Greally 1994.

Study characteristics
Methods	Randomised. Double‐blinded.
Participants	24 participants aged 5.5 years to 19.5 years recruited. CF diagnosed by raised sweat sodium (>70 mmol/l) and established respiratory disease (FEV1 < 85% predicted).
Interventions	Soluble prednisolone 2 mg/kg/ daily for 14 days and then 1 mg/kg/ day on alternate days for 10 weeks (maximum dose 40 mg) or identical inert placebo tablets.
Outcomes	The following were measured at baseline, 14 days and 12 weeks: FEV1, FVC, Serum interleukin‐ 1‐ alpha, interleukin‐ 2R, IgG. Specific side effects (raised blood pressure, high blood sodium, low blood potassium, fluid retention and glucose intolerance) were looked for at each visit.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Described as randomised, but method not stated.
Allocation concealment (selection bias)	Unclear risk	Unclear.
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Described as double‐blind and placebo and prednisolone tablets were identical, but true blinding might not have been possible since at the doses used, it would have been obvious which participants were in the treatment group.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No withdrawals.

CF: cystic fibrosis
FEV1: forced expiratory volume at one second
FVC: forced vital capacity
IgA: immunoglobulin A
IgG: immunoglobulin G
IgM: immunoglobulin M
mmol/l: millimoles per litre
PEFR: peak expiratory flow rate
P. aeruginosa: Pseudomonas aeruginosa