Renal dysfunctions and clinical correlates in adolescents with restrictive anorexia nervosa

The alteration of kidney function in adolescents with anorexia nervosa (AN) is a frequent, but still poorly investigated, consequence of AN. In this study, we analyzed glomerular filtration rate with the Cockroft-Gault formula in a group of 148 adolescents with Anorexia Nervosa and correlated it to clinical and biochemical data collected at admission.

A retrospective study was conducted on 148 patients hospitalized from 2016 to 2019 for severe malnutrition due to restrictive AN. We measured glomerular filtration rate and correlated it with the patients' anamnestic history, nutritional status and biochemical data.

For the 148 AN patients, 40 (27%) resulted at admission at stage 1 of kidney damage (GFR>90 mL/min), 88 patients (59%) at stage 2 (GFR 89-60 mL/min), 17 patients (11%) at stage 3A (GFR 59-45 mL/min) and 3 patients (2%) at stage 3B (GFR 44-30 mL/min). Results outlined a correlation between the entity of kidney damage and BMI at admission and before illness onset, but not with the rapidity and entity of weight loss. Further, more severe renal damages corresponded to major biochemical and hormonal alterations.

Results of our study confirm that kidney damage is a frequent condition in adolescents with restrictive-type AN and support making kidney functionality tests part of routine care in patients with AN.