Relationship between lung function and quantitative computed tomographic parameters of airway remodeling, air trapping, and emphysema in patients with asthma and chronic obstructive pulmonary disease: A single-center study - 05/05/16
Abstract |
Background |
There is a paucity of studies comparing asthma and chronic obstructive pulmonary disease (COPD) based on thoracic quantitative computed tomographic (QCT) parameters.
Objectives |
We sought to compare QCT parameters of airway remodeling, air trapping, and emphysema between asthmatic patients and patients with COPD and explore their relationship with airflow limitation.
Methods |
Asthmatic patients (n = 171), patients with COPD (n = 81), and healthy subjects (n = 49) recruited from a single center underwent QCT and clinical characterization.
Results |
Proximal airway percentage wall area (%WA) was significantly increased in asthmatic patients (62.5% [SD, 2.2]) and patients with COPD (62.7% [SD, 2.3]) compared with that in healthy control subjects (60.3% [SD, 2.2], P < .001). Air trapping measured based on mean lung density expiratory/inspiratory ratio was significantly increased in patients with COPD (mean, 0.922 [SD, 0.037]) and asthmatic patients (mean, 0.852 [SD, 0.061]) compared with that in healthy subjects (mean, 0.816 [SD, 0.066], P < .001). Emphysema assessed based on lung density measured by using Hounsfield units below which 15% of the voxels lie (Perc15) was a feature of COPD only (patients with COPD: mean, −964 [SD, 19.62] vs asthmatic patients: mean, −937 [SD, 22.7] and healthy subjects: mean, −937 [SD, 17.1], P < .001). Multiple regression analyses showed that the strongest predictor of lung function impairment in asthmatic patients was %WA, whereas in the COPD and asthma subgrouped with postbronchodilator FEV1 percent predicted value of less than 80%, it was air trapping. Factor analysis of QCT parameters in asthmatic patients and patients with COPD combined determined 3 components, with %WA, air trapping, and Perc15 values being the highest loading factors. Cluster analysis identified 3 clusters with mild, moderate, or severe lung function impairment with corresponding decreased lung density (Perc15 values) and increased air trapping.
Conclusions |
In asthmatic patients and patients with COPD, lung function impairment is strongly associated with air trapping, with a contribution from proximal airway narrowing in asthmatic patients.
Le texte complet de cet article est disponible en PDF.Key words : Asthma, chronic obstructive pulmonary disease, airway remodeling, quantitative computed tomography, asthma-COPD overlap syndrome, small airway disease, emphysema, gas trapping
Abbreviations used : BSA, COPD, CT, GINA, ICC, KCO, LA, MLDE/I, Perc15, QCT, TA, WA
Plan
| Supported by GlaxoSmithKline, Novartis, Roche, a Wellcome Trust Senior Fellowship (CEB), the Airway Disease Predicting Outcomes through Patient Specific Computational Modelling (AirPROM) project (funded through FP7 EU grant), the Leicester National Institute for Health Research (NIHR) Respiratory Biomedical Research Unit, and the MRC-ABPI COPD consortium (COPDMAP). S.G. is a National Institute for Health Research (NIHR) Clinical Lecturer and is funded by a research and career development training scheme. This article presents independent research funded by the National Institute for Health Research (NIHR). The views expressed are those of the authors and not necessarily those of the NHS, the NIHR, or the Department of Health. |
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| Disclosure of potential conflict of interest: R. Kajekar is employed by Novartis Pharmaceutical. R. K. is employed by and is shareholder in Novartis Pharmaceuticals AG, Switzerland. M. Laurencin is an employee of Novartis Pharmaceuticals AG. R. P. Marshall and A. R. Sousa are employees of and shareholders in GlaxoSmithKline. S. Siddiqui receives consultancy fees from Chiesi at ERS 2015; is on advisory boards for Chiesi, Boehringer, Astra Zeneca, Roche, and GlaxoSmithKline; is a consultant for Stallergenes and Mundipharma; received grants from Sir Jules Thorne Trust Grant, Chiesi Onulus Grant, and Chiesi Gift in Aid; and receives payment for ERS 2015: AirPROM Small Airway Symposium. S. Gupta received funds from the National Institute for Health Research, received a grant from the Royal College of Radiologists Pump Priming Grant Scheme, and has a pending grant from the Academy of Medical Sciences Starter Grants for Clinical Lecturers Scheme. C. E. Brightling received a grant from GlaxoSmithKline, Novartis, Roche, MRC, and FP7 EU; received a grant from GlaxoSmithKline, Novartis, BI, Astra Zeneca, Chiesi, Pfizer, and Vectura; and is a consultant for GlaxoSmithKline, Novartis, BI, Astra Zeneca, Chiesi, Pfizer, and Vectura. The rest of the authors declare that they have no relevant conflicts of interest. |
Vol 137 - N° 5
P. 1413 - mai 2016 Retour au numéro
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