Anorexia nervosa (AN) is an eating disorder that can lead to severe medical complications. Kidney injuries are unknown in patients with extremely malnourished AN (BMI <13). The primary objective of the study is to evaluate the frequency and to determine the profiles of patients who may develop kidney injuries. The secondary objective is to evaluate the evolution of kidney injuries after a phase of refeeding. Guidelines for medical treatments and dietary intakes will be recommended to avoid severe or irreversible renal disease.

Anorexia nervosa is an eating disorder that can lead to undernutrition and severe somatic complications. The clinical nutrition unit in Paul Brousse hospital provide care to adult patients with a severe forms of AN. Kidney complications are poorly known and little explored. Indeed, patients suffering from AN have a higher prevalence of kidney failure due to the absence of a reference methods. Kidney injuries come from multiple origin like chronic ionic disorders, dehydration and hyperprotein diet. The aim of this study will be to evaluate kidney injuries and to follow its evolution during refeeding. Blood and urine simple of Cystatine C will be add to routine analyses. This will allow us to know if, there is a concordance between the reference technique (measurement of glomerular filtration rate by isotopic method 99mTC-DTPA) and the measurement of Cystatin C. Thus, guidelines of dietary intake and medical treatments can be achieved in order to prevent severe forms requiring dialysis and kidney transplantation.

Inclusion Criteria:

• Patient with undernutrition (BMI < 18,5);
• Patient with AN according to DSM-5 criteria, validated by Eating Disorder Diagnostic Scale and EDDS-questionnaire;
• Patient informed and signed a consent form;
• Patient affiliated to a social security plan.

Exclusion Criteria:

• Patient no-reponding to all criteria of DSM-5;
• Patient with a renal comorbidity no-related to AN;
• Patient under AME scheme;
• Pregnancy or breastfeeding;
• Participation to another interventional study.

Patients with anorexia nervosa