants (25 %) had been previously admitted due to an eating disorder. Remarkable venous pH decrease and pCO2 elevation remained stable during the follow-up period. Hypercarbia at discharge was associated with readmission being twice more likely. The odds of readmission increased as discharge pCO2 rose. These findings did not depend on the AN subtype or the participant sex. Electrolytes persisted within the normal range. Conclusions Hypercarbia and respiratory acidosis are common alterations in children and adolescents hospitalized due to AN destabilization. Hypercarbia persists for at least 6 months after discharge, despite clinical improvement, and is associated with higher odds of readmission. This is the first study to identify a laboratory alteration as a potential indicator of readmission in AN. Further research is needed to fully understand the consequences of hypercarbia on people diagnosed of AN.