The Rapid FEV1 Decline in Chronic Obstructive Pulmonary Disease Is Associated with Predominant Emphysema: A Longitudinal Study

Background: Early identification of patients with COPD and prone to more rapid decline in lung function is of particular interest from both a prognostic and therapeutic point of view. The aim of this study was to identify the clinical, functional and imaging characteristics associated with the rapid FEV1 decline in COPD. Methods: Between 2001 and 2005, 131 outpatients with moderate COPD in stable condition under maximum inhaled therapy underwent clinical interview, pulmonary function tests and HRCT imaging of the chest and were followed for at least 3 years. Results: Twenty-six percent of patients had emphysema detected visually using HRCT. The FEV1 decline was 42 +/- 66 mL/y in the total sample, 88 +/- 76 mL/y among rapid decliners and 6 +/- 54 mL/y among the other patients. In the univariable analysis, the decline of FEV1 was positively associated with pack-years (p < 0.05), emphysema at HRCT (p < 0.001), RV (p < 0.05), FRC (p < 0.05), FEV1 (p < 0.01) at baseline and with number of hospitalizations per year (p < 0.05) during the follow-up. Using multivariable analysis, the presence of emphysema proved to be an independent prognostic factor of rapid decline (p = 0.001). When emphysema was replaced by RV, the model still remained significant. Conclusions: The rapid decline in lung function may be identified by the presence of emphysema at HRCT or increased RV in patients with a long smoking history.