COVID-19 is characterized by rapid progression in a number of patients. The case-fatality rate ranged from 1.4% in the general population by the statistic of 1099 cases, [39] to 49% in patients with critical illness in summary of a report of 72 314 cases from Chinese Center for Disease Control and Prevention [71]. Early identification of patients at risk of developing critical illness would allow for early triage, timely clinical management, and optimization of medical resources [72]. The overall problem encountered in China during the first few months of the epidemic was the difficulty of identifying patients who were more likely to develop severe illness out of the thousands of daily confirmed cases as soon as possible. However, no tool was available at the initial stage of the epidemic to inform clinicians in China.