Chronic cough and sputum production: a clinical COPD phenotype?: Table 1–

Abstract

Chronic obstructive pulmonary disease (COPD) is characterised by incompletely reversible airflow limitation and its severity has been categorised using the level of forced expiratory volume in 1 s (FEV1) [1]. Because marked heterogeneity existed between subjects with comparable FEV1 [2], it has been proposed that identification of subgroups of COPD subjects could represent an alternative to the current FEV1-based classification [3]. A consensus report proposed that COPD phenotypes, as defined by “a single or combination of disease attributes that describes differences between individuals with COPD as they relate to clinically meaningful outcomes (symptoms, exacerbations, response to therapy, rate of disease progression or death)”, could represent the future of COPD [4]. Chronic cough and sputum production (chronic bronchitis) have long been recognised as a consequence of tobacco smoking. In the 1960s, the British hypothesis proposed that chronic cough and sputum production encouraged bronchial infection, which promoted airway and alveolar damage and led to airflow limitation [5]. In their classical study reported in 1976, Fletcher and Peto [6] concluded that while chronic cough and sputum production and airflow limitation both occurred in smokers, they were largely unrelated disease processes. Almost 20 yrs later, Vestbo et al . [7] reported that chronic cough and sputum production were associated with an excess FEV1 decline and increased risk of hospitalisation because of COPD. Data from the Lung Health Study further indicated that chronic cough and sputum production were associated with increased lower respiratory illnesses (exacerbations) in subjects with mild airflow limitation [8]. These two studies shed new light on the potential importance of chronic cough and …