Holopainen 1982.

Methods	2‐arm, double‐blind, parallel‐group RCT, with a 16‐week duration of treatment and follow‐up
Participants	Location: Sweden, no information on number of sites Setting of recruitment and treatment: unclear Sample size: Number randomised: 10 in intervention, 9 in comparison Number completed: 10 in intervention, 8 in comparison Participant (baseline) characteristics: Age mean (range): group A: 43.5 (26 to 60); group B: 40 (18 to 62) Gender (M/F): group A: 6/4; group B: 4/5 Main diagnosis: perennial, intrinsic nasal symptoms associated with small nasal polyps Polyps status: 100% with polyps Previous sinus surgery status: unclear (there is a comment, "When necessary the number of polyps was reduced by surgical measures so that the test solution could easily be administered", but no further details are given) Other important effect modifiers: none provided Inclusion criteria: no further details available Exclusion criteria: none stated
Interventions	Intervention (n = 10): budesonide nasal spray 400 μg daily, 2 puffs into each nostril, twice a day, for 16 weeks Comparator group (n = 9): placebo nasal spray (same solvent as intervention but without the active ingredient), 2 puffs into each nostril, twice a day, for 16 weeks Use of additional interventions (common to both treatment arms): all patients underwent a wash‐out period of 2 weeks before the study
Outcomes	Outcomes of interest in the review: Primary outcomes 1. Disease severity, measured by patient‐reported symptom score cards recording nasal blocking, running, sneezing, itching and side effects according to a 0 to 3 scale daily for 2 weeks prior to check‐up. Last check‐up at 16 weeks. 2. Disease severity, measured by physician rhinoscopy to assess mucosal congestion and nasal discharge 3. Significant adverse effect: epistaxis Secondary outcomes: 4. Size of polyps (on a 0 to 3 scale) Other outcomes reported by the study: Saccharin test for measuring mucociliary activity Nasal smear for evaluating epithelial changes Biopsy of the nasal polyps Plasma cortisol determination Peak nasal inspiratory flow
Notes	Although the paper states "When necessary the number of polyps was reduced by surgical measures so that the test solution could be easily administered", there was no report of this having been carried out.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "…randomly assigned…" Comment: no further information
Allocation concealment (selection bias)	Unclear risk	Comment: no information
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "The placebo was identical with the active spray but without budesonide… the other a correspondent dose of only the solvent" Comment: identical‐looking and solvent used
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Comment: low risk, since blinding is adequate
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "One patient with severe nasal blocking and obstructing polyps had to withdraw from the trial after 12 weeks of placebo treatment." This patient was not reported in the safety outcomes. Comment: only 1 drop‐out (5%). Unlikely to have an important impact on outcomes.
Selective reporting (reporting bias)	High risk	Comment: methods section reports that nasal discharge would be physician‐assessed by rhinoscopy (pg 222, bullet point 1). No results are reported for this outcome.
Other bias	Unclear risk	Comment: no information regarding the validation of the disease severity measures. Only limited information provided in the study about baseline characteristics, pre‐randomisation procedures etc.