New Hope for Snorers
Abstracts & Commentary
By Barbara A. Phillips, MD, MSPH, Professor of Medicine, University of Kentucky; Director, Sleep Disorders Center, Samaritan Hospital, Lexington. Dr. Phillips serves on the speaker's bureau of Cephalon, Boehringer Ingelheim, Merck, ResMed, and GlaxoSmithKline, and is a consultant for Boehringer Ingelheim, Wyeth-Ayerst, and ResMed.
Synopsis: Oral appliances are effective in the treatment of snoring and mild-to-moderate sleep apnea, and are indicated for patients with mild-to-moderate obstructive sleep apnea who prefer oral appliances to CPAP, do not respond to CPAP, are not appropriate candidates for CPAP, or fail treatment attempts with CPAP.
Sources: Kushida CA, et al. Practice parameters for the treatment of snoring and obstructive sleep apnea with oral appliances. Sleep. 2006;29:240-243; Ferguson KA, et al. Oral appliances for snoring and obstructive sleep apnea: A review. Sleep. 2006;29:244-262.
This pair of papers was produced by the standards of Practice committee of the American Academy of Sleep Medicine (AASM) using their standard procedure of vetting and reviewing the peer-reviewed literature on the topic to produce a review paper, then creating a practice guideline based on that review.
For the review, the task force addressed the following questions:
1. What is the efficacy of oral appliances in the treatment of snoring and obstructive sleep apnea in the short and long term?
2. By what mechanisms do oral appliances improve snoring and obstructive sleep apnea?
3. Do patients use oral appliances in the short and long term?
4. What short and long-term side effects occur with the use of oral appliances?
5. How do oral appliances compare with nasal continuous positive airway pressure (CPAP), surgery, and other treatments for snoring and sleep apnea?
6. What device selection and procedures are best for implementing oral appliances in the treatment of sleep-disordered breathing?
A PubMed search was conducted for peer-reviewed papers in the English language that included original research on oral appliances; task force members contributed relevant articles that did not appear in the PubMed search. One hundred thirty-one papers were included in this review. Task force members graded the evidence using a method adapted from Sackett,1 and extracted data relevant to the questions posed above to produce evidence tables.
The literature assembled demonstrated a 52% chance of control of sleep apnea with an oral appliance. Successful treatment was much more likely in patients with mild-to-moderate sleep apnea (variously defined as an apnea plus hypopnea index [AHI] of less than 30 or 40 events per hour of sleep). Greater degrees of mandibular protrusion were associated with greater likelihood of successful treatment. Several studies suggested that a high body mass index (BMI) was associated with less likelihood of benefit with oral appliance treatment. The data assembled demonstrated that oral appliances are not as effective as CPAP, but are generally better accepted by patients. They appear to work by enlarging the upper airway and reducing its collapsibility. Assessment of compliance with oral appliances is generally by self-report, and is comparable to adherence rates with CPAP. There is a tendency for oral appliance use to decrease over time. Minor side effects include salivation and temporomandibular joint pain; the most significant side effect is bite change, which does not always resolve after cessation of use. Oral appliances are not as effective as CPAP in improving the AHI, but are generally better accepted by patients. Oral appliances outperform uvulopalatopharyngoplasty (UPPP) in both the short and the long term.
Based on this review of the literature, a panel of experts produced the accompanying Practice Parameter paper addressing the use of oral appliances to treat sleep apnea and snoring. This paper states that oral appliances are effective in the treatment of snoring and mild to moderate sleep apnea. They are indicated for patients with mild to moderate obstructive sleep apnea who prefer oral appliances to CPAP, do not respond to CPAP, are not appropriate candidates for CPAP, or fail treatment attempts with CPAP. The panel recommends that the devices be fitted by "dental personnel" and that "dental specialists" see patients who have oral appliances in follow-up. The panel recommended that the diagnosis of sleep apnea (or snoring) be established by polysomnography and that follow-up sleep study be performed to assess the efficacy of the oral appliance or if symptoms persist or recur.
Commentary
This pair of papers is extremely important because of the very high (and increasing!) prevalence of sleep apnea, the severity of its sequelae, and the cumbersome nature of CPAP treatment. Sleep apnea is conservatively estimated to afflict 5% of Americans,2 but some estimates are much higher.3
The findings of these papers are mirrored by the Cochrane Database, which reports, "CPAP is effective in reducing symptoms of sleepiness and improving quality-of-life measures in people with moderate and severe obstructive sleep apnea [OSA]. It is more effective than oral appliances in reducing respiratory disturbances in these people but subjective outcomes are more equivocal. Certain people tend to prefer oral appliances to CPAP where both are effective. This could be because they offer a more convenient way of controlling OSA."4
The review published in the Sleep and the Cochrane data base focuses extensively on the effect of oral appliance treatment on the AHI and subjective symptoms (sleepiness, quality of life). Indeed, those are important outcomes. However, the best-proven and most significant consequences of sleep apnea are cardiovascular sequelae and automobile crashes. Sleep apnea is now listed first among the treatable causes of hypertension by the Joint National Council on High Blood Pressure.5 This finding is based on several large, well-done studies demonstrating significantly increased risk of hypertension in those with even mild sleep-disordered breathing as well as improvement of blood pressure with CPAP treatment in the absence of any other treatment.6,7 There is also evidence strongly linking sleep apnea with ischemic events, arrhythmias, pulmonary artery hypertension, cerebrovascular events, and congestive heart failure; all of the cardiovascular consequences of sleep-disordered breathing have been demonstrated to improve with CPAP treatment.8 In addition to cardiovascular morbidity and mortality, it is clear that people with untreated sleep apnea are at increased risk for car wrecks, and that effective treatment with CPAP can reduce that risk.9,10
There is, in fact, a small amount of evidence that oral appliances can reduce blood pressure in individuals with sleep apnea, though not to the degree that CPAP does.11,12 As of this writing, data about the effect of oral appliances on other cardiovascular outcomes and on car crashes are lacking.13 So, despite these very encouraging new recommendations about oral appliance use, it is important to remember that oral appliance therapy is second-line to CPAP treatment, and not appropriate for patients with severe sleep apnea.
On the other hand, this new vetting of oral appliances by both the AASM and the Cochrane Database should reduce substantially the number of hapless patients who are subjected to upper airway surgery, which has also recently been scrutinized by Cochrane, and which concluded, "The studies assembled in the review do not provide evidence to support the use of surgery in sleep apnea/hypopnea syndrome, as overall significant benefit has not been demonstrated."
In the clinical practice of medicine, this means that patients with snoring and mild sleep apnea who do not tolerate CPAP now have a viable, effective treatment option other than CPAP (which works better) or surgery (which doesn't).
References
1. Sackett DL. Rules of evidence and clinical recommendations for the management of patients. Can J Cardiol. 1993;9:487-489.
2. Young T, et al. Epidemiology of obstructive sleep apnea: a population health perspective. Am J Respir Crit Care Med. 2002;165:1217-1239.
3. Hiestand DM, et al. Prevalence of risk factors for obstructive sleep apnea in the US: Results from the Sleep in America Poll. Chest. In press.
4. Giles TL, et al. Continuous positive airways pressure for obstructive sleep apnoea in adults. Cochrane Database Syst Rev. 2006 Jan 25;(1):CD001106.
5. Chobanian AV, et al. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: the JNC 7 report. JAMA. 2003;289:2560-2572; Erratum in: JAMA. 2003;290:197.
6. Pepperell JC, et al. Ambulatory blood pressure after therapeutic and subtherapeutic nasal continuous positive airway pressure for obstructive sleep apnoea: a randomised parallel trial. Lancet. 2002;359:204-210.
7. Becker HF, et al. Effect of nasal continuous positive airway pressure treatment on blood pressure in patients with obstructive sleep apnea. Circulation. 2003;107:68-73.
8. Phillips B. Sleep-disordered breathing and cardiovascular disease. Sleep Med Rev. 2005;9:131-140.
9. Turkington PM, et al. Time course of changes in driving simulator performance with and without treatment in patients with sleep apnoea hypopnoea syndrome. Thorax. 2004;59:56-59.
10. George CF. Reduction in motor vehicle collisions following treatment of sleep apnoea with nasal CPAP. Thorax. 2001;56:508-512.
11. Gotsopoulos H, et al. Oral appliance therapy reduces blood pressure in obstructive sleep apnea: a randomized, controlled trial. Sleep. 2004;27:934-941.
12. Yoshida K. Effect on blood pressure of oral appliance therapy for sleep apnea syndrome. Int J Prosthodont. 2006;19:61-66.
13. Sundaram S, et al. Cochrane Database Syst Rev. 2005 Oct 19;(4):CD001004.
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