Renal Function Outcome in Hospitalized Adolescent Girls with Anorexia Nervosa.

Purpose: Renal complications are classically described in anorexia nervosa (AN). Our aim was to study the initial renal function and its outcome after refeeding in a population of female adolescents hospitalized for AN, and to look for predictive factors of the development of renal failure. Methods: Renal function was assessed using the Cockcroft and Gault formula before and after the refeeding period in 106 inpatient AN girls in an adolescent medical unit. Predictive factors for renal impairment and potential for recovery were sought using patient anamnestic, anthropometric and biological characteristics. Results: Creatinine clearance was reduced at admission, and improved significantly at discharge (63.9 mL/min vs. 84.2 mL/min, p<0.01). Only 4 patients presented an initial normal renal function, 58 a mild reduction, and 44 a moderate reduction. At discharge, these figures were respectively 40, 56 and 10. The positive predictive factors identified were BMI (r=0.22; p=0.02), weight gain (r=0.64; p<0.01) and potassium levels at admission (r=0.23, p=0.02). No differences were observed for creatinine clearance levels at admission between restrictive (ANR) and binge/ purging (ANBP) patients, but clearance rates at discharge among ANR were statistically better (87.7 mL/min vs. 75.8 mL/min, p<0.01). Conclusion: Impairment of renal function in hospitalized anorexic adolescents may be transient or persistent after refeeding depending of initial malnutrition severity and nutritional status at the time of discharge. It seems essential not to under-diagnose the persistence of renal function deficiency following the refeeding phase, in order to limit the risk of severe renal impairment or end-stage renal disease in adulthood