title: Impact of comorbidities on physical activity in COPD.
abstract: OBJECTIVE
  Both comorbidities and physical inactivity have been shown to impair quality of life and contribute to hospital admissions and mortality in chronic obstructive pulmonary disease (COPD) patients. We hypothesized that the comorbid status predicts the level of daily physical activity (PA) in COPD.
  
  
  METHODS
  In 228 patients with COPD (76% men; median (quartiles) age: 64 (59/69) years; percentage of predicted forced expiratory volume in 1 s (FEV1 % pred): 44 (31/63)), comorbidities were assessed by medical history, clinical interviews, examination and blood analysis. PA level (PAL) was measured by an activity monitor (SenseWear Pro, Bodymedia Inc., Pittsburgh, PA, USA). The association between PAL and comorbidities was investigated by univariate and multivariate regression analysis.
  
  
  RESULTS
  Seventy-nine percent of the COPD patients had at least one additional chronic comorbidity, 56% had two or more comorbidities and 35% had three or more comorbidities. In univariate analysis body mass index, the number of pack years and having at least one additional comorbidity was negatively associated with PAL while there was a positive nonlinear association between FEV1 and PAL. The presence of at least one additional comorbidity was independently associated with PAL irrespective of airflow limitation.
  
  
  CONCLUSIONS
  In this cohort, almost 80% of COPD patients had at least one additional chronic comorbidity. The level of daily PA seems to be significantly impaired by the presence of comorbidities irrespective of the type of comorbidity and independent of the degree of airflow limitation.
  
  
  BACKGROUND
  NCT01527773 at http://www.clinicalTrials.gov.
authors.affiliation: Pulmonary Division, University Hospital of Zurich, Zurich, Switzerland.
authors.forename: Noriane A
authors.initials: NA
authors.lastname: Sievi
authors.forename: Oliver
authors.initials: O
authors.lastname: Senn
authors.forename: Thomas
authors.initials: T
authors.lastname: Brack
authors.forename: Martin H
authors.initials: MH
authors.lastname: Brutsche
authors.forename: Martin
authors.initials: M
authors.lastname: Frey
authors.forename: Sarosh
authors.initials: S
authors.lastname: Irani
authors.forename: Jörg D
authors.initials: JD
authors.lastname: Leuppi
authors.forename: Robert
authors.initials: R
authors.lastname: Thurnheer
authors.forename: Daniel
authors.initials: D
authors.lastname: Franzen
authors.forename: Malcolm
authors.initials: M
authors.lastname: Kohler
authors.forename: Christian F
authors.initials: CF
authors.lastname: Clarenbach
mesh_terms: D000368:Aged; D015331:Cohort Studies; D015897:Comorbidity; D003324:Coronary Artery Disease / Q000453:epidemiology*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D015999:Multivariate Analysis; D009765:Obesity / Q000453:epidemiology*; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology / Q000503:physiopathology / Q000523:psychology; D011788:Quality of Life; D012129:Respiratory Function Tests / Q000379:methods; D013557:Switzerland / Q000453:epidemiology
keywords: activity monitor; airflow limitation; chronic obstructive pulmonary disease; comorbidity; physical activity level