Von Mühlendahl 1982.

Study characteristics
Methods	Randomised, double‐blind controlled trial
Participants	Study period: January 1979 to April 1980 Setting: 3 paediatric clinics in West Berlin, Germany Inclusion criteria: children admitted to hospital with a diagnosis of pseudo‐croup to 1 of 3 paediatric clinics in West Berlin Exclusion criteria: children who were already somnolent or cyanotic at admission (stage III or IV or pseudo‐croup) Baseline demographics (N = 406; 349 included in the evaluation): proportion males: not reported age distribution: treatment: 15 were < 1 year; 50 were 1 to 1 11/12 years; 96 were 2 to 5 11/12 years; 15 were 6 to 10 11/12 years control: 11 were < 1 year; 44 were 1 to 1 11/12 years; 107 were 2 to 5 11/12 years; 11 were 6 to 10 11/12 years croup score: treatment: 77 had a score of 1 to 3; 99 had a score ≥ 4 control: 67 had a score of 1 to 3; 106 had a score ≥ 4
Interventions	Treatment (N = 176): single dose 6 mg oral dexamethasone Control (N = 173): single dose 6 mg oral placebo
Outcomes	Change in croup score from baseline to 6 and 12 hours
Notes	Funding source: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: insufficient information provided to permit a judgement
Allocation concealment (selection bias)	Unclear risk	Comment: insufficient information provided to permit a judgement
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Comment: described as double‐blind. Unclear who was blinded. Subjective outcomes
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Comment: described as double‐blind. Unclear who was blinded. Subjective outcomes
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Comment: of 406 children, 57 (14%) failed to complete the study. 24 (7%) were eliminated due to protocol violation; 19 (5%) received further doses of steroids; and 4 (1%) developed measles. Unclear what group the lost children were in. Did not use intention‐to‐treat analysis
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

CI: confidence interval
ED: emergency department
IU: international units
LOCF: last observation carried forward
NHS: National Health Service
SD: standard deviation
SE: standard error