Clinical indexes:
All cases were PCR positive. The clinical indexes were collected as shown in Table 2 , including WBC, NEC, LC, PLT, Hb, ALT, AST, K+, Na+, Cr, CK, LDH, TNI, BNP, CRP, OI(PO2/FiO2)and D-dimer. All indexes were described with mean and SD. It was found that WBC, NEC, LC, PLT, Hb, K+, Na+, LDH, CRP, OI (Oxygenation Index) and D-dimer had the statistical significant change (p<0.001), so did AST(p<0.05). The decreased indexes were WBC, LC, PLT, K+, Na+, OI, while LDH, CRP, D-dimer would be higher (Figure 2) . ALT, Cr, BNP and TNI were normal.
We further analyzed the correlation between these indexes and clinical features. The severity had no correlation with generation, gender, WBC, NEC, K+, Na+, AST, CRP, PLT, Hb, latency or Fer, but had significant in correlated to age, temperate, LC, LDH, D-dimer, OI (Supplement 1). To make it clear, partial results were picked from Supplement 1 asTable 3 . It was showed that severity had the positive correlation with D-dimer (R2=0.293, p=0.033), and age (R2=0.325, p=0.009), temperate (R2=0.339,p=0.006), LDH (R2=0.472, p<0.001), while had negative correlation with LC(R2=-0.385, p=0.002<0.01) and OI(R2=-0.712, p<0.001) (Table 3, Figure 3 ). Besides, age had negative correlation with K+, LC and OI; temperate were negative correlated to LC (R2=-0.279, p=025) and OI (R2=-0.433, p=0.001); D-dimer also had the correlation with LDH (R2=0.421, p=0.002); OI had negative correlation with most of features and clinical indexes, such as severity (R2=-0.712, p<0.001), age (R2=-0.298, p=0.021), temperate (R2=-0.433, p=0.001), LDH (R2=-0.552, p<0.001), D-dimer (R2=-0.311, p=0.023), except positive for LC (R2=0.403, p=0.001).
To find whether there was the difference between patients who were discharged and those still in hospitalization, we also did an independent-samples T test, but the results showed no differences. SeeSupplement Table 2.