Median [interquartile range] for continuous variables, number (%) for categorical variables.
*Mann-Whitney U test for continuous variables, Fisher’s exact test for categorical variables.
Use of mechanical ventilation or extracorporeal membrane oxygenation during admission.
SMD: standardized mean difference, BMI: Body Mass Index, COPD: chronic obstructive pulmonary disease, VAS: Visual Analogue Scale, QOL: Quality of Life