Does sputum eosinophilia predict the response to systemic corticosteroids in children with difficult asthma?

Little evidence exists to guide the management of children with difficult asthma. The aim of this study was to determine whether children with difficult asthma, associated with sputum eosinophilia, are more likely to benefit from further treatment with high-dose systemic corticosteroids, compared to those without sputum eosinophilia. Induced sputum was obtained from 20 children aged between 8 and 15 years with difficult asthma before and after a systemic corticosteroid trial (prednisolone 40 mg/day for 14 days or a single 80 mg dose of intramuscular triamcinolone). Subjects were defined as "eosinophilic" if the baseline sputum eosinophil percentage was >= 2.5% or "non-eosinophilic" if <2.5%. Clinical response to the corticosteroid trial was assessed using spirometry and clinical data and defined by an increase in pre-bronchodilator forced expiratory volume in 1 sec (FEV1) >9% predicted and/or an overall subjective improvement. Seventeen children had evidence of satisfactory adherence to the systemic corticosteroid treatment; eight of these were "eosinophilic" and nine were "non-eosinophilic" subjects. Following the trial there was a similar clinical improvement in both groups, with FEV1 increasing in both the "eosinophilic" and "non-eosinophilic" groups (median change in FEV1 16 [range 5-54]% vs. 12.5 [1-29]% predicted). Sputum eosinophils fell in the "eosinophilic" group (median 17.5 [range 3-37]% vs. 0 [0-23]%, P = 0.054), with no change in the "non-eosinophilic" group (0 [0-2]% vs. 0 [0-1]%, P = 0.12). Sputum neutrophils did not change in either the "eosinophilic" (22.5 [5-50]% vs. 25 [0-91]%) or the "non-eosinophilic" group (27.5 [0-96] vs. 44 [9-96]%). In conclusion children with difficult asthma may benefit clinically from high-dose systemic corticosteroids even in the absence of sputum eosinophilia.