What Is the Natural History of COPD during its Later Stages?
Much of our knowledge of the natural history of COPD comes from cross-sectional studies of symptoms and spirometry in occupational cohorts performed more than a quarter century ago. Those studies provided little information about the late stages of COPD. Furthermore, they were performed outside the context of current medical management (e.g., long-term oxygen therapy), without modern measures of the disease (e.g., CT assessment of emphysema), and with little emphasis on exercise limitation as an important, quantifiable manifestation of severe disease. Improvements in clinical care for those with severe COPD would be aided by longitudinal studies of late stage disease that correlate advanced measures of the disease with outcome. 5. What Is the Pathogenetic Relationship between COPD and Lung Cancer? Epidemiologic studies have demonstrated comorbidity of COPD and lung cancer in excess of that attributable to smoking, suggesting that these conditions may share genetic risk factors or invol
