Use of sputum eosinophil counts to guide management in children with severe asthma
- 1National Heart and Lung Institute, Respiratory Paediatrics, Imperial College, London, UK
- 2Department of Respiratory Paediatrics, Royal Brompton Hospital, London, UK
- 3Division of Paediatric Respiratory Medicine, Department of Paediatrics, Inselspital and University of Bern, Switzerland
- Correspondence to Dr Louise Fleming, Department of Respiratory Paediatrics, Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK;
Contributors AB and NW were the principal investigators, obtained funding for the study, participated in the study design and writing of the report. LF carried out the study visits, data management, data analyses, interpretation of results and writing of the report. NR carried out all the sputum cell counts, participated in idea formation and the writing of the report. All authors approved the final version.
- Received 30 November 2010
- Accepted 22 June 2011
- Published Online First 8 August 2011
Background Previous studies in adults with asthma incorporating the control of sputum eosinophils into management strategies have shown significant reductions in exacerbations. A study was undertaken to investigate whether this strategy would be successful in children with severe asthma.
Methods 55 children (7–17 years) with severe asthma were randomised to either a conventional symptom-based management strategy or to an inflammation-based strategy (principally sputum eosinophils). Children were seen 3-monthly over a 1-year period.
Results The annual rate of total and major exacerbations (courses of oral corticosteroids) was non-significantly lower in the inflammatory management group compared with the symptom management group (3.6 vs 4.8, incident rate ratio (IRR) 0.75, 95% CI 0.54 to 1.04, p=0.082; and 1.9 vs 2.7 IRR 0.73, 95% CI 0.42 to 1.28, p=0.274 for total and major exacerbations, respectively). Significantly fewer subjects in the inflammatory management group experienced an exacerbation within 28 days of a study visit. There were small non-significant differences in measures of asthma control (symptom-free days and short-acting β agonist use) favouring the inflammatory management group. There was no significant difference in the inhaled corticosteroid dose prescribed over the course of the study.
Conclusion Incorporating the control of sputum eosinophils into the management algorithm did not significantly reduce overall exacerbations or improve asthma control. Exacerbations were reduced in the short term, suggesting that more frequent measurements would be needed for a clinically useful effect and that controlling inflammation may have a role to play in subgroups of children with severe asthma.
- Sputum eosinophil counts
- exhaled nitric oxide
- exhaled airway markers
- paediatric asthma
Funding The study was funded by a grant from the British Lung Foundation.
Competing interests None.
Ethics approval This study was conducted with the approval of the Royal Brompton Hospital ethics committee.
Provenance and peer review Not commissioned; externally peer reviewed.