Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.13/807645

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Title
Assessment and reproducibility of non-eosinophilic asthma using induced sputum
Author/Creator
Simpson, Jodie L.;  McElduff, Patrick;  Gibson, Peter G.
Institution
The University of Newcastle. Faculty of Health, School of Medicine and Public Health
Description
Background: The assessment of eosinophilic airway inflammation using induced sputum identifies a corticosteroid-responsive subtype that can be used to guide anti-inflammatory therapy. The stability of airway inflammation in asthma over time is not known, yet this information is crucial to inflammation-based patient management. Objective: The aim of this study was to determine the reproducibility of non-eosinophilic asthma. Methods: Participants with stable asthma (n = 26) underwent a sputum induction each month for 5 months. Sputum was dispersed and differential cell counts were performed. The reproducibility of inflammatory subtype with different eosinophil cut points (starting at 1% eosinophils) was examined and the minimum number of visits required to determine inflammatory subtype was calculated. Results: One hundred and twenty- two sputum samples were obtained (success 94%). All cut points greater than 2% eosinophils were reproducible and a 3% cut point resulted in the highest agreement with a ĸ statistic of 0.538. Specificity and sensitivity were high for determining inflammatory subtype after 1 or 3 sputum samples. Conclusions: A cut point of 3% eosinophils should be used to distinguish eosinophilic from non-eosinophilic airway inflammation in asthma. This allows a single sputum sample to be used to reliably determine the presence of eosinophilia.
Relation
Respiration Vol. 79, Issue 2, p. 147-151
Publisher Link
http://dx.doi.org/10.1159/000245899
Date
2009
Publisher
Karger
Keyword(s)
asthma;  eosinophils;  non eosinophilic asthma;  induced sputum
Resource Type
journal article
Identifier
http://hdl.handle.net/1959.13/807645
Identifier
ISSN:0025-7931
Reviewed
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Subject
"Respiration"
 
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