Background: Since the initial version of this systematic review in 1997, a number of randomised trials examining the benefit of glucocorticoids have been published, reflecting a continued interest in the use of glucocorticoids to treat patients with croup. The objective of this review was to provide evidence to guide clinicians in their treatment of patients with croup by determining the effectiveness of glucocorticoids and to identify areas of uncertainty for future research.

Objectives: To determine the effect of glucocorticoids for children with croup.

Search strategy: We searched The Cochrane Central Register of Controlled Trials (CENTRAL) (issue 1, 2003), MEDLINE (January 1966 to April 2003) and Excerpta Medica/EMBASE (January 1974 to August 2003). We also contacted authors of identified croup trials published in the last ten years to inquire about additional published or unpublished trials.

Selection criteria: Randomised controlled trials that examine children with croup and objectively measure the effectiveness of glucocorticoid treatment.

Data collection and analysis: Based on review of the title and abstract (when available), two researchers identified studies for potential relevance. The complete text was retrieved and using a priori inclusion criteria, the studies were independently reviewed for relevance by two reviewers. Two observers independently assessed quality. Differences with respect to inclusion status and quality assessment were resolved by consensus. Data were extracted using a structured form by one reviewer and checked for accuracy by a second reviewer. Standard statistical analyses were performed.

Main results: Thirty-one studies were deemed relevant for inclusion (N = 3736). Glucocorticoid treatment was associated with an improvement in the Westley score at six hours with a weighted mean difference of -1.2 (95% confidence interval -1.6 to -0.8) and at 12 hours -1.9 (-2.4 to -1.3); at 24 hours this improvement was no longer significant (-1.3, -2.7 to 0.2). Fewer return visits and/or (re)admissions occurred in patients treated with glucocorticoids (relative risk 0.50; 0.36 to 0.70). Length of time spent in accident and emergency or hospital (weighted mean difference 12 hours, five to 19 hours) was significantly decreased for patients treated with glucocorticoids. Use of epinephrine decreased for children treated with a glucocorticoid (risk difference 10%; 1 to 20). No other decreases in additional treatments were found in the primary analysis. Publication bias does not impact results importantly. No between-trial significant differences were found between populations with mild and moderate croup. Oral dexamethasone may be superior to intramuscular dexamethasone.

Reviewer's conclusions: Dexamethasone and budesonide are effective in relieving the symptoms of croup as early as six hours after treatment. Fewer return visits and/or (re)admissions are required and the length of time spent in hospital is decreased in inpatients. Dexamethasone is also effective in mild croup populations. Research is required to examine the most beneficial method for disseminating croup practice guidelines and to increase the uptake of evidence to improve outcomes.