Dodd 2000.

Methods	Randomised, double‐blind placebo‐controlled trial. Cross‐over design. Duration: 2 treatment periods of 14‐days with a 7‐day wash out period between each period. Measurements were taken at the beginning and end of each treatment period.
Participants	23 participants randomised. Age: (mean) 27.5 years. Withdrawals were not discussed within the paper. Disease severity was not discussed.
Interventions	Treatment: 2.5 mg rhDNase once daily. Control: 2.5 ml 0.9% saline once daily.
Outcomes	FEV1.
Notes	Raw data provided; however no data legend therefore unable to analyse, FEV1 not reported in abstract.
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	Unclear risk	No discussion of whether ITT analysis performed. Withdrawals were not discussed within the paper.
Selective reporting (reporting bias)	Low risk	None identified.
Other bias	High risk	Cross‐over trial with 7‐day washout period, which is not long enough for lung function to return to baseline; however data from this trial were not available for analysis in this review.