title: [Validation of the Yale Physical Activity Survey in chronic obstructive pulmonary disease patients].
abstract: BACKGROUND
  Patients with chronic obstructive pulmonary disease (COPD) perform limited physical activity. Surprisingly, there is a lack of research in COPD about the validity of physical activity questionnaires. Our aim was to validate the Yale Physical Activity Survey in COPD patients in order to quantify and classify their levels of physical activity.
  
  
  METHODS
  172 COPD patients from 8 university hospitals in Spain wore an accelerometer (SenseWear(®)Pro(2)Armband) for 8 days and answered the questionnaire 15 days later. Statistical analyses used to compare both tools measures included: (i) Spearman's correlation coefficient, (ii) intraclass correlation coefficient (ICC) and Bland-Altman plots, (iii) distribution of accelerometer measurements according to tertiles of the questionnaire, and (iv) receiver operating characteristic (ROC) curves to detect sedentary patients.
  
  
  RESULTS
  94% of participants were men, 28% were active smokers and 7% were currently working. Mean (standard deviation) age was 70 (8) years, mean post-bronchodilator FEV(1) was 52 (15)% predicted, and median (p25-p75) steps taken was 5,702 (3,273-9,253) steps per day(-1). Spearman correlations were low to moderate (from 0.29 to 0.52, all P<.001). ICCs showed weak agreement (from 0.34 to 0.40, all P<.001). A wide variability in agreement was observed in the Bland-Altman plots. Significant differences in accelerometer measurements were found according to questionnaire tertiles (all P<.001). The area under the ROC for identifying sedentarism was 0.71 (95% CI: 0.63-0.79).
  
  
  CONCLUSIONS
  The Yale Physical Activity Survey may be a valid tool to classify, but not to quantify, physical activity performed by COPD patients. The summary index of this questionnaire, based on seven short questions, shows the best validity properties. This suggests that it should be considered a screening tool to identify patients at risk for sedentarism.
authors.affiliation: Centre de Recerca en Epidemiologia Ambiental (CREAL), Barcelona, España.
authors.forename: David
authors.initials: D
authors.lastname: Donaire-Gonzalez
authors.forename: Elena
authors.initials: E
authors.lastname: Gimeno-Santos
authors.forename: Ignasi
authors.initials: I
authors.lastname: Serra
authors.forename: Josep
authors.initials: J
authors.lastname: Roca
authors.forename: Eva
authors.initials: E
authors.lastname: Balcells
authors.forename: Esther
authors.initials: E
authors.lastname: Rodríguez
authors.forename: Eva
authors.initials: E
authors.lastname: Farrero
authors.forename: Josep M
authors.initials: JM
authors.lastname: Antó
authors.forename: Judith
authors.initials: J
authors.lastname: Garcia-Aymerich
mesh_terms: D000054:Acceleration; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D002245:Carbon Dioxide / Q000097:blood; D015897:Comorbidity; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D009043:Motor Activity; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood / Q000453:epidemiology / Q000503:physiopathology; D012372:ROC Curve; D012720:Severity of Illness Index; D012907:Smoking / Q000453:epidemiology; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires; D014797:Vital Capacity
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen