Prevalence of Kidney Injury and Associations with Critical Illness and Death in Patients with COVID-19

Abstract

Background and objectives: Coronavirus disease 2019 is spreading rapidly across the world. This study aimed to assess the characteristics of kidney injury and its association with disease progression and death of patients with coronavirus disease 2019.

Design, setting, participants, & measurements: This is a retrospective study. Two representative cohorts were included. Cohort 1 involved severe and critical patients with coronavirus disease 2019 from Wuhan, China. Cohort 2 was all patients with coronavirus disease 2019 in Shenzhen city (Guangdong province, China). Any kidney injury was defined as the presence of any of the following: hematuria, proteinuria, in-hospital AKI, or prehospital AKI. AKI was defined according to the Kidney Disease Improving Global Outcomes (KDIGO) creatinine criteria. The primary outcome was death at the end of follow-up. The secondary outcome was progression to critical illness during the study period.

Results: A total of 555 patients were enrolled; 42% of the cases (229 of 549) were detected with any kidney injury, 33% of the cases (174 of 520) were detected with proteinuria, 22% of the cases (112 of 520) were detected with hematuria, and 6% of the cases (29 of 520) were detected with AKI. Of the 29 patients with AKI, 21 cases were recognized as in-hospital AKI, and eight were recognized as prehospital AKI. Altogether, 27 (5%) patients died at the end of follow-up. The death rate was 11% (20 of 174) in patients with proteinuria, 16% (18 of 112) in patients with hematuria, and 41% (12 of 29) in the AKI settings. Multivariable Cox regression analysis showed that proteinuria (hazard ratio, 4.42; 95% confidence interval, 1.22 to 15.94), hematuria (hazard ratio, 4.71; 95% confidence interval, 1.61 to 13.81), and in-hospital AKI (hazard ratio, 6.84; 95% confidence interval, 2.42 to 19.31) were associated with death. Among the 520 patients with noncritical illness at admission, proteinuria (hazard ratio, 2.61; 95% confidence interval, 1.22 to 5.56) and hematuria (hazard ratio, 2.50; 95% confidence interval, 1.23 to 5.08) were found to be associated with progression to critical illness during the study period.

Conclusions: Kidney injury is common in coronavirus disease 2019, and it is associated with poor clinical outcomes.

Podcast: This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2020_09_18_CJN04780420.mp3.

Keywords: COVID-19; acute kidney injury; critical illness; hematuria; proteinuria.

Graphical abstract

Figure 1.

The prevalence of kidney injury indicators increased in parallel with disease severity of COVID-19. The prevalence of kidney injury according to (A) cohorts and (B) disease severity at admission. Disease severity was classified as mild and moderate, severe, or critical; 35 individuals for proteinuria, 35 individuals for hematuria, 35 individuals for in-hospital AKI, 35 individuals for prehospital AKI, and six individuals for any kidney injury were excluded due to missing data.

Figure 2.

Kaplan–Meier analysis showed a significantly higher death rate for patients with proteinuria, hematuria, in-hospital AKI, and prehospital AKI. Cumulative incidence for death of patients subgrouped by (A) proteinuria, (B) hematuria, (C) in-hospital AKI, and (D) prehospital AKI.

Figure 3.

Kaplan–Meier analysis showed a significantly higher progression rate for patients with proteinuria, hematuria, and prehospital AKI at admission. Cumulative incidence for disease progression to critical illness of patients subgrouped by (A) proteinuria, (B) hematuria, (C) in-hospital AKI, and (D) prehospital AKI.