Methods
Study population and data collection
Subjects of this study were adults with COVID-19 and underlying chronic respiratory diseases (admission date from Jan 26th to April 3rd, 2020) in Sino-French New City Branch of Tongji hospital. COVID-19 patients were diagnosed according to World Health Organization (WHO) interim guideline [57]. All patients were confirmed by the positive findings in reverse-transcriptase–polymerase-chain-reaction (RT-PCR) assay of SARS-CoV-2 RNA in throat swab specimens. The study was approved by the Institutional Review Board of Tongji Hospital, Huazhong University of Science and Technology.
The demographic information, clinical characteristics (included medical history, symptoms, comorbidities, smoking history, and allergic history) and radiological results of each patient were obtained from the electronic medical record system of Sino-French New City Branch of Tongji hospital and analyzed by three independent researchers. The severity of COVID-19 was staged according to the guidelines for diagnosis and treatment of COVID-19 published by Chinese National Health Committee (Version 5-7).