Acute Kidney Injury Complicating Critical Forms of COVID-19: Risk Factors and Prognostic Impact

Background: Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) mainly affects the respiratory tract, but different organs may be involved including the kidney. Data on acute kidney injury (AKI) in critical forms of coronavirus disease 2019 (COVID-19) are scarce. We aimed to assess the incidence, risk factors and prognostic impact of AKI complicating critical forms of COVID-19.

Methods: A retrospective descriptive case/control monocentric study conducted in a medical intensive care unit of a tertiary teaching hospital over a period of 18 months.

Results: We enrolled 144 patients, with a mean age of 58±13 years old and a male predominance (sex-ratio: 1.25). Forty-one (28%) developed AKI within a median of 4 days (Q1: 3, Q3: 8.5) after hospitalization. It was staged KDIGO class 3, in about half of the cases. Thirteen patients underwent renal replacement therapy and renal function improved in seven cases. Diabetes (OR: 6.07; 95% CI: (1,30-28,4); p: 0.022), nephrotoxic antibiotics (OR: 21; 95% CI: (3,2-146); p: 0.002), and shock (OR: 12.21; 95% CI: (2.87-51.85); p: 0.031,) were the three independent risk factors of AKI onset. Mortality was significantly higher in AKI group (HR:12; 95% CI: (5.81-18.18); p:0.041) but AKI didn't appear to be an independent risk factor of poor outcome. In fact, age > 53 years (p: 0.018), septic shock complicating hospital acquired infection (p: 0.003) and mechanical ventilation (p<0.001) were the three prognostic factors in multivariate analysis.

Conclusions: The incidence of AKI was high in this study and associated to an increased mortality. Diabetes, use of nephrotoxic antibiotics and shock contributed significantly to its occurrence. This underlines the importance of rationalizing antibiotic prescription and providing adequate management of patients with hemodynamic instability in order to prevent consequent AKI.