Materials and Method

Study Design and participants

In a retrospective cross-sectional study at Shariati hospital in Tehran, Iran, we included all patients admitted with the diagnosis of COVID-19 based on the criteria published by WHO on January 12th, 2020 (WHO.), from February 25th, 2020, to April 21st, 2020. Patients with respiratory symptoms and one of the followings were admitted to the hospital: 1) loss of consciousness, 2) Respiratory rate more than 24, 3) pulse rate more than 90, 4) Systolic blood pressure less than 90 mmHg, 5) abnormal respiratory sounds, or 6) O2 saturation less than 93%. Furthermore, high-risk patients with respiratory symptoms or fever underwent computed tomography scans of the lung (CT scans). In case of a suggestive lung CT scan of COVID-19 infection, the patients were transferred to the COVID ward. Patients with a negative lung CT scan underwent further workup. Patients who were already admitted to the hospital were transferred to the COVID ward if they experienced COVID-19 infection during hospitalization. We used the census sampling method, and after exclusion of cases with missed data, four hundred and four patients were selected. Two radiologists reviewed all the images and patients with not suggestive lung CT scan and negative SARS-CoV2 RT-PCR were excluded. We extracted clinical data, laboratory findings, and lung CT scans from the remaining three hundred fifty-four patients’ medical records. The study was approved by the ethics committee of Tehran University of Medical Sciences. The ethics committee waived the requirement for informed patient consent for this retrospective study subject to the anonymity of patients.