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.