[Symptoms and natural history of COPD: role of the distal airways].

Symptoms and natural history of COPD: role of the distal airways. The natural history of chronic obstructive pulmonary disease (COPD) is characterized by a progressive worsening of airway obstruction and health-related quality of life, and an increased risk of death. Symptoms of COPD are dominated by cough, sputum production and dyspnoea whose intensity varies between individuals and during the progression of the disease. The symptoms and natural history of COPD result from damage to the airways, including remodelling and inflammation, which commence and are predominant in the distal airways (DA). This article examines the relationship between symptoms and the natural history of COPD in the light of large cohorts published in the literature. The role of the DA in the development and intensity of symptoms and in the natural history of COPD is difficult to define. We have attempted to examine this role using either published studies which have evaluated the relationship between lung structure and the clinical phenotypes of COPD or studies involving the earlier stages of the disease when damage to the DA are known to be predominant. These data suggest a potential role for early therapies targeting remodelling and inflammation in the distal airways of patients suffering from COPD.