Kheirandish‐Gozal 2016.

Methods	Parallel group RCT
Participants	64 children, aged 2 to 10 years, with symptomatic snoring (AHI ≥ 2 hours total sleep time)
Interventions	Montelukast 4 mg or 5 mg (depending on the child's age) orally for 16 weeks; comparison against placebo for 16 weeks
Outcomes	AHI, respiratory arousal index, adenoid size
Notes	Enrolment period: January 2008 to December 2012 Funding sources: Investigator‐initiated grant from Merck Sharp and Dohme Corp. Declaration of interest: not provided
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"[...] using a table of random digits to generate the allocation sequence"
Allocation concealment (selection bias)	Unclear risk	Unclear how allocation concealment was achieved. "A clinical research coordinator randomly assigned each child to either one of the two treatment groups by block randomisation (n=4/block)" "[...] the clinical pharmacy at the medical center handled delivery of medication to subjects per protocol randomisation."
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Unclear who was blinded. "randomized, double‐blind controlled study"
Incomplete outcome data (attrition bias) All outcomes	Low risk	"[...] of the seven children who withdrew from the study after enrolment, four were in the montelukast group and three children were in the placebo group."
Selective reporting (reporting bias)	High risk	Trial registration specified need for adenotonsillectomy as primary outcome, but paper does not report on it.
Other bias	Low risk	None.

AHI: apnoea/hypopnoea index; OAHI: obstructive apnoea/hypopnoea index; OSA: obstructive sleep apnoea; PSG: polysomnography; RCT: randomised controlled trial; REM: rapid eye movement.