Verberne 1998 b.

Methods	Double‐blind, randomised, parallel‐group trial; multi‐centre
Participants	SYMPTOMATIC PARTICIPANTS RANDOMLY ASSIGNED: N = 90 ANALYSED: N = 90 INTERVENTION: ICS (beclomethasone + salmeterol 400 μg/d): 60 CONTROL: ICS (beclomethasone 800 μg/d): 30 WITHDRAWALS: reported AGE: mean (range) years INTERVENTION: ICS (beclomethasone 400 μg/d): 10.8 (6‐16) CONTROL: ICS (beclomethasone 800 μg/d): 11.4 (6‐16) GENDER: male N (%) INTERVENTION: ICS (beclomethasone 400 μg/d): 40 (60) CONTROL: ICS (beclomethasone 800 μg/d): 36 (60) ASTHMA SEVERITY: mild to moderate asthma ASTHMA DURATION: mean (range) years INTERVENTION: ICS (beclomethasone 400 μg/d): 7.8 years CONTROL: ICS (beclomethasone 800 μg/d): 9.0 years MEAN (± SD) β2‐AGONIST USE (puffs/d): not reported DOSE OF ICS AT STUDY ENTRY AND AT RUN‐IN: 200‐800 μg/d at least 3 months before the start of the study ATOPY (% of participants): 89% ELIGIBILITY CRITERIA As above EXCLUSION CRITERIA: not reported WITHDRAWAL CRITERIA As above
Interventions	PROTOCOL DURATION Run‐in = 6 weeks Intervention = 54 weeks DEVICE: All drugs were administered as Rotadisks in combination with a Diskhaler (Glaxo Wellcome, Greenford, UK) DOSE OF ICS INTERVENTION: beclomethasone 400 μg + salmeterol 100 μg/d CONTROL: beclomethasone 800 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: "Randomization was stratified by sex, age, center, baseline FEV1 and prior dose of ICS, using a computerized minimization method"
Allocation concealment (selection bias)	Low risk	Central allocation (including telephone, web‐based and pharmacy‐controlled randomisation): "independent randomisation center"
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