The relationship of depression in asthma - chronic obstructive pulmonary disease overlap syndrome

Purpose To clarify the relationship between asthma - chronic obstructive pulmonary disease overlap syndrome (ACOS) and depression. Methods We identified 10,911 patients who received an ACOS diagnosis and concurrent treatment between January 2000 and December 2009. Subjects without ACOS were included in the non-ACOS cohort (n = 10,911). Cox proportional hazard regression analysis was performed to compare the risk of depression between the ACOS and non-ACOS cohorts. Results The risk of depression was higher in the ACOS cohort than in the non-ACOS cohort (adjusted hazard ratios (aHRs) = 1.67, 95% confidence interval [CI] = 1.48 - 1.88). In the ACOS cohort, the aHRs for depression were [2.44 (95% CI = 1.45 - 4.11); 2.36 (95% CI = 1.58 - 3.52)] in patients [aged 20 - 39 years; without comorbidity]. In the ACOS cohort, the aHRs for depression were 1.70 (95% CI = 1.51 - 1.93) and 1.84 (95% CI = 1.55 - 2.19) in patients without inhaled corticosteroids (ICSs) and oral steroids (OSs) use, respectively. Moreover, the aHRs for the risk of depression were 1.16 (95% CI = 0.95 - 1.41) and 1.12 (95% CI = 0.96 - 1.29) in patients with ICSs and OSs use, respectively. Conclusion The risk of depression is higher in ACOS patients, even in those without comorbidities or in young adults. The events of the depression were not significant difference in patients receiving the ICSs/OSs between the ACOS and the non-ACOS cohorts.