Renal Histopathological Lesions Associated with SARS-CoV-2 Infection in Patients with no History of Kidney Disease: A Systematic Review

Background and Aims: Structural and functional lung damage is the most documented impairment in SARS-CoV-2. Nevertheless, the virus's impact extends beyond pulmonary manifestations, affecting various organs and tissues, including the kidneys, known for their expression of ACE2, the virus's cell entry receptor. The objective of this review is to provide a comprehensive summary of studies investigating kidney injuries in individuals lacking prior renal conditions following SARS-CoV-2 infection.

Methodology: A literature search encompassed studies published between December 2019 and September 2022, adhering to the PRISMA protocol. Electronic search strategies were developed to identify relevant studies across several bibliographic databases, including Pubmed, Scopus, Web of Knowledge, Embase, Scielo, Lilacs, Bireme, and Cochrane databases. A comprehensive analysis was undertaken, encompassing 43 studies involving 128 patients selected based on stringent inclusion criteria: a confirmed diagnosis of SARS-COV-2 infection, observable renal alterations through microscopy, and/or viral presence detected in the kidneys.

Results: The included patients, primarily male (60.1%) with an average age of 53, exhibited prevalent comorbidities such as hypertension, diabetes, and obesity. The predominant outcome was death (43.7%), and various renal lesions were identified, with sclerosis, hyalinosis, tubular necrosis, and vascular injuries being the most common. Tubular lesions combined with glomerular lesions were frequently observed, regardless of comorbidity status. A greater predominance of renal involvement in patients with associated comorbidities, mainly arterial hypertension. The limited detection of the virus in renal tissue suggests a multifactorial origin of renal lesions, not solely attributed to the virus itself. The risk of bias assessment revealed mostly high-quality studies, with 24 assessed as low risk, 15 as moderate, and four as high risk.

Conclusion: Ours results provides a comprehensive analysis of kidney injuries in COVID-19 patients, emphasizing the significant role of comorbidities such as hypertension, diabetes, and obesity in contributing to the severity and occurrence of renal complications. Notably, hypertension emerges as a prominent risk factor. The findings suggest a multifaceted manifestation of kidney injury induced by SARS-CoV-2, involving both direct viral impact on kidney tissue and a systemic response to the infection. The study underscores the importance of understanding the renal implications of COVID-19 for guiding targeted interventions and future research in this critical area.