Background: The progression of emphysema and airflow limitation in chronic obstructive pulmonary disease (COPD) leads to static hyperinflation. However, few studies have been conducted so far regarding the prognostic value of static hyperinflation mar...
Background: The progression of emphysema and airflow limitation in chronic obstructive pulmonary disease (COPD) leads to static hyperinflation. However, few studies have been conducted so far regarding the prognostic value of static hyperinflation marked by residual volume (RV)/ total lung capacity (TLC). Therefore we attempted to find the independent factors related to static hyperinflation and to test the hypothesis that static hyperinflation is associated with the prognosis of COPD. Methods: We analyzed 380 COPD patients of our Korean Obstructive Lung Disease (KOLD) cohort who were recruited from 16 hospitals in Korea from June 2005 to April 2012. Hyperinflated COPD was defined as 40% or more of RV/ TLC. Results: Patients with hyperinflated COPD was older and male dominant, and had worse pulmonary function (represented by lower FEV1, FEV1/FVC, and FVC), higher emphysema index, and severer air-trapping, compared to non-hyperinflated COPD group (p<0.05). Multiple logistic regression analysis demonstrated that age (OR = 1.071), FEV1 (OR = 0.923), FEV1/FVC (OR = 0.948), and emphysema index (OR = 1.036) were independently associated with severe static hyperinflation ( RV/TLC =40%) (p<0.05). According to the severity of static hyperinflation, mean survival period was shorter (RV/TLC = 60% : 77.7 ± 4.6 months, 40 = RV/TLC <60 : 94.3 ± 1.9 months, RV/TLC < 40 % : 95.1 ± 1.8 months, p<0.05) and acute exacerbation was more frequent (p<0.05). Conclusions: Old age, emphysema index, FEV1, and FEV1/FVC were independent factors associated with hyperinflated COPD. The survival period was shorter according to the severity of static hyperinflation. This study was supported by a grant from the Korea Healthcare Technology R&D Project, Ministry for health and welfare (A102065).