Understanding Early COPD.

Whereas COPD is currently defined as the presence of spirometric obstruction, the pathologic changes in individuals at risk including chronic mucus hypersecretion and emphysema have been recognized for centuries. At the same time, we have struggled to define criteria that would help us identify patients at an early stage, prior to the development of pulmonary function abnormality. The concept of GOLD 0 was introduced in the hopes that symptoms would help to identify those at greatest risk for progression. While symptoms are a risk factor, in particular chronic bronchitis, the term was abandoned as the majority of individuals at risk who progress to COPD do not have symptoms. Since then, the related terms pre-COPD and early COPD have been introduced. They are similar in that the term pre-COPD identifies individuals based on symptoms, physiologic, or radiographic abnormality that do not meet criteria for COPD but are clearly at risk. The term early COPD extends that concept further, focusing on individuals who have early physiologic or radiographic abnormality but at the same time are young, thereby excluding those with late mild disease who may be less likely to progress. Whereas individuals with early COPD are now being recruited for observational studies, we are still challenged with determining the best way to identify patients at risk who should undergo additional testing as well as developing specific therapies for patients with early-stage disease.