Kidney Disease Associated With Anorexia Nervosa: A Case Series With Kidney Biopsies

RATIONALE & OBJECTIVE: Anorexia nervosa is often intractable and induces various physical disorders, including kidney disease and mineral disorders, occasionally progressing to kidney failure. No consensus-based clinical practice guidelines have been established for patients with anorexia nervosa referred to a nephrologist. STUDY DESIGN: Patients with anorexia nervosa–associated kidney disease diagnosed were analyzed retrospectively. Kidney outcomes were defined as doubling of serum creatinine level and/or progression to end-stage kidney disease. SETTING & PARTICIPANTS: Patients with a history of anorexia nervosa with kidney disease, including electrolyte abnormalities, who were referred to our hospital between 1992 and 2017 were included. RESULTS: 14 female patients were included. The time from anorexia nervosa onset to the initial visit with a nephrologist was 17.8 years. At the first visit, median body mass index was 13.4 kg/m(2), median serum creatinine level was 1.9 mg/dL, and median serum potassium level was 2.7 mmol/L. All patients showed hypokalemia and addictive vomiting or diuretic/laxative abuse. During the median observation period of 3.1 years, kidney outcomes occurred in 9 patients, and 2 died due to their anorexia nervosa. 4 patients underwent kidney biopsy. The kidney biopsy findings of these patients included hypertrophy of the juxtaglomerular apparatus, advanced glomerular collapse, and interstitial fibrosis, consistent with ischemic kidney injury and hypokalemic nephropathy. LIMITATIONS: The sample size was small, and kidney function was assessed based on serum creatinine levels in patients with anorexia nervosa with low muscle mass. CONCLUSIONS: Most patients with anorexia nervosa referred to nephrologists had kidney disease at the time of the first visit. Improving kidney outcomes of patients with anorexia nervosa may require earlier collaboration between psychiatrists and nephrologists.