Elkholy 2021.

Study characteristics
Methods	Single‐centre, parallel‐group RCT with 1 year of follow‐up Randomised by child
Participants	Location: Egypt, single centre Setting of recruitment and treatment: ENT and paediatric outpatient clinics at Al‐Azhar University Hospital, Cairo Study dates: September 2018 to March 2020 Sample size: Number randomised: 40 Number completed: 40 Participant (baseline) characteristics: Age, years (SD): Ventilation tubes plus adenoidectomy: 7.3 years (1.90) Adenoidectomy alone: 6.1 years (1.2) Sex Ventilation tubes plus adenoidectomy: 8 males, 12 females Adenoidectomy alone: 10 males, 10 females Inclusion criteria: Children with OME and adenoid hypertrophy, aged 5 to 15 years Persistent or recurrent OM despite proper medical treatment for 3 to 6 months Exclusion criteria: Children with naso‐facial malformation, cleft palate or allergic rhinitis A history of adenoid operation or ventilation tube insertion Any other ear problem
Interventions	Intervention: Ventilation tube insertion (unclear if one or both ears, type of ventilation tube not stated) and adenoidectomy N = 20 Comparator: Adenoidectomy alone N = 20
Outcomes	Persistence of OME at 2 weeks follow‐up
Funding sources	Not stated
Declarations of interest	The authors state that they have no conflict of interest
Notes	Research integrity checklist: No retraction notices identified Prospective registration was not identified Baseline characteristics are not excessively similar No reason is given for full follow‐up No implausible results were identified The number randomised to each group was identical, and there is no description of block randomisation
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	“Included children were randomly divided into two groups based on the consecutive number of enrollments those with odd number were included into group A while those of even number were included in group B”. Quasi‐randomised allocation.
Allocation concealment (selection bias)	High risk	“Included children were randomly divided into two groups based on the consecutive number of enrollments those with odd number were included into group A while those of even number were included in group B”. Quasi‐randomised allocation, allowing group allocation to be predicted.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants and study personnel would have been aware of the group allocation. No blinding was used.
Blinding of outcome assessment (detection bias) All outcomes	High risk	No indication is given that outcome assessors were blinded. Outcomes were assessed by study personnel, therefore we assume they were aware of the group allocation.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Full follow‐up is reported.
Selective reporting (reporting bias)	Unclear risk	No protocol was available to assess the intended reporting plan.
Other bias	High risk	Data were only available after 2 weeks of follow‐up, which is too short to fully assess the benefit of this intervention. Data from later time points were incompletely reported, precluding their inclusion in the review.