Association of Total Airway Count on Computed Tomography with Pulmonary Function Decline in Early-Stage COPD: A Population-Based Prospective Cohort Study

Fan Wu; Changbin Jiang; Yumin Zhou; Youlan Zheng; Heshen Tian; Haiqing Li; Zhishan Deng; Ningning Zhao; Huai Chen; Pixin Ran

doi:10.2147/COPD.S339029

Association of Total Airway Count on Computed Tomography with Pulmonary Function Decline in Early-Stage COPD: A Population-Based Prospective Cohort Study

Int J Chron Obstruct Pulmon Dis. 2021 Dec 18:16:3437-3448. doi: 10.2147/COPD.S339029. eCollection 2021.

Authors

Fan Wu^#^{1

2}, Changbin Jiang^#¹, Yumin Zhou^#^{1

2}, Youlan Zheng^#¹, Heshen Tian¹, Haiqing Li¹, Zhishan Deng¹, Ningning Zhao¹, Huai Chen³, Pixin Ran^{1

2}

Affiliations

¹ National Center for Respiratory Medicine, State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, People's Republic of China.
² Guangzhou Laboratory, Bio-island, Guangzhou, People's Republic of China.
³ Department of Radiology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, People's Republic of China.

^# Contributed equally.

Abstract

Background: It has been found that the degree of terminal bronchiole destruction is associated with the severity of COPD. However, total airway count (TAC) of CT-visible and its relationship with COPD lung function severity and pulmonary function decline remains controversial. The present study aimed to determine whether TAC is significantly reduced in early-stage COPD (GOLD stage I-II) compared with healthy control subjects and whether TAC is associated with annual decline in pulmonary function in Chinese patients with early-stage COPD.

Methods: A total of 176 participants were enrolled in this study, of which 139 participants had undergone at least two spirometry measurements within 7 years (average 5.5 [standard deviation 0.8] years) after baseline data acquisition. CT-visible TAC was measured by summing all airway segments using semi-automated software. Average lumen diameter, average inner area, emphysema index, air trapping, and inspiratory Pi10 were also measured. Multivariable linear analysis was performed to evaluate variables that were significantly related to pulmonary function parameters and to evaluate the correlation between TAC and annual decline in longitudinal pulmonary function.

Results: Compared with healthy control subjects, CT-visible TAC was significantly reduced by 51% in GOLD II and by 31% in GOLD I after adjustment. TAC had the greatest impact on pre-bronchodilator FEV₁, pre-bronchodilator FVC, post-bronchodilator FEV₁, and post-bronchodilator FEV₁/FVC (both p<0.001) among all CT indicators measured. TAC has the best correlation with inspiratory Pi10 (ρ=-0.751, p<0.001), an evaluation indicator of the degree of airway remodeling. TAC was independently associated with annual decline in pre-bronchodilator FEV₁ (p=0.023), post-bronchodilator FEV₁ (p=0.018), and post-bronchodilator FEV₁/FVC (p<0.001).

Conclusion: This finding suggests that CT-visible TAC may be an evaluation indicator of the degree of airway remodeling, and was diminished in greater COPD lung function severity, and independently associated with disease progression. Early-stage COPD patients have already occurred lung structural changes and early intervention may be needed to ameliorate the progression of disease.

Clinical trial registration: ChiCTR-OO-14004264.

Keywords: COPD; TAC; chronic obstructive pulmonary disease; computed tomography; total airway count.

MeSH terms

Cohort Studies
Forced Expiratory Volume
Humans
Lung / diagnostic imaging
Prospective Studies
Pulmonary Disease, Chronic Obstructive* / diagnostic imaging
Tomography, X-Ray Computed / methods

Grants and funding

This study was supported by the National Key Research and Development Program (2016YFC1304101, 2012BAI05B01), the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program (2017BT01S155), the National Natural Science Foundation of China (81970045 and 82000045), the Science and Technology Program of Guangzhou (202102080045) and Zhongnanshan Medical Foundation of Guangdong Province (ZNSA-202003, ZNSA-202012, and ZNSA-2020013).