Randomised controlled trials (RCTs) that compared the clinical efficacy or safety of salmeterol and fluticasone propionate in a single inhaler (fluticasone propionate/salmeterol) versus increased doses of inhaled corticosteroids, administered once or twice daily, in adults or adolescents (aged at least 12 years) with asthma, were eligible for inclusion. Included trials were required to be double blind and parallel group RCTs with a duration of at least 12 weeks.
The primary outcomes were changes in lung function variables. Secondary outcomes included asthma exacerbation (defined as clinical deterioration or decrease in peak expiratory flows below a set threshold), use of rescue medication, symptom-free 24 hours, and overall or drug-related adverse events and discontinuation.
Most trials in the review were open to both adults and adolescents. The age range of included participants was 12 to 80 years and asthma severity varied. One trial specifically selected participants with a smoking history. The intervention group received 100 to 500 micrograms (µg) of fluticasone propionate combined with 50 to 100 µg of salmeterol daily. The control group received 200 to 1000 µg of fluticasone propionate or 400 to1600 µg of budesonide daily, in most cases administered in two doses by dry powder inhaler (Diskus or Turbuhaler) or metered dose inhaler. All the included trials permitted short-acting β-antagonist to be used as a rescue medication. Symptom-scoring methods used in the primary trials were heterogeneous. Trial duration was usually 12 weeks (range 12 to 52 weeks).
The authors did not state how the papers were selected for the review or how many reviewers performed the selection.