Acute kidney injury in 3182 patients admitted with COVID-19: a single center retrospective case-control study

Procaccini, Fabio L; Alcázar Arroyo, Roberto; Albalate Ramón, Marta; Torres Aguilera, Esther; Navarro, Juan Martín; Ryan Murua, Pablo; Cintra Cabrera, Melissa; Ortega Díaz, Mayra; Puerta Carretero, Marta; de Sequera Ortiz, Patricia

BACKGROUND: Acute kidney injury (AKI) may develop in COVID-19 patients and may be associated with a worse outcome. The aim of this study is to describe AKI incidence during the first 45 days of the SARS-CoV2 pandemic in Spain, its reversibility and the association with mortality. METHODS: Observational retrospective case-control study based on patients hospitalized between March 1 and April 15, 2020 with SARS-CoV2 infection and AKI. Confirmed AKI cases were compared with stable kidney function patients for baseline characteristics, analytical data, treatment and renal outcome. Patients with end-stage kidney disease were excluded. RESULTS: AKI incidence was 17.22% among 3182 admitted COVID-19 patients and acute kidney disease (AKD) incidence was 6.82%. The most frequent causes of AKI were prerenal (68.8%) and sepsis (21.9%). Odds ratio for AKI was increased in patients with pre-existent hypertension (OR 2.58, 95% CI 1.71-3.89) and chronic kidney disease (OR 2.14, 95% CI 1.33-3.42) and in those with respiratory distress (OR 2.37, 95% CI 1.52-3.70). Low arterial pressure at admission increased the risk for stage 3 AKI (OR 1.65, 95% CI 1.09-2.50). Baseline kidney function was not recovered in 45.73% of overall AKI cases and in 52.75% of AKI patients with prior chronic kidney disease. Mortality was 38.5% compared to 13.4% of the overall sample population. AKI increased mortality risk at any time of hospitalization (HR 1.45, 95% CI 1.09-1.93). CONCLUSIONS: AKI is frequent in COVID-19 patients and is associated to mortality, independently from acute respiratory distress syndrome. AKD was also frequent and merits adequate follow-up.