Factors Associated with Refeeding Hypophosphatemia in Adolescents and Young Adults Hospitalized with Anorexia Nervosa

Abstract

Refeeding Hypophosphatemia (RH) is the most common complication of nutritional restoration during medical hospitalization for individuals with anorexia nervosa (AN). Characterized by a drop in serum phosphorus levels, consequences of RH can be seen throughout the body and are potentially life threatening. Despite the seriousness of this outcome, little is known about which individuals with AN are at greatest risk of developing RH and best practices for prevention. The purpose of this retrospective cohort study was to examine demographic, feeding, and biochemical factors found in hospitalized adolescent and young adults (AYA) diagnosed with AN that may contribute to the development of RH. Individuals diagnosed with AN who were admitted to Boston Children’s Hospital between the years of 2010-2016 were considered for inclusion. Three hundred charts were analyzed using logistic regression to determine factors associated with RH and multivariate regression to determine factors associated with serum phosphorus nadir. In the final logistic regression model, receiving nasogastric tube feeding (p=0.54), age at admission (p=.022), weight gain during hospitalization (p=.003), serum potassium level (p=.001), and serum magnesium level (p=.024) significantly contributed to the model. Odds of RH were 3 times higher in those who received NG feeding, 1.2 times higher for each year of increasing age, 1.5 times higher for each kilogram of weight gain, 9.2 times higher for each unit reduction in potassium, and 13.7 times higher for each unit reduction in magnesium. With regards to phosphorus nadir, 1-unit increase in magnesium resulted in 1.2 increase in phosphorus, and each unit of admit BMI increased phosphorus by .060. The results indicate that NG feeding, age, weight gain, electrolyte abnormalities, and admit BMI are potential indicators of development of RH in AYA hospitalized with AN. This study will inform clinicians of risk factors associated with RH, and may guide further investigation into the clinical management of AYA diagnosed with AN.