title: Depressive symptoms and chronic obstructive pulmonary disease: effect on mortality, hospital readmission, symptom burden, functional status, and quality of life.
abstract: BACKGROUND
  Depressive symptoms are common among patients with chronic obstructive pulmonary disease (COPD), but depression's impact on COPD outcomes has not been fully investigated. We evaluated the impact of comorbid depression on mortality, hospital readmission, smoking behavior, respiratory symptom burden, and physical and social functioning in patients with COPD.
  
  
  METHODS
  In this prospective cohort study, 376 consecutive patients with COPD hospitalized for acute exacerbation were followed up for 1 year. The independent associations of baseline comorbid depression (designated as a Hospital Anxiety and Depression Scale score of > or =8) with mortality, hospital readmission, length of stay, persistent smoking, and quality of life (determined by responses to the St George Respiratory Questionnaire) were evaluated after adjusting for potential confounders.
  
  
  RESULTS
  The prevalence of depression at admission was 44.4%. The median follow-up duration was 369 days, during which 57 patients (15.2%) died, and 202 (53.7%) were readmitted at least once. Multivariate analyses showed that depression was significantly associated with mortality (hazard ratio, 1.93; 95% confidence interval, 1.04-3.58), longer index stay (mean, 1.1 more days; P = .02) and total stay (mean, 3.0 more days; P = .047), persistent smoking at 6 months (odds ratio, 2.30; 95% confidence interval, 1.17-4.52), and 12% to 37% worse symptoms, activities, and impact subscale scores and total score on the St George Respiratory Questionnaire at the index hospitalization and 1 year later, even after controlling for chronicity and severity of COPD, comorbidities, and behavioral, psychosocial, and socioeconomic variables.
  
  
  CONCLUSIONS
  Comorbid depressive symptoms in patients with COPD are associated with poorer survival, longer hospitalization stay, persistent smoking, increased symptom burden, and poorer physical and social functioning. Interventions that reduce depressive symptoms may potentially affect COPD outcomes.
authors.affiliation: Gerontological Research Programme, Faculty of Medicine, National University of Singapore, Singapore. pcmngtp@nus.edu.sg
authors.forename: Tze-Pin
authors.initials: TP
authors.lastname: Ng
authors.forename: Mathew
authors.initials: M
authors.lastname: Niti
authors.forename: Wan-Cheng
authors.initials: WC
authors.lastname: Tan
authors.forename: Zhenying
authors.initials: Z
authors.lastname: Cao
authors.forename: Kian-Chung
authors.initials: KC
authors.lastname: Ong
authors.forename: Philip
authors.initials: P
authors.lastname: Eng
mesh_terms: D000368:Aged; D003866:Depressive Disorder / Q000401:mortality* / Q000523:psychology; D005260:Female; D005500:Follow-Up Studies; D006304:Health Status; D006801:Humans; D007902:Length of Stay / Q000639:trends; D008297:Male; D010359:Patient Readmission / Q000639:trends*; D011379:Prognosis; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000401:mortality* / Q000523:psychology; D011788:Quality of Life; D012008:Recurrence; D012846:Singapore / Q000453:epidemiology; D011795:Surveys and Questionnaires; D015996:Survival Rate / Q000639:trends