Lildholdt 1997.

Methods	Allocation: prospective, randomised, blinded trial Design: parallel, multi‐phased trial. Patients in this comparison were from phase I of the study (after failing 1 month's initial medical treatment)
Participants	Number: 34, out of 126 recruited into phase 1 of trial Age: > 18 years Gender: not indicated Setting: hospital otorhinolaryngology outpatient clinic or specialty private practice (Sweden) Eligibility criteria: bilateral nasal polyps confirmed by biopsy Exclusion criteria: recent steroid treatment (sustained release within 3 months, systemic within 2 months or topical within 1 month), pregnancy or acute purulent sinusitis "Treatment success" after 4 weeks of medical treatment in phase 1 as judged by improvement in at least 3 of the following assessments: investigator's assessment of polyp size; patient's overall assessment of polyposis; patient's assessment of sense of smell; patient's overall assessment of treatment efficacy; PEF index improvement (of at least 10%) Baseline characteristics: symptom score, polyp size score, peak expiratory flow (PEF) index (nasal PEFR/oral PEFR), semi‐quantitative smell test
Interventions	Intervention group: n = 18: snare polypectomy under local anaesthetic in addition to 400 µg topical budesonide daily Comparator group: n = 16: single intramuscular injection of betamethasone in addition to 400 µg topical budesonide daily Use of additional interventions: phase 1 of trial: double‐blind, placebo‐controlled treatment with 2 different doses of topical budesonide (200 µg, n = 44; or 400 µg, n = 40) or placebo (n = 42)
Outcomes	Primary outcome: symptom scores (blocked nose, runny nose, sneezing) at 12 months Secondary outcomes: symptom scores (blocked nose, runny nose, sneezing) at 1, 3, 6 and 9 months; polyp scores, PEFR index and smell tests at 1, 3, 6, 9 and 12 months
Declaration of interest	Not indicated
Source of funding	Astra Draco
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method of randomisation is not described
Allocation concealment (selection bias)	Unclear risk	Not described
Blinding (performance bias and detection bias) All outcomes	High risk	Participants cannot be blinded to surgery Not possible to blind assessor to surgical versus medical participants on endoscopy
Incomplete outcome data (attrition bias) All outcomes	High risk	Unclear how many of the 34 patients randomised into surgical versus medical treatments were available at 12 months. However, this is likely to be high risk as only about 60% of the overall trial participants were available
Selective reporting (reporting bias)	High risk	The outcomes for phase 2 of the trial (medical versus surgical subgroups) are not reported separately so outcomes cannot be assessed and data were insufficient for meta‐analysis
Other bias	Low risk	—