Critical roles of cytokine storm and secondary bacterial infection in acute kidney injury development in COVID-19: A multi-center retrospective cohort study

Acute kidney injury (AKI) may develop in patients with coronavirus disease 2019 (COVID-19) and is associated with in-hospital death. We investigated the incidence of AKI in 223 hospitalized COVID-19 patients and analyzed the influence factors of AKI. The incidence of cytokine storm syndrome and its correlation with other clinicopathologic variables were also investigated. We retrospectively enrolled adult patients with virologically confirmed COVID-19 who were hospitalized at three hospitals in Wuhan and Guizhou, China between February 13, 2020, and April 8, 2020. We included 124 patients with moderate COVID-19 and 99 with severe COVID-19. AKI was present in 35 (15.7%) patients. The incidence of AKI was 30.3% for severe COVID-19 and 4.0% for moderate COVID-19 (p < 0.001). Furthermore, cytokine storm was found in 30 (13.5%) patients and only found in the severe group. Kidney injury at admission (odds ratio [OR]: 3.132, 95% confidence interval [CI]: 1.150–8.527; p = 0.025), cytokine storm (OR: 4.234, 95% CI: 1.361–13.171; p = 0.013), and acute respiratory distress syndrome (ARDS) (OR: 7.684, 95% CI: 2.622–22.523; p < 0.001) were influence factors of AKI. Seventeen (48.6%) patients who received invasive mechanical ventilation developed AKI, of whom 64.7% (11/17) died. Up to 86.7% of AKI patients with cytokine storms may develop a secondary bacterial infection. The leukocyte counts were significantly higher in AKI patients with cytokine storm than in those without (13.0 × 10⁹/L, interquartile range [IQR] 11.3 vs. 8.3 × 10⁹/L, IQR 7.5, p = 0.005). Approximately 1/6 patients with COVID-19 eventually develop AKI. Kidney injury at admission, cytokine storm and ARDS are influence factors of AKI. Cytokine storm and secondary bacterial infections may be responsible for AKI development in COVID-19 patients.