CAT and chronic obstructive pulmonary disease: The total scores of psychological distress were positively correlated with years of having COPD (rs = 0.156, P < 0.01), frequency of acute exacerbations (rs = 0.114, P < 0.05), CAT score (rs = 0.415, P < 0.01), and the mMRC score (rs = 0.301, P < 0.01).