The natural history of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is an important cause of morbidity worldwide 1-3. It is one chronic disease that continues to increase in prevalence and mortality 4-6, and is projected to continue to increase into the future. Understanding the natural history of COPD has been important in the field of pulmonary medicine, dating back to the seminal work of Burrows 7, and Fletcher and Peto 8,9. Since then, researchers have championed different hypotheses about COPD development, with 2 hypotheses prevailing: the “British”—presence of cough and sputum is the key factor 10; and the “Dutch”—presence of increased airways responsiveness is the major factor 11. In recent years, the recognition that COPD has important genetic and environmental components has provided the basis for ongoing research 12,13. This review will explore the current knowledge regarding the natural history of COPD. It will include the present understanding of COPD risk factors, phenotypes, and burden. Also described will be COPD progression, including the traditional “accelerated lung function decline” paradigm, as well as newer paradigms that include the role of exacerbations and complications or comorbid diseases.