LAUSR

Background: Although depression is considered one of the comorbidities of chronic obstructive pulmonary disease (COPD), the clinical characteristics of depression in patients with early COPD remain unknown. We aimed to use national-level data to identify the clinical features and risk factors of depression in patients with early COPD. Methods: We examined 7,550 subjects who were registered in the Korean National Health and Nutrition Examination Survey database of 2013 because that was the only year in which the Patient Health Questionnaire-9 for depression status was administered. COPD patients whose forced expiratory volume in 1 s was 50% or more were included in the analysis. Results: Of the 391 subjects with early COPD, 16.9% also had depression. The patients with depression were predominantly female and living alone, with low income; they also had lower levels of education, were underweight, and had a greater prevalence of diabetes compared with the patients without depression. The overall quality of life of the subjects with depression was lower than that of those without depression, and only the quality of life index correlated significantly and positively with depression severity. In the multivariate regression analysis, female sex [adjusted odds ratio, 2.09; 95% confidence interval, 1.04–4.19; p = 0.04] and comorbid diabetes [adjusted odds ratio, 2.22; 95% confidence interval, 1.07–4.57; p = 0.03] were identified as significant risk factors for depression. Conclusions: In patients with early COPD, depression was associated with a low quality of life, and female sex and comorbid diabetes were significant risk factors for the depression.