Inclusion Criteria:  According to the WHO guidelines, a confirmed diagnosis of COVID-19 was defined as a positive result of a quantitative real-time reverse-transcriptase-polymerase chain reaction (RT-PCR) detection in a nasopharyngeal swab.  Exclusion Criteria:  patients younger than 18 years, patients diagnosed with chronic kidney disease before admission, patients on maintenance dialysis or awaiting renal transplantation and patients taking any nephrotoxic medications a week prior to admission