COVID-19 and Kidney Disease: A Clinical Perspective.

Coronavirus disease-19 (COVID-19), caused by severe acute respiratory syndrome Coronavirus- 2 (SARS-CoV-2), has caused a global pandemic with high morbidity and mortality. The presence of several comorbidities has been associated with a worse prognosis, with chronic kidney disease being a critical risk factor. Regarding COVID-19 complications, other than classical pneumonia and thromboembolism, acute kidney injury (AKI) is highly prevalent and represents a poor prognostic indicator linked to increased disease severity and mortality. Its pathophysiology is multifactorial, revolving around inflammation, endothelial dysfunction, and activation of coagulation, while the direct viral insult of the kidney remains a matter of controversy. Indirectly, COVID-19 AKI may stem from sepsis, volume depletion, and administration of nephrotoxic agents, among others. Several markers have been proposed for the early detection of COVID-19 AKI, including blood and urinary inflammatory and kidney injury biomarkers, while urinary SARS-CoV-2 load may also be an early prognostic sign. Concerning renal replacement therapy (RRT), general principles apply to COVID-19 AKI, but sudden RRT surges may mandate adjustments in resources. Following an episode of COVID-19 AKI, there is a gradual recovery of kidney function, with pre-existing renal impairment and high serum creatinine at discharge being associated with kidney disease progression and long-term dialysis dependence. Finally, kidney transplant recipients represent a special patient category with increased susceptibility to COVID- 19 and subsequent high risk of severe disease progression. Rates of mortality, AKI, and graft rejection are significantly elevated in the presence of COVID-19, highlighting the need for prevention and careful management of the disease in this subgroup.