title: Does the COPD assessment test (CAT(TM)) questionnaire produce similar results when self- or interviewer administered?
abstract: OBJECTIVE
  The COPD assessment test (CAT) is a questionnaire that assesses the impact of chronic obstructive pulmonary disease (COPD) on health status, but some patients have difficulties filling it up by themselves. We examined whether the mode of administration of the Spanish version of CAT (self vs. interviewer) influences its scores and/or psychometric properties.
  
  
  METHODS
  Observational, prospective study in 49 Spanish centers that includes clinically stable COPD patients (n = 153) and patients hospitalized because of an exacerbation (ECOPD; n = 224). The CAT was self-administered (CAT-SA) or administered by an interviewer (CAT-IA) based on the investigator judgment of the patient's capacity. To assess convergent validity, the Saint George's Respiratory Disease Questionnaire (SGRQ) and the London Chest Activity of Daily Living (LCADL) instrument were also administered. Psychometric properties were compared across modes of administration.
  
  
  RESULTS
  A total of 118 patients (31 %) completed the CAT-SA and 259 (69 %) CAT-IA. Multiple regression analysis showed that mode of administration did not affect CAT scores. The CAT showed excellent psychometric properties in both modes of administration. Internal consistency coefficients (Cronbach's alpha) were high (0.86 for CAT-SA and 0.85 for CAT-IA) as was test-retest reliability (intraclass correlation coefficients of 0.83 for CAT-SA and CAT-IA). Correlations with SGRQ and LCADL were moderate to strong both in CAT-SA and CAT-IA, indicating good convergent validity. Similar results were observed when testing longitudinal validity.
  
  
  CONCLUSIONS
  The mode of administration does not influence CAT scores or its psychometric properties. Hence, both modes of administration can be used in clinical practice depending on the physician judgment of patient's capacity.
authors.affiliation: Thorax Institute, Hospital Clinic, IDIBAPS, University of Barcelona, Barcelona, Spain.|FISIB, CIBERES, Mallorca, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Agusti
authors.affiliation: Hospital de Requena, Requena, Valencia, Spain.
authors.forename: J J
authors.initials: JJ
authors.lastname: Soler-Cataluña
authors.affiliation: Centro de salud Francia, Fuenlabrada, Madrid, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Molina
authors.affiliation: GlaxoSmithKline, Tres Cantos, Madrid, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Morejon
authors.affiliation: GlaxoSmithKline, Tres Cantos, Madrid, Spain. mgarcialosa@es.imshealth.com.|IMS Health, C/Dr. Ferran 25-27, 08034, Barcelona, Spain. mgarcialosa@es.imshealth.com.
authors.forename: M
authors.initials: M
authors.lastname: Garcia-Losa
authors.affiliation: IMS Health, C/Dr. Ferran 25-27, 08034, Barcelona, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Roset
authors.affiliation: IMS Health, C/Dr. Ferran 25-27, 08034, Barcelona, Spain.
authors.forename: X
authors.initials: X
authors.lastname: Badia
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011594:Psychometrics / Q000295:instrumentation; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis*; D011788:Quality of Life; D015203:Reproducibility of Results; D012959:Socioeconomic Factors; D013030:Spain; D011795:Surveys and Questionnaires
keywords: CAT; COPD; Mode of administration; Quality of life; Questionnaire
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