Jodie L Simpson1, Patrick McElduff, Peter G Gibson. 1. Centre for Asthma and Respiratory Disease, The University of Newcastle, Callaghan, NSW, Australia. Jodie.simpson@hnehealth.nsw.gov.au
Abstract
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 kappa 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. Copyright 2009 S. Karger AG, Basel.
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 kappa 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. Copyright 2009 S. Karger AG, Basel.
Authors: Mats W Johansson; Shih-Tsung Han; Kristin A Gunderson; William W Busse; Nizar N Jarjour; Deane F Mosher Journal: Am J Respir Crit Care Med Date: 2012-01-06 Impact factor: 21.405
Authors: Lakshitha P Gunawardhana; Peter G Gibson; Jodie L Simpson; Miles C Benton; Rodney A Lea; Katherine J Baines Journal: Epigenetics Date: 2014-08-11 Impact factor: 4.528