Evidence Trace, complete trial record
In plain terms
In plain terms: Nasal valve (nasal EPAP) for obstructive sleep apnea shows early signals in human research but the evidence is limited -- small trials, surrogate endpoints, or not yet independently replicated. It is an emerging area, not yet a proven one.
Nasal valve (nasal EPAP) for obstructive sleep apnea
C
Limited: small, mixed or unreplicated trials
The endpoint this grade is based on: Surrogate biomarker endpoint
The evidence as the record states it
Berry et al. (Sleep, 2011; PMID 21461326): AERO, multicenter sham-controlled double-blind trial, 250 randomized, 3 months, funded by the device maker. Kryger et al. (J Clin Sleep Med, 2011; PMID 22003339): single-arm 12-month extension in 41 responders, shown as context. Rossi et al. (Thorax, 2013; PMID 23723343): placebo-controlled trial during CPAP withdrawal, null. Wheeler et al. (J Clin Sleep Med, 2016; PMID 27306393): crossover in acute stroke, null. Chopra et al. (J Clin Sleep Med, 2014; PMID 24812544): case report of complex sleep apnea with the valve.
PMID 21461326 PMID 23723343 PMID 27306393 PMID 22003339 PMID 24812544
Evidence by specific use
Apnea-hypopnea index and Epworth sleepiness in obstructive sleep apnea
Grade C
In a sham-controlled trial of 250 adults funded by the device maker, the valve cut the apnea-hypopnea index by 43 percent at 3 months against 10 percent on sham, and Epworth scores fell (Berry et al., Sleep, 2011; PMID 21461326). In 67 people with moderate to severe sleep apnea taken off CPAP, it did no better than a placebo valve on breathing, oxygen or sleepiness (Rossi et al., Thorax, 2013; PMID 23723343), and after stroke it made no significant difference (Wheeler et al., J Clin Sleep Med, 2016; PMID 27306393). Positive and null controlled trials: C.
PMID 21461326 PMID 23723343 PMID 27306393
Why Grade C and not Grade B
Grade C reflects early or limited human evidence -- small trials, surrogate endpoints, or preliminary findings not yet independently replicated. The evidence points in a promising direction but does not yet meet the standard for Grade B. A single well-powered, independently replicated trial with a meaningful endpoint would move this to Grade B or higher.
What this grade covers and what it does not
Grade C on the apnea-hypopnea index and daytime sleepiness: one maker-funded sham-controlled trial was positive (Berry et al., 2011; PMID 21461326) and an independent placebo-controlled trial in moderate to severe disease was null (Rossi et al., 2013; PMID 23723343). WHY NOT B: the second controlled trial did not repeat the first. WHAT THIS GRADE DOES NOT COVER: snoring without sleep apnea, mouth taping and other nasal devices, cardiovascular outcomes, and long-term use beyond the open-label extension in people who had already responded.
What would move this grade
A well-powered randomized trial with an objective, clinically meaningful primary endpoint and at least one independent replication would support Grade B or higher.
How to track whether this is working
Apnea-hypopnea index on a home sleep study with the valves in place, and the Epworth Sleepiness Scale.