Distribution of selected variables between severe H7N9 and H1N1pdm patients.

a Patients with missing data were excluded for each variable.b Pearson chi-square test was used for comparing proportions and continuity correction or Fisher’s Exact Test was used if appropriate. Mann-Whitney U test was used for comparing medians.c Age and gender were adjusted using General Linear Model (for BMI) or Cox proportional hazards model (for selected time durations) for continuous variables and Logistic regression model for categorical variables.d Interquartile range (IQR), Frequency (FREQ), Body mass index (BMI)Distribution of selected variables between severe H7N9 and H1N1pdm patients.