Suicidal ideation and suicide attempts in chronic obstructive pulmonary disease: The Korea National Health and Nutrition Examination Survey (KNHANES IV, V) from 2007-2012

BACKGROUND: There is good evidence for an association between chronic obstructive pulmonary disease (COPD) and depression, but there are few studies on the relationship between COPD and suicidal ideation/suicidal attempts. AIMS: To evaluate the mental health of patients with COPD in Korea and to compare it with that of the general population. METHODS: We analysed data of 15,718 subjects (age >= 40 years) who participated in the 2007-2012 Korea National Health and Nutrition Examination Survey. COPD was defined according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria for people aged >= 40 years. We compared the mental health outcomes of 2,506 patients with COPD (2,355 GOLD stages I and II; 151 GOLD stages III and IV) with those of 13,212 controls. RESULTS: Suicidal thoughts were reported by 16.0% of patients in stages I and II, by 23.8% of those in stages III and IV and by 15.7% of controls (P = 0.023). Suicidal attempts were reported by 0.6% of patients in stages I and II, by 2.6% of those in stages III and IV and by 1.0% of controls (P = 0.019). The crude odds ratio (OR) for suicidal ideation in those in stages III and IV was 1.68 (95% confidence interval (CI), 1.16-2.46), and the OR for suicidal attempts in stages III and IV was 2.83 (95% CI, 1.03-7.75). In multivariate analysis, the OR for suicidal ideation in stages III and IV was 1.67 (95% CI, 1.12-2.49) and that for suicidal attempts was 2.94 (95% CI, 1.03-8.31). CONCLUSIONS: GOLD stages III and IV COPD were associated with a marked increase in suicidal behaviour.