Outcomes of critically ill coronavirus disease 2019 patients requiring kidney replacement therapy: A retrospective cohort study

Background: Coronavirus disease 2019 (COVID-19) has resulted in high hospitalization rates worldwide. Acute kidney injury (AKI) in patients hospitalized for COVID-19 is frequent and associated with disease severity and poor outcome. The aim of this study was to investigate the incidence of kidney replacement therapy (KRT) in critically ill patients with COVID-19 and its implication on outcome.

Methods: We retrospectively analyzed all COVID-19 patients admitted to the Department of Intensive Care Medicine at the University Medical Center Hamburg-Eppendorf (Germany) between 1 March 2020 and 31 July 2021. Demographics, clinical parameters, type of organ support, length of intensive care unit (ICU) stay, mortality and severity scores were assessed.

Results: Three-hundred critically ill patients with COVID-19 were included. The median age of the study population was 61 (IQR 51-71) years and 66% (n = 198) were male. 73% (n = 219) of patients required invasive mechanical ventilation. Overall, 68% (n = 204) of patients suffered from acute respiratory distress syndrome and 30% (n = 91) required extracorporeal membrane oxygenation (ECMO). We found that 46% (n = 139) of patients required KRT. Septic shock (OR 11.818, 95% CI: 5.941-23.506, p < 0.001), higher simplified acute physiology scores (SAPS II) (OR 1.048, 95% CI: 1.014-1.084, p = 0.006) and vasopressor therapy (OR 5.475, 95% CI: 1.127-26.589, p = 0.035) were independently associated with the initiation of KRT. 61% (n = 85) of patients with and 18% (n = 29) without KRT died in the ICU (p < 0.001). Cox regression found that KRT was independently associated with mortality (HR 2.075, 95% CI: 1.342-3.208, p = 0.001) after adjusting for confounders.

Conclusion: Critically ill patients with COVID-19 are at high risk of acute kidney injury with about half of patients requiring KRT. The initiation of KRT was associated with high mortality.