title: Chronic bronchitis is an independently associated factor for more symptom and high-risk groups.
abstract: BACKGROUND
  The chronic bronchitis (CB) phenotype has been associated with poor quality of life and an increased risk of disease in patients with COPD. However, little information exists regarding the relationship between the CB phenotype and the COPD assessment test (CAT) score. The goal of this study was to reveal the different pattern of CAT scores between CB and non-CB patients. Moreover, we aimed to investigate whether the CB phenotype is an independently associated factor for more symptom and high-risk groups.
  
  
  METHODS
  Data were obtained from the Korea COPD Subgroup Study cohort recruited from 46 centers in South Korea since April 2012. CB patients were defined as having a chronic cough and sputum for 3 months per year, for a period of 2 consecutive years. We investigated the pattern of CAT and subquestionnaire scores between CB and non-CB patients. We also analyzed the proportion of CB phenotypes in each Global initiative for chronic Obstructive Lung Disease (GOLD) stage. Finally, we performed a logistic regression analysis to identify whether the CB phenotype was an independently associated factor for more symptom and high-risk groups.
  
  
  RESULTS
  Of the 1,106 study patients, 11.5% of patients were found to have a CB phenotype. CB phenotypes were most common in GOLD III (GOLD 2006) and GOLD D (GOLD 2015) stages. CAT scores were significantly higher in CB patients not only in terms of the total score but also for each subquestionnaire. Logistic regression revealed that the CB phenotype is an independently associated factor for more symptom and high-risk groups.
  
  
  CONCLUSIONS
  The present study revealed that CB patients have higher CAT scores and subquestionnaire results compared to non-CB patients. Additionally, we demonstrated that the CB phenotype is an independently associated factor for both more symptom and high-risk groups.
authors.affiliation: Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Seoul St Mary's Hospital.
authors.forename: Joon Young
authors.initials: JY
authors.lastname: Choi
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Yeouido St Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul.
authors.forename: Hyoung Kyu
authors.initials: HK
authors.lastname: Yoon
authors.affiliation: Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Internal Medicine, Chonbuk National University Medical School, Jeonju.
authors.forename: Seoung Ju
authors.initials: SJ
authors.lastname: Park
authors.affiliation: Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Internal Medicine, Hallym University Kangdong Sacred Heart Hospital, Seoul.
authors.forename: Yong Bum
authors.initials: YB
authors.lastname: Park
authors.affiliation: Regional Center for Respiratory Disease, Yeungnam University Medical Center, Yeungnam University College of Medicine, Daegu.
authors.forename: Kyeong-Cheol
authors.initials: KC
authors.lastname: Shin
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Soonchunhyang University Cheonan Hospital, Cheonan.
authors.forename: Ju Ock
authors.initials: JO
authors.lastname: Na
authors.affiliation: Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Konkuk University School of Medicine, Seoul.
authors.forename: Kwang Ha
authors.initials: KH
authors.lastname: Yoo
authors.affiliation: Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Hallym University Medical Center, Hallym University College of Medicine, Anyang, Republic of Korea.
authors.forename: Ki-Suck
authors.initials: KS
authors.lastname: Jung
authors.affiliation: Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Seoul St Mary's Hospital.
authors.forename: Young Kyoon
authors.initials: YK
authors.lastname: Kim
authors.affiliation: Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Seoul St Mary's Hospital.
authors.forename: Chin Kook
authors.initials: CK
authors.lastname: Rhee
mesh_terms: D000368:Aged; D029481:Bronchitis, Chronic / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D016009:Chi-Square Distribution; D005260:Female; D005541:Forced Expiratory Volume; D006304:Health Status; D006305:Health Status Indicators; D006801:Humans; D016015:Logistic Models; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010641:Phenotype; D011237:Predictive Value of Tests; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D014797:Vital Capacity
keywords: COPD assessment test; chronic bronchitis; chronic obstructive pulmonary disease