Suchergebnisse

Yong Suk Jo,1 Sung Kyoung Kim,2 Seoung Ju Park,3 Soo-Jung Um,4 Yong-Bum Park,5 Ki Suck Jung,6 Deog Kyeom Kim,7 Kwang Ha Yoo8 1Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine, Kyung Hee University Hospital, Seoul, Republic of Korea; 2Department of Internal Medicine, Division of Pulmonology, St Vincent's Hospital, The Catholic University of Korea, Seoul, Republic of Korea; 3Department of Internal Medicine, Chonbuk National University Medical School, Jeonju, Republic of Korea; 4Department of Internal Medicine, Division of Pulmonology, Dong-A University Hospital, Busan, Republic of Korea; 5Department of Internal Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, Hallym University Kangdong Sacred Heart Hospital, Seoul, Republic of Korea; 6Department of Internal Medicine, Division of Pulmonary Medicine, Hallym University Sacred Heart Hospital, Hallym University Medical School, Anyang, Republic of Korea; 7Department of Internal Medicine, Seoul Metropolitan Government, Seoul National University Boramae Medical Center, Seoul, Republic of Korea; 8Department of Internal Medicine, Division of Pulmonary and Allergy Medicine, Konkuk University School of Medicine, Seoul, Republic of Korea Background and objective: FEV1 is the gold standard for assessment of COPD. We compared efficacy of FEV1, inspiratory capacity (IC), and IC to total lung capacity (TLC) ratio in the evaluation of COPD and their association with exacerbation.Methods: We analyzed the association of dyspnea severity, quality of life status, and lung function with lung function measurements and exacerbation risk in 982 patients enrolled in the Korea COPD Subgroup Registry and Subtype Research study. Exacerbation and longitudinal lung function change were evaluated in 3 years' follow-up.Results: The FEV1, IC, and IC to TLC ratio showed comparable negative correlations with dyspnea severity and quality of life status, and positive correlation with exercise capacity. In patients with >2 events/year, annual rate of change in FEV1 and IC tended to decline more rapidly in those with FEV1 50% (-14.46±19.40 mL/year vs 12.29±9.24 mL/year, P=0.213; -4.75±17.28 mL/year vs -78.05±34.16 mL/year, P=0.056 for FEV1 and IC, respectively), without significance.Conclusion: Longitudinal changes in IC and FEV1 were not significantly associated with exacerbation risk. Keywords: COPD, exacerbation, FEV1, inspiratory capacity

Chronic obstructive pulmonary disease (COPD) results in high morbidity and mortality among patients nationally and globally. The Korean clinical practice guideline for COPD was revised in 2018. The guideline was drafted by the members of the Korean Academy of Tuberculosis and Respiratory Diseases as well as the participating members of the Health Insurance Review and Assessment Service, Korean Physicians' Association, and Korea Respiration Trouble Association. The revised guideline encompasses a wide range of topics, including the epidemiology, diagnosis, assessment, monitoring, management, exacerbation, and comorbidities of COPD in Korea. We performed systematic reviews assisted by an expert in meta-analysis to draft a guideline on COPD management. We expect this guideline to facilitate the treatment of patients with respiratory conditions by physicians as well other health care professionals and government personnel in South Korea.

Jung-Kyu Lee,1 Chin Kook Rhee,2 Kyungjoo Kim,2 Seung Won Ra,3 Jae Ha Lee,4 Ki-Suck Jung,5 Kwang Ha Yoo,6 Yoo-Il Kim,7 Deog Kyeom Kim1 1Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Republic of Korea; 2Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, the Catholic University of Korea, Seoul, Republic of Korea; 3Department of Internal Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Republic of Korea; 4Division of Pulmonology and Critical Care Medicine, Department of Internal Medicine, Inje University Haeundae Paik Hospital, Inje University College of Medicine, Busan, Republic of Korea; 5Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang, Republic of Korea; 6Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Konkuk University School of Medicine, Seoul, Republic of Korea; 7Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Republic of KoreaCorrespondence: Deog Kyeom KimDivision of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, #395 Shindaebang-2-Dong, Dongjak-Gu, Seoul 156-707, Republic of KoreaTel +82-2-870-2228Fax +82-2-831-0714Email kimdkmd@snu.ac.krBackground: Methylxanthines and leukotriene receptor antagonists (LTRA) are not a first-line medical treatment for chronic obstructive pulmonary disease (COPD) but are frequently prescribed despite limited evidence. We aimed to elucidate the real prescribing status and clinical impacts of these agents in early COPD patients.Methods: Patients with mild-to-moderate COPD (FEV1>50%) were selected from the Korean National Health and Nutrition Examination Survey data between 2007 and 2012. Besides analyzing the prescription status of methylxanthines and LTRA and the contributing factors to the prescription, we evaluated the clinical impacts of these drugs on the exacerbation, hospitalization, and medical costs.Results: Of 2269 patients with mild-to-moderate COPD, 378 patients (16.7%) were under medical treatments, and the users of methylxanthines and/or LTRA were 279 patients (12.3%); however, only 139 patients (6.1%) were inhaler users. The contributing factors for the prescription of methylxanthines were a comorbidity of asthma or allergic disease, poor lung function, low quality of life, prescribing doctor from the specialty of internal medicine, and an institution type of private hospital. The prescription of LTRA was associated with the comorbidity of allergic disease. The methylxanthine and/or LTRA users had more hospital utilization but did not have significant differences in acute exacerbations and medical cost for hospital utilization, compared with the non-users.Conclusion: Methylxanthines and LTRA were used in a significant proportion of patients with mild-to-moderate COPD in real fields without favorable impacts on the exacerbations, hospitalizations, or medical costs. The use of more effective inhaled medications should be encouraged.Keywords: pulmonary disease, chronic obstructive, methylxanthine, leukotriene antagonists, drug prescriptions

Hyeon-Kyoung Koo,1 Sung-Woo Park,2 Jeong-Woong Park,3 Hye Sook Choi,4 Tae-Hyung Kim,5 Hyoung Kyu Yoon,6 Kwang Ha Yoo,7 Ki-Suck Jung,8 Deog Kyeom Kim9 1Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Ilsan Paik Hospital, Inje University College of Medicine, Ilsan, Republic of Korea; 2Division of Allergy and Respiratory Medicine, Department of Internal Medicine, Soon Chun Hyang University Bucheon Hospital, Bucheon, Republic of Korea; 3Department of Pulmonary and Critical Care Medicine, Gachon University, Gil Medical Center, Incheon, Republic of Korea; 4Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Internal Medicine, Hallym University Kangdong Sacred Heart Hospital, Seoul, Republic of Korea; 5Division of Pulmonary and Critical Care Medicine, Hanyang University Guri Hospital, Hanyang University College of Medicine, Guri, Republic of Korea; 6Department of Internal Medicine, The Catholic University of Korea, Yeouido St Mary's Hospital, Seoul, Republic of Korea; 7Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Konkuk University School of Medicine, Seoul, Republic of Korea; 8Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang, Republic of Korea; 9Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul National University College of Medicine, Seoul, Republic of Korea Background and purpose: Chronic cough can be a dominant symptom of chronic obstructive pulmonary disease (COPD), although its clinical impact remains unclear. The aim of our study was to identify phenotypic differences according to the presence of chronic cough or sputum and evaluate the impact of chronic cough on the risk of acute exacerbation of COPD (AECOPD). Methods: In a nationwide COPD cohort including 1,613 COPD patients, patients with chronic cough only, those with sputum only, those with chronic bronchitis (CB), and those without cough and sputum were compared with regard to dyspnea, lung function, quality of life (QoL), and risk of AECOPD. Results: The rates of chronic cough, chronic sputum, and both were 23.4%, 32.4%, and 18.2%, respectively. Compared with patients without chronic cough, those with chronic cough exhibited a lower forced expiratory volume in 1 second (% predicted) and diffusing capacity of the lungs for carbon monoxide (% predicted), more frequent AECOPD, more severe dyspnea, and worse QoL. Pulmonary function, dyspnea severity, and QoL worsened in the following order: without cough or sputum, with sputum only, with cough only, and with CB. Multivariate analyses revealed chronic cough as an independent risk factor for a lower lung function, more severe dyspnea, and a poor QoL. Moreover, the risk of future AECOPD was significantly associated with chronic cough (odds ratio 1.56, 95% CI 1.08–2.24), but not with chronic sputum. Conclusion: Our results suggest that chronic cough should be considered as an important phenotype during the determination of high-risk groups of COPD patients. Keywords: pulmonary disease, chronic obstructive, cough, exacerbation, severity

Hyun Lee,1,* Byung Woo Jhun,1,* Juhee Cho,2–4 Kwang Ha Yoo,5 Jin Hwa Lee,6 Deog Kyeom Kim,7 Jong Deog Lee,8 Ki-Suck Jung,9 Jung Yeon Lee,10 Hye Yun Park1 1Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea; 2Center for Clinical Epidemiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea; 3Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; 4Department of Clinical Research Design and Evaluation, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul, South Korea; 5Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Konkuk University School of Medicine, Seoul, South Korea; 6Division of Pulmonary and Critical Care Medicine, School of Medicine, Ewha Womans University, Seoul, South Korea; 7Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul National University College of Medicine, Seoul, South Korea; 8Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Gyeongsang National University Hospital, Jinju, South Korea; 9Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Hallym University Medical Center, Hallym University College of Medicine, Anyang, South Korea; 10Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Chungju Hospital, Konkuk University School of Medicine, Chungju, South Korea *These authors contributed equally to this work Background: Patients with chronic obstructive pulmonary disease (COPD) often have poor health-related quality of life (HRQoL) that is disproportionate to their degree of airflow limitation. This study evaluated the association between St George's Respiratory Questionnaire for COPD (SGRQ-C) score and forced expiratory volume in one second and investigated the factors responsible for high SGRQ-C score according to severity of airflow limitation.Methods: Data from 1,264 COPD patients were obtained from the Korean COPD Subgroup Study (KOCOSS) cohort. Patients were categorized into two groups according to severity of airflow limitation: mild-to-moderate and severe-to-very severe COPD groups. We evaluated the clinical factors associated with high SGRQ-C score (≥25) in each COPD patient group.Results: Of the 1,264 COPD patients, 902 (71.4%) had mild-to-moderate airflow limitation and 362 (28.6%) had severe-to-very severe airflow limitation. Of the mild-to-moderate COPD patients, 59.2% (534/902) had high SGRQ-C score, while 80.4% (291/362) of the severe-to-very severe COPD patients had high SGRQ-C score. The association between SGRQ-C score and post-bronchodilator forced expiratory volume in one second (% predicted) was very weak in the mild-to-moderate COPD patients (r=–0.103, p=0.002) and weak in the severe-to-very severe COPD patients (r=–0.219, p<0.001). Multiple logistic regression analysis revealed that age, being an ex- or current smoker, lower level of education, cough, dyspnea, and number of comorbidities with congestive heart failure, hyperlipidemia, and depression were significantly associated with high SGRQ-C score in mild-to-moderate COPD patients. In comparison, being an ex-smoker and having respiratory symptoms including sputum and dyspnea were significant factors associated with high SGRQ-C score in severe-to-very severe COPD patients.Conclusions: In addition to the respiratory symptoms of dyspnea and cough, high SGRQ-C score was associated with extra-pulmonary comorbidities in mild-to-moderate COPD patients. However, only respiratory symptoms such as sputum and dyspnea were significantly associated with high SGRQ-C score in severe-to-very severe COPD patients. This indicates the need for an improved management strategy for relieving respiratory symptoms in COPD patients with poor HRQoL. In addition, attention should be paid to extra-pulmonary comorbidities, especially in mild-to-moderate COPD patients with poor HRQoL. Keywords: chronic obstructive pulmonary disease, morbidity, quality of life

Jin Hwa Song,1 Chang-Hoon Lee,1 Jin Woo Kim,2 Won-Yeon Lee,3 Ji Ye Jung,4 Joo Hun Park,5 Ki Suck Jung,6 Kwang Ha Yoo,7 Yong Bum Park,8 Deog Keom Kim9 1Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University Hospital, 2Division of Pulmonology, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, 3Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju, Gangwon-do, 4Division of Pulmonology, Department of Internal Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, 5Department of Pulmonary and Critical Care Medicine, Ajou University School of Medicine, Suwon, 6Division of Pulmonary Medicine, Department of Internal Medicine, Hallym University Sacred Heart Hospital, Hallym University Medical School, Anyang, Gyeonggi-do, 7Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Konkuk University Medical Center, Konkuk University School of Medicine, 8Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Kangdong Sacred Heart Hospital, 9Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul National University College of Medicine, Seoul, Republic of Korea Background: Recent studies that assessed the relevance of the blood eosinophil count as a biomarker in patients with COPD may have overestimated it because they included patients with asthma–COPD overlap syndrome (ACOS). We investigated the clinical implications of the blood eosinophil count in patients with non-ACOS COPD.Patients and methods: From a Korean COPD Subtype Study (KOCOSS) cohort, we selected patients with non-ACOS COPD after excluding ACOS patients according to Spanish criteria. Clinical characteristics and the incidence of moderate-to-severe exacerbation were compared among the four groups stratified according to the quartiles of blood eosinophil percent and count.Results: Of the KOCOSS cohort of 1,132 patients with COPD, 467 non-ACOS COPD patients (41.2%) with data of blood eosinophil count remained after excluding those with ACOS based on the Spanish definition. There was no difference in clinical characteristics among groups classified according to the quartiles of eosinophil percent and count. On multivariate logistic regression, eosinophil quartiles in percent and absolute count were not associated with the incidence of moderate-to-severe acute exacerbations of COPD (AECOPD). The eosinophil count did not affect the risk of AECOPD or forced expiratory volume in 1 second (FEV1) changes according to exposure to inhaled corticosteroid (ICS). However, by increasing the cutoff value for the eosinophil count from 200/µL to 600/µL, the odds ratio for risk of exacerbation increased serially from 0.82 to 2.96 on trend analysis.Conclusion: In patients with non-ACOS COPD, the blood eosinophil count and percent were not associated with FEV1 changes, quality of life (QoL), AECOPD frequency, or response to ICS. The clinical implication of the blood eosinophil count should not be overestimated in patients with non-ACOS COPD. Keywords: eosinophil, chronic obstructive lung disease, asthma, acute exacerbation, inhaled corticosteroid

Jin Hwa Song,1 Chang-Hoon Lee,1 Soo-Jung Um,2 Yong Bum Park,3 Kwang Ha Yoo,4 Ki Suck Jung,5 Sang-Do Lee,6 Yon-Mok Oh,6 Ji Hyun Lee,7 Eun Kyung Kim,7 Deog Kyeom Kim8,9 On behalf of KOLD, KOCOSS, and SNU airway registry investigators 1Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea; 2Division of Respiratory Medicine, Department of Internal Medicine, Dong-A University College of Medicine, Dong-A University Medical Center, Busan, Republic of Korea; 3Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Kangdong Sacred Heart Hospital, Seoul, Republic of Korea; 4Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea; 5Division of Pulmonary Medicine, Department of Internal Medicine, Hallym University Sacred Heart Hospital, Hallym University Medical School, Anyang Gyeonggi-do, Republic of Korea; 6Department of Pulmonary and Critical Care Medicine and Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Songpa-gu, Seoul, Republic of Korea; 7Department of Internal Medicine, CHA Bundang Medical Center, CHA University, Seongnam Gyeonggi-do, Republic of Korea; 8Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Republic of Korea; 9Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea Purpose: While GOLD classification has been revised, its clinical impacts on outcomes of COPD patients have not been widely evaluated in real-world cohorts.Materials and methods: According to 2007, 2013, and 2017 GOLD classifications, distribution and clinical characteristics of group-shifted patients and the risk of acute exacerbation were analyzed in combined Korean COPD cohorts. Future risk for annual moderate-to-severe exacerbation was estimated as incidence rate ratio (IRR) and compared by groups.Results: Among 1,880 COPD patients, in GOLD 2017 classification, groups B and A were increased to 61.2% and 22.2% of total population, while group C was shrunken to 2.2% and patients with higher risk were decreased (16.6% in GOLD 2017 vs 44.7% in GOLD 2013). The kappa coefficient of agreement of both systems was 0.581 (agreement 71.7%). Groups B and D showed higher IRR of moderate-to-severe exacerbation than group A (IRR 2.4 and 5.3 respectively, P<0.001), whereas group C was not different from group A. When groups C and D were combined, the IRR for acute exacerbation for each group showed good linear trends (2.5 [1.6–3.7] for group B and 4.8 [3.0–7.7] for combined group [C+D], P<0.001).Conclusions: In the revised GOLD 2017 system, COPD patients with higher risk were much decreased in Korean cohorts, and group C was negligible in size and clinical impacts on expecting future exacerbation. Serial increase in the risk for exacerbation was more concrete and predictable when group C was combined with group D. Keywords: pulmonary disease, chronic obstructive/classification, pulmonary disease, chronic obstructive/diagnosis, chronic obstructive/epidemiology, risk factors, severity of illness index

Jung-Ki Yoon,1 Jung-Kyu Lee,2 Chang-Hoon Lee,1 Yong Il Hwang,3 Hyunkuk Kim,4 Dongil Park,5 Ki-Eun Hwang,6 Sang-Heon Kim,7 Ki-Suck Jung,3 Kwang Ha Yoo,8 Seung Won Ra,9 Deog Kyeom Kim2,10 1Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea; 2Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Republic of Korea; 3Department of Internal Medicine, College of Medicine, Hallym University Sacred Heart Hospital, Anyang, Republic of Korea; 4Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Inje University Haeundae Paik Hospital, Busan, Republic of Korea; 5Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Chungnam National University Hospital, Daejeon, Republic of Korea; 6Department of Internal Medicine, Wonkwang University, School of Medicine, Iksan, Republic of Korea; 7Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Republic of Korea; 8Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea; 9Department of Internal Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Republic of Korea; 10Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of KoreaCorrespondence: Deog Kyeom KimDivision of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Republic of KoreaTel +82-2-870-2228Fax +82-2-831-0714Email kimdkmd@snu.ac.krIntroduction: Blood eosinophils are a predictive marker for the use of inhaled corticosteroids (ICS). However, there is concern over whether a single measure of blood eosinophils is sufficient for outlining a treatment plan. Here, we evaluated the association between variability in blood eosinophils and the effects of ICS in stable COPD cohorts.Methods: COPD patients in the Korean COPD Subtype Study and the Seoul National University Airway Registry from 2011 to 2018 were analyzed. Based on blood eosinophils at baseline and at 1-year follow-up, the patients were classified into four groups with 250/μL as a cutoff value: consistently high (CH), consistently low (CL), variably increasing (VI), and variably decreasing (VD). We compared rates of acute exacerbations (AEs) according to ICS use in each group after calibration of severity using propensity score matching.Results: Of 2,221 COPD patients, 618 were analyzed and a total of 125 (20%), 355 (57%), 63 (10%), and 75 (12%) patients were classified into the CH, CL, VI, and VD groups, respectively. After calibration, we found that ICS users tended to have a lower AE rate in the CH group (RR 0.41, 95% CI 0.21– 0.74) and VI group (RR 0.45, 95% CI 0.22– 0.88), but not in the CL group (RR 1.42, 95% CI 1.08– 1.89) and VD group (RR 1.71, 95% CI 1.00– 2.96).Conclusion: More than one-fifth of patients had an inconsistent blood eosinophil level after the 1-year follow-up, and the AE-COPD rate according to ICS differed based on variability in eosinophils. Regular follow-up of blood eosinophils is required for COPD patients.Keywords: COPD, eosinophils, inhaled corticosteroids, acute exacerbations of COPD, COPD treatment

Yeon-Mok Oh,1,* Keu Sung Lee,2,* Yoonki Hong,3,* Sung Chul Hwang,2 Jae Yeol Kim,4 Deog Keom Kim,5 Kwang Ha Yoo,6 Ji-Hyun Lee,7 Tae-Hyung Kim,8 Seong Yong Lim,9 Chin Kook Rhee,10 Hyoung Kyu Yoon,11 Sang Yeub Lee,12 Yong Bum Park,13 Jin Hee Jung,14 Woo Jin Kim,3 Sang-Do Lee,1 Joo Hun Park2 1Department of Pulmonary and Critical Care Medicine and Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea; 2Department of Pulmonary and Critical Care Medicine, Ajou University School of Medicine, Suwon, Korea; 3Department of Internal Medicine and Environmental Health Center, Kangwon National University, Kangwon National University Hospital, Chuncheon, Korea; 4Department of Internal Medicine, Chung-Ang University College of Medicine, Seoul, Korea; 5Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul National University College of Medicine, Seoul, Korea; 6Department of Internal Medicine, Konkuk University School of Medicine, Seoul, Korea; 7Department of Internal Medicine, CHA Bundang Medical Center, CHA University, Seongnam, Korea; 8Division of Pulmonology, Department of Internal Medicine, Hanyang University College of Medicine, Guri, Korea; 9Division of Pulmonary and Critical Care Medicine, Department of Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea; 10Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Seoul St Mary's Hospital, Catholic University of Korea, Seoul, Korea; 11Division of Respiratory and Critical Care Medicine, Department of Internal Medicine, College of Medicine, Korea University Anam Hospital, Seoul, Korea; 12Division of Respiratory and Critical Care Medicine, Department of Internal Medicine, College of Medicine, Korea University Anam Hospital, Seoul, Korea; 13Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Hallym University Kangdong Sacred Heart Hospital, Seoul, Korea; 14Department of Biomedical Informatics, Ajou University School of Medicine, Suwon, Korea *These authors contributed equally to this work Background: High blood eosinophil count is a predictive biomarker for response to inhaled corticosteroids in prevention of acute exacerbation of COPD, and low blood eosinophil count is associated with pneumonia risk in COPD patients taking inhaled corticosteroids. However, the prognostic role of blood eosinophil count remains underexplored. Therefore, we investigated the associated factors and mortality based on blood eosinophil count in COPD.Methods: Patients with COPD were recruited from 16 hospitals of the Korean Obstructive Lung Disease cohort (n=395) and COPD in Dusty Area cohort (n=234) of Kangwon University Hospital. The two merged cohorts were divided based on blood eosinophil count into three groups: high (≥5%), middle (2%–5%), and low (<2%).Results: The high group had longer six-minute walk distance (high =445.8±81.4, middle =428.5±88.0, and low =414.7±86.3 m), higher body mass index (23.3±3.1, 23.1±3.1, and 22.5±3.2 kg/m2), lower emphysema index (18.5±14.1, 22.2±15.3, and 23.7±16.3), and higher inspiratory capacity/total lung capacity ratio (32.6±7.4, 32.4±9.2, and 29.9% ± 8.9%) (P<0.05). The survival period increased with increasing blood eosinophil count (high =9.52±0.23, middle =8.47±1.94, and low =7.42±0.27 years, P<0.05). Multivariate linear regression analysis revealed that the emphysema index was independently and negatively correlated with blood eosinophil count (P<0.05).Conclusion: In COPD, the severity of emphysema was independently linked with low blood eosinophil count and the longer survival period was associated with increased blood eosinophil count, though it was not proven in the multivariate analysis. Keywords: blood eosinophil, COPD, biomarker