Permut 2010.

Methods	Randomised, cross‐over trial, non‐inferiority trial
Participants	POSA Participants randomised: 38 Gender: 25 male, 13 female Age group: 49 ± 12 years Inclusion criteria POSA defined as AHI ≥ 5 with symptoms of excessive sleepiness or AHI of ≥ 15 with a 50% decrease in the AHI while sleeping in non‐supine position as compared to supine position AHI must have fallen to < 5 when the participant was in non‐supine position Participant must have slept in the lateral position for a minimum of 1 hour during the study Mild‐moderate OSA (AHI ≤ 30) Exclusion criteria Conditions that might interfere with sleep (e.g. heart failure, chronic respiratory disorders, narcolepsy) Current use of ventilatory stimulants or depressants Obesity hypoventilation syndrome Facial abnormalities that preclude use of CPAP Pregnancy
Interventions	Intervention: Zzoma® positional sleeper. It consists of semirigid synthetic foam contained in a backpack‐type material worn using a Velcro elastic belt Control: CPAP Duration: 1 night each on intervention and on CPAP
Outcomes	AHI Mean SaO2 Lowest SaO2 Percentage of total sleep time with SaO2 < 90% Sleep efficiency Spontaneous arousal index Sleep architecture Participant's preference of the intervention
Notes	Setting: Comment: study applicable to POSA as defined by the study Disclosure: "Financial support was provided by an Innovator Circle Grant from Abington Memorial Hospital, Abington, PA. Sleep Specialists, LLC, supplied the positional devices for the study and paid for a portion of the polysomnograms that were performed at Abington Memorial Hospital. Drs. Crocetti and Krachman have a financial interest in Sleep Specialists, LLC, makers of the Zzoma Positional Sleeper. The other authors have indicated no financial conflicts of interest"
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	The procedure for randomisation is not mentioned. High risk may be mitigated by the cross‐over design of the study.
Allocation concealment (selection bias)	Unclear risk	The procedure of allocation concealment is not mentioned. High risk may be mitigated by the cross‐over design of the study.
Blinding of participants and personnel (performance bias) Objective outcomes ( AHI)	High risk	Not mentioned, but likely not blinded considering nature of intervention
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not mentioned
Incomplete outcome data (attrition bias) All outcomes	Low risk	Low dropout rate. One participant lost after randomisation
Selective reporting (reporting bias)	High risk	Reporting is not according to the standard reporting of non‐inferiority trial. Non‐inferiority has not been demonstrated (as P = 0.16), but the study authors report this as the intervention showing 'equivalence' with that of the active control. The outcomes are reported as median and interquartile range, and as difference between baseline and following the intervention, and not between the intervention and the control. In most of the critical parameters, the study does not report the comparison of outcomes between the intervention and the control.
Other bias	High risk	The reporting of the study was not appropriate. The results from baseline are reported interchangeably with between‐group comparison. Non‐inferiority is not properly reported. The study is reported as a superiority trial. The reported result of the study is misleading. However, this issue is not a problem if the results are pooled for meta‐analysis. The reported outcome of the study independently should be considered high risk of bias due to selective outcome reporting and improper reporting vis‐a‐vis the design of the study. Overall poor‐quality study