ABSTRACT
The clinical course of chronic obstructive pulmonary disease (COPD) includes frequent
episodes of increased severity of symptoms, commonly referred to as exacerbations.
At first glance, such episodes of clinical instability were considered mere
epiphenomena in the natural history of COPD. However, recent emerging evidence
indicates that, quite to the contrary, exacerbations greatly contribute to the decline
of health-related quality of life (HRQoL) (1), have a negative impact on disease
progression (2,3), and increase the risk of mortality (4). In addition, exacerbations
cause enormous socioeconomic costs including utilization of health care resources (5).
This challenge to the traditional point of view corresponds to a shift in how we
currently conceive the natural history of COPD, now seen not simply as chronic airflow
limitation, but rather as a complex and multidimensional disease in which lung and
systemic inflammation play a significant etiopathogenic role.
