Positive predictive value for response to custom mandibular advancement device (MAD) therapy based on a trial of prefab device ApneaRX was essentially 100% in a recent proof of concept feasibility pilot.
Apnea Sciences’ prefab ApneaRX is self-titrated by the patient at home, eliminating the need for the in-lab titration that is required with other oral appliance predictive tools available on the market today. Dennis Hwang, MD, lead study investigator and medical director, sleep medicine department at Kaiser Permanente in Fontana, Calif, says the ambulatory aspect of ApneaRX is why the prefab device was chosen for this study. “The world is moving toward the ambulatory setting, and in-lab testing may not be very cost-effective,” Hwang tells Sleep Review. “My goal is to find a more cost-effective method to see who will respond and who will not respond to an oral appliance.”
Accurate Predictions
“Oral appliance is a really great therapy and a therapy that will be under consideration as a first line therapy as we move forward,” Hwang says. “CPAP, oral appliances, and perhaps Provent are therapies that could potentially be appropriate for first line therapy.”
However, unlike with CPAP and Provent, there is no generally accepted way to determine if a patient is a good candidate for an oral appliance before prescribing the therapy. Hwang says, “With CPAP, the patient will physiologically respond to it. With Provent, there’s a question if the patient will have a physiological response, but Provent is easy and cheap to test before you prescribe it.” Oral appliance predictions are generally made on obstructive sleep apnea (OSA) severity and on craniofacial features, but those methods are imperfect, Hwang says.
“You have a good therapy with oral appliances, but it is also expensive. So you’re committing the patient to a therapy and to using it, but you have no idea if it will work or not, or if the patient will adhere to therapy. Having a predictive mechanism will really be critical for us moving into the future,” Hwang says.
The Pilot Study
The poster “Feasibility Pilot Evaluating the Use of Pre-Fabricated Titratable Mandibular Advancement Device for Management of Obstructive Sleep Apnea” was presented at the 2014 SLEEP Conference.
In the study, OSA patients were enrolled in a MAD Education Class, then those that maintained interest were set up with ApneaRX. Patients were asked to advance it 1 mm every 1 to 2 nights with a target of 7+ mm advancement and resolution of snoring. No patients reported problems with self-titrating, Hwang says. A home sleep test was scheduled 2 weeks after the fitting, and those clinically appropriate were referred to dentists for custom MADs.
Efficacy of ApneaRX mimicked that reported in literature for custom MAD, although a significant number of patients “opted out” prior to a sleep test with MAD (mostly due to discomfort), thus selection bias could be present, the poster states.
Future of Predictive Devices
Regarding the significant opt-outs, one cause was the prefab device being too bulky and so not fitting in every patient’s mouth. To remedy this problem, the manufacturer is releasing a slimmer version (shown), says Pat Maley, chief operating officer of Apnea Sciences. “We’re coming out with one that’s targeted toward women, standard, and small sizes,” Maley says.
Hwang expects that in the future the oral appliance predictive devices that currently require an in-lab titration may develop at-home options. For now, he is looking to conduct more trials of prefab ApneaRX, specifically to ascertain its negative predictive value. “We want to take the patients that don’t respond to the prefab device and still get them a custom oral appliance and see what the negative predictive value is,” Hwang says. If the negative predictive value is also near 100%, the predictive devices may become part of the physician’s toolbox to treat sleep apnea.
