Compared with those with CAT<10 and mMRC 0–1, COPD patients with CAT⩾10 and mMRC ⩾2 were older in age and had a higher percentage of presence of wheezing, more severe airway obstruction, less FEV1 and FVC, more severe airflow limitation, parallel higher mMRC scales and higher CAT scores and more exacerbations, respectively (see Supplementary Tables S1 and S2 in the Supplementary Material). Here, CAT is linked to Airway obstruction.