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ATLANTA -- An oral appliance for people with obstructive sleep apnea (OSA) was noninferior to continuous positive airway pressure (CPAP) for reducing 24-hour mean arterial blood pressure (BP) in patients with hypertension and increased cardiovascular risk, a randomized trial showed.

Compared with baseline, the 24-hour mean arterial BP decreased by 2.5 mm Hg at 6 months in the group who used the mandibular advancement device, while there was no change in the CPAP group, for a between-group difference of -1.6 mm Hg (95% CI -3.51 to 0.24, non-inferiority P<0.001), reported Chi-Hang Lee, MBBS, MD, of Yong Loo Lin School of Medicine at the National University of Singapore, during the American College of Cardiology annual meeting.

This study was simultaneously published in the .

The group using the oral appliance also had a larger between-group reduction in all secondary ambulatory BP parameters compared with the CPAP group, with the most pronounced effects observed in the asleep BP parameters, the researchers noted. Both groups had improved daytime sleepiness based on the Epworth Sleepiness Scale.

With the mandibular advancement device, the median duration of usage was 5.5 hours per night, and 74.7% used the device for ≥4 hours per night, which is the American Academy of Sleep Medicine recommendation for improvement in clinical symptoms; 56.5% used it for ≥6 hours per night. For the CPAP group, the median duration of usage was 5 hours per night, and 70.2% used the device for ≥4 hours per night and 23.2% used it for ≥6 hours per night.

The researchers targeted hypertension in the trial because high blood pressure is a major risk factor for cardiac and cerebrovascular diseases. OSA, Lee said, is an under-diagnosed and modifiable cause of hypertension. He noted that hypertension guidelines recommend screening and treatment of OSA in patients with hypertension. CPAP is the first-line treatment for OSA; however, many patients either decline to use CPAP or find it challenging to stick to the treatment, he noted.

"This device has greater potential for a public health impact than almost anything else that is being talked about here," Edward Fry, MD, immediate past president of the American College of Cardiology and chair of cardiology at Ascension St. Vincent Heart Center in Indianapolis, told MedPage Today.

"In my practice, whenever I tell someone they need to be checked for sleep apnea -- which is tantamount to saying you are going to be on CPAP -- they either don't do it or they tell me they won't do it. So if there is a solution for controlling sleep apnea other than CPAP, patients will pursue it," he said. "What is also interesting is that the blood pressure reduction with the oral device was non-inferior to CPAP and maybe a bit better. So this may be a palatable -- or should we say 'soft palatable' -- solution to this problem."

Lee noted that "looking at the totality of evidence available in the literature, it is still reasonable to say that CPAP is the first-line treatment until we have more data on this mandibular advancement device. However, for patients who truly cannot tolerate or accept using a CPAP, we should be more open-minded in looking for an alternative therapy such as a mandibular advancement device, which, based on our study, numerically had a better blood pressure reduction in patients compared with a CPAP."

"The mandibular advancement device patients simply used it longer," he added. "That also might explain why the blood pressure reduction at nighttime, when the patients are actually using it, had a better reduction in the mandibular advancement device arm."

Lee and colleagues suggested that the oral appliance might help OSA by reducing airway collapse via advancing the mandible. They recruited 321 patients over the age of 40 who were diagnosed with uncontrolled hypertension and high cardiovascular risk to undergo sleep studies to determine if they had OSA.

Of this group, 220 patients were diagnosed with moderate to severe OSA (Apnea-Hypopnea Index ≥15 events/hour), and were randomly assigned to the oral appliance (n=85) or CPAP (n=98), instructed in their use, and were told to sleep with the device for as long as possible over the 6-month study. Both devices had built-in trackers that recorded use.

Median patient age was 61-62, 84-87% were men, and median body mass index was 27-28. Of the patients in the oral appliance group, 47.3% had hypertension for over 10 years, 48.2% were on two BP medications, 60% had coronary artery disease, 59% had diabetes, 78.2% had hyperlipidemia, 29% had previous myocardial infarction, and 46.4% had previous PCI. For the CPAP group, 40.9% had hypertension for over 10 years, 38.2% were on one BP medication and 32.3% were on two, 61.8% had coronary artery disease, 59% had diabetes, 78.2% had hyperlipidemia, 30% had previous myocardial infarction, and 51.8% had previous PCI.

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