title: Detecting exacerbations using the Clinical COPD Questionnaire.
abstract: BACKGROUND
  Early treatment of COPD exacerbations has shown to be important. Despite a non-negligible negative impact on health related quality of life, a large proportion of these episodes is not reported (no change in treatment). Little is known whether (low burden) strategies are able to capture these unreported exacerbations.
  
  
  METHODS
  The Clinical COPD Questionnaire (CCQ) is a short questionnaire with great evaluative properties in measuring health status. The current explorative study evaluates the discriminative properties of weekly CCQ assessment in detecting exacerbations.
  
  
  RESULTS
  In a multicentre prospective cohort study, 121 patients, age 67.4 ± 10.5 years, FEV1 47.7 ± 18.5% pred were followed for 6 weeks by daily diary card recording and weekly CCQ assessment. Weeks were retrospectively labeled as stable or exacerbation (onset) weeks using the Anthonisen symptom diary-card algorithm. Change in CCQ total scores are significantly higher in exacerbation-onset weeks, 0.35 ± 0.69 compared to -0.04 ± 0.37 in stable weeks (p < 0.001). Performance of the Δ CCQ total score discriminating between stable and exacerbation onset weeks was sufficient (area under the ROC curve 0.75). At a cut off point of 0.2, sensitivity was 62.5 (50.3-73.4), specificity 82.0 (79.3-84.4), and a positive and negative predictive value of 43.5 (35.0-51.0) and 90.8 (87.8-93.5), respectively. Using this cut off point, 22 (out of 38) unreported exacerbations were detected while 39 stable patients would have been false positively 'contacted'.
  
  
  CONCLUSIONS
  Weekly CCQ assessment is a promising, low burden method to detect unreported exacerbations. Further research is needed to validate discriminative performance and practical implications of the CCQ in detecting exacerbations in daily care.
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands. j.c.a.trappenburg@umcutrecht.nl
authors.forename: Jaap C A
authors.initials: JC
authors.lastname: Trappenburg
authors.forename: Irene
authors.initials: I
authors.lastname: Touwen
authors.forename: Gerdien H
authors.initials: GH
authors.lastname: de Weert-van Oene
authors.forename: Jean
authors.initials: J
authors.lastname: Bourbeau
authors.forename: Evelyn M
authors.initials: EM
authors.lastname: Monninkhof
authors.forename: Theo J M
authors.initials: TJ
authors.lastname: Verheij
authors.forename: Jan-Willem J
authors.initials: JW
authors.lastname: Lammers
authors.forename: Augustinus J P
authors.initials: AJ
authors.lastname: Schrijvers
mesh_terms: D000368:Aged; D000465:Algorithms; D002170:Canada; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications*; D011788:Quality of Life; D012372:ROC Curve; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires