Kerwin 2008 b.

Methods	DESIGN: randomised, parallel‐group, double‐blind, placebo‐controlled trial; in multiple centres
Participants	SYMPTOMATIC PARTICIPANTS RANDOMLY ASSIGNED: N = 204 INTERVENTION: ICS (budesonide 180 μg/d): 108 CONTROL: ICS (budesonide 360 μg/d): 96 WITHDRAWALS: reported AGE: mean (SD) years: INTERVENTION: ICS (budesonide 180 μg/d): 11.7 (2.9) CONTROL: ICS (budesonide 360 μg/d): 11.5 (2.9) GENDER: male N (%) INTERVENTION: CS (budesonide 180 μg/d): 76 (70.4) CONTROL: ICS (budesonide 360 μg/d): 67 (69.8) ASTHMA SEVERITY: mild asthma ASTHMA DURATION: mean (SD) years INTERVENTION: ICS (budesonide 180 μg/d): 7.1 (4.2) CONTROL: ICS (budesonide 360 μg/d): 7.2 (4.1) MEAN (± SD) β2‐AGONIST USE (puffs/d): INTERVENTION: ICS (budesonide 180 μg/d): 0.4 (0.9) CONTROL: ICS (budesonide 360 μg/d): 0.5 (1.0) DOSE OF ICS AT STUDY ENTRY AND AT RUN‐IN: Participants continued their usual ICS therapies (if any) and added a once‐daily placebo treatment ATOPY (% of participants): not reported ELIGIBILITY CRITERIA As above EXCLUSION CRITERIA As above
Interventions	PROTOCOL DURATION Run‐in = 11 to 17 days Intervention = 12 weeks DEVICE: dry powder inhaler DOSE OF ICS INTERVENTION: budesonide 180 μg/d CONTROL: budesonide 360 μg/d CRITERIA FOR WITHDRAWAL FROM STUDY: reported
Outcomes	As above
Notes	As above
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Using a computer random number generator
Allocation concealment (selection bias)	Unclear risk	Insufficient information
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Blinding of participants and key study personnel ensured
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Blinding of participants and key study personnel ensured
Incomplete outcome data (attrition bias) All outcomes	Low risk	No missing outcome data
Selective reporting (reporting bias)	Low risk	Study protocol not available but published reports include all expected outcomes, including those that were prespecified
Other bias	Low risk	Study apparently free of other sources of bias