Schematic illustration of the frequent exacerbator phenotype. While many patients with chronic obstructive pulmonary disease (COPD) experience exacerbations, there is a subgroup of patients who enter a destructive cycle of frequent exacerbations with associated poorer outcome. This phenotype appears to be maintained over time.
Wedzicha et al. BMC Medicine 2013 11:181 doi:10.1186/1741-7015-11-181