Factors contributing to quality of life in COPD patients in South Korea

Objectives: 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. Patients and 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. Conclusion: 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.