Hamadan University of Medical Sciences Avicenna Journal of Clinical Microbiology and Infection 2383-0298 12 1 2025 03 30 Blood Urea Nitrogen and Creatinine Clinical Prognosis in Patients with Severe Coronavirus Disease 19 29 33 10.34172/ajcmi.3600 EN Hassan Mahmoudi https://orcid.org/0000-0002-3962-4668 Mohammad Yousef Alikhani https://orcid.org/0000-0003-4577-4029 Narges Mofrad Taheri Alireza Behzadi Journal Article 10.34172/ajcmi.3600 2024 12 27 2025 03 05 Background: COVID-19 is a new respiratory tract infection disease with an evolving understanding of its epidemiology and clinical appearances. Kidney defects seem to be common in patients with COVID-19. In addition, urea and creatinine (Cr) levels often occur at the beginning or during the infection. This evidence shows that COVID-19 also attacks the kidneys. The aim of this study was to evaluate changes in biochemical parameters associated with kidney function, including urea and Cr, in patients with COVID-19. Methods: A retrospective analysis of the plasma Cr and urea levels of 100 COVID-19 patients with normal plasma Cr and urea was conducted at the first clinical presentation of COVID-19. Results: Blood urea nitrogen and Cr levels increased in 35 (35%) out of 100 patients with COVID-19 2–4 days after the onset of viral infection. The mean serum urea level and the mean Cr concentration were 34.75±0.10, 37.64±0.32, 39.81±0.10, and 42.56±0.35 mg/dL, as well as 1.50±0.026, 1.51±0.016, 1.99±0.012, and 2.58±0.020 mg/dL, respectively, in the first clinical presentation and 2, 3, and 4 days after the onset of viral infection. Conclusion: The analysis of Cr and urea levels in patients at the onset of the disease and after 2–4 days revealed that impaired kidney function occurs in COVID-19 patients, and it is one of the leading causes of death in these patients.