Fuchs 1994.

Methods	Randomised, double‐blind trial. Parallel design with 3 arms. Duration: 24 weeks. Measurements were taken on days 7, 14 and every 14 days thereafter.
Participants	968 participants randomised, diagnosed CF on genotype, sweat test or clinically. Age: over 5 years. More participants aged 17 ‐ 23 years were in the once daily rhDNase arm. Disease status: FVC > 40 % predicted and clinically stable. 25 people withdrew from the trial, 8 in the placebo group and once‐daily group and 9 in the twice‐daily group.
Interventions	Treatment 1: nebulised rhDNase 2.5 mg once daily (n = 322). Treatment 2: nebulised rhDNase 2.5 mg twice daily (n = 321). Control: placebo (n = 325).
Outcomes	Outcomes included in this review: mean % change in FVC and FEV1, number of participants needing IV antibiotics for at least 1 chest exacerbation (protocol defined), mean number of days IV antibiotics used, mean number of days as an inpatient, number of deaths and number experiencing an adverse event. Not included in this review: CF symptom score, dyspnoea score. Cost of treatment is reported by von der Schulenberg (1995), Oster (1995) and Menzin (1996).
Notes
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 principle was used. 25 participants withdrew from the trial, 8 in the placebo group and once‐daily group and 9 in the twice‐daily group.
Selective reporting (reporting bias)	Unclear risk	Measurements were taken on days 7, 14 and every 14 days thereafter. The published trial reported the end of trial results only.
Other bias	Low risk	None identified.