title: Can COPD patients who hyperinflate during daily life activities be identified by laboratory tests?
abstract: BACKGROUND
  Identification of patients with chronic obstructive pulmonary disease (COPD) who develop dynamic hyperinflation (DH) during activities in daily life (ADL) is important, because of the association between DH and dyspnea and exercise limitation.
  
  
  OBJECTIVE
  We aimed to answer the question whether measurements of DH during metronome-paced tachypnea (MPT) or cardiopulmonary exercise testing (CPET) can be used to identify patients who develop DH during ADL.
  
  
  METHODS
  DH was measured by tracking changes in inspiratory capacity during CPET, MPT and ADL. Bland-Altman plots were used to evaluate agreement in DH between methods. With a receiver operating characteristic (ROC) analysis, the overall accuracy of MPT and CPET to identify patients who hyperinflate during ADL was assessed.
  
  
  RESULTS
  There are broad limits of agreement in DH between methods. ROC curve analyses showed good overall accuracy of both CPET and MPT to identify patients who hyperinflate during ADL. For CPET, area under the curve (AUC) = 0.956 (95% CI 0.903-1.009). For MPT, AUC = 0.840 (95% CI 0.699-0.981). Sensitivity and specificity to identify patients who hyperinflate during ADL with CPET were 96 and 83%, respectively, and with MPT, they were 89 and 77%, respectively.
  
  
  CONCLUSIONS
  Both CPET and MPT can serve as screening tools to identify patients who are susceptible to developing DH during ADL. In practice, MPT is the most simple and inexpensive surrogate. However, the sensitivity of MPT is not optimal. When DH does not occur during CPET, it is unlikely to occur during ADL.
authors.affiliation: Radboud University Nijmegen Medical Centre, Department of Pulmonary Diseases, Nijmegen, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Lahaije
authors.forename: H
authors.initials: H
authors.lastname: van Helvoort
authors.forename: R
authors.initials: R
authors.lastname: Dekhuijzen
authors.forename: Y
authors.initials: Y
authors.lastname: Heijdra
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D004198:Disease Susceptibility; D005080:Exercise Test; D006801:Humans; D008875:Middle Aged; D011237:Predictive Value of Tests; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*