https://orcid.org/0000-0002-8496-6931
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Abstract
Purpose
We explored the differences in clinical manifestations of COPD patients regarding emphysema distribution along with evidence of airway involvement in chest computed tomography (CT) scans.
Patients and Methods
The patients were divided into three groups according to the emphysema distribution: the upper dominant (UD), lower dominant (LD), and homogeneous (HD) groups. Airway wall thickness was quantitatively measured and the presence of bronchiectasis and/or bronchial wall thickening (BE/BWT) was visually assessed. Baseline characteristics including the evidence of airway involvement and long-term outcomes were compared among the three groups. Non-severe patients of each group were first treated with 3 months of ICS/LABA combination after 2 weeks of wash-out period and lung functions before and after the treatment were compared.
Results
Of the 425 patients, 141 were in the UD, 107 in LD, and 177 in HD. The LD had more severe airway obstruction with lower emphysema index (EI) than the UD (LD vs UD; FEV1, 49.5–14.9 vs 54.6–16.5; EI, 21.0 [IQR: 14.0–33.1] vs 26.3 [IQR: 15.8–39.0]). The LD showed thicker airways (higher WA% and Pi10) and more severe air trapping (higher RV and RV/TLC) than UD. A larger proportion of patients in LD had BE/BWT (35.5% in LD vs 11.3% in UD). In LD, more patients experienced acute exacerbations and the time to first exacerbation was shorter than UD. Non-severe patients in LD treated with 3 months of ICS/LABA combined inhalers showed a notable reduction of RV than UD (LD vs UD; −531.1–936.5 vs −86.5–623.5).
Conclusion
The LD showed a more prominent airway involvement than UD, which may cause more frequent exacerbations and a marked reduction of RV after the ICS/LABA combination treatment in LD. Phenotyping of the COPD patients using quantitatively measured emphysema distribution would be useful for predicting treatment response and exacerbation.
Abbreviations
ATI, air-trapping index; BD, bronchodilator; BMI, body mass index; BE, bronchiectasis; BODE, Body mass index, degree of airflow Obstruction and Dyspnea and Exercise capacity; BWT, bronchial wall thickening; CI, confidence interval; CLE, centrilobular emphysema; COPD, chronic obstructive pulmonary disease; CT, computed tomography; DLco, diffusing capacity of carbon monoxide; EI, emphysema index; FEV1, forced expiratory volume in 1 sec; FOV, field of view; FVC, forced vital capacity; HD, homogeneous group; HU, Hounsfield units; IC, inspiratory capacity; ICS/LABA, inhaled corticosteroid and long-acting β2-agonist; IQR, interquartile range; KOLD cohort, Korean Obstructive Lung Disease cohort; LD, lower dominant emphysema group; mMRC, modified Medical Research Council; OR, odds ratio; Pi10, the square root of the wall area at the internal perimeter of 10 mm diameter airway; PLE, panlobular emphysema; PSE, paraseptal emphysema; RV, residual volume; SD, standard deviation; SGRQ, Saint George Respiratory Questionnaire; TLC, total lung capacity; UD, upper dominant emphysema group; WA, wall area; LA, luminal area; 6MWD, 6 min walk distance; 6MWT, 6 min walk test.
Ethics Statements
The present study was approved by the institutional review board of the Asan Medical Center Institutional Review Board (No. 2005-0345) and by the Institutional Review Boards of the other 15 hospitals taking part (ie, CHA Bundang Medical Center, Ewha Womans University Mokdong Hospital, Korea University Anam Hospital, Hanyang University Guri Hospital, Ilsan Paik Hospital, Kangbuk Samsung Hospital, Kangnam Sacred Heart Hospital, Kangwon National University Hospital, Seoul National University Hospital, Seoul National University Bundang Hospital, Ajou University Hospital, Konkuk University Hospital, Seoul St. Mary’s Hospital, Yeouido St. Mary’s Hospital, and the National Medical Center). Written informed consent was provided by all patients.
Acknowledgments
We authors thank the members of the KOLD Study Group for the provision of the KOLD Cohort data (Obstructive Lung Disease Research Foundation http://www.oldrf.org): Prof. Sang-Do Lee, Prof. Yeon-Mok Oh, Prof. Jin Won Huh, Prof. Seung Won Ra, Prof. Jae Seung Lee, Prof. Sei Won Lee (Univ. of Ulsan), Prof. Deog Kyeom Kim, Prof. Sang-Min Lee, Prof. Ho Il Yoon (Seoul National Univ.), Prof. Tae-Hyung Kim, Prof. Sang-Heon Kim (Hanyang Univ.), Prof. Young Sam Kim, Prof. Won Yeon Lee (Yonsei Univ.), Prof. Woo Jin Kim (Kangwon National Univ.), Prof. Hye Kyeong Park, Prof. Sung-Soon Lee (Inje Univ.), Prof. Ji-Hyun Lee, Prof. Eun Kyung Kim (Bundang CHA Hospital), Prof. Jin Hwa Lee (Ewha Womans Univ.), Prof. Sang Yeub Lee (Korea Univ.), Prof. Seong Yong Lim, Prof. Hye Yun Park (Sungkyunkwan Univ.), Prof. Tae Rim Shin, Prof. Yong Il Hwang, Prof. Yong Bum Park (Hallym Univ.), Prof. Seung Soo Sheen, Prof. Joo Hun Park (Ajou Univ.), Prof. Kwang Ha Yoo (Konkuk Univ.), Prof. Yee Hyung Kim (Kyung Hee Univ.), and Prof. Chin Kook Rhee (Catholic Univ.). The participating institutions of the Korean Obstructive Lung Disease Study Group are shown in the Supplementary Materials.
Author Contributions
All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis, and interpretation, or in all these areas; took part in drafting, revising, or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.
Disclosure
Sang Min Lee reports stock in Coreline Soft, Co. Ltd (less than 0.1% of the whole stock; I am just one of the consultants for software feedback for Coreline Soft, Co. Ltd), outside the submitted work. The authors report no other potential conflicts of interest in this work.