title: Factors contributing to quality of life in COPD patients in South Korea.
abstract: OBJECTIVE
  Chronic obstructive pulmonary disease (COPD) is a chronic lung disease, and the burden of COPD is expected to increase in the rapidly aging nation of South Korea. This study aims to examine the factors contributing to health-related quality of life (HRQOL) in COPD patients.
  
  
  METHODS
  This study was based on 6-year-data obtained from the Korean National Health and Nutrition Examination Survey 2007-2012. COPD was diagnosed in 2,734 survey participants and the severity was graded according to the criteria set by the Global Initiative for Chronic Obstructive Lung Disease. The EuroQol-5D (EQ-5D) index was used to assess the quality of life.
  
  
  RESULTS
  The EQ-5D index scores for COPD patients and the general population were 0.915±0.003 and 0.943±0.001, respectively. Males, younger people, and patients with higher education attainment and income levels had a higher utility score. In addition, the adjusted EQ-5D index scores for severity level IV significantly decreased by 0.100 (P=0.041), compared to the severity group I scores. No significant differences were found in stage II and III patients. Comorbidities (excluding cancer and hypertension) appeared to negatively influence HRQOL among COPD patients. In particular, depression (EQ-5D index score =-0.089, P=0.0003) and osteoporosis (EQ-5D index score=-0.062, P=0.0039) had a significant influence, while smoking status did not appear to influence patient HRQOL.
  
  
  CONCLUSIONS
  In this study, we found that the higher the severity of COPD, the lower the quality of life. In particular, patients with depression and osteoporosis had a relatively low utility score. Therefore, these comorbidities should be carefully monitored in order to improve quality of life.
authors.affiliation: Department of Global Health and Population, Harvard School of Public Health, Boston, MA, USA; Institute of Health and Environment, Graduate School of Public Health, Seoul National University, Seoul, South Korea.
authors.forename: Hye-Young
authors.initials: HY
authors.lastname: Kwon
authors.affiliation: Institute of Health and Environment, Graduate School of Public Health, Seoul National University, Seoul, South Korea.
authors.forename: Eugene
authors.initials: E
authors.lastname: Kim
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D015897:Comorbidity; D017281:Cost of Illness; D003430:Cross-Sectional Studies; D003863:Depression / Q000175:diagnosis / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology / Q000503:physiopathology / Q000523:psychology; D011788:Quality of Life; D056910:Republic of Korea / Q000453:epidemiology; D012720:Severity of Illness Index; D012737:Sex Factors; D012959:Socioeconomic Factors
keywords: COPD; EQ5D; HRQOL; KNHANES; South Korea
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