Patients with septic shock in the intensive care unit have a high risk to develop acute kidney injury (AKI) and AKI is an independent risk factor of mortality. Given the absence of validated pharmacological treatments for limiting the progression of AKI or for accelerating recovery from AKI, early intervention and the restoration of the glomerular filtration rate (GFR) in this context of septic shock might improve the patients' prognosis. One major challenge is to determine whether or not the AKI is reversible (return to normal function KDIGO 0 within 72 hours). In this retrospective study the investigators will analyze all patients admitted for a septic shock in three French ICUs between the 1st january 2014 and 01st January 2017 who developed an AKI (KDIGO ≥1) at admission and who had a determination of the urine concentration of TIMP2\*IGFBP7 at admission. The investigators will determine the best threshold of TIMP2\*IGFBP7 to distinguish the population of patients who will return to normal kidney function within 72 hours (KDIGO 0).