Study Design and Participants

This cohort study was performed in 102 COVID-19 patients who were admitted to Beijing Youan Hospital (designated to treat patients with SARS-CoV-2 pneumonia) between January 21 and March 20, 2020. The diagnosis of COVID-19 was based on the WHO interim guideline (11). The severity of COVID-19 was classified following the instruction of the National Institute for Viral Disease Control and Prevention, China (7th edition). Twenty-six participants were excluded from the study due to the lack of available blood samples (n = 17) or no CT examination (n = 1) or death (n = 8). A total of 76 patients were finally recruited, and their data were analyzed in the study. Figure 1 shows the flowchart of the study.

Flowchart of COVID-19 patients in the analysis.

The epidemiological data were recorded, including local residence in Wuhan or traveling to Wuhan in the recent 14 days before the disease onset. General information such as age, practice of smoking, disease history, and drug use were collected. Previous medical history, such as disease history of cardiovascular disease, chronic respiratory disease, hypertension, and diabetes, were recorded.

The Institutional Review Board of the Capital Medical University approved the study. All participants gave written informed consent before participating in the study.