Patients With Acute Renal Failure During Severe COVID-19

Inclusion criteria: * Major subject (≥18 years old) * Subject hospitalized in an intensive care unit, Strasbourg, Nancy or Reims hospitals, for severe COVID-19 between February 1, 2020 and July 31, 2020. * Having presented acute renal failure KDIGO 2 (assessed on a doubling of serum creatinine compared to the patient's reference values) or 3 (serum creatinine greater than 3 times the patient's reference, or anuria, or any recourse to extra-purification renal) * Having left hospital alive after initial treatment for COVID-19 * Subject not having expressed his opposition, after information, to the reuse of his data for the purposes of this research. Exclusion criteria: * Subject having expressed opposition to participating in the study * Subject under guardianship or guardianship * Subject under safeguard of justice