FACTORS INFLUENCING DEATH RATE IN COVID-19-ASSOCIATED ACUTE KIDNEY INJURY

Abstract BACKGROUND AND AIMS During a 2-year pandemic, COVID-19 proved to be a condition with a high potential to affect various organs other than the lungs. Acute kidney injury (AKI) in hospitalized COVID-19 patients is associated with a poor prognosis. The aim of this study was to identify factors influencing in-hospital mortality. METHOD In a retrospective analysis, we included 268 adult patients with RT-PCR-confirmed SARS-CoV-2 infection and AKI admitted to two Emergency University Hospitals during a 6-month period, between 1 November 2020 and 30 April 2021. Data were retrieved from the electronic databases of the two hospitals. We analysed kidney and patient outcomes at discharge and the potential risk factors for mortality in AKI patients. We defined and staged AKI according to KDIGO 2012 creatinine criteria. RESULTS In our cohort the mean age was 72.28 years, 169 (63%) patients were men, and 111 (41.4%) had previously known chronic kidney disease. 81 patients were classified as having stage 1 AKI, 79 patients had stage 2 AKI and 108 had stage 3 AKI. A total of 135 (50.37%) patients died during hospitalization. Statistic analysis using the Mann–Whitney U-test revealed significant differences (P < .01) between survivors and non-survivors regarding peak values of serum urea (137.9 versus 190.9 mg/dL), creatinine (2.88 versus 3.94 mg/dL), procalcitonin (3.56 versus 15.86 ng/mL), C-reactive protein (92.32 versus 176.09 mg/L), interleukin-6 (243 versus 9552 pg/mL), ferritin (1331 versus 5189 ng/ml) and d-dimers (3.68 versus 6.88 mcg/ml). No significant differences were found between survivors and non-survivors regarding peak values of erythrocyte sedimentation rate (69 versus 71 mm/1 h; P = .35) and fibrinogen (629 versus 645 mg/dL; P = .24) and also regarding the lowest lymphocyte count during hospitalization (519 versus 649/mmc; P = .80). The analysis using Fisher’s exact test showed that deceased patients were significantly more associated with AKI KDIGO stage 2 or 3 (51.9%/63% versus 32.1%), with higher need for renal replacement theraphy (RRT) (68.8% versus 47.9%), with ICU (intensive care unit) admission (90.1% versus 22.3%) (Table 1). Moreover, death was associated more frequently with partial or absent renal function recovery (20%/50% versus 6.4%) (P < .05) (Table 1). In a logistic regression model (using KDIGO stages, serum urea and need for RRT), it was proved that only serum urea had a significant prediction power (P = .001): every increase of serum urea with 1 unit increases the risk of death by 1.007 times (95% confidence interval 1.003–1.011). CONCLUSION Mortality of COVID-19 patients associating AKI is proportionally augmented by both markers of severity of SarS-CoV-2 and also by severity of AKI. In our study, the peak value of serum urea during hospitalization was the best predictor for death in COVID-19.