Stangerup 1992.

Methods	Randomised controlled trial
Participants	Unilateral or bilateral OME for at least 3/12 diagnosed by tympanometry 100 children Aged 3 to 10
Interventions	Otovent 3 times a day for 2 weeks, extended to 4 weeks in those with persistent OME, or no treatment Control group received equal care except for the intervention
Outcomes	Tympanometry Otitis media (days 14, 30, 60 and 90)
Notes	Results reported as ears
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation described as "consecutively randomised" as individuals; no method of randomisation described
Allocation concealment (selection bias)	Unclear risk	No statement
Comparability of groups at pre‐test	Low risk	"No statistically significant differences were computed between the treated group and the control group with regard to nursing conditions, occurrence of acute otitis media, adenoidectomy, grommet insertion, or the use of antibiotics in the year preceding the study period"
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not stated
Incomplete outcome data (attrition bias) All outcomes	High risk	Experimental: 42% attrition based on 42 ears completing the study from an original randomised 73 (50 participants). 30% attrition at 2 weeks due to non‐adherence (22/73). Analysis based on 51 ears who maintained adherence to intervention in first 2 weeks. Control: 67% attrition based on 49 ears completing the study from an original randomised 73 ears (50 participants) Retention of participants in the study stated, but only for those that completed follow‐up at 2 weeks plus 2 of the 3 follow‐up points (experimental 92%, control 94%). Data not supplied for individuals completing full 90 days of study.
Selective reporting (reporting bias)	Low risk	No evidence of selective reporting

ENT: ear, nose and throat 
 MEE: middle ear effusion 
 OME: otitis media with effusion 
 PTA: pure‐tone audiogram 
 TPP: tympanometric peak pressure