title: History of pneumonia is a strong risk factor for chronic obstructive pulmonary disease (COPD) exacerbation in South Korea: the Epidemiologic review and Prospective Observation of COPD and Health in Korea (EPOCH) study.
abstract: BACKGROUND
  In South Korea, chronic obstructive pulmonary disease (COPD) is one of the ten leading causes of death. COPD exacerbations are significantly associated with mortality in COPD patients. This study was conducted to investigate the epidemiology of COPD in South Korea, specifically the clinical characteristics of South Korean COPD patients, the COPD exacerbation rate and the risk factors associated with COPD exacerbations.
  
  
  METHODS
  This study covers a 2-year interval. One year was data collected retrospectively and the second year was prospectively obtained data.
  
  
  RESULTS
  A total of 1,114 subjects were enrolled in the study. These subjects were observed for a period of 1 year from the enrollment, and a total of 920 subjects completed the study. A total of 1,357 COPD exacerbations occurred in 711 subjects (63.8%) out of the total of 1,114 subjects during the study period of 2 years. Multivariate logistic regression results showed that if patients had had a pneumonia before the retrospective year of analysis, they had a 18 times greater chance of having an exacerbation during the prospective year when other variables were controlled. Also, the subjects who had a history of two or more exacerbations during the retrospective year were approximately 6 times more likely to experience the COPD exacerbation compared to those who did not.
  
  
  CONCLUSIONS
  This study examined the demographic and clinical characteristics of South Korean COPD patients and found that a history of pneumonia and two or more occurrences of exacerbation within 1 year was significantly associated with a higher rate of COPD exacerbation.
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Yong Il
authors.initials: YI
authors.lastname: Hwang
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Sang Haak
authors.initials: SH
authors.lastname: Lee
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Jee Hong
authors.initials: JH
authors.lastname: Yoo
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Bock Hyun
authors.initials: BH
authors.lastname: Jung
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Kwang Ha
authors.initials: KH
authors.lastname: Yoo
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Moon Jun
authors.initials: MJ
authors.lastname: Na
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Jong Deog
authors.initials: JD
authors.lastname: Lee
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Myung Jae
authors.initials: MJ
authors.lastname: Park
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Chi Young
authors.initials: CY
authors.lastname: Jung
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Jae Jeong
authors.initials: JJ
authors.lastname: Shim
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Kyung Chan
authors.initials: KC
authors.lastname: Kim
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Yeon Jae
authors.initials: YJ
authors.lastname: Kim
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Hye Sook
authors.initials: HS
authors.lastname: Choi
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Ik Su
authors.initials: IS
authors.lastname: Choi
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Choon-Taek
authors.initials: CT
authors.lastname: Lee
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Sang Do
authors.initials: SD
authors.lastname: Lee
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Do Jin
authors.initials: DJ
authors.lastname: Kim
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Soo-Taek
authors.initials: ST
authors.lastname: Uh
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Ho Sung
authors.initials: HS
authors.lastname: Lee
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Young Sam
authors.initials: YS
authors.lastname: Kim
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Kwan Ho
authors.initials: KH
authors.lastname: Lee
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Seung Won
authors.initials: SW
authors.lastname: Ra
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Hak Ryul
authors.initials: HR
authors.lastname: Kim
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Soo Jeon
authors.initials: SJ
authors.lastname: Choi
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: In Won
authors.initials: IW
authors.lastname: Park
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Yong Bum
authors.initials: YB
authors.lastname: Park
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: So Young
authors.initials: SY
authors.lastname: Park
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Jaehee
authors.initials: J
authors.lastname: Lee
authors.affiliation: 1 Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea ; 2 St. Paul's Hospital, The Catholic University of Korea, Seoul, Korea ; 3 Kyung Hee University Hospital at Gangdong, Seoul, Korea ; 4 GangNeung Asan Hospital, Gangneung, Korea ; 5 Konkuk University Medical Center, Seoul, Korea ; 6 Konyang University Hospital, Daejeon, Korea ; 7 Gyeongsang National University Hospital, Jinju-si, Korea ; 8 Kyung Hee University Medical Center, Seoul, Korea ; 9 Keimyung University Dongsan Medical Center, Daegu, Korea ; 10 Korea University Guro Hospital, Seoul, Korea ; 11 Daegu Catholic University Medical Center, Daegu, Korea ; 12 Daegu Fatima Hospital, Daegu, Korea ; 13 Dongguk University Gyeongju Hospital, Gyeongju-si, Korea ; 14 Maryknoll Medical Center, Busan, Korea ; 15 Seoul National University Bundang Hospital, Seongnam, Korea ; 16 Asan Medical Center, Seoul, Korea ; 17 Soonchunhyang University Bucheon Hospital, Bucheon, Korea ; 18 Soonchunhyang University Seoul Hospital, Seoul, Korea ; 19 Soonchunhyang University Cheonan Hospital, Cheonan, Korea ; 20 Severance Hospital, Seoul, Korea ; 21 Yeungnam University Medical Center, Daegu, Korea ; 22 Ulsan University Hospital, Ulsan, Korea ; 23 Wonkwang University School of Medicine, Iksan, Korea ; 24 Inje University Sanggye Paik Hospital, Seoul, Korea ; 25 Chung-Ang University Hospital, Seoul, Korea ; 26 Hallym University Kangdong Sacred Heart Hospital, Anyang-si, Korea ; 27 Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Ki-Suck
authors.initials: KS
authors.lastname: Jung
keywords: Chronic obstructive pulmonary disease (COPD); South Korea; chronic bronchitis; exacerbation; pneumonia