Factors associated with quality of life measured by EQ-5D in Korean COPD patients

Objective: The aim of this study is to evaluate the influencing factors of health related quality of life measured by EQ-5D with respect to the degree of airway obstruction in Korean using the Korean National Health and Nutritional Examination Survey (KNHANES IV-V)(2007-2010) Method: Baseline EQ-5D visual analog scale(VAS) score and EQ-5D utility scores were obtained from 1,178 adults with COPD and 1,178 adults with normal lung function in the KNHANES IV-V. The factors affecting EQ-5D score were evaluated by multiple linear regression analysis. Results: The mean EQ-5D VAS and utility scores were significantly lower in the COPD group (EQ -5D VAS, 71.2; EQ-5D, 0.90) than the normal lung function group (EQ-5D VAS, 73.5; EQ-5D, 0.92, p <0.001). The EQ-5D VAS and EQ-5D utility scores were significantly different among three severity groups after correction for age, sex, BMI, smoking history and comorbidity( p <0.05). The mean EQ-5D VAS score for patients with mild, moderate and severe COPD were 72.8, 70.8 and 63.8 respectively. The mean utility score were 0.90 for patients with mild COPD, 0.90 for patient with moderate COPD and 0.86 for patients with severe COPD. The influencing factors for the EQ-5D utility score were sex, age, household income, educational level, depressive symptoms in two weeks, activity limitation and comorbidity. Conclusion: This result showed that severity of COPD was associated with the decline of EQ-5D VAS and utility score. Although it has limitation, a generic instrument EQ-5D will be useful to access quality of life in COPD. Multidimensional management for psycho-social health and concurrent disease should be considered to improve quality of life in Koreans with COPD.