title: Physical Activity Characteristics across GOLD Quadrants Depend on the Questionnaire Used.
abstract: BACKGROUND
  The GOLD multidimensional classification of COPD severity combines the exacerbation risk with the symptom experience, for which 3 different questionnaires are permitted. This study investigated differences in physical activity (PA) in the different GOLD quadrants and patient's distribution in relation to the questionnaire used.
  
  
  METHODS
  136 COPD patients (58±21% FEV1 predicted, 34F/102M) completed COPD assessment test (CAT), clinical COPD questionnaire (CCQ) and modified Medical Research Council (mMRC) questionnaire. Exacerbation history, spirometry and 6MWD were collected. PA was objectively measured for 2 periods of 1 week, 6 months apart, in 5 European centres; to minimise seasonal and clinical variation the average of these two periods was used for analysis.
  
  
  RESULTS
  GOLD quadrants C+D had reduced PA compared with A+B (3824 [2976] vs. 5508 [4671] steps.d-1, p<0.0001). The choice of questionnaire yielded different patient distributions (agreement mMRC-CAT κ = 0.57; CCQ-mMRC κ = 0.71; CCQ-CAT κ = 0.72) with different clinical characteristics. PA was notably lower in patients with an mMRC score ≥2 (3430 [2537] vs. 5443 [3776] steps.d-1, p <0.001) in both the low and high risk quadrants.
  
  
  CONCLUSIONS
  Using different questionnaires changes the patient distribution and results in different clinical characteristics. Therefore, standardization of the questionnaire used for classification is critical to allow comparison of different studies using this as an entry criterion.
  
  
  BACKGROUND
  ClinicalTrials.gov NCT01388218.
authors.affiliation: KU Leuven, Department of Rehabilitation Sciences, B-3000, Leuven, Belgium.|University Hospitals Leuven, Department of Respiratory Diseases, B-3000, Leuven, Belgium.
authors.forename: Heleen
authors.initials: H
authors.lastname: Demeyer
authors.affiliation: Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain.|CIBER Epidemiologia y Salud Publica (CIBERESP), Barcelona, Spain.|Universitat Pompeu Fabra (UPF), Barcelona, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Gimeno-Santos
authors.affiliation: ELEGI/Colt laboratory, UoE/MRC Centre for Inflammation Research, The University of Edinburgh, Edinburgh, Scotland.
authors.forename: Roberto A
authors.initials: RA
authors.lastname: Rabinovich
authors.affiliation: KU Leuven, Department of Rehabilitation Sciences, B-3000, Leuven, Belgium.|University Hospitals Leuven, Department of Respiratory Diseases, B-3000, Leuven, Belgium.
authors.forename: Miek
authors.initials: M
authors.lastname: Hornikx
authors.affiliation: Dept of Critical Care Medicine, Pulmonary Rehabilitation Centre, Evangelismos Hospital, M. Simou and G.P. Livanos Laboratories, National and Kapodistrian University of Athens, Thorax Foundation, Athens, Greece.
authors.forename: Zafeiris
authors.initials: Z
authors.lastname: Louvaris
authors.affiliation: Department of Pulmonology, Leiden University Medical Center, Leiden, Netherlands.
authors.forename: Willem I
authors.initials: WI
authors.lastname: de Boer
authors.affiliation: Astra Zeneca, Mölndal, Sweden.
authors.forename: Niklas
authors.initials: N
authors.lastname: Karlsson
authors.affiliation: Department of General Practice, University Medical Center Groningen, Groningen, Netherlands.
authors.forename: Corina
authors.initials: C
authors.lastname: de Jong
authors.affiliation: Department of Primary Care, University of Groningen, University Medical Centre Groningen, Groningen, Netherlands.
authors.forename: Thys
authors.initials: T
authors.lastname: Van der Molen
authors.affiliation: Dept of Critical Care Medicine, Pulmonary Rehabilitation Centre, Evangelismos Hospital, M. Simou and G.P. Livanos Laboratories, National and Kapodistrian University of Athens, Thorax Foundation, Athens, Greece.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Vogiatzis
authors.affiliation: University Hospitals Leuven, Department of Respiratory Diseases, B-3000, Leuven, Belgium.
authors.forename: Wim
authors.initials: W
authors.lastname: Janssens
authors.affiliation: Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain.|CIBER Epidemiologia y Salud Publica (CIBERESP), Barcelona, Spain.|Universitat Pompeu Fabra (UPF), Barcelona, Spain.
authors.forename: Judith
authors.initials: J
authors.lastname: Garcia-Aymerich
authors.affiliation: KU Leuven, Department of Rehabilitation Sciences, B-3000, Leuven, Belgium.|University Hospitals Leuven, Department of Respiratory Diseases, B-3000, Leuven, Belgium.
authors.forename: Thierry
authors.initials: T
authors.lastname: Troosters
authors.affiliation: NIHR Respiratory Biomedical Research Unit of the Royal Brompton and Harefield NHS foundation Trust and Imperial College London, London, United Kingdom.
authors.forename: Michael I
authors.initials: MI
authors.lastname: Polkey
mesh_terms: D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D029424:Pulmonary Disease, Chronic Obstructive / Q000145:classification / Q000503:physiopathology*; D011795:Surveys and Questionnaires