TABLE VIII.D. 5.

Evidence for effects of nasal dilators on OSA

Study	Year	LOE (1a–5)	Study design	Study groups	Clinical end-point	Conclusion
Yagihara et al.1441	2017	2b	Randomized crossover study	26 patients with severe OSA randomized to either 1 month of nasal dilator strips or nasal CPAP and then crossover after 2 weeks.	Sleep architecture, AHI, arousal index, oxygen saturation, sleep questionnaires.	Nasal dilator strips in patients with severe OSA had no effect on objective sleep outcomes (sleep architecture and respiratory events).
Camacho et al.1442	2016	1a	SR	14 studies (five internal dilators, nine external dilators). Most of the studies were individual case–control or prospective case-series.	Effect of nasal dilators on sleep stages, AHI, apnea index, lowest oxygen saturation, snoring, sleepiness, and sub-analysis comparing internal to external dilators.	Nasal dilators did not improve AHI or most PSG metrics except for internal nasal dilators which had a mild improvement on the apnea index.
Amaro et al.1447	2012	2b	Randomized crossover study	12 patients with acromegaly and moderate to severe OSA underwent a randomized crossover study using CPAP and nasal dilator strips.	Sleep architecture, apnea index, hypopnea index, apnea hypopnea index, central apnea, oxygen saturation, sleep questionnaires.	Nasal dilator strips had no reduction on objective sleep parameters; subjective sleep improvement, but less than in the CPAP group.
Djupesland et al.901	2001	2b	Randomized crossover study	18 patients with nocturnal nasal obstruction, severe snoring, and without severe OSA (mean AHI 9.3) underwent a randomized crossover study comparing external nasal dilator strips vs. placebo strips.	Nasal patency, AHI, oxygen saturation, sub-analysis based on nocturnal nasal dimensions.	Improvement in AHI and oxygen saturation was noted only by a subset of patients with severe nasal obstruction based on rhinometry.
Pevernagie et al.904	2000	2b	Double-blind crossover RCT	Effect of external nasal dilators on chronic rhinitis patient with snoring. Mean AHI for the group was 6.	Effect on snoring, sleep architecture, objective sleep parameters.	External nasal dilators improved snoring but had no effect on objective sleep apnea measures.
Schonhofer et al.1431	2000	4	Individual case series	21 patients with OSA who used the internal nasal dilator (Nozovent) for 1 month.	Effect on snoring, sleep architecture, objective sleep parameters, sleep questionnaires.	No effect on objective sleep parameters or snoring.
Gosepath et al.1444	1999	4	Individual case series	26 patients undergoing polysomnography with and without an external nasal dilator (Breathe right nasal strips).	Effect on RDI, correlation with other factors such as comorbidities, age, and rhinologic factors.	Nineteen out of the 26 patients experienced a reduction in RDI.
Bahammam et al.1439	1999	2b	Double-blind crossover RCT	18 patients in a double blinded crossover RCT comparing external nasal dilators to placebo.	Effect on nasal airway, sleep architecture, AHI, oxygen saturation.	External nasal dilators had no effect on AHI.
Redline et al.1310	1998	3b	Prospective cohort	Effect of CPAP vs. nasal dilators and conservative management.	Snoring, RDI, oxygen saturation, sleep questionnaires.	CPAP was superior to conservative therapy (included nasal dilators).
Wenzel et al.1440	1997	4	Individual case series	1. 30 patients with OSA. 2. 20 patients with snoring without OSA.	Effect on objective sleep parameters and snoring.	Neither the degree of OSA or snoring in patients without OSA was changed.
Hoffstein et al.1448	1993	4	Individual case series	15 patients underwent sleep study with and without an internal nasal dilator (Nozovent).	Snoring, apneas, hypopneas, oxygen saturation.	Internal nasal dilator had a weak effect on snoring and no effect on obstructive sleep apnea measures.
Hoijer et al.1443	1992	4	Individual case series	10 patients used an internal nasal dilator (Nozovent) for 10 nights, and then they had two sleep studies one with and one without the device at a random order.	Rhinomanometry, apnea index, oxygen saturation, snoring noise, questionnaires.	Internal nasal dilator reduced the apnea index, severity of oxygen desaturation, and snoring noise.
Metes et al.1445	1992	4	Individual case series	Effect of internal nasal dilator (Nozovent) on nasal resistance and sleep outcomes in a subset of patients who are heavy snorers with OSA.	Nasal resistance, snoring, apnea index, hypopnea index, oxygen saturation.	Internal nasal dilators improved nasal resistance significantly but there was no effect on objective sleep outcomes in a subset of patients who heavy snorers and have OSA.
Kerr et al.902	1992	4	Individual case series	10 OSA patients treated with a nasal dilator and topical nasal vasoconstriction.	Rhinomanometry, sleep architecture, oxygen saturation, AHI, apnea index.	Despite a 73% mean drop in nasal resistance, there was no improvement in objective obstructive sleep apnea measures.