title: Daily physical activity, functional capacity and quality of life in patients with COPD.
abstract: BACKGROUND
  In the therapy of chronic obstructive pulmonary disease (COPD), it is a major goal to improve health-related quality of life (HRQOL). Patients with COPD often suffer from exertional dyspnea and adopt a sedentary lifestyle, which could be associated with poorer HRQOL. The aim of this study was to investigate the independent association of objectively measured daily physical activity and functional capacity with HRQOL in patients with COPD.
  
  
  METHODS
  In this cross-sectional study conducted at the University Hospital Basel, Switzerland, 87 stable patients (58.6% male, mean age: 67.3 ± 9.6 yrs) with COPD in GOLD grades I (n = 23), II (n = 46), III (n = 12) and IV (n = 6) were investigated. To assess HRQOL, the COPD assessment test (CAT) was completed. Patients performed spirometry and 6-min walk test. Physical activity was measured by the SenseWear Mini Armband on 7 consecutive days. By performing a multiple linear regression analysis, independent predictors of CAT score were identified.
  
  
  RESULTS
  Age (β = -0.39, p = 0.001), average daily steps (β = -0.31, p = 0.033) and 6-min walk distance (β = -0.32, p = 0.019) were found to be independent predictors of CAT score, whereas physical activity duration above 3 METs (p = 0.498) and forced expiratory volume in 1 s in% of predicted (p = 0.364) showed no significant association.
  
  
  CONCLUSIONS
  This study showed that average daily steps and functional capacity are independent determinants of HRQOL in patients with COPD. This emphasizes the importance to remain active and mobile, which is associated with better HRQOL.
authors.affiliation: 1Medical University Clinic, Cantonal Hospital Baselland , Liestal, Switzerland and Medical Faculty, University of Basel, Basel , Switzerland.
authors.forename: Selina
authors.initials: S
authors.lastname: Dürr
authors.forename: Stefanie
authors.initials: S
authors.lastname: Zogg
authors.forename: David
authors.initials: D
authors.lastname: Miedinger
authors.forename: Esther Helen
authors.initials: EH
authors.lastname: Steveling
authors.forename: Sabrina
authors.initials: S
authors.lastname: Maier
authors.forename: Jörg Daniel
authors.initials: JD
authors.lastname: Leuppi
mesh_terms: D061725:Accelerometry; D000367:Age Factors; D000368:Aged; D003430:Cross-Sectional Studies; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D011788:Quality of Life; D014797:Vital Capacity; D016138:Walking / Q000502:physiology*
keywords: 6-min walk distance; COPD assessment test (CAT); Daily steps; SenseWear Mini armband; health-related quality of life