Study design, setting, and participants
This retrospective cross sectional study was carried out in Masih
Daneshvari hospital, a respiratory center dedicated for COVID-19
patients in Tehran, Iran. COVID-19 patients admitted to the hospital
from March 12-26, 2020 were enrolled to the study. COVID-19 cases were
confirmed by polymerase chain reaction (PCR) test according to WHO case
definition [1]. The study protocol was approved by ethical review
board of national research institute of tuberculosis and lung diseases.
Written informed consent by the patients was waived due
to the retrospective nature of the investigation.