82 (64.57%) were woman and 45 (35.43%) were man, the mean age was 50.90 years. All patients were diagnosed according to the guidelines for diagnosis and treatment for COVID-19, and classified into mild, moderate, severe and critical type based on the severity of symptoms.
1) Severe patients should meet at least one of the following criterions: First, shortness of breath with respiration rate (RR)>=30 times/min. Second, oxygen saturation<=93% in resting state. Third, partial pressure of arterial oxygen (PaO2)-to-fraction of inspired oxygen (FiO2) ratio<=300 mm Hg. Obvious lesion progression >50% within 24-48 hours on pulmonary imaging were also recognized as severe cases.
2) Critical cases were defined when one of the following conditions met: First, respiratory failure and require mechanical ventilation. Second, shock occurred. Third, combined with other organ failure and treated in intensive care unit.
3) Mild and moderate cases were defined as non-severe group, while severe and critical patients were categorized as severe group in this study.