The effect of acute kidney injury on mortality in patients with COVID-19 ARDS

ABSTRACT Aim: COVID-19 ARDS is a condition that can cause severe respiratory failure along with dysfunction in one or more organs outside the respiratory system. The deterioration of kidney functions, added to the respiratory failure, complicates the patient's treatment. The incidence of kidney injury associated with COVID-19 ARDS is between 20-50%. In our study, we staged acute kidney injury caused by COVID-19 ARDS and investigated the impact of increasing kidney damage on mortality. Materials and Methods: In our study, data from 800 patients treated in the Sadi Sun intensive care unit at Cerrahpaşa Medical Faculty from the beginning of the COVID-19 pandemic to 2021 were reviewed. Patients without a 7-day survival period among the 450 patients who developed kidney injury according to KDIGO criteria were excluded from the study. The remaining 204 patients, who met these criteria, were divided into two groups based on their survival status. Age, gender, comorbidities, admission SOFA score, ARDS severity, mechanical ventilation (MV) support, urine output, vasopressor support, CRRT treatment, AKI development, and urea and creatinine levels (Day 1, Day 3, and Day 7) were assessed between the two independent groups using the t-test. For the comparison of laboratory values according to survival status, the Independent Sample T-test was used for parameters with normal distribution, while the Mann-Whitney U test was used for parameters without normal distribution. Cross tables were created for the comparison of categorical variables based on survival status, and number (n), percentage (%), and chi-square test statistics were provided. The Cohran's Q test was used to compare the time-dependent (Day 1, Day 3, Day 7) rates of CRRT treatment presence. Kaplan-Meier test was used for survival analysis and curve generation. Results: As in other studies, our research found that acute kidney injury negatively affects survival, and increasing severity of injury raises mortality rates. In Group T, 62.3% (n=43) of individuals received MV support, while 75.8% (n=100) of individuals in Group E were on MV support. A statistically significant difference was found in the presence of MV support based on survival status (χ2=3.986, p=0.046). The mean CRRT duration for individuals in Group T was 0.75±3.51, while it was 1.21±2.75 in Group E. A statistically significant difference was detected between CRRT durations based on survival status (z=2.209, p=0.027). A statistically significant difference was found between Groups T and E in terms of urine output (ml/day) on Days 1, 3, and 7 (p<0.05). The average urine output on Day 1, Day 3, and Day 7 in Group T was higher than in Group E. The average urine output in Group T on Day 1 was 1327.79±616.63, on Day 3 it was 2010.29±871.29, and on Day 7 it was 1933.39±1127.02. A statistically significant difference was found among the three time points (Day 1, Day 3, Day 7) in Group T's urine output measurements (χ2=26.217, p<0.001). The average urine output on Day 1 in Group E was 1179.94±767.21, on Day 3 it was 1531.19±101.69, and on Day 7 it was 1461.37±1297.25. A statistically significant difference was also found among the three time points (Day 1, Day 3, Day 7) in Group E's urine output measurements (χ2=8.871, p=0.012) (Table 3). Exitus developed in 72 patients with AKI stage-1 on Day 1, in 17 patients with AKI stage-2, and in 15 patients with AKI stage-3. The average follow-up duration for patients with AKI stage-1 on Day 1 was 18.91 days, for AKI stage-2 it was 14.41 days, and for AKI stage-3 it was 12.95 days, and this was found to be statistically significant (p=0.009) (Table 12). Exitus developed in 64 patients with AKI stage-1 on Day 3, in 17 patients with AKI stage-2, and in 22 patients with AKI stage-3. The average follow-up duration for patients with AKI stage-1 on Day 3 was 19.84 days, for AKI stage-2 it was 13.79 days, and for AKI stage-3 it was 11.78 days, and this was found to be statistically significant (p<0.001) (Table 13). Exitus developed in 63 patients with AKI stage-1 on Day 7, in 13 patients with AKI stage-2, and in 36 patients with AKI stage-3. The average follow-up duration for patients with AKI stage-1 on Day 7 was 20.37 days, for AKI stage-2 it was 13.45 days, and for AKI stage-3 it was 11.59 days, and this was found to be statistically significant (p<0.001) (Table 14). Conclusion: Acute kidney injury in patients with COVID-19 ARDS is correlated with increased mortality rates. Close monitoring of kidney functions in the intensive care management of these patients is crucial for preserving kidney function. In the future, more research on the prevention and treatment of AKI will make significant contributions to improving clinical outcomes. Keywords: Covid-19, ARDS, akut kidney injury, mortality