Tuberc Respir Dis.  2012 Jan;72(1):8-14.

Contributors of the Severity of Airflow Limitation in COPD Patients

• Hong Y
• Chae EJ
• Seo JB
• Lee JH
• Kim EK
• Lee YK
• Kim TH
• Kim WJ
• Lee JH
• Lee SM
• Lee S
• Lim SY
• Shin TR
• Yoon HI
• Sheen SS
• Ra SW
• Lee JS
• Huh JW
• Lee SD
• Oh YM

Abstract

BACKGROUND
Although airway obstruction in chronic obstructive pulmonary disease (COPD) is due to pathologic processes in both the airways and the lung parenchyma, the contribution of these processes, as well as other factors, have not yet been evaluated quantitatively. We therefore quantitatively evaluated the factors contributing to airflow limitation in patients with COPD.
METHODS
The 213 COPD patients were aged >45 years, had smoked >10 pack-years of cigarettes, and had a post-bronchodilator forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) <0.7. All patients were evaluated by medical interviews, physical examination, spirometry, bronchodilator reversibility tests, lung volume, and 6-minute walk tests. In addition, volumetric computed tomography (CT) was performed to evaluate airway wall thickness, emphysema severity, and mean lung density ratio at full expiration and inspiration. Multiple linear regression analysis was performed to identify the variables independently associated with FEV1 - the index of the severity of airflow limitation.
RESULTS
Multiple linear regression analysis showed that CT measurements of mean lung density ratio (standardized coefficient beta=-0.46; p<0.001), emphysema severity (volume fraction of the lung less than -950 HU at full inspiration; beta=-0.24; p<0.001), and airway wall thickness (mean wall area %; beta=-0.19, p=0.001), as well as current smoking status (beta=-0.14; p=0.009) were independent contributors to FEV1.
CONCLUSION
Mean lung density ratio, emphysema severity, and airway wall thickness evaluated by volumetric CT and smoking status could independently contribute to the severity of airflow limitation in patients with COPD.

Keyword

Pulmonary Disease, Chronic Obstructive; Forced Expiratory Volumes; Tomography, X-Ray Computed

MeSH Terms

Aged
Airway Obstruction
Cone-Beam Computed Tomography
Emphysema
Forced Expiratory Volume
Humans
Linear Models
Lung
Pathologic Processes
Physical Examination
Pulmonary Disease, Chronic Obstructive
Smoke
Smoking
Spirometry
Tobacco Products
Tomography, X-Ray Computed
Vital Capacity
Smoke

Figure

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  Figure 1 Selection of the study subjects from all subjects with obstructive lung disease. COPD: chronic obstructive pulmonary disease; CT: computed tomography.

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