Alshehr 2005.

Study characteristics
Methods	Randomised, double‐blind trial
Participants	Study period: September 1998 to December 2002 Setting: emergency rooms and outpatient clinics in 3 medical institutes, Abha City, Saudi Arabia Inclusion criteria: children aged 3 months to 9 years who had been given a diagnosis of croup and had persistent, moderately severe respiratory distress (Westley croup score > 3) Exclusion criteria: symptoms or signs suggesting another cause of stridor; history of chronic pulmonary disease; severe systemic disease; immune dysfunction; stridor or intubation for more than 1 month; glucocorticoid therapy in the last 4 weeks before study entry Baseline characteristics (N = 72): proportion male: treatment: 56%; comparator: 53% mean (SD) age, months: treatment: 16.8 (12); comparator: 17.6 (13) median (range) Westley croup score: treatment: 5.0 (3 to 6); comparator: 4.5 (3 to 6)
Interventions	Treatment (N = 36): single dose 0.15 mg/kg oral dexamethasone Comparator (N = 36): single dose 0.6 mg/kg oral dexamethasone
Outcomes	Change in Westley croup score from baseline to 4, 12, and 24 hours; hospitalisation; length of stay in hospital; use of mist tent
Notes	All children received mist therapy throughout the observation period. Funding source: not reported.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "A blocked randomization code was produced by random‐number generating software"
Allocation concealment (selection bias)	Low risk	Quote: "To make the study drugs indistinguishable from each other, they were packaged in opaque containers and diluted on the same amount of solution." "A blocked randomization code was produced ... and the code was not broken until after the study ended and all decisions regarding data analysis were finalized"
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "double‐blind" "To make the study drugs indistinguishable from each other, they were packaged in opaque containers and diluted on the same amount of solution."
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "double‐blind"; "to make the study drugs indistinguishable from each other, they were packaged in opaque containers and diluted on the same amount of solution"; "the code was not broken until after the study ended and all the decisions regarding data analysis were finalized"
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: 14% (N = 12) of children recruited were excluded prior to randomisation. All randomised children were followed up.
Selective reporting (reporting bias)	Unclear risk	Comment: no protocol identified. All prespecified outcomes in the methods appeared in the results.
Other bias	Low risk	Comment: no other sources of bias identified
Overall risk of bias All outcomes	Unclear risk	Comment: at least 1 domain judged as unclear risk, and no domains judged as high risk