title: The COPD assessment test and St George's Respiratory Questionnaire: are they equivalent in subjects with COPD?
abstract: BACKGROUND
  The chronic obstructive pulmonary disease (COPD) assessment test (CAT) is a short questionnaire that has facilitated health status measurements in subjects with COPD. However, it remains controversial as to whether the CAT can be used as a suitable substitute for the St George's Respiratory Questionnaire (SGRQ). This study investigated the reliability and score distributions of the CAT and SGRQ and evaluated which factors contributed to health status for each questionnaire.
  
  
  METHODS
  A total of 109 consecutive subjects with stable COPD from a single center were enrolled in this study. Each subject completed pulmonary function tests, exercise tests, and the following self-administered questionnaires: the Baseline Dyspnea Index, the Hospital Anxiety and Depression Scale, the CAT, and SGRQ.
  
  
  RESULTS
  Internal consistencies of CAT and SGRQ total scores were both excellent (Cronbach's α coefficients =0.890 and 0.933). Statistically significant correlations were observed between CAT and SGRQ total scores (R=0.668, P<0.001). Correlations of CAT scores with parameters related to pulmonary function, dyspnea, exercise performance, and psychological factors were inferior to correlations with those parameters with SGRQ total scores. Both multiple regression analyses and principal component analyses revealed that there were slight differences between SGRQ total scores and CAT scores.
  
  
  CONCLUSIONS
  The CAT is similar to SGRQ in terms of discriminating health status. However, we demonstrated that what is assessed by the CAT may differ slightly from what is measured by SGRQ.
authors.affiliation: Department of Respiratory Medicine and Allergy, Tosei General Hospital, Seto, Japan; Division of Respiratory Medicine, Department of Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Mariko
authors.initials: M
authors.lastname: Morishita-Katsu
authors.affiliation: Department of Pulmonary Medicine, National Center for Geriatrics and Gerontology, Obu, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Nishimura
authors.affiliation: Department of Respiratory Medicine and Allergy, Tosei General Hospital, Seto, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Taniguchi
authors.affiliation: Department of Respiratory Medicine and Allergy, Tosei General Hospital, Seto, Japan.
authors.forename: Tomoki
authors.initials: T
authors.lastname: Kimura
authors.affiliation: Department of Respiratory Medicine and Allergy, Tosei General Hospital, Seto, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kondoh
authors.affiliation: Department of Respiratory Medicine and Allergy, Tosei General Hospital, Seto, Japan.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Kataoka
authors.affiliation: Department of Rehabilitation, Tosei General Hospital, Seto, Japan.
authors.forename: Tomoya
authors.initials: T
authors.lastname: Ogawa
authors.affiliation: Department of Rehabilitation, Tosei General Hospital, Seto, Japan.
authors.forename: Fumiko
authors.initials: F
authors.lastname: Watanabe
authors.affiliation: School of Rehabilitation Sciences, Seirei Christopher University, Hamamatsu, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Arizono
authors.affiliation: Department of Respiratory Medicine and Allergology, Kinki University School of Medicine, Osakasayama, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Nishiyama
authors.affiliation: Data Research Section, Kondo P.P. Inc., Osaka, Japan.
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Nakayasu
authors.affiliation: Department of Respiratory Medicine, Fujita Health University, Nagoya, Japan.
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Imaizumi
authors.affiliation: Division of Respiratory Medicine, Department of Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Hasegawa
mesh_terms: D000368:Aged; D003430:Cross-Sectional Studies; D005080:Exercise Test; D005260:Female; D005541:Forced Expiratory Volume; D006304:Health Status; D006801:Humans; D007564:Japan; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D025341:Principal Component Analysis; D011379:Prognosis; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000503:physiopathology; D012044:Regression Analysis; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013147:Spirometry; D011795:Surveys and Questionnaires; D014797:Vital Capacity
keywords: COPD assessment test; St George’s Respiratory Questionnaire; chronic obstructive pulmonary disease; health status