title: The COPD Assessment Test: Can It Discriminate Across COPD Subpopulations?
abstract: BACKGROUND
  The COPD Assessment Test (CAT) is a valid disease-specific questionnaire measuring health status. However, knowledge concerning its use regarding patient and disease characteristics remains limited. Our main objective was to assess the degree to which the CAT score varies and can discriminate between specific patient population groups.
  
  
  METHODS
  The Canadian Cohort Obstructive Lung Disease (CanCOLD) is a random-sampled, population-based, multicenter, prospective cohort that includes subjects with COPD (Global Initiative for Chronic Obstructive Lung Disease [GOLD] classifications 1 to 3). The CAT questionnaire was administered at three visits (baseline, 1.5 years, and 3 years). The CAT total score was determined for sex, age groups, smoking status, GOLD classification, exacerbations, and comorbidities.
  
  
  RESULTS
  A total of 716 subjects with COPD were included in the analysis. The majority of subjects (72.5%) were not previously diagnosed with COPD. The mean FEV1/FVC ratio was 61.1 ± 8.1%, with a mean FEV1% predicted of 82.3 ± 19.3%. The mean CAT scores were 5.8 ± 5.0, 9.6 ± 6.7, and 16.1 ± 10.0 for GOLD 1, 2, and 3+ classifications, respectively. Higher CAT scores were observed in women, current smokers, ever-smokers, and subjects with a previous diagnosis of COPD. The CAT was also able to distinguish between subjects who experience exacerbations vs those who had no exacerbation.
  
  
  CONCLUSIONS
  These results suggest that the CAT, originally designed for use in clinically symptomatic patients with COPD, can also be used in individuals with mild airflow obstruction and newly diagnosed COPD. In addition, the CAT was able to discriminate between sexes and subjects who experience frequent and infrequent exacerbations.
  
  
  BACKGROUND
  ClinicalTrials.gov; No.: NCT00920348; Study ID No.: IRO-93326.
authors.affiliation: Respiratory Epidemiology and Clinical Research Unit, Research Institute of McGill University Health Centre and McGill University, Montreal, QC, Canada.
authors.forename: Nisha
authors.initials: N
authors.lastname: Gupta
authors.affiliation: Respiratory Epidemiology and Clinical Research Unit, Research Institute of McGill University Health Centre and McGill University, Montreal, QC, Canada.
authors.forename: Lancelot
authors.initials: L
authors.lastname: Pinto
authors.affiliation: Respiratory Epidemiology and Clinical Research Unit, Research Institute of McGill University Health Centre and McGill University, Montreal, QC, Canada.
authors.forename: Andrea
authors.initials: A
authors.lastname: Benedetti
authors.affiliation: Respiratory Epidemiology and Clinical Research Unit, Research Institute of McGill University Health Centre and McGill University, Montreal, QC, Canada.
authors.forename: Pei Zhi
authors.initials: PZ
authors.lastname: Li
authors.affiliation: University of British Columbia, Vancouver, BC, Canada.
authors.forename: Wan C
authors.initials: WC
authors.lastname: Tan
authors.affiliation: Ottawa University, Ottawa, ON, Canada.
authors.forename: Shawn D
authors.initials: SD
authors.lastname: Aaron
authors.affiliation: University of Toronto, Toronto, ON, Canada.
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Chapman
authors.affiliation: University of British Columbia, Vancouver, BC, Canada.
authors.forename: J Mark
authors.initials: JM
authors.lastname: FitzGerald
authors.affiliation: Dalhousie University, Halifax, NS, Canada.
authors.forename: Paul
authors.initials: P
authors.lastname: Hernandez
authors.affiliation: University of Saskatchewan, Saskatoon, SK, Canada.
authors.forename: Darcy D
authors.initials: DD
authors.lastname: Marciniuk
authors.affiliation: Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, QC, Canada.
authors.forename: François
authors.initials: F
authors.lastname: Maltais
authors.affiliation: Queens University, Kingston, ON, Canada.
authors.forename: Denis E
authors.initials: DE
authors.lastname: O'Donnell
authors.affiliation: University of British Columbia, Vancouver, BC, Canada.
authors.forename: Don
authors.initials: D
authors.lastname: Sin
authors.affiliation: University of Calgary, Calgary, AB, Canada.
authors.forename: Brandie L
authors.initials: BL
authors.lastname: Walker
authors.affiliation: Respiratory Epidemiology and Clinical Research Unit, Research Institute of McGill University Health Centre and McGill University, Montreal, QC, Canada. Electronic address: jean.bourbeau@mcgill.ca.
authors.forename: Jean
authors.initials: J
authors.lastname: Bourbeau
mesh_terms: D000368:Aged; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000145:classification* / Q000503:physiopathology*; D011788:Quality of Life; D015203:Reproducibility of Results; D018570:Risk Assessment; D012307:Risk Factors; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
keywords: COPD; health-related quality of life; patient-reported outcome