title: The influence of COPD on health-related quality of life independent of the influence of comorbidity.
abstract: OBJECTIVE
  The goal of this study was to determine the influence of chronic obstructive pulmonary disease (COPD) on health-related quality of life (HRQL) independent of comorbidity.
  
  
  METHODS
  Patients with COPD in general practice, >/=40 years, were selected. To recruit controls, a random sample of persons without COPD and >/=40 years, was taken. HRQL was assessed with the SF-36 and comorbidity was determined by questionnaire.
  
  
  RESULTS
  The influence of COPD on HRQL independent of comorbidity (represented by adjusted regression coefficients) was significant for physical functioning (-27.6), role functioning due to physical problems (-21.6), vitality (-14.4), and general health (-25.7), and was minor and not significant for social functioning (-5.6), mental health (-1.3), role functioning due to emotional problems (-2.7), and bodily pain (-2.5). Comorbidity contributed significantly to the HRQL of all domains (-7.6 to -27.1).
  
  
  CONCLUSIONS
  COPD patients can be impaired in all domains of HRQL. However, impairments in physical functioning, vitality, and general health are related to COPD and to some extent to comorbidity, while impairments in social and emotional functioning do not seem to be related to COPD, but only to comorbidity.
authors.affiliation: Department of General Practice, Division of Public Health, Academic Medical Center-University of Amsterdam, P.O. Box 22660, 1100 DD, Amsterdam, The Netherlands. j.g.van_manen@lumc.nl
authors.forename: Jeannette G
authors.initials: JG
authors.lastname: van Manen
authors.forename: Patrick J E
authors.initials: PJ
authors.lastname: Bindels
authors.forename: Friedo W
authors.initials: FW
authors.lastname: Dekker
authors.forename: Bernardus J A M
authors.initials: BJ
authors.lastname: Bottema
authors.forename: Jaring S
authors.initials: JS
authors.lastname: van der Zee
authors.forename: C Joris
authors.initials: CJ
authors.lastname: Ijzermans
authors.forename: Egbert
authors.initials: E
authors.lastname: Schadé
mesh_terms: D000368:Aged; D002908:Chronic Disease; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010358:Patient Participation; D029424:Pulmonary Disease, Chronic Obstructive / Q000523:psychology*; D011788:Quality of Life; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires