Koo HK, et al. - Researchers identified phenotypic differences according to the presence of a chronic cough or sputum as well as assessed the impact of a chronic cough on the risk of acute exacerbation of chronic obstructive pulmonary disease {COPD} (AECOPD). In a nationwide COPD cohort involving one thousand, six hundred thirteen COPD patients, patients with chronic cough only, those with sputum only, those with chronic bronchitis (CB), and those without cough and sputum were contrasted with regard to dyspnea, lung function, quality of life (QoL), and risk of AECOPD. During the determination of high-risk groups of COPD patients, chronic cough should be considered as an important phenotype.