EGFR and acute kidney injury: Notably, acute kidney injury (AKI) is noted in 9.2% of population in South Korea.2 In Cheng et al.’s large prospective cohort study including 701 patients with COVID-19,3 the prevalence of proteinuria, hematuria, EGFR under 60 ml/min/1.73m2, and AKI occurring during the study period was 43.9%, 26.7%, 13.1%, and 5.1%, respectively.