title: Influence of pulmonary emphysema on COPD assessment test-oriented categorization in GOLD document.
abstract: BACKGROUND
  The COPD assessment test (CAT) score is a key component of the multifactorial assessment of COPD in the Global initiative for chronic Obstructive Lung Disease (GOLD) guidelines of 2014. Nevertheless, little is known regarding the differences among COPD categories in terms of clinical parameters such as pulmonary function or radiological findings. Thus, our aims in this study were to evaluate the associations between CAT scores and pulmonary clinical parameters, and to investigate factors that could discriminate between a "less symptomatic group" (categories A and C) and a "more symptomatic group" (categories B and D) among stable COPD patients.
  
  
  METHODS
  We enrolled 200 outpatients at Chiba University Hospital. Study subjects were assessed by CAT, pulmonary function testing, and multidetector computed tomography (MDCT). We assessed possible correlations between these indices.
  
  
  RESULTS
  CAT scores were negatively correlated with percentage of the forced expiratory volume in 1 second predicted value (FEV1 %predicted) and percentage of the diffusing capacity for carbon monoxide per liter of lung volume predicted value (DLCO/VA [%predicted]) results and positively correlated with low attenuation volume percentage (LAV%) and residual volume to total lung capacity ratios (RV/TLC). In the "more symptomatic group" (category B or D), the mean DLCO/VA (%predicted) was significantly lower and the mean LAV% and RV/TLC was significantly higher than those in the "less symptomatic group" (category A or C), respectively. Interestingly, those in category B had higher mean LAV% compared to those in category C.
  
  
  CONCLUSIONS
  CAT scores were significantly correlated with pulmonary function parameters and emphysematous changes on MDCT. The new GOLD classification system would be a step toward a phenotypic approach, especially taking into account the degree of emphysema and hyperinflation.
authors.affiliation: Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Tada
authors.affiliation: Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Kawata
authors.affiliation: Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Ikari
authors.affiliation: Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Kasahara
authors.affiliation: Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Yoriko
authors.initials: Y
authors.lastname: Sakurai
authors.affiliation: Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Iesato
authors.affiliation: Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Rintaro
authors.initials: R
authors.lastname: Nishimura
authors.affiliation: Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.
authors.forename: James
authors.initials: J
authors.lastname: West
authors.affiliation: Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Tatsumi
mesh_terms: D000368:Aged; D005260:Female; D005541:Forced Expiratory Volume; D006785:Hospitals, University; D006801:Humans; D007564:Japan; D008168:Lung / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008176:Lung Volume Measurements; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D010641:Phenotype; D011237:Predictive Value of Tests; D011653:Pulmonary Diffusing Capacity; D029424:Pulmonary Disease, Chronic Obstructive / Q000145:classification / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D011656:Pulmonary Emphysema / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D012129:Respiratory Function Tests / Q000379:methods*; D012720:Severity of Illness Index
keywords: COPD assessment test; diffusing capacity; emphysema; residual volume ratio