Clinical Characteristics of Non-Smoking Chronic Obstructive Pulmonary Disease Patients: Findings from the KOCOSS Cohort

Joon Young Choi, Jin Woo Kim, Yee Hyung Kim, Kwang Ha Yoo, Ki Suck Jung, Jin Hwa Lee, Soo Jung Um, Won Yeon Lee, Dongil Park, Hyoung Kyu Yoon

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2 Scopus citations


Chronic obstructive pulmonary disease (COPD) has been regarded as a disease of smokers, but the prevalence of non-smoking COPD patients have been reported to be considerable. We investigated differences in clinical characteristics between smoking and non-smoking COPD patients. We used data from the Korea COPD Subgroup Study (KOCOSS) database, which is a multicenter cohort that recruits patients from 54 medical centres in Korea. Comprehensive comparisons of smoking and non-smoking COPD patients were performed based on general characteristics, exacerbations, symptom scores, radiological findings, and lung-function tests. Of the 2477 patients included in the study, 8.1% were non-smokers and 91.9% were smokers. Non-smoking COPD patients were more likely to be female and to have a higher body mass index and lower level of education. Non-smoking COPD patients had more comorbidities, including hypertension, osteoporosis, and gastroesophageal reflux disease, and experienced more respiratory and allergic diseases. No significant differences in exacerbation rates, symptom scores, or exercise capacity scores were observed between the two groups. Smoking COPD patients had more emphysematous lung according to the radiological findings, and non-smoking patients had more tuberculosis-destroyed lung and bronchiectasis. Lung-function testing revealed no significant difference in the forced expiratory capacity in 1 sec between the two groups, but smokers had more rapid lung-function decline in the 5 years of follow-up data. We found differences in general characteristics and radiological findings between smoking and non-smoking COPD patients. No significant differences in exacerbation or symptom scores were observed, but decline in lung function was less steep in non-smoking patients. Supplemental data for this article is available online at

Original languageEnglish
Pages (from-to)174-181
Number of pages8
JournalCOPD: Journal of Chronic Obstructive Pulmonary Disease
Issue number1
StatePublished - 2022

Bibliographical note

Publisher Copyright:
© 2022 The Author(s). Published with license by Taylor & Francis Group, LLC.


  • COPD
  • KOCOSS database
  • South Korea
  • cohort study
  • non-smoking COPD


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