CT Scan Findings of Emphysema Predict Mortality in COPD

Background: Emphysematous change as assessed by CT imaging has been reported to correlate with COPD prognostic factors such as FEV1 and diffusing capacity of the lung for carbon Monoxide (DLCO). However, few studies have assessed the relationship between CT scan assessment and COPD mortality from mild to severe stages of the disease. In this study, we analyzed this relationship in patients with various stages of COPD. Methods: Two hundred and fifty-one outpatients with stable COPD were included in the study. CT scan and pulmonary function tests were performed at study entry in a single institution. The percentage of low attenuation area was measured to quantitatively evaluate emphysematous change with a custom-made software. Prognostic data also were collected, and the median follow-up time was 8 years. Results: Of the 251 patients, 79 died, with 40 classified as respiratory deaths not involving lung cancer. Univariate Cox analysis revealed that emphysematous change as assessed by CT scan, lung function, age, or BMI were significantly correlated with mortality. Multivariate analysis revealed that emphysematous change as assessed by CT scan had the best association with mortality. Conclusions: Emphysematous change as.assessed by CT scan predicts respiratory mortality in outpatients with various stages of COPD. CHEST 2010; 138(3):635-640