ABSTRACT
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.
ABSTRACT
Background: Dysregulation of complement system is thought to be a major player in development of multi-organ damage and adverse outcomes in patients with coronavirus disease 2019 (COVID-19). This study aimed to examine associations between complement system activity and development of severe acute kidney injury (AKI) among hospitalized COVID-19 patients. Materials and Methods: In this multicenter, international study, complement as well as inflammatory and thrombotic parameters were analyzed in COVID-19 patients requiring hospitalization at one US and two Hungarian centers. The primary endpoint was development of severe AKI defined by KDIGO stage 2+3 criteria, while the secondary endpoint was need for renal replacement therapy (RRT). Complement markers with significant associations with endpoints were then correlated with a panel of inflammatory and thrombotic biomarkers and assessed for independent association with outcome measures using logistic regression. Results: A total of 131 hospitalized COVID-19 patients (median age 66 [IQR, 54-75] years; 54.2% males) were enrolled, 33 from the US, and 98 from Hungary. There was a greater prevalence of complement over-activation and consumption in those who developed severe AKI and need for RRT during hospitalization. C3a/C3 ratio was increased in groups developing severe AKI (3.29 vs. 1.71; p < 0.001) and requiring RRT (3.42 vs. 1.79; p < 0.001) in each cohort. Decrease in alternative and classical pathway activity, and consumption of C4 below reference range, as well as elevation of complement activation marker C3a above the normal was more common in patients progressing to severe AKI. In the Hungarian cohort, each standard deviation increase in C3a (SD = 210.1) was independently associated with 89.7% increased odds of developing severe AKI (95% CI, 7.6-234.5%). Complement was extensively correlated with an array of inflammatory biomarkers and a prothrombotic state. Conclusion: Consumption and dysregulation of complement system is associated with development of severe AKI in COVID-19 patients and could represent a promising therapeutic target for reducing thrombotic microangiopathy in SARS-CoV-2 infection.