Study designs of evaluations included in the review
Randomised placebo-controlled studies. The studies had to report concealment of allocation to be included in the review. Studies in which groups differed in the interventions used (other than the administration of corticosteroids) were excluded.
Specific interventions included in the review
Studies of systemic corticosteroids compared with placebo were eligible for inclusion. The specific corticosteroids were: methylprednisone (intramuscular), hydrocortisone (intravenous) then prednisone (oral), dexamethasone (intramuscular, oral and intravenous) and prednisolone (oral). The doses were not reported.
Participants included in the review
Hospitalised infants with bronchiolitis who did not require mechanical ventilation were included. The age of the children ranged from 1 to 24 months.
Outcomes assessed in the review
The studies had to report data on the length of stay (LOS), duration of symptoms (DOS) and/or clinical scores. These, together with oxygen saturation, were selected as the a priori outcome measures. Clinical score and oxygen saturation were analysed for 24 and 72 hours after the initial treatment.
How were decisions on the relevance of primary studies made?
The authors stated that study articles and abstracts were evaluated, and those studies which appeared to meet inclusion criteria were selected for further review. The selected studies were independently reviewed by two reviewers for inclusion in the review. Any disagreements were resolved through discussion, and consensus was achieved in the selection of articles for analysis. The authors were blinded to the results of the studies, as well as to the journal and author names.