Association between Chronic Kidney Disease or Acute Kidney Injury and Clinical Outcomes in COVID-19 Patients.

Background: A population-based study would be useful to identify the association between chronic kidney disease (CKD) or acute kidney injury (AKI) and prognosis of coronavirus disease 2019 (COVID-19) patients.

Methods: This retrospective study utilized the claim data from Korea. Patients who underwent COVID-19 testing and were confirmed to be positive were included and divided into the following three groups based on the presence of CKD or requirement of maintenance dialysis: Non-CKD (participants without CKD), non-dialysis CKD (ND-CKD), and dialysis-dependent CKD (DD-CKD) patients. We collected data on the development of severe clinical outcomes and death during follow-up. Severe clinical outcomes were defined as the use of inotropics, conventional oxygen therapy, high-flow nasal cannula, mechanical ventilation, or extracorporeal membrane oxygenation and the development of AKI, cardiac arrest, myocardial infarction, or acute heart failure after the diagnosis of COVID-19. AKI was defined as the initiation of renal replacement therapy after the diagnosis of COVID-19 in patients not requiring maintenance dialysis. Death was evaluated according to survival at the end of follow-up.

Results: Altogether, 7,341 patients were included. The median duration of data collection was 19 (interquartile range, 11-28) days. On multivariate analyses, odds ratio (OR) for severe clinical outcomes in the ND-CKD group was 0.88 (95% confidence interval [CI], 0.64-1.20; = 0.422) compared to the Non-CKD group. The DD-CKD group had ORs of 7.32 (95% CI, 2.14-33.90; = 0.004) and 8.32 (95% CI, 2.37-39.21; = 0.002) compared to the Non-CKD and ND-CKD groups, respectively. Hazard ratio (HR) for death in the ND-CKD group was 0.79 (95% CI, 0.49-1.26; = 0.318) compared to the Non-CKD group. The DD-CKD group had HRs of 2.96 (95% CI, 1.09-8.06; = 0.033) and 3.77 (95% CI, 1.29-11.06; = 0.016) compared to the Non-CKD and ND-CKD groups, respectively. DD-CKD alone was associated with severe clinical outcomes and higher mortality. There was no significant difference in frequency of severe clinical outcomes or mortality rates between the Non-CKD and ND-CKD groups. In patients not requiring maintenance dialysis, AKI was associated with old age, male sex, and high Charlson's comorbidity index score but not with the presence of CKD. HRs for patients with AKI were 11.26 (95% CI, 7.26-17.45; < 0.001) compared to those for patients without AKI in the multivariate analysis. AKI was associated with severe clinical outcomes and patient survival, rather than underlying CKD.

Conclusion: CKD requiring dialysis is associated with severe clinical outcomes and mortality in patients with COVID-19; however, the development of AKI is more strongly associated with severe clinical outcomes and mortality.