title: Depression, but not sleep disorder, is an independent factor affecting exacerbations and hospitalization in patients with chronic obstructive pulmonary disease.
abstract: OBJECTIVE
  Patients with chronic obstructive pulmonary disease (COPD) may experience depression and sleep disorders, which can adversely affect their health-related quality of life (HRQOL). The aim of this study was to investigate depression and sleep disorders among 85 COPD patients and 46 control subjects, aged 40 years and over.
  
  
  METHODS
  Patients underwent spirometry and arterial blood gas analysis, self-completed St. George's respiratory questionnaire and were assessed on the center for epidemiologic studies depression (CES-D) and the Pittsburgh sleep quality index (PSQI). The frequency of exacerbations among COPD patients was prospectively monitored for 12 months.
  
  
  RESULTS
  The prevalence of depression and sleep disorders was significantly higher among COPD patients than control subjects. The relative risks (95% confidence interval) of depression and sleep disorders were 7.58 (1.03 to 55.8) and 1.82 (1.03 to 3.22), respectively, in COPD patients compared with control subjects. Among COPD patients, there was a correlation between CES-D and PSQI. Lower body mass index, more severe dyspnoea, poorer HRQOL, lower partial pressure of arterial oxygen and higher partial pressure of arterial carbon dioxide were significantly associated with the incidence of depression and sleep disorders. Exacerbations and hospitalizations were more frequent among COPD patients with depression than those with sleep disorders alone or those without depression or sleep disorders.
  
  
  CONCLUSIONS
  Depression and sleep disorders are very common co-morbidities among COPD patients and significantly reduce activities and HRQOL among these patients. Depression, but not sleep disorder, is an independent risk factor for exacerbations and hospitalization among COPD patients.
authors.affiliation: Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume, Japan.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Ito
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Kawayama
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Shoji
authors.forename: Noriko
authors.initials: N
authors.lastname: Fukushima
authors.forename: Kazuko
authors.initials: K
authors.lastname: Matsunaga
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Edakuni
authors.forename: Naohisa
authors.initials: N
authors.lastname: Uchimura
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Hoshino
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002245:Carbon Dioxide / Q000097:blood; D003863:Depression / Q000453:epidemiology* / Q000523:psychology; D018450:Disease Progression; D004417:Dyspnea / Q000453:epidemiology / Q000523:psychology; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D008297:Male; D010100:Oxygen / Q000097:blood; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology*; D011788:Quality of Life; D012129:Respiratory Function Tests; D012720:Severity of Illness Index; D012893:Sleep Wake Disorders / Q000453:epidemiology* / Q000523:psychology; D011795:Surveys and Questionnaires
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen