Independent of the severity of  airflow obstruction, a 5% increase in total lung emphysema in those with 35% or greater emphysema is associated with a 1.18-fold increase in chronic obstructive pulmonary disease (COPD) exacerbation frequency; a 1-mm increase in segmental airway wall thickness is associated with a 1.84-fold increase in COPD exacerbation frequency.

 

There changes can be detected  noninvasively with CT

→ identify patients at risk for more frequent exacerbations with more targeted medical therapy.