Association of Depression with Disease Severity in Patients with Chronic Obstructive Pulmonary Disease

Patients with chronic obstructive pulmonary disease (COPD), which is predicted to be the third most common cause of death worldwide by 2020, often suffer from depression, one of the most common and modifiable comorbidities of COPD. This study assessed the prevalence of depression in patients with COPD and the association of depression with disease severity. This was a multicenter, prospective cross-sectional study of 245 patients with stable COPD. Disease severity was assessed using two scales: the global initiative for chronic obstructive lung disease (GOLD) stage and BODE index. Depression was measured using the Centers for Epidemiologic Studies Depression (CES-D) scales. Data were analyzed using descriptive statistics, Spearman correlation, and multivariate logistic regression. Depression defined as a CES-D score of 24 and higher was observed in 17.6 % of patients with COPD. The prevalence of depression increased with disease severity based on the BODE quartile (r = 0.16; P = 0.014). By contrast, no difference was observed in the prevalence of depression among the severity groups using the GOLD staging system (r = - 0.01; P = 0.898). Elementary school graduates were more likely to experience depression than graduates of high school and above [odds ratio (OR) = 3.67; 95 % confidence interval (CI) 1.37-9.85] and patients in BODE quartile II were more likely to experience depression than those with BODE quartile I (OR = 2.5; 95 % CI 1.04-6.06). Depression was associated with disease severity according to the BODE quartile in patients with COPD. BODE quartile II was a significant predictor of depression. Screening patients with a high risk of depression and proactive intervention for those patients are needed.