Influence of pulmonary emphysema on COPD assessment test-oriented categorization in GOLD document
Received 15 February 2015
Accepted for publication 16 April 2015
Published 19 June 2015 Volume 2015:10(1) Pages 1199—1205
Checked for plagiarism Yes
Review by Single-blind
Peer reviewer comments 3
Editor who approved publication: Dr Richard Russell
Toshio Suzuki,1 Yuji Tada,1 Naoko Kawata,1 Jun Ikari,1 Yasunori Kasahara,1 Yoriko Sakurai,1 Ken Iesato,1 Rintaro Nishimura,1 James West,2 Koichiro Tatsumi1
1Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan; 2Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
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.
Conclusion: 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.
Keywords: COPD assessment test, diffusing capacity, emphysema, residual volume ratio
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