Supplementary Material for: The Involvement of Chronic Kidney Disease and Acute Kidney Injury in Disease Severity and Mortality in Patients with COVID-19: A Meta-Analysis

Background: A meta-analysis was performed to evaluate the association of chronic kidney disease (CKD) and acute kidney injury (AKI) with the clinical prognosis of patients with coronavirus disease 2019 (COVID-19). Methods: The PubMed, EMBASE, Cochrane Library, medRxiv, Social Science Research Network, and Research Square databases (from December 1, 2019 to May 15, 2020) were searched to identify studies that reported the associations of CKD/AKI and disease severity/mortality. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated and meta-regression was performed. Results: In total, 42 studies enrolling 8,932 participants were included in this meta-analysis. The quality of most included studies was moderate to high. Compared with patients without previously diagnosed CKD, those with CKD had a significantly increased risk of progressing to a severe condition (OR 2.31, 95% CI 1.64–3.24) or death (OR 5.11, 95% CI 3.36–7.77). Similarly, compared with patients without AKI, those with AKI had a significantly increased risk of progressing to a severe condition (OR 11.88, 95% CI 9.29–15.19) or death (OR 30.46, 95% CI 18.33–50.59). Compared with patients with previously diagnosed CKD, those with AKI were more likely to progress to a severe condition (pgroup < 0.001, I2 = 98.3%) and even to death (pgroup < 0.001, I2 = 96.5%). Age had a significant impact on the association between CKD and disease severity (p = 0.001) but had no impact on the associations between AKI and disease severity (p = 0.80), between CKD and mortality (p = 0.51), or between AKI and mortality (p = 0.86). Four important complications (cardiac injury, shock, acute respiratory distress syndrome, and liver injury) did not significantly affect the associations between CKD/AKI and disease severity/mortality, indicating that CKD/AKI may be independent clinical prognostic indicators for patients with COVID-19. Conclusions: In COVID-19 patients, CKD/AKI was associated with worse outcomes compared with those without CKD/AKI. AKI was associated with higher risks of severity and mortality than CKD.