Chatfield 1991.

Methods	RCT. Duration: follow up to each child's third birthday. Multicentre in Wales and West Midlands (UK) (number of centres not stated).
Participants	Infants with CF diagnosed by neonatal screening or clinically (alternate weeks). Followed up to age 3 years. n = 132: 57 prophylaxis; 75 'as required'. Mean (SD) age at diagnosis: 122 (255) days prophylaxis; 260 (379) 'as required'. Data available at 1, 2 & 3 years.
Interventions	Continuous oral flucloxacillin versus intermittent antibiotics 'as required'.
Outcomes	Growth; inpatient days; participants with isolates of common pathogens; P aeruginosa.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method not described, unclear.
Allocation concealment (selection bias)	Unclear risk	Not described.
Blinding (performance bias and detection bias) All outcomes	High risk	Unblinded. No placebo.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Intention‐to‐treat analysis: not possible (infants with meconium ileus not randomised and therefore excluded from analysis). 1 participant lost to follow up and 1 infant died.
Selective reporting (reporting bias)	Unclear risk	Study reported outcomes up to 3 years of age. Only summary statistics have been presented in abstracts, and full paper describes the methodology, but does not present results by antibiotic groups.
Other bias	High risk	Infants with meconium ileus not randomised. Additional information from the authors.