Exacerbation-related variables reflecting the clinical presentation or severity of the exacerbation.

Data expressed as mean (standard deviation) and absolute (relative) frequencies depending on the nature of the variable.
* p value calculated by Chi-squared test or Student T test for independent variables as appropriate.
FVC: forced vital capacity. FEV1: forced expiratory volume in the first second. PaO2: partial pressure of oxygen in arterial blood. PaCO2: partial pressure of carbon dioxide in arterial blood
Exacerbation-related variables reflecting the clinical presentation or severity of the exacerbation.