COPD heterogeneity: what this will mean in practice.

COPD is a complex collection of conditions. All share the feature of limited expiratory air flow. It is a "disease" in the same sense as is "chronic renal failure." Like most other chronic organ failure "diseases," COPD has disparate causes, and patients are heterogeneous in their prognosis and response to treatment. Unlike many other diseases, the heterogeneity of COPD is just beginning to be described. A number of large trials funded by the National Institutes of Health and industry promise to refine the classification of COPD. Based on accurate diagnosis of COPD subtypes, novel treatments can be more effectively developed and implemented. The clinical implications of improved understanding of COPD heterogeneity will be better care and outcomes for COPD patients, which will depend on increased diagnostic accuracy and selective administration of treatments.