Laube 1996.

Methods	Randomised, double‐blind trial. Parallel design. Duration: 6 days.
Participants	20 adults with stable stage CF, FVC 35% ‐ 75% predicted and non‐smokers. Age: over 18 years. The published paper stated that there were no withdrawals.
Interventions	Treatment: 2.5 mg nebulised rhDNase twice daily (n = 10). Control: placebo twice daily (n = 10).
Outcomes	Included in this review: mean change in % predicted FVC and FEV1. Not included: aerosol distribution homogeneity, changes in mucociliary clearance and changes in cough frequency.
Notes	Measurements were taken on day 6 only and reported in the paper.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Stated as randomised but no method was described.
Allocation concealment (selection bias)	Unclear risk	Method unclear.
Blinding (performance bias and detection bias) All outcomes	Low risk	Described as double blind, no further details.
Incomplete outcome data (attrition bias) All outcomes	Low risk	ITT analysis was used in this trial. The published paper stated that there were no withdrawals.
Selective reporting (reporting bias)	Low risk	None identified.
Other bias	Low risk	None identified.