Objective: To investigate the characteristics and the risk factors of coronavirus disease 2019 (COVID-19) associated acute kidney injury (AKI).
Methods: A retrospective cohort study was performed to examine the basic data, clinical characteristics and prognosis of patients with COVID-19 in Zhongnan Hospital of Wuhan University and Wuhan Fourth Hospital from January 1st to February 1st in 2020. According to the diagnostic criteria of Kidney Disease: Improving Global Outcomes (KDIGO), patients with AKI were included in AKI group and those without AKI were included in non-AKI group. The differences of each index between the two groups were compared. The prognostic value of AKI for COVID-19 was analyzed by Kaplan-Meier survival curve and Cox regression.
Results: A total of 394 COVID-19 patients were included, with a total mortality of 5.6%; 37 (9.4%) of them developed AKI. The mortality of patients with COVID-19 associated AKI was 18.9%. There were significant differences in age, gender, smoking history, hypertension history, malignancy history, cardiovascular disease history and cerebrovascular disease history between the two groups. In addition to the difference of serum creatinine (SCr) and blood urea nitrogen (BUN), white blood cell count (WBC), neutrophil count (NEU), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), D-dimer, procalcitonin (PCT) and C-reaction protein (CRP) in AKI group were significantly higher than those in non-AKI group [WBC (×109/L): 5.75 (4.13, 7.83) vs. 4.52 (3.35, 5.90), NEU (×109/L): 4.55 (2.81, 6.11) vs. 3.06 (2.03, 4.50), AST (U/L): 40.0 (24.5, 69.5) vs. 30.0 (23.0, 42.5), LDH (μmol×s-1×L-1): 5.21 (3.68, 7.57) vs. 4.24 (3.05, 5.53), D-dimer (μg/L): 456 (266, 2 172) vs. 290 (152, 610), PCT (μg/L): 0.33 (0.03, 1.52) vs. 0.01 (0.01, 0.11), CRP (mg/L): 53.80 (26.00, 100.90) vs. 23.60 (9.25, 51.10), all P < 0.05], while lymphocyte count (LYM) and platelet count (PLT) were decreased [LYM (×109/L): 0.68 (0.47, 1.05) vs. 0.91 (0.63, 1.25), PLT (×109/L): 142.0 (118.0, 190.0) vs. 171.0 (130.0, 2 190.0), both P < 0.05]. The mortality of AKI group was significantly higher than that of non-AKI group [18.9% (7/37) vs. 4.2% (15/357), P < 0.01]. Kaplan-Meier survival curve showed that the 30-day cumulative survival of AKI group was lower than that of non-AKI group (log-rank: P = 0.003). Cox analysis also showed that AKI increased the odds of patients with COVID-19 mortality by 3.2-fold [hazard ratio (HR) = 3.208, 95% confidence interval (95%CI) was 1.076-9.566, P = 0.037].
Conclusions: The risk of AKI is higher in patients with COVID-19. Early intervention to prevent AKI in patients with COVID-19 is of great significance to improve the prognosis of patients.