- Title
- Assessment and reproducibility of non-eosinophilic asthma using induced sputum
- Creator
- Simpson, Jodie L.; McElduff, Patrick; Gibson, Peter G.
- Relation
- Respiration Vol. 79, Issue 2, p. 147-151
- Publisher Link
- http://dx.doi.org/10.1159/000245899
- Publisher
- Karger
- Resource Type
- journal article
- Date
- 2009
- 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.
- Subject
- asthma; eosinophils; non eosinophilic asthma; induced sputum
- Identifier
- uon:7452
- Identifier
- http://hdl.handle.net/1959.13/807645
- Identifier
- ISSN:0025-7931
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