CONCLUSIONS
Together, these studies demonstrate that exacerbations represent an important event in the natural history of COPD patients and are associated with significant morbidity and mortality. Though substantial progress has been made in the understanding of the aetiology of exacerbations in COPD, much still needs to be learned. The complexity of the host– pathogen interaction that determines the onset and course of exacerbations needs further exploration, including examination of host cellular and molecular mechanisms, and the determinants of pathogen virulence and their interaction with airway epithelial cells and macrophages. Exacerbations have a significant impact on patients’ lung function, quality of life and exercise performance. Exacerbations are associated with increased morbidity and mortality and have a significant
socioeconomic impact. Patients with frequent exacerbations often experience impaired quality of life and faster decline in lung function over time. In addition, exacerbations, including those requiring hospitalisation, are the largest item associated with the direct cost in the treatment of COPD.