Long-Term Renal Outcomes Among COVID-19 ICU Survivors Admitted With Acute Kidney Injury

Introduction Acute kidney injury (AKI) is associated with poor outcomes in intensive care unit (ICU) patients with COVID-19. The need for renal replacement therapy (RRT) was frequently reported among these patients. However, the long-term prognosis of new-onset AKI detected on ICU admission is not well defined, in opposition to AKI occurring at any time during ICU stay. We evaluated the long-term outcomes of early-AKI (present on admission) in COVID patients requiring ICU during the pandemic; identified AKI risk factors and the impact of RRT on survival and renal outcomes (short and long term).  Methods We conducted an observational study with retrospective analysis charts of COVID-19 adult patients consecutively admitted to the ICU at CHIREC Hospital, Brussels, Belgium, between March 2020 and April 2021. AKI criteria were assessed using KDIGO (Kidney Disease Improving Global Outcomes) criteria at baseline and daily during ICU stay. The data are reported at admission, at the time of the worst AKI stage, at ICU discharge, and at long-term follow-up 3.5 years after ICU discharge. Results Among the 247 COVID-19 patients admitted to the ICU, 236 were included in the analysis. Early AKI was detected in 87 (37%) patients. Age, acute respiratory distress syndrome, hypertension, diabetes, and obesity were significantly associated with the development of AKI. Sixty (69%) patients were in stage 1, nine (10%) in stage 2, and 18 (21%) in stage 3. Among patients with early AKI, 52 survived to the ICU, and 47 were available for long-term follow-up. ICU mortality was higher in patients with AKI stage 3 (66%) than those with AKI stage 1 (32%), and this mortality increased with AKI progression and the need for renal replacement therapy (RRT). In the early-AKI group, 22 patients (25%) required RRT during ICU stay, two (9%) received RRT at admission, while 20 (90%) received RRT during ICU stay. Among these 22 patients, 19 (86%) died in the ICU, while three (13%) survived to follow-up and were able to discontinue RRT.  Conclusions Early AKI is common in COVID-19 ICU patients with acute respiratory failure and is associated with increased ICU length of stay compared with that of no-AKI patients. Patients with poor progression of AKI during their ICU stay and those with RRT requirements have a high mortality rate; however, survivors generally experience sufficient renal recovery to discontinue RRT. Early-AKI survivors without RRT requirements show excellent recovery of renal function.