COVID-19 infection and the kidney.

Despite initial reports, renal involvement, including acute kidney injury, has emerged as a serious complication of COVID-19 disease, particularly in critically ill patients. The reported prevalence varies considerably, which may reflect reporting practices, although differences in pre-existing comorbidities and socioeconomic factors, and differences between ethnic groups, almost certainly contribute. Renal involvement may present as an active urinary sediment or as changes in serum creatinine levels and urine output leading to acute kidney injury. In common with acute kidney injury complicating critical illness, the cause is often multifactorial and often presents as part of a multiorgan dysfunction syndrome. Treatment is, in the main, supportive, with kidney replacement therapy required in nearly 25% of reported cases. Few data currently exist as to the long-term burden of COVID-19-associated acute kidney injury but evidence suggests that only approximately one-third of patients are discharged with recovered renal function.