165. Renal Function in Patients Hospitalized With Anorexia Nervosa Undergoing Medical Stabilization: Findings From the Study of Refeeding to Optimize iNpatient Gains (StRONG)


      Renal impairment is an established medical complication in patients with malnutrition due to restrictive eating disorders. Electrolyte derangements, nephrolithiasis, acute kidney injury, and impaired osmoregulation are reported as renal complications. We sought to evaluate renal function in hospitalized adolescents and young adults (AYA) with Anorexia Nervosa (AN) and Atypical Anorexia Nervosa (AAN) undergoing medical stabilization.


      This is a secondary analysis of data from the Study of Refeeding to Optimize Inpatient Gains (StRONG) trial, a multicenter randomized controlled trial comparing higher-calorie refeeding (HCR) versus lower-calorie refeeding (LCR) in 120 AYA hospitalized with medical instability secondary to AN or AAN. Vital sign measurements, weight [to calculate percent of median body mass index (%mBMI)], electrolytes, and fluid status were evaluated at baseline and daily. Renal function was quantified using daily creatinine measurement and calculation of the glomerular filtration rate (GFR) using the modified Schwartz equation. Unpaired t-tests compared group by GFR. Generalized mixed linear regression compared GFR over time by treatment arm (HCR versus LCR).


      Of the 111 participants who completed treatment protocol, mean (SD) age was 16.5 (2.5) years, and 33% had a baseline GFR less than 90 mL/min/1.73m2, suggesting renal impairment. %mBMI in those with GFR < 90 mL/min/1.73m2 was 84.6 (.10) vs. 84.9 (.12) in those with GFR > 90 mL/min/1.73m2 (p=.89). GFR improvement throughout hospitalization was significantly greater in those treated with higher calorie refeeding (p=.04), and in those admitted with GFR < 90 mL/min/1.73m2 ( p<.05).


      Renal impairment is evident on admission in a significant number of AYA hospitalized with AN and AAN. Higher calorie refeeding led to greater improvement in GFR as compared to lower calorie refeeding, particularly for those with more significant renal impairment on admission. These findings support the efficacy of HCR in restoring medical stability and reversing negative consequences of malnutrition faster than LCR.

      Sources of Support

      National Institute Child Health & Human Development #R01HD082166; Identifier NCT02488109.