The occurrence of renal failure during severe forms of COVID-19 is common (20-35% of patients treated in intensive care) and associated with an unfavorable short-term prognosis, but the medium-term renal outcome is not is not known.

The aim of the study is to establish the frequency of chronic kidney failure after AKI KDIGO 2 and 3 occurring during severe COVID-19 in intensive care.

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

- Major subject hospitalized in an intensive care unit, Strasbourg, Nancy or Reims Hospitals, for severe COVID-19 between February 1, 2020 and July 31, 2020.