Association of Urinary Indices and Urine Microscopy with the Progression of Acute Kidney Injury and Mortality in Hospitalized Patients with Severe COVID-19

Background AKI is one of the most common complications of COVID-19. Urinary indices and microscopy are valuable for differentiating between prerenal and intrinsic AKI. Our aim was to investigate the possible association between urinary indices and urine microscopy and AKI progression and mortality. Materials and Methods It is an observational retrospective cohort study that included urine density, sodium, potassium, FeNa, FeUN, blood urea nitrogen/Cr, osmolarity, and sediment of patients with severe COVID-19 and AKI stage 1. The findings in the urine sediment were assessed using the Perazella score. Independent associations were evaluated using Univariate and Cox regression. Results A total of 217 patients were included. The mean age of the subjects was 56±14 years, 32.7% were females, 42.9% had diabetes, and 30% had hypertension. Of the 217 patients with AKI stage 1, 67.3% remained at stage 1, and 13.8% and 18.9% progressed to stages 2 and 3, respectively. The 28-day mortality rate was 27.2% for all patients. After Cox regression analysis, the risk for AKI progression with a Perazella score stage 3 was hazard ratio (HR): 2.630 [1.279 - 5.407]. Moreover, the Perazella scores stage 2 (HR: 3.465 [1.196 - 10.034]) and stage 3 (HR: 2.857 [1.321 - 6.178]) were associated with increased 28-mortality. Conclusion Urinary indices were not associated with AKI progression or 28-day mortality. However, urine sediment was independently associated with the progression to AKI stages 2 and 3 and a higher risk of mortality.