O'Byrne 1996.

Methods	Setting: Canada, multicentre study, primary care Randomisation: yes, by computer‐generated randomisation sequence Allocation concealment: yes (coding undertaken centrally by pharmaceutical company sponsors) Design: parallel Intervention period: 4 months Masking: double blind Excluded: not stated Withdrawals: stated Baseline characteristics: comparable Jadad score=4
Participants	47 adults: 25M 32F Mean (SD) age: BUD 400 32(9.0) years, BUD 800 37(17.8) years, placebo 36(12.7) years Inclusion criteria: Adults over the age of 18 with asthma requiring the use of inhaled bronchodilators Diurnal PEFR variability 10% or greater for at least 3 out of 7 days of the screening period Exclusion criteria: Inhaled or oral steroids in last 3 months Felt to require inhaled corticosteroids by primary care physician at the time of enrolment
Interventions	BUD: 1. 100mcg 2pfs 2xdaily (400 mcg/d) 2. BUD 200mcg 2pfs 2xdaily (800 mcg/d) Placebo: 2 pfs 2xdaily Delivery device: MDI+spacer
Outcomes	Change in morning PEFR compared to baseline Change in evening PEFR compared to baseline % of patients reporting: any symptoms; waking at night; waking early due to asthma; requiring bronchodilators > 4xdaily during previous month No. of patients attending hospital emergency dept due to acute asthma exacerbation Withdrawal due to asthma exacerbation Economic analysis
Notes	Reply from author confirming use of allocation concealment.
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment?	Low risk	A ‐ Adequate