Materials and Methods: Four-hundred-eighty-two moderate and severe COVID-19 patients who had the data of urinalysis performed in the pre-COVID-19 period at most three months before the onset of COVID-19 diagnosis, during COVID-19 disease, and 15 days after they completely recovered from the COVID-19 disease were included in the study. Parameters of bilirubin, erythrocyte, leukocyte, protein, glucose, acidity (pH), and density were analyzed in urine samples, and the results were recorded.

Results: CRP, e-GFR, fibrinogen and D-dimer values were found to be significantly different between the three groups (for all parameters p<0.05). A negative correlation was found between e-GFR and both CRP (p<0.001, r:-0.289) and D-dimer (p:0.02, r:-0.129) values of the patients during COVID-19. Urine pH, presence of leukocyturia, presence of microscopic hematuria and presence of proteinuria were found to be significantly different between the three groups (for all parameters p<0.05). It was determined that these four parameters increased significantly during the COVID-19 period and decreased in the post-COVID-19 period. A negative correlation between urine density and e-GFR (p:0.04, r:-0.175) and a positive (p:0.02, r:0.195) correlation between urine density and CRP were detected during COVID-19.

Conclusion: The significant presence of hematuria and proteinuria during COVID-19 disease in line with the literature data supports the opinion that the disease causes renal involvement. The tendency of the parameters on the post-COVID 15th day to return to normal ranges shows that the effects of the inflammation are reversible after the patients recover from the disease.