MICROVASCULAR THROMBOSIS AND ACUTE KIDNEY INJURY IN COVID-19: AN UMBRELLA REVIEW

Abstract

This umbrella review synthesized evidence on the association between SARS-CoV-2-related microvascular and thromboinflammatory mechanisms and acute kidney injury (AKI), emphasizing renal outcomes, mortality, and renal replacement therapy (RRT). The review followed PRISMA 2020 and was prospectively registered in PROSPERO (CRD420251132701). PubMed/MEDLINE, Scopus, and Embase were searched for systematic reviews, meta-analyses, and umbrella reviews. Study selection and data extraction were performed independently by two reviewers, risk of bias was assessed using ROBIS, and primary-study overlap among first-order evidence syntheses was quantified using the Corrected Covered Area (CCA). Six evidence syntheses were included. AKI incidence was 9.2% (95% CI 4.6–13.9) in hospitalized patients, 32.6% (95% CI 8.5–56.6) in critically ill patients, and 20% (95% CI 14–28) in children with multisystem inflammatory syndrome. In the pediatric MIS-C synthesis, AKI was associated with increased mortality (OR 4.68; 95% CI 1.06–20.70). Primary-study overlap was high overall (CCA 12.7%) and very high among adult evidence syntheses (CCA 26.7%). No de novo pooling or recalculation of published effect estimates was performed. Current evidence supports an association between COVID-19-associated AKI and adverse outcomes and is compatible with a contributory role of endothelial dysfunction and thromboinflammatory injury, although causal inference remains limited by observational evidence, overlap, and heterogeneity.