title: Natural course of early COPD.
abstract: OBJECTIVE
  Few studies have examined the natural course of early COPD. The aim of this study was to observe the natural course of early COPD patients. We also aimed to analyze medical utilization and costs for early COPD during a 6-year period.
  
  
  METHODS
  Patients with early COPD were selected from Korean National Health and Nutrition Examination Survey (KNHANES) data. We linked the KNHANES data of patients with early COPD to National Health Insurance data.
  
  
  RESULTS
  A total of 2,397 patients were enrolled between 2007 and 2012. The mean forced expiratory volume in 1 second (FEV1) was 78.6%, and the EuroQol five dimensions questionnaire (EQ-5D) index value was 0.9. In total, 110 patients utilized health care for COPD in 2007, and this number increased to 179 in 2012. The total mean number of days used per person increased from 4.9 in 2007 to 7.8 in 2012. The total medical cost per person also increased from 248.8 US dollar (USD) in 2007 to 780.6 USD in 2013. A multiple linear regression revealed that age, lower body mass index, lower FEV1(%), and lower EQ-5D score were significantly associated with medical costs.
  
  
  CONCLUSIONS
  Even in early COPD patients, some of them eventually progressed and utilized health care for COPD.
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
authors.affiliation: Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Seoul St Mary's Hospital.
authors.forename: Kyungjoo
authors.initials: K
authors.lastname: Kim
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: Pharmaceutical Policy Evaluation Research Team, Research Institution.
authors.forename: Jee-Ae
authors.initials: JA
authors.lastname: Kim
authors.affiliation: Big Data Division, Health Insurance Review and Assessment Service, Wonju.
authors.forename: Sang Hyun
authors.initials: SH
authors.lastname: Kim
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.
authors.forename: Sang Haak
authors.initials: SH
authors.lastname: Lee
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: Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang.
authors.forename: Ki-Suck
authors.initials: KS
authors.lastname: Jung
authors.affiliation: Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Konkuk University School of Medicine, Seoul, Republic of Korea.
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 Sacred Heart Hospital, Hallym University College of Medicine, Anyang.
authors.forename: Yong Il
authors.initials: YI
authors.lastname: Hwang
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D001993:Bronchodilator Agents / Q000191:economics / Q000627:therapeutic use; D018450:Disease Progression; D016527:Drug Costs; D004636:Emergency Service, Hospital / Q000191:economics / Q000706:statistics & numerical data; D005260:Female; D005541:Forced Expiratory Volume; D006295:Health Resources / Q000191:economics / Q000706:statistics & numerical data*; D006304:Health Status; D017721:Hospital Costs; D006801:Humans; D016014:Linear Models; D008168:Lung / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D010343:Patient Admission / Q000191:economics; D011379:Prognosis; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000191:economics / Q000453:epidemiology / Q000628:therapy*; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D011795:Surveys and Questionnaires; D013997:Time Factors; D014797:Vital Capacity
chemical_list: D001993:Bronchodilator Agents
keywords: HIRA; KNHANES; NHI; cost; early COPD; utilization