Characteristics of patients with kidney injury associated with COVID-19

To explore the characteristics of COVID-19 infection related kidney injury, we retrospectively collected cases of COVID-19 patients with definite clinical outcomes (discharge or death) and relevant laboratory results from Jan 3 to Mar 30, 2020 in Tongji hospital, Wuhan, China. 1509 patients were included, 1393 cases with normal baseline serum creatinine, and 116 cases with elevated baseline serum creatinine (EBSC). On admission, the prevalence of elevated serum creatinine, elevated blood urea nitrogen (BUN) and estimated glomerular filtration (eGFR) under 60 ml/min/1.73 m² were 7.7%, 6.6% and 7.2%, respectively. The incidence of in-hospital death in the patients with EBSC was 7.8%, which was significantly higher than those with normal serum creatinine (1.2%). Inflammatory, immunological, and organ damage indices were relatively higher in the EBSC group, in which lymphocytes, albumin, and hemoglobin were significantly lower. Kaplan-Meier analysis revealed age above 65 years, males, comorbidities (especially for cardiovascular disease and tumor patients), lymphocyte count < 1.5 × 10⁹/L, leukocyte count > 10 × 10⁹/L, EBSC, eGFR < 60 ml/min/1.73 m² were associated with in-hospital death. Multivariate Cox proportional hazard regression confirmed that EBSC (HR: 2.643, 95% CI: 1.111-6.285, P = 0.028), eGFR < 60 ml/min/1.73 m² (HR: 3.889, 95% CI: 1.634-9.257, P = 0.002), were independent risk factors after adjusting for age, sex, any comorbidity, leukocyte and lymphocyte count. Therefore, the prevalence of kidney injury in patients with COVID-19 was high and associated with in-hospital mortality. Early detection and effective intervention of kidney injury may reduce COVID-19 deaths.