The perception of breathlessness varies between individuals. This is a well-established concept in asthma, but mostly unexplored in COPD; the relationship between airflow limitation (FEV1, % ref.) and breathlessness (mMRC) is weak.
The perception of breathlessness varies significantly among COPD patients with similar severity of airflow limitation; those with poorer perception report less exacerbations as compared to those with frequent exacerbations.
It is a cross-sectional comparison of breathlessness perception in COPD patients with frequent exacerbations (≥2 or ≥1 with hospitalization in the previous year) or without frequent exacerbations (0 or 1 without hospitalization in the previous year).
To assess "Breathlessness Perception" the investigators will increase the ventilatory demand of the patients by CO2-rebreathing method. CO2 rebreathing test will be conducted to evaluate the acute ventilatory response to CO2 inhalation used to estimate central chemoreceptor responsiveness in patients with the obstructive pulmonary disease.
Simple descriptive statistics (unpaired T-test) and correlation analysis (bivariate and multivariate) will be used to analyze results.
