Bailey 2008

Methods	A randomised, double‐blind, multi‐centre, parallel‐group study over 52 weeks from November 2004 to April 2007, at 59 centres in the USA. Run‐in 2 weeks on usual ICS, and then 4 weeks on fluticasone 250 μg twice daily
Participants	Population: 475 adolescents and adults (12 to 65 years) of African descent with persistent asthma and symptomatic while taking low‐dose ICS Baseline characteristics: mean age 32 years; FEV₁ 85% predicted Concomitant ICS used by 100% of participants Inclusion criteria: 12 years of age or older with documented clinical history of persistent asthma for at least 6 months; had been symptomatic when using ICS (fluticasone propionate 200 μg daily or equivalent) for at least 4 weeks before entering the run‐in period; FEV₁ % predicted between 60% and 90%, with at least 12% reversibility following 2 to 4 puffs of albuterol  Exclusion criteria: participants were included in the 52‐week study period only if when on the 2‐week run‐in taking low‐dose ICS twice daily, they showed FEV₁ ≥ 60% predicted, and in the last 7 days of run‐in, they had ≥ 4 days of albuterol use or were symptomatic; they were excluded if they had an exacerbation in the 4 weeks on fluticasone 250 μg twice daily
Interventions	• Fluticasone propionate and salmeterol 100/50 μg Diskus twice daily • Fluticasone propionate 100 μg Diskus twice daily alone
Outcomes	Primary outcome: rate of asthma exacerbation
Notes	Sponsored by GSK
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not reported
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding (performance bias and detection bias) All outcomes	Low risk	"Double‐blind treatment period"
Independent Assessment of causation (detection bias) Asthma‐related events	High risk	Causation of SAEs not independently assessed
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	70/239 lost to follow‐up on combined treatment, and 85/236 on fluticasone alone
Selective reporting (reporting bias)	Low risk	Full data on GlaxoSmithKline website (SFA103153)