Saiman 2010.

Methods	Multi‐centre placebo‐controlled parallel design.
Participants	Young CF patients (6‐18 years) without chronic P. aeruginosa airway infection (clear (2 or more cultures) for > 12 months)
Interventions	Azithromycin (250 mg 3 times a week, increased to 500, if weight >36 kg) versus placebo; for 6 months.
Outcomes	Primary: relative change in FEV1 from baseline. Secondary: respiratory exacerbations; treatment requirements; and adverse events. Acquisition of resistant bacteria in respiratory culture. Authors contacted for full data on nutritional outcomes.
Notes	Second North American study.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	University of South Florida generated assignments via secure centralized randomisation system.
Allocation concealment (selection bias)	Low risk	Data co‐ordinating centre distributed blinded study drug kits.
Blinding (performance bias and detection bias) All outcomes	Low risk	Identically packaged tablets.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Modified ITT analysis (3 patients in placebo arm did not receive study drug and were removed) of primary outcome and most others.
Selective reporting (reporting bias)	Low risk	All outcomes reported.
Other bias	Low risk	Very clearly reported study.