Clement 2006.

Methods	Randomised, multicentre, double‐blind, placebo‐controlled trial.
Participants	82 young people with CF (6‐21 years, mean age 11.0 years, SD 3.3 years), 40 in azithromycin group, 42 in placebo group. 35 in treatment group and 37 in placebo group completed trial. FEV1 >40% predicted.
Interventions	Azithromycin 250 mg tablet 3 times per week (>40 kg, 500 mg) versus placebo.
Outcomes	Relative change in FEV1 & FVC % predicted, number of pulmonary exacerbations, additional antibiotic treatment (oral and IV), lung microbiology and adverse events.
Notes	French study.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Centralised secure randomisation department".
Allocation concealment (selection bias)	Low risk	Centralised, study number assigned by interactive voice response system, study kits distributed by chief pharmacist in each centre.
Blinding (performance bias and detection bias) All outcomes	Low risk	Identically packaged, all participants and investigators blinded.
Incomplete outcome data (attrition bias) All outcomes	Low risk	A complete ITT analysis undertaken on primary outcome and pulmonary exacerbation data. Some per protocol analysis on other outcomes.
Selective reporting (reporting bias)	Unclear risk	Some data at intermediate time points not reported (requested from authors, who kindly provided some IPD, although intermediate time points not available).
Other bias	Low risk	None identified.