title: Association of depression with disease severity in patients with chronic obstructive pulmonary disease.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Internal Medicine, Pusan National University School of Medicine, 179 Gudeok-ro, Seo-gu, Busan, 602-739, Republic of Korea.
authors.forename: Ki Uk
authors.initials: KU
authors.lastname: Kim
authors.forename: Hye-Kyung
authors.initials: HK
authors.lastname: Park
authors.forename: Hee Young
authors.initials: HY
authors.lastname: Jung
authors.forename: Jong-Joon
authors.initials: JJ
authors.lastname: Ahn
authors.forename: Eunsoo
authors.initials: E
authors.lastname: Moon
authors.forename: Yun Seong
authors.initials: YS
authors.lastname: Kim
authors.forename: Min Ki
authors.initials: MK
authors.lastname: Lee
authors.forename: Haejung
authors.initials: H
authors.lastname: Lee
mesh_terms: D000368:Aged; D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D003863:Depression / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D005260:Female; D006801:Humans; D016015:Logistic Models; D008168:Lung / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011237:Predictive Value of Tests; D015995:Prevalence; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D012720:Severity of Illness Index