Lee 1993.

Methods	A prospective, randomised, double blinded, placebo‐controlled clinical trial Comparison of single dose of IM dexamethasone versus oral dexamethasone Randomization was accomplished using computer‐generated random set of numbers (9 blocks). Allocation concealment was reported but method was not described.
Participants	Patients diagnosed with asthma (based on the American Thoracic Society criteria, 1962), presented to ED with acute asthma and did not require hospital admission Exacerbation severity not discussed. Exacerbation severity estimated as mild/moderate based on baseline PEF Ages: enrolled patients 16 to 60 years. Mean age of IM corticosteroid group: 37 years (SD: 4). Mean age of oral corticosteroid group: 40 years (SD: 4) Patients who received systemic corticosteroids prior to enrolment in the study were excluded. Set in Taiwan Sex: 20 men, 16 women
Interventions	Patients were divided into 3 groups (A, B, and C) Group A received single IM placebo versus oral placebo treatment for 7 days. Group B received single IM dexamethasone (10 mg) versus oral placebo treatment for 7 days. Group C received single IM placebo versus oral dexamethasone 1.5 mg twice a day for 7 days. Tapering of dexamethasone was as follows: 3.0 mg day 1 and 2, 2.0 mg day 3, 1.5 mg day 4, 1.0 mg day 5, 0.75 mg day 6 and 0.5 mg day 7) Co‐interventions in the ED: oxygen, IV aminophylline, and fenoterol inhalation Co‐interventions at discharge: oral anhydrous long‐acting theophylline 250 mg twice daily, beta₂‐agonist inhaler as needed The use of ICS and supplemental corticosteroids were not permitted
Outcomes	Primary and secondary outcomes were not defined. Relapse (defined as a need for another ED visit) within 7 days and between 11 and 21 days Symptoms (coughing, wheezing) and the number of daily beta₂‐agonist inhaler use PEF and FEV1/FVC (%)
Notes	Attempts to contact the authors failed No registered protocol was identified
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Patients randomised via block randomised computer generated numbers. Quote (p. 26): "The subjects were randomly assigned into one of three groups using a double blind model. Randomisation was by means of a set of computer‐generated set of random‐numbers in blocks of nine."
Allocation concealment (selection bias)	Unclear risk	No information on allocation concealment provided.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Double‐blinded study. Oral corticosteroids and oral placebo were indistinguishable from each other but no information provided as to whether IM corticosteroids were indistinguishable from IM placebo. Quote (p. 26): "The subjects were randomly assigned into one of three groups using a double blind model." "The oral dexamethasone and oral placebo were indistinguishable."
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No information provided on outcome assessment blinding.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Study did not report attrition/exclusions.
Selective reporting (reporting bias)	Unclear risk	No protocol available.
Other bias	Unclear risk	Source of funded not provided.