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Fixed airways obstruction among patients with severe asthma: findings from the Singapore General Hospital-Severe Asthma Phenotype Study

BACKGROUND: A subset of severe asthma patients has fixed airways obstruction, which is characterized by incomplete reversibility to bronchodilator challenge. We aimed to elucidate the factors associated with fixed airways obstruction in a cohort of patients with severe asthma in Singapore. METHODS:...

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Autores principales: Yii, Anthony Chau Ang, Tan, Gan Liang, Tan, Keng Leong, Lapperre, Therese Sophie, Koh, Mariko Siyue
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4265441/
https://www.ncbi.nlm.nih.gov/pubmed/25467558
http://dx.doi.org/10.1186/1471-2466-14-191
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author Yii, Anthony Chau Ang
Tan, Gan Liang
Tan, Keng Leong
Lapperre, Therese Sophie
Koh, Mariko Siyue
author_facet Yii, Anthony Chau Ang
Tan, Gan Liang
Tan, Keng Leong
Lapperre, Therese Sophie
Koh, Mariko Siyue
author_sort Yii, Anthony Chau Ang
collection PubMed
description BACKGROUND: A subset of severe asthma patients has fixed airways obstruction, which is characterized by incomplete reversibility to bronchodilator challenge. We aimed to elucidate the factors associated with fixed airways obstruction in a cohort of patients with severe asthma in Singapore. METHODS: 245 patients from the Singapore General Hospital-Severe Asthma Phenotype Study (SGH-SAPS) were screened. These patients fulfilled World Health Organization criteria for "treatment-resistant severe asthma" and were all on combination of high-dose inhaled corticosteroids and long-acting beta2 agonists. 76 patients had pre- and postbronchodilator lung function tests and were selected for analysis. They were divided into two groups based on postbronchodilator (Post BD) forced expiratory volume in one second, PostBDFEV(1) % predicted: ≥70% (Non-Fixed Obs) and < 70% (Fixed Obs). We compared clinical and demographic parameters between the two groups. RESULTS: Patients in the Fixed Obs group were more frequently past or current smokers and had a higher pack-year smoking history. Overall, pack-year smoking history had a modest negative correlation with PostBDFEV(1) % predicted. Atopy, allergen sensitization (type and numbers), comorbidities, symptoms, health care utilization and medication use did not differ between the two groups. The prebronchodilator FEV(1) % predicted, FEV(1)/FVC and FVC % predicted were significantly lower in the Fixed Obs group. In addition, prebronchodilator FVC % predicted accounted for more variability than FEV(1)/FVC in predicting PostBDFEV(1)% predicted. CONCLUSION: Smoking is associated with fixed airways obstruction in patients with treatment-resistant severe asthma in Singapore. Furthermore, our results suggest that both small and large airways obstruction contribute independently to fixed airways obstruction in severe asthma.
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spelling pubmed-42654412014-12-15 Fixed airways obstruction among patients with severe asthma: findings from the Singapore General Hospital-Severe Asthma Phenotype Study Yii, Anthony Chau Ang Tan, Gan Liang Tan, Keng Leong Lapperre, Therese Sophie Koh, Mariko Siyue BMC Pulm Med Research Article BACKGROUND: A subset of severe asthma patients has fixed airways obstruction, which is characterized by incomplete reversibility to bronchodilator challenge. We aimed to elucidate the factors associated with fixed airways obstruction in a cohort of patients with severe asthma in Singapore. METHODS: 245 patients from the Singapore General Hospital-Severe Asthma Phenotype Study (SGH-SAPS) were screened. These patients fulfilled World Health Organization criteria for "treatment-resistant severe asthma" and were all on combination of high-dose inhaled corticosteroids and long-acting beta2 agonists. 76 patients had pre- and postbronchodilator lung function tests and were selected for analysis. They were divided into two groups based on postbronchodilator (Post BD) forced expiratory volume in one second, PostBDFEV(1) % predicted: ≥70% (Non-Fixed Obs) and < 70% (Fixed Obs). We compared clinical and demographic parameters between the two groups. RESULTS: Patients in the Fixed Obs group were more frequently past or current smokers and had a higher pack-year smoking history. Overall, pack-year smoking history had a modest negative correlation with PostBDFEV(1) % predicted. Atopy, allergen sensitization (type and numbers), comorbidities, symptoms, health care utilization and medication use did not differ between the two groups. The prebronchodilator FEV(1) % predicted, FEV(1)/FVC and FVC % predicted were significantly lower in the Fixed Obs group. In addition, prebronchodilator FVC % predicted accounted for more variability than FEV(1)/FVC in predicting PostBDFEV(1)% predicted. CONCLUSION: Smoking is associated with fixed airways obstruction in patients with treatment-resistant severe asthma in Singapore. Furthermore, our results suggest that both small and large airways obstruction contribute independently to fixed airways obstruction in severe asthma. BioMed Central 2014-12-03 /pmc/articles/PMC4265441/ /pubmed/25467558 http://dx.doi.org/10.1186/1471-2466-14-191 Text en © Yii et al.; licensee BioMed Central Ltd. 2014 This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research Article
Yii, Anthony Chau Ang
Tan, Gan Liang
Tan, Keng Leong
Lapperre, Therese Sophie
Koh, Mariko Siyue
Fixed airways obstruction among patients with severe asthma: findings from the Singapore General Hospital-Severe Asthma Phenotype Study
title Fixed airways obstruction among patients with severe asthma: findings from the Singapore General Hospital-Severe Asthma Phenotype Study
title_full Fixed airways obstruction among patients with severe asthma: findings from the Singapore General Hospital-Severe Asthma Phenotype Study
title_fullStr Fixed airways obstruction among patients with severe asthma: findings from the Singapore General Hospital-Severe Asthma Phenotype Study
title_full_unstemmed Fixed airways obstruction among patients with severe asthma: findings from the Singapore General Hospital-Severe Asthma Phenotype Study
title_short Fixed airways obstruction among patients with severe asthma: findings from the Singapore General Hospital-Severe Asthma Phenotype Study
title_sort fixed airways obstruction among patients with severe asthma: findings from the singapore general hospital-severe asthma phenotype study
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4265441/
https://www.ncbi.nlm.nih.gov/pubmed/25467558
http://dx.doi.org/10.1186/1471-2466-14-191
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