Treating OSA: Current and emerging therapies beyond CPAP

Continuous positive airway pressure (CPAP) is the standard treatment for moderate‐to‐severe obstructive sleep apnoea (OSA). However, adherence to CPAP is limited and non‐CPAP therapies are frequently explored. Oral appliance (OA) therapy is currently widely used for the treatment of snoring, mild, moderate and severe OSA. The most commonly used and studied OA consists of a maxillary and mandibular splint which hold the lower jaw forward during sleep. The efficacy of OA is inferior to CPAP; however, the effectiveness as measured by sleepiness, quality of life, endothelial function and blood pressure is similar likely due to higher acceptance and subjective adherence. Upper airway stimulation augments neural drive by unilaterally stimulating the hypoglossal nerve. The Stimulation Therapy for Apnea Reduction (STAR) study enrolled 126 patients and demonstrated a 68% reduction in OSA severity. A high upfront cost and variable response are the main limitations. Oropharyngeal exercises consist of a set of isometric and isotonic exercises involving the tongue, soft palate and lateral pharyngeal wall. The collective reported trials (n = 120) showed that oropharyngeal exercises can ameliorate OSA and snoring (~30–40%). Nasal EPAP devices consist of disposable one‐way resister valve. A systematic review (n = 345) showed that nasal EPAP reduced OSA severity by 53%. The Winx device consists of a mouthpiece placed inside the oral cavity that is connected by tubing to a console that generates negative pressure. Winx may provide successful therapy for ~30–40% of OSA patients. In conclusion, several non‐CPAP therapies to treat OSA are currently available.     

Spousal involvement in CPAP adherence among patients with obstructive sleep apnea

Purpose  

To determine the effects of spousal involvement on continuous positive airway pressure (CPAP) adherence and response to CPAP problems in male patients with obstructive sleep apnea (OSA).     

CPAP adherence reduces cardiovascular risk among older adults with obstructive sleep apnea

Study objectives

To examine (1) the impact of adherence to continuous positive airway pressure (CPAP) therapy on risk for cardiovascular (CVD) events among a nationally representative sample of older adults with obstructive sleep apnea (OSA), and (2) the heterogeneity of this effect across subgroups defined by race, sex, and socioeconomic status.

Methods

We conducted a retrospective cohort study among Medicare beneficiaries aged ≥?65 years with OSA (2009–2013). Monthly indicators of CPAP adherence (charges for machines, masks, or supplies) were summed over 25 months to create a CPAP adherence variable. New CVD events (ischemic heart disease, cardiac and peripheral procedures) were modeled as a function of CPAP adherence using generalized estimating equations. Heterogeneity of the effect of CPAP on new CVD events was evaluated based on race, sex, and socioeconomic status.

Results

Among 5024 beneficiaries diagnosed with OSA who initiated CPAP, 1678 (33%) demonstrated new CVD events. Following adjustment for demographic and clinical characteristics, CPAP adherence was associated with reduced risk of new CVD events (hazard ratio 0.95; 95% confidence interval 0.94, 0.96) over 25 months. When analyses were stratified by time since the first CPAP charge, the protective effect remained significant for the 12- and 6-month, but not 3-month, outcome models. No significant differences were observed in the protective effect of CPAP based on race, sex, or socioeconomic status.

Conclusions

In this national study of older adult Medicare beneficiaries with OSA, CPAP adherence was associated with greatly reduced risk for CVD events. This risk reduction was consistent across race, sex, and socioeconomic subgroups.

     

Predictors of CPAP compliance in different clinical settings: primary care versus sleep unit

Background

Good adherence to continuous positive airway pressure (CPAP) treatment improves the patient’s quality of life and decreases the risk of cardiovascular disease. Previous studies that have analyzed the adherence to CPAP were performed in a sleep unit (SU) setting. The involvement of primary care (PC) in the management of obstructive sleep apnea (OSA) patients receiving CPAP treatment could introduce factors related to the adherence to treatment.

Objectives

The objective was to compare the baseline predictors of CPAP compliance in SU and PC settings.

Methods

OSA patients treated with CPAP were followed for 6 months in SU or PC setting. We included baseline clinical and anthropometrical variables, the Epworth Sleep Scale (ESS) score, the quality of life index, and the Charlson index. A logistic regression was performed for each group to determine the CPAP compliance predictors. Discrimination and calibration were performed using the area under the curve and Hosmer-Lemeshow tests.

Results

We included 191 patients: 91 in the PC group and 100 in the SU group. In 74.9% of the patients, the compliance was ≥ 4 h per day, with 80% compliance in the SU setting and 69.2% compliance in the PC setting (p = 0.087). The predictors of CPAP compliance were different between SU and PC settings. Body mass index, ESS, and CPAP pressure were predictors in the SU setting, and ESS, gender, and waist circumference were predictors in the PC setting.

Conclusions

The predictors of adequate CPAP compliance vary between SU and PC settings. Detecting compliance predictors could help in the planning of early interventions to improve CPAP adherence.

     

Effect of CPAP therapy on endothelial function in obstructive sleep apnoea: A systematic review and meta‐analysis

Obstructive sleep apnoea (OSA) is a prevalent sleep‐related breathing disorder associated with adverse cardiovascular outcome. Endothelial dysfunction is one of the proposed mechanistic links between OSA and the increased cardiovascular risk. Treatment with continuous positive airway pressure (CPAP) may reverse this detrimental pathophysiological consequence of OSA. Most studies on the effect of CPAP on endothelial function in OSA are limited by their low sample size. The objective of this systematic review was to assess the effect CPAP therapy on endothelial function in patients with OSA. We conducted a systematic review and meta‐analysis searching literature databases up to August 2013 for randomized controlled trials (RCTs) on the effect of CPAP on endothelial function in OSA, assessed by flow‐mediated dilatation (FMD) and other validated techniques. The primary outcome for the meta‐analysis (DerSimonian/Laird random‐effects method) was the treatment effect on FMD. Eight RCTs comparing the effects of therapeutic CPAP versus subtherapeutic CPAP (or no intervention) on endothelial function involving 245 OSA patients were included in the systematic review. The studies are consistent in effect direction, showing an improvement of endothelial function by CPAP. Four RCTs involving 150 patients could be used for the meta‐analysis. Compared to the control group, CPAP therapy (range 2–24 weeks) significantly increased absolute % FMD by 3.87% (95% confidence interval: 1.93–5.80, P < 0.001). In patients with OSA, CPAP therapy improves endothelial function significantly and to a clinically important extent.     

A novel, simplified approach to starting nasal CPAP therapy in OSA

BACKGROUND: Due to ever increasing referral rates, we have had to move the nasal CPAP induction program for patients with obstructive sleep apnoea (OSA) out of the sleep laboratories and into an outpatient setting. We report the effects this has had on patient outcomes. METHODS: The last 75 patients with OSA who had an overnight CPAP titration in the sleep laboratory (group 1) were compared with the first 75 coming to an afternoon clinic and set up on CPAP in groups, and who had their CPAP pressure determined from an algorithm (group 2). They were assessed at 1 and 11 months using the Epworth Sleepiness Score, compliance with CPAP (h/night), whether still using CPAP, and the number of clinic appointments required in the first 11 months. RESULTS: The two groups were similar at baseline. There were no differences in any of the outcome measures. ESS values fell from 14.6 to 5.0 and from 14.0 to 5.1 at 11 months in groups 1 and 2, respectively: compliance, 5.2 versus 5.1 h/night; clinic appointments, 1.75 versus 1.96; discontinuation rates at 1 month, 8% and 7%, and at 11 months, 25% and 21%. CONCLUSIONS: Using these simple outcome measures, we have shown that using an outpatient-based approach, and CPAP pressure based on an algorithm, have not reduced the efficacy of our CPAP induction program for patients with OSA.     

Breathing irregularity during wakefulness associates with CPAP acceptance in sleep apnea

Purpose

Individuals have different breathing patterns at rest, during wakefulness, and during sleep, and patients with sleep apnea are no different. The hypothesis for this study was that breathing irregularity during wakefulness associates with CPAP acceptance in obstructive sleep apnea (OSA).

Methods

From a 2007–2010-database of patients with a diagnostic polysomnography (PSG) and prescribed CPAP (n?=?380), retrospectively, 66 patients who quit CPAP treatment at 6 months were identified. Among them, 27 OSA patients quit despite having no side effects for discontinuing CPAP (Group A) and were compared to a matched group (age, body mass index, and apnea–hypopnea index) with good 6-month CPAP adherence (Group B; n?=?21). Five minutes of respiratory signal during wakefulness at the initial PSG were extracted from respiratory inductance plethysmography recordings, and measured in a blinded fashion. The coefficients of variation (CV) for the breath-to-breath inspiration time (T _i), expiration time (T _e), T _i?+?T _e (T _tot), and relative tidal volume, as well as an independent information theory-based metric of signal pattern variability (mutual information) were compared between groups.

Results

The CV for tidal volume was significantly greater (p?=?0.001), and mutual information was significantly lower (p?=?0.041) in Group A as compared to Group B.

Conclusions

Differences in two independent measures of breathing irregularity correlated with CPAP rejection in OSA patients without nasal symptoms or comorbidity. Prospective studies of adherence should examine traits of breathing stability.     

In patients with minimally symptomatic OSA can baseline characteristics and early patterns of CPAP usage predict those who are likely to be longer-term users of CPAP

Background

Long-term continuous positive airway pressure (CPAP) usage varies between individuals. It would be of value to be able to identify those who are likely to benefit from CPAP (and use it long term), versus those who would not, and might therefore benefit from additional help early on. First, we explored whether baseline characteristics predicted CPAP usage in minimally symptomatic obstructive sleep apnoea (OSA) patients, a group who would be expected to have low usage. Second, we explored if early CPAP usage was predictive of longer-term usage, as has been shown in more symptomatic OSA patients.

Methods

The MOSAIC trial was a multi-centre randomised controlled trial where minimally symptomatic OSA patients were randomised to CPAP, or standard care, for 6 months. Here we have studied only those patients randomised to CPAP treatment. Baseline characteristics including symptoms, questionnaires [including the Epworth sleepiness score (ESS)] and sleep study parameters were recorded. CPAP usage was recorded at 2–4 weeks after initiation and after 6 months. The correlation and association between baseline characteristics and 6 months CPAP usage was assessed, as was the correlation between 2 and 4 weeks CPAP usage and 6 months CPAP usage.

Results

One hundred and ninety-five patients randomised to CPAP therapy had median [interquartile range (IQR)] CPAP usage of 2:49 (0:44, 5:13) h:min/night (h/n) at the 2–4 weeks visit, and 2:17 (0:08, 4:54) h/n at the 6 months follow-up visit. Only male gender was associated with increased long-term CPAP use (male usage 2:56 h/n, female 1:57 h/n; P=0.02). There was a moderate correlation between the usage of CPAP at 2–4 weeks and 6 months, with about 50% of the variability in long-term use being predicted by the short-term use.

Conclusions

In patients with minimally symptomatic OSA, our study has shown that male gender (and not OSA severity or symptom burden) is associated with increased long-term use of CPAP at 6 months. Although, in general, early patterns of CPAP usage predicted longer term use, there are patients in whom this is not the case, and patients with low initial usage may need to extend their CPAP trial before a decision about longer-term use is made.     

Long-term nasal CPAP does not ameliorate obstructive sleep apnoea

Fifty-seven patients with obstructive sleep apnoea (OSA) were treated for at least six months with nasal continuous positive airway pressure (CPAP). At follow-up, sleep studies were performed in which CPAP was not used for the first half of the night. We compared the severity of OSA at follow-up without CPAP to the severity of OSA during the patient's initial diagnostic study. Apnoea and hypopnoea index (AHI) fell from 41.4 ± 7.5 (mean ±95% CI) to 34.8 ± 7.9 (p= 0.06 by Wilcoxon test) and minimum oxygen saturation rose from 71.6 ± 3.2 to 78.5 ± 2.6 (p<0.001). Some of this change may have been due to reduced REM sleep in the follow-up study (10.5±2.1% Total Sleep Time vs 7.4±2.4% TST, p<0.05). Long-term nasal CPAP was not associated with any reduction of obesity (BMI before CPAP 31.9 ± 1.0, after CPAP 31.7 ± 1.0 (p= 0.39). Systolic arterial pressure fell (before CPAP 143.0 ±4.5 mmHg, after CPAP 136.3 ± 4.6, p < 0.05) but diastolic pressure did not (before CPAP 88.5 ± 3.0 mmHg, after CPAP 85.6 ±2.9 mmHg, p = 0.11). We concluded that the effect of CPAP treatment for six or more months was a small fall in AHI and a small rise in minimum Sa0₂, but that this would be of marginal clinical significance, and may be artefactual. (Aust NZ J Med 1991; 21: 235–238.)     

A continuous positive airway pressure trial as a novel approach to the diagnosis of the obstructive sleep apnea syndrome

OBJECTIVES: Treatment of obstructive sleep apnea syndrome (OSA) is often delayed because polysomnography, the recommended standard diagnostic test, is not readily available. We evaluated whether the diagnosis of sleep apnea could be inferred from the response to a treatment trial with nasal continuous positive airway pressure (CPAP). DESIGN: Study on diagnostic accuracy. SETTING: Sleep-disorders clinic of a university hospital. PATIENTS: Seventy-six sleepy snorers consecutively referred for sleep apnea evaluation. INTERVENTIONS: CPAP treatment trial over 2 weeks as an initial diagnostic test in comparison with polysomnography, and treatment success over > or = 4 months. MEASUREMENTS AND RESULTS: The main outcome was diagnostic accuracy of the CPAP trial. The trial result was positive if the patient had used CPAP for > 2 h per night and wished to continue therapy. This suggested sleep apnea. The trial was evaluated in terms of predicting an obstructive apnea/hypopnea index (AHI) > 10/h during polysomnography performed for validation, and in terms of identifying sleep apnea patients treated successfully over > or = 4 months. Forty-four of 76 patients (58%) had sleep apnea as confirmed by an AHI > 10/h. The CPAP trial predicted sleep apnea with a sensitivity of 80%, a specificity of 97%, and positive and negative predictive values of 97% and 78%, respectively. In 35 of 76 sleep apnea patients (46%) with positive CPAP trial results, polysomnography could have been avoided. These patients were prescribed long-term CPAP therapy. After 4 months, 33 of 35 patients (94%) still used CPAP, and their symptoms remained improved. These patients were identified by the CPAP trial with positive and negative predictive values of 92% and 100%, respectively. CONCLUSIONS: In a selected population, a CPAP trial may help to diagnose OSA, to identify patients who benefit from CPAP, and to reduce the need for polysomnography.     

Long‐term use of continuous positive airway pressure therapy in coronary artery disease patients with nonsleepy obstructive sleep apnea

Background

Excessive daytime sleepiness is a frequent symptom of obstructive sleep apnea (OSA) and has been proposed as a motivator for adherence to continuous positive airway pressure (CPAP) therapy. However, excessive daytime sleepiness is absent in many patients with coronary artery disease (CAD) and concomitant OSA. We evaluated long‐term use of CPAP and predictors of CPAP use in nonsleepy and sleepy OSA patients from a CAD cohort.

Hypothesis

Long‐term CPAP use is lower in CAD patients with nonsleepy OSA vs sleepy OSA.

Methods

Nonsleepy (Epworth Sleepiness Scale [ESS] score < 10) OSA patients randomized to CPAP (n = 122) and sleepy (ESS ≥10) OSA patients offered CPAP (n = 155) in the RICCADSA trial in Sweden were included in this substudy. The median follow‐up was 4.8 years for the main trial, with a predefined minimum follow‐up of 2 years.

Results

The probability of remaining on CPAP at 2 years was 60% in nonsleepy patients and 77% in sleepy patients. Multivariate analyses indicated that age and hours of CPAP use per night at 1 month were independently associated with long‐term CPAP use in nonsleepy patients. In the sleepy phenotype, body mass index, acute myocardial infarction at baseline, and hours of CPAP use per night at 1 month were predictors of long‐term CPAP use.

Conclusions

Long‐term use of CPAP is likely to be challenging for CAD patients with nonsleepy OSA. Early CPAP use is an important predictor of continued long‐term use of CPAP, so optimizing patients' initial experience with CPAP could promote adherence.

     

Determinants of continuous positive airway pressure adherence in a sleep clinic cohort of South Florida Hispanic veterans

Purpose

There are little existing data on continuous positive airway pressure (CPAP) adherence in US Hispanic veterans with obstructive sleep apnea (OSA). Our aim was to describe determinants of 1-month adherence in a sleep clinic cohort of South Florida Hispanic veterans.

Methods

Hispanic veterans referred to the Miami VA sleep clinic were recruited and completed questionnaires about sleep apnea risk, sleep quality, insomnia symptoms, sleepiness, depression/anxiety, acculturation, personality traits, and cognitions about OSA and CPAP. Individuals at risk for OSA were scheduled for baseline polysomnography (PSG), followed by in-lab CPAP titration or a trial of auto-CPAP. Participants with OSA accepting CPAP therapy were asked to return after 7 and 30 days of treatment for adherence verification and to repeat questionnaires.

Results

One hundred twenty-four participants (94 % men) were enrolled with 114 completing overnight PSG. Eighty-six out of 95 participants (91 %) with sleep apnea syndrome or moderate to severe OSA accepted CPAP treatment. Fifty-nine participants completed both follow-up visits with a mean CPAP use at 30 days of 3.6?±?2.0 h. The only independent predictor of 7-day mean daily CPAP use was the baseline Insomnia Severity Index while the best predictor of 30-day mean daily CPAP use was the 7-day mean daily use.

Conclusions

Our study suggests that South Florida Hispanic veterans with OSA evaluated in a sleep clinic show poor CPAP adherence. Insomnia and poor early use predicted poor adherence overall. Larger prospective studies with other race–ethnic groups are needed to determine the role of ethnicity and race in CPAP adherence among US veterans with OSA.     

Effect of a 2 week CPAP treatment on mood states in patients with obstructive sleep apnea: a double-blind trial

Obstructive sleep apnea (OSA) is a common disease with significant medical and psychiatric comorbidities. The literature documenting the effects of continuous positive airway pressure (CPAP) treatment on mood in OSA patients is mixed. We previously observed that 1 week of CPAP treatment did not result in improvements in mood beyond those observed in a group treated with placebo–CPAP. This study examined the effect of a 2 week CPAP treatment on mood in a placebo-controlled design in OSA patients. Fifty patients with untreated sleep apnea were evaluated by polysomnography and completed the Profile of Mood States (POMS) pre-/post-treatment. The patients were randomized for 2 weeks to either therapeutic CPAP or placebo–CPAP (at insufficient pressure). Both the therapeutic CPAP and the placebo–CPAP groups showed significant improvements in POMS total score, tension, fatigue, and confusion. No significant time × treatment effect was observed for either group. We could not show a specific beneficial impact of CPAP treatment on mood in OSA patients.     

The effect of nightly nasal CPAP treatment on underlying obstructive sleep apnea and pharyngeal size

Nasal continuous positive airway pressure (CPAP) is an effective treatment for obstructive sleep apnea (OSA). It is usually prescribed for nightly use; however, recent studies show that patients often do not wear the appliance consistently. Previous studies have also suggested that nasal CPAP may improve a patient's underlying OSA even when the mask is not in place. We investigated 12 men with OSA to see if nasal CPAP used nightly for six weeks would improve their underlying sleep-disordered breathing. We also studied pharyngeal volumes measured using magnetic resonance imaging and a computer-controlled digitizing pad. Patients with more severe OSA had improvement after six weeks; however, they still demonstrated significant OSA. Patients with less severe OSA did not have significant change. We were unable to show a significant difference in any patient's awake pharyngeal volumes. We conclude that patients with OSA should be encouraged to wear their nasal CPAP machines regularly.     

CPAP compliance in patients with obstructive sleep apnea syndrome

Obstructive sleep apnea syndrome (OSAS) is characterized by repeated cessations of breathing during sleep. Major symptoms of this disease are excessive daytime sleepiness, snoring, and witnessed apnea. Most of the patients are treated with CPAP. In this study, we aimed to evaluate the factors affecting adherence to the CPAP treatment. Seventy-one patients were enrolled to this study. Patients were divided into three groups according to CPAP usage. Group I consisted of patients who had never used CPAP, group II consisted of patients who had used CPAP occasionally, and group-III patients had used CPAP treatment regularly. Group-III patients had higher apnea–hypopnea index (AHI) than groups I and II (respectively, 56.6 ± 27.7, 26.3 ± 7.5, and 32.3 ± 7.06; p < 0.000 for both). Oxygen desaturation index was significantly higher in group-III patients comparing to groups I and II (44.6 ± 22.3, 15.9 ± 8.3, and 25.6 ± 9.5; p < 0.000 for all). Our findings have shown that only very severe patients use the CPAP device regularly (mean AHI 56.6 ± 27.7). Compliance to CPAP treatment seemed to be poor in patients with moderate to severe, AHI about 30, OSAS. Considering the well-established benefits of CPAP treatment in patients with true indications, patients should be encouraged to use CPAP regularly, and complications of OSAS should be keynoted.     

Reversal of central sleep apnea using nasal CPAP

Based on the theory that obstructive (OSA) and central (CSA) sleep apneas share common pathophysiologic mechanisms, we attempted to treat eight patients with predominantly CSA by continuous positive airway pressure (CPAP). All patients exhibited repetitive episodes of CSA and mixed sleep apneas (MSA) in the supine position with a mean duration of 23.7 +/- 0.7 s and 34.5 +/- 1.3 s, respectively. The pattern of apnea changed when the subject lay in the lateral position. Five patients were observed to develop OSA in the lateral position with a mean duration of 27.2 +/- 1.5 s, while the other three patients snored continuously. High levels of CPAP (range 9.0 to 16.5 cm H2O) prevented all CSA and MSA and resulted in quiet breathing in all eight patients. Intermediate levels of CPAP produced firstly MSA, then purely OSA and/or continuous snoring. Low levels of nasal CPAP also prevented OSA and snoring occurring in the lateral posture in all subjects (range 2.0 to 8.3 cm H2O). Three patients are currently on home CPAP therapy for a range of four to 36 months. We conclude that upper airway collapse in the supine posture has a key role in the induction of CSA. We suggest that a reflex inhibition of respiration through activation of supraglottic mucosal receptors during passive oropharyngeal airway closure caused CSA in these patients.     

Stage-matched intervention for adherence to CPAP in patients with obstructive sleep apnea: a randomized controlled trial

Purpose

The objective of the study was to evaluate the effectiveness of stage-matched intervention on adherence to continuous positive airway pressure (CPAP) in patients with obstructive sleep apnea syndrome.

Methods

One hundred and ten Chinese patients with newly diagnosed obstructive sleep apnea syndrome were enrolled in this study. They were randomly assigned into stage-matched care (SMC) and standard care (SC) groups (55 patients in each group). Patients in the SMC group received stage-matched intervention at different stages of behavior changes, and the SC group received only routine care. The intervention was based on the health action process approach theory and included risk perception, outcome expectancy, and self-efficacy. Questionnaires included the Self-Efficacy Measure for Sleep Apnea, the Epworth Sleepiness Scale (ESS), and the Pittsburgh Sleep Quality Index (PSQI). Data were collected at baseline and 1 and 3 months after home CPAP treatment, and hours of CPAP usage was also recorded at 1 and 3 months of follow-up.

Results

At 1 month, CPAP usage was 5.59?±?0.56 h/night (mean ± SD) vs 5.28?±?0.67 h/night in the SMC and SC groups, respectively (p?=?0.016). At 3 months, CPAP usage was 5.65?±?0.50 vs 5.26?±?0.82 h/night in the SMC and SC groups, respectively (p?=?0.006). Repeated ANOVA analysis demonstrated that risk perception, outcome expectancy, and self-efficacy in the SMC group were significantly higher than those of the SC group (p?<?0.05). Moreover, the time × group interaction was significant for outcome expectancy and self-efficacy, indicating that the groups differed significantly in changes in outcome expectancy and self-efficacy over the three time points. There was a significant difference between the SMC and SC groups in terms of improvement in ESS (p?<?0.001) and PSQI (p?=?0.013) after 3 months of CPAP treatment.

Conclusions

Stage-matched intervention could not only facilitate intention formation and enhance treatment self-efficacy but significantly improve CPAP adherence in OSA patients for the 3-month treatment.     

Dental appliance treatment for obstructive sleep apnea

Oral appliances for the treatment of obstructive sleep apnea (OSA) are worn during sleep to maintain the patency of the upper airway by increasing its dimensions and reducing its collapsibility. Oral appliances are a simpler alternative to continuous positive airway pressure (CPAP). Over the last decade, there has been a significant expansion of the evidence base to support the use of oral appliances, with robust studies demonstrating their efficacy. This work has been underpinned by the recognition of the importance of upper airway anatomy in the pathophysiology of OSA. The updated practice parameters of the American Academy of Sleep Medicine now recommend their use for mild-to-moderate OSA, or for patients with severe OSA who are unable to tolerate CPAP or refuse treatment with CPAP. Oral appliances have been shown to have a beneficial impact on a number of important clinical end points, including the polysomnographic indexes of OSA, subjective and objective measures of sleepiness, BP, aspects of neuropsychological functioning, and quality of life. Elucidation of the mechanism of action of oral appliances has provided insight into the factors that predict treatment response and may improve the selection of patients for this treatment modality. Longitudinal studies to characterize the long-term adverse effects of oral appliance use are now beginning to emerge. Although less efficacious than CPAP for improving the polysomnographic indexes of OSA, oral appliances are generally preferred by patients. This has the potential to translate to better patient adherence and may provide an equivalent health outcome.