Hadfield 2000.

Methods	Randomised, double blind, placebo‐controlled. Parallel design.
Participants	46 adults (over 16 years old) with CF and nasal polyps, excluding those who were pregnant or breast feeding, taking oral steroids, taking more than 1500 micrograms of inhaled steroid per day, had a severely deviated nasal septum or had undergone a surgical nasal polypectomy within the preceding 6 months.
Interventions	Nasal drops in the form of either betamethasone sodium diphosphate nasal drops or passive placebo drops containing an identical vehicle, prescribed as two drops to be used twice a day for 6 weeks, in a head down and forwards position. 22 participants received the active form of the drug with only 10 completing the course. 24 participants were prescribed the placebo and 11 of this group completed.
Outcomes	Primary outcome was polyp size. Secondary outcomes were subjective symptom scores.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation was conducted using random number tables by the study centre.
Allocation concealment (selection bias)	Low risk	Pharmacy controlled.
Blinding (performance bias and detection bias) All outcomes	Low risk	Nasal drops in the form of either betamethasone sodium diphosphate nasal drops or passive placebo drops containing an identical vehicle produced by the pharmacy.
Incomplete outcome data (attrition bias) All outcomes	High risk	The trial was analysed on an available case basis. No patients were excluded. Dropouts were reported but not included in analysis. Only 22 participants completed the treatment of the 46 that commenced. This was rationalised by comparing the completing and non‐completing groups which were comparable for both treatment and placebo groups. Non‐completers were contacted by telephone or letter but reasoning for study dropout was notably weak or absent.
Selective reporting (reporting bias)	High risk	One of the secondary outcomes of subjective nasal symptoms by the visual analogue staging system is not fully reported which was pre‐specified measurements. Analysis is reported but none of the raw results are stated.
Other bias	Low risk	None identified.

CF: cystic fibrosis