title: Impacts of coexisting bronchial asthma on severe exacerbations in mild-to-moderate COPD: results from a national database.
abstract: BACKGROUND
  Acute exacerbations are major drivers of COPD deterioration. However, limited data are available for the prevalence of severe exacerbations and impact of asthma on severe exacerbations, especially in patients with mild-to-moderate COPD.
  
  
  METHODS
  Patients with mild-to-moderate COPD (≥40 years) were extracted from Korean National Health and Nutrition Examination Survey data (2007-2012) and were linked to the national health insurance reimbursement database to obtain medical service utilization records.
  
  
  RESULTS
  Of the 2,397 patients with mild-to-moderate COPD, 111 (4.6%) had severe exacerbations over the 6 years (0.012/person-year). Severe exacerbations were more frequent in the COPD patients with concomitant self-reported physician-diagnosed asthma compared with only COPD patients (P<0.001). A multiple logistic regression presented that asthma was an independent risk factor of severe exacerbations in patients with mild-to-moderate COPD regardless of adjustment for all possible confounding factors (adjusted odds ratio, 1.67; 95% confidence interval, 1.002-2.77, P=0.049). In addition, age, female, poor lung function, use of inhalers, and low EuroQoL five dimensions questionnaire index values were independently associated with severe exacerbation in patients with mild-to-moderate COPD.
  
  
  CONCLUSIONS
  In this population-based study, the prevalence of severe exacerbations in patients with mild-to-moderate COPD was relatively low, compared with previous clinical interventional studies. Coexisting asthma significantly impacted the frequency of severe exacerbations in patients with mild-to-moderate COPD, suggesting application of an exacerbation preventive strategy in these patients.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Hyun
authors.initials: H
authors.lastname: Lee
authors.affiliation: Division 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, South Korea.
authors.forename: Chin Kook
authors.initials: CK
authors.lastname: Rhee
authors.affiliation: Division of Allergy, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Byung-Jae
authors.initials: BJ
authors.lastname: Lee
authors.affiliation: Division of Allergy, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Dong-Chull
authors.initials: DC
authors.lastname: Choi
authors.affiliation: Pharmaceutical Policy Evaluation Research Team, Research Institution, Health Insurance Review and Assessment Service, Seoul, South Korea.
authors.forename: Jee-Ae
authors.initials: JA
authors.lastname: Kim
authors.affiliation: Big Data Division, Health Insurance Review and Assessment Service, Seoul, South Korea.
authors.forename: Sang Hyun
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Division of Chronic Disease Control, Korea Centers for Disease Control and Prevention, Osong, South Korea.
authors.forename: Yoolwon
authors.initials: Y
authors.lastname: Jeong
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Hanyang University Guri Hospital, Hanyang University College of Medicine, Gyeonggi-do, South Korea.
authors.forename: Tae-Hyung
authors.initials: TH
authors.lastname: Kim
authors.affiliation: Department of Pulmonary and Critical Care Medicine, Chungju Hospital, Konkuk University School of Medicine, Chungju City, South Korea.
authors.forename: Gyu Rak
authors.initials: GR
authors.lastname: Chon
authors.affiliation: Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Hallym University Medical Center, Hallym University College of Medicine, Anyang, South Korea.
authors.forename: Ki-Suck
authors.initials: KS
authors.lastname: Jung
authors.affiliation: Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, St Paul's Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea.
authors.forename: Sang Haak
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Academic Primary Care, Division of Applied Health Sciences, University of Aberdeen, Aberdeen, UK.
authors.forename: David
authors.initials: D
authors.lastname: Price
authors.affiliation: Division of Pulmonary, Allergy and Critical Care Medicine Department of Internal Medicine, Konkuk University School of Medicine, Seoul, South Korea.
authors.forename: Kwang Ha
authors.initials: KH
authors.lastname: Yoo
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Hye Yun
authors.initials: HY
authors.lastname: Park
mesh_terms: D000368:Aged; D001249:Asthma / Q000150:complications*; D003430:Cross-Sectional Studies; D016208:Databases, Factual; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications*; D056910:Republic of Korea; D012189:Retrospective Studies; D012720:Severity of Illness Index
keywords: acute exacerbation; bronchial asthma; chronic obstructive pulmonary disease