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AAFP Home Page > News & Publications > Journals > American Family Physician® > Vol. 73/No. 5 (March 1, 2006)

Cochrane for Clinicians

Putting Evidence into Practice

Oral Appliances for Obstructive Sleep Apnea?

The Cochrane Abstract on the next page is a summary of a review from the Cochrane Library. It is accompanied by an interpretation that will help clinicians put evidence into practice. Vanessa Cook, M.D., and Michael Schooff, M.D., present a clinical scenario and question based on the Cochrane Abstract, followed by an evidence-based answer and a full critique of the review.

EB CME This clinical content conforms to AAFP criteria for evidence-based continuing medical education (EB CME). EB CME is clinical content presented with practice recommendations supported by evidence that has been reviewed systematically by an AAFP-approved source. The practice recommendations in this activity are available online at

Clinical Scenario

A 58-year-old man presents with excessive fatigue and daytime sleepiness. After polysomnography, he is found to have severe obstructive sleep apnea.

Clinical Question

Should oral appliances be considered a first-line treatment for obstructive sleep apnea?

Evidence-Based Answer

Although oral appliances provide improved subjective sleepiness and sleep-disordered breathing, continuous positive airway pressure (CPAP) is more effective. Oral appliances should not be used as a first-line treatment but rather should be reserved for patients who cannot tolerate CPAP or who refuse to use it.1

Cochrane Abstract

Background. Obstructive sleep apnea-hypopnea is a syndrome characterized by recurrent episodes of partial or complete upper airway obstruction during sleep that usually are terminated by an arousal. Nasal continuous positive airway pressure (CPAP) is the primary treatment for obstructive sleep apnea-hypopnea, but many patients are unable or unwilling to comply with this treatment. Oral appliances are an alternative treatment for sleep apnea.

Objectives. The objective was to review the effects of oral appliances in the treatment of sleep apnea in adults.

Search Strategy. The authors1 searched the Cochrane Airways Group Sleep Apnea RCT Register. Searches were current as of June 2004. Reference lists of articles also were searched.

Selection Criteria. Randomized trials comparing oral appliances with control or other treatments in adults with sleep apnea.

Data Collection and Analysis. Trial quality was assessed and two reviewers extracted data independently. Study authors were contacted for missing information.

Primary Results. Thirteen trials involving a total of 553 participants were included. All the studies had some shortcomings, such as small sample size, under-reporting of methods and data, and lack of blinding.

Oral appliances versus control appliances (five studies): Oral appliances reduced daytime sleepiness in two crossover trials (weighted mean difference [WMD] -1.81 [95% confidence interval (CI): -2.72 to -0.90]), and improved apnea-hypopnea index (-13.17 [-18.53 to -7.80] parallel group data-four studies).

Oral appliances versus CPAP (seven studies): Oral appliances were less effective than continuous positive pressure in reducing apnea-hypopnea index (WMD 13 [95% CI: 7.63 to 18.36], parallel studies-two trials; WMD 6.96 [4.82 to 9.10] crossover studies-six trials). However, no significant difference was observed on symptom scores. Nasal continuous positive pressure was more effective at improving minimum arterial oxygen saturation during sleep compared with oral appliances. In two small crossover studies, participants preferred oral appliance therapy to CPAP.

Oral appliances versus surgery (one study): Symptoms of daytime sleepiness were initially lower with surgery, but this difference disappeared at 12 months. Apnea-hypopnea index initially did not differ significantly, but did so after 12 months in favor of oral appliances.

Reviewers' Conclusions. There is some evidence suggesting that oral appliance use improves subjective sleepiness and sleep-disordered breathing compared with a control. Nasal CPAP appears to be more effective in improving sleep-disordered breathing than oral appliances. Until there is more definitive evidence on the effectiveness of oral appliances, it would appear to be appropriate to restrict oral appliance therapy to patients with sleep apnea who are unwilling or unable to comply with CPAP therapy.

imageThese summaries have been derived from Cochrane reviews published in the Cochrane Database of Systematic Reviews in the Cochrane Library. Their content has, as far as possible, been checked with the authors of the original reviews, but the summaries should not be regarded as an official product of the Cochrane Collaboration; minor editing changes have been made to the text (

Practice Pointers

Obstructive sleep apnea affects up to 4 percent of adults and leads to daytime sleepiness, low oxygen levels during sleep, pulmonary hypertension, systemic hypertension, right-sided heart failure, and arrhythmias.2 Daytime sleepiness can cause motor vehicle collisions, injuries at work, and poor work performance.3

Physicians should consider diagnostic testing for obstructive sleep apnea in patients who have apneas; awakening with a choking sensation; snoring; hypertension; daytime sleepiness; obesity; or a short, thick neck with a circumference greater than 16 inches in a woman or greater than 17 inches in a man.4 Many patients do not realize that they snore or have nocturnal arousals, but questioning a sleep partner may help suggest the diagnosis.5 Causes of obstructive sleep apnea include hypothyroidism, restrictive lung disease from scoliosis, and neuromuscular disorders such as postpolio syndrome.5 Diagnostic testing typically is with polysomnography. Overnight unattended oximetry is another option for patients at high risk who do not have access to a sleep laboratory.4

Treatment options for obstructive sleep apnea include behavioral changes (e.g., weight loss, good sleep hygiene, elimination of alcohol and sleep medications, sleeping on the side), CPAP, surgery, and oral appliances.4,6 Behavioral changes should be recommended for all patients with obstructive sleep apnea and may be sufficient treatment for those with mild disease.4

Positive airway pressure devices are the most consistently successful and extensively studied treatment for obstructive sleep apnea.7 However, compliance is a concern because CPAP can be uncomfortable, can cause mucous membrane drying, and may induce claustrophobia. Modification of CPAP using bilevel pressure ventilation reduces the work of breathing, and some patients, especially those with chronic lung disease, find this more tolerable.8

Oral appliances, manufactured or fitted by a dentist or oral surgeon, are used to move the tongue or mandible forward. They help prevent the collapse of the tongue and soft tissues in the back of the throat to facilitate maintenance of an open airway without CPAP. Adverse effects of oral appliances include temporomandibular joint discomfort, bite change, and excessive salivation or dryness of the mouth. This Cochrane review1 did not address individual mandibular and tongue repositioning devices, a variety of which are on the market. It also was unable to break down the individual studies into smaller population subgroups because the populations were already heterogeneous. Despite these limitations, most of the studies included in this review showed similar results: oral appliances are a viable alternative for patients who are unwilling or unable to use CPAP, but appliances are not as effective as CPAP in the treatment of obstructive sleep apnea.

Finally, surgical modifications to the anatomy may be considered in patients with significant disease who want more invasive treatments after conservative measures have failed. Altering the uvula and soft palate, maxillomandibular advancement, genial tubercle and tongue advancement, and combinations of these may be performed, with or without improvement in sleep apnea. Surgery entails recovery time and is more appropriate for younger patients with severe apnea who are healthy enough to undergo these procedures.8 Bariatric surgery also may be considered as a treatment for patients with morbid obesity to help decrease the severity of obstructive sleep apnea.8 Controlled studies of any type of surgery to relieve symptoms of obstructive sleep apnea are lacking.9

The Authors

VANESSA COOK, M.D., is a family physician in private practice in Emporia, Kan. She received her medical degree from the University of Kansas School of Medicine in Kansas City and completed a family medicine residency at the Clarkson Family Medicine Residency Program in Omaha, Neb.

MICHAEL SCHOOFF, M.D., is associate director of the Clarkson Family Medicine Residency Program in Omaha. He received his medical degree from the Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, Md., and completed a family medicine residency at Womack Army Medical Center, Fort Bragg, N.C.

Address correspondence to Michael Schooff, M.D., Clarkson Family Medicine, 4200 Douglas St., Omaha, NE 68131 (e-mail: Reprints are not available from the authors.


1. Lim J, Lasserson TJ, Fleetham J, Wright J. Oral appliances for obstructive sleep apnoea. Cochrane Database Syst Rev 2004;(4):CD004435.

2. Bradley TD, Phillipson EA. Sleep disorders. In: Murray JF, Nadel JA, eds. Textbook of respiratory medicine, vol 2. 3rd ed. Philadelphia: W.B. Saunders, 2002:2153-69.

3. Lieberman JA III. Treatment of patients with obstructive sleep apnea. [Letter.] Am Fam Physician 2005;71:861-2.

4. Institute for Clinical Systems Improvement. Diagnosis and treatment of obstructive sleep apnea. Bloomington, Minn.: Institute for Clinical Systems Improvement, 2005.

5. Victor LD. Obstructive sleep apnea. Am Fam Physician 1999;60:2279-86.

6. Sleep apnea. Accessed online November 7, 2005, at:

7. White J, Cates C, Wright J. Continuous positive airways pressure for obstructive sleep apnoea. Cochrane Database Syst Rev 2001;(4):CD001106.

8. Victor LD. Treatment of obstructive sleep apnea in primary care. Am Fam Physician 2004;69:561-8.

9. Bridgman SA, Dunn KM, Ducharme F. Surgery for obstructive sleep apnoea. Cochrane Database Syst Rev 1998;(1):CD001004.

Cochrane Briefs

Improving Outpatient Referrals to Secondary Care

Clinical Question

What is the best way to improve the appropriateness of outpatient referrals from primary to secondary care?

Evidence-Based Answer

The interventions that have the best supporting evidence are the distribution of guidelines with standard referral forms and the involvement of specialist consultants in education. Disseminating guidelines without forms and providing physicians with feedback on referral patterns are not proven to be effective.

Practice Pointers

Improving the referral process is a high priority for family medicine. In 2001, the Institute of Medicine issued a report1 on the state of the health care system that included several goals for overhaul: to make the system safe, effective, patient-centered, timely, efficient, and equitable. Appropriate use of subspecialty care is a key component of these goals.1 In 2004, the Future of Family Medicine Project Leadership Committee developed a template for the transformation of the specialty and the creation of a new model of family medicine.2 A centerpiece of this document is that every patient should have a medical home.2

Grimshaw and colleagues searched for studies of interventions to change or improve outpatient referrals. They found 17 trials with 23 different comparisons. Four out of five studies reported a benefit to dissemination of guidelines with structured referral sheets (checklists to accompany referral letters). These referral sheets prompt primary care physicians to perform prereferral management or tests. In one study, use of a structured referral sheet for infertility consultation yielded absolute increases of 16 percent in the number of primary care physicians who elicited a five-point sexual history, 24 percent in the number of women who received five tests before referral, and 18 percent in the number of men who received two tests before referral.3 All of the studies evaluated referral patterns for only one condition, and only about one half of referrals were accompanied by a completed referral sheet. Overuse of referral checklists for a wider range of conditions could be counterproductive.

Two out of three studies showed involvement of consultants in educational activities to be effective. In a study assessing the impact on referrals of monthly workshops about orthopedic problems, the intervention produced an increase in the use of injections by primary care physicians (30.6 versus 11.7 percent control, P < .001), a reduction in subsequent referrals to orthopedic surgeons (35.4 versus 68.0 percent control, P < .001), and an increase in the number of patients whose symptoms resolved after one year (35.4 versus 23.7 percent control, P < .05).4

Other effective interventions included patient management with a family physician rather than an internist; attachment of a physical therapist to a primary care office; requirement of an in-house second opinion before referral; and changes in the reimbursement scheme, from capitation to a mixed capitation and fee-for-service system and from low-cost fee-for-service to high-cost fee-for-service or capitation. Strategies that were not proven effective included passive dissemination of local consensus referral guidelines, feedback on referral rates, and discussion with an independent medical advisor.


1. Institute of Medicine; Committee on Quality of Health Care in America. Crossing the quality chasm: a new health system for the 21st century. Washington, D.C.: National Academy Press, 2001.

2. Martin JC, Avant RF, Bowman MA, Bucholtz JR, Dickinson JR, Evans KL, et al; Future of Family Medicine Project Leadership Committee. The Future of Family Medicine: a collaborative project of the family medicine community. Ann Fam Med 2004;2(suppl 1):S3-32.

3. Emslie C, Grimshaw J, Templeton A. Do clinical guidelines improve general practice management and referral of infertile couples? BMJ 1993;306:1728-31.

4. Vierhout WP, Knotterus JA, van Ooij A, Crebolder HF, Pop P, Wesselingh-Megens AM, et al. Effectiveness of joint consultation sessions of general practitioners and orthopaedic surgeons for locomotor-system disorders. Lancet 1995;346:990-4.

Grimshaw JM, et al. Interventions to improve outpatient referrals from primary care to secondary care. Cochrane Database Syst Rev 2005;(3):CD005471.

Cyclic vs. Continuous or Extended- Cycle Combined Contraceptives

Clinical Question

Are continuous and extended-cycle combined contraceptives safe and effective?

Evidence-Based Answer

Evidence shows no difference in safety or effectiveness between cyclic and continuous or extended-cycle combined contraceptives. There are fewer menstrual symptoms with extended-cycle contraceptives. Patients' satisfaction and adherence is similar for all types.

Practice Pointers

American women in the 21st century experience earlier menarche, have fewer babies, breastfeed for shorter periods, and live longer than women in past centuries, and therefore they have many more episodes of bleeding over their lifetimes. Bleeding with contraceptives is caused by pill withdrawal rather than endometrial buildup. There is no biologic reason why monthly cycles are necessary. Because many women prefer fewer days of vaginal bleeding per year, continuous and extended-cycle oral contraceptives have been developed.

To assess the safety and effectiveness of combined oral contraceptives with longer cycle lengths, Edelman and colleagues reviewed the literature for randomized controlled trials comparing 28-day cyclical contraceptives (21 active pills, seven placebos) with continuous combined contraceptives. They found six studies comparing 28-day cycles of combined oral contraceptives with cycles ranging from 49 to 365 days. There was no difference between the regular and extended cycles in satisfaction, adherence, pregnancy rates, or safety. Patients taking continuous oral contraceptives had four to 14 fewer days of bleeding per trimester. In the two studies that included a sonogram or endometrial biopsy, no evidence of endometrial hyperplasia was found after nine cycles.

Although combined oral contraceptive pills also are used to treat conditions such as acne and dysmenorrhea,1,2 there have been no studies on the use of continuous combined oral contraceptives for purposes other than the prevention of pregnancy. Limited data in this review suggest that women taking continuous dosing have fewer headaches and less genital irritation, fatigue, bloating, and menstrual pain.


1. Arowojolu AO, Gallo MF, Grimes DA, Garner SE. Combined oral contraceptive pills for treatment of acne. Cochrane Database Syst Rev 2004;(3):CD004425.

2. Proctor ML, Roberts H, Farquhar CM. Combined oral contraceptive pill (OCP) as treatment for primary dysmenorrhoea. Cochrane Database Syst Rev 2001;(4):CD002120.

Edelman AB, et al. Continuous or extended cycle vs. cyclic use of combined oral contraceptives for contraception. Cochrane Database Syst Rev 2005;(3):CD004695.

The series coordinator for AFP is Clarissa Kripke, M.D., Department of Family and Community Medicine, University of California, San Francisco.

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