title: Usefulness of the Chronic Obstructive Pulmonary Disease Assessment Test to evaluate severity of COPD exacerbations.
abstract: BACKGROUND
  The Chronic Obstructive Pulmonary Disease (COPD) Assessment Test (CAT) is an eight-item questionnaire designed to assess and quantify the impact of COPD symptoms on health status. COPD exacerbations impair quality of life and are characterized by worsening respiratory symptoms from the stable state. We hypothesized that CAT scores at exacerbation relate to exacerbation severity as measured by exacerbation duration, lung function impairment, and systemic inflammation.
  
  
  OBJECTIVE
  To evaluate the usefulness of the CAT to assess exacerbation severity.
  
  
  METHODS
  One hundred sixty-one patients enrolled in the London COPD cohort completed the CAT at baseline (stable state), exacerbation, and during recovery between April 2010 and June 2011.
  
  
  RESULTS
  Frequent exacerbators had significantly higher baseline CAT scores than infrequent exacerbators (19.5 ± 6.6 vs. 16.8 ± 8.0, P = 0.025). In 152 exacerbations, CAT scores rose from an average baseline value of 19.4 ± 6.8 to 24.1 ± 7.3 (P < 0.001) at exacerbation. Change in CAT score from baseline to exacerbation onset was significantly but weakly related to change in C-reactive protein (rho = 0.26, P = 0.008) but not to change in fibrinogen (rho = 0.09, P = 0.351) from baseline to exacerbation. At exacerbation, rises in CAT score were significantly associated with falls in FEV(1) (rho = -0.20, P = 0.032). Median recovery time as judged by symptom diary cards was significantly related to the time taken for the CAT score to return to baseline (rho = 0.42, P = 0.012).
  
  
  CONCLUSIONS
  The CAT provides a reliable score of exacerbation severity. Baseline CAT scores are elevated in frequent exacerbators. CAT scores increase at exacerbation and reflect severity as determined by lung function and exacerbation duration.
authors.affiliation: Academic Unit of Respiratory Medicine, University College London Medical School, Royal Free Campus, Rowland Hill Street, London, United Kingdom. alexander.mackay@ucl.ac.uk
authors.forename: Alex J
authors.initials: AJ
authors.lastname: Mackay
authors.forename: Gavin C
authors.initials: GC
authors.lastname: Donaldson
authors.forename: Anant R C
authors.initials: AR
authors.lastname: Patel
authors.forename: Paul W
authors.initials: PW
authors.lastname: Jones
authors.forename: John R
authors.initials: JR
authors.lastname: Hurst
authors.forename: Jadwiga A
authors.initials: JA
authors.lastname: Wedzicha
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002097:C-Reactive Protein / Q000378:metabolism*; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D018836:Inflammation Mediators / Q000032:analysis*; D008297:Male; D010358:Patient Participation; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000503:physiopathology*; D015203:Reproducibility of Results; D012129:Respiratory Function Tests; D057566:Self Report; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires
chemical_list: D018836:Inflammation Mediators; D002097:C-Reactive Protein