AKI: acute kidney injury; APACHE: Acute Physiology and Chronic Health Evaluation; CKD: chronic kidney disease; COVID-19: coronavirus disease 2019; CT: computed tomography; ICU: intensive care unit; Mg: magnesium; PTH: parathyroid hormone; RT-PCR: reverse transcription-polymerase chain reaction; TCZ: tocilizumab. Here, PTH is linked to chronic kidney disease.