Mandibular advancement device and CPAP upon cardiovascular parameters in OSA

Association between elevated homocysteine levels and obstructive sleep apnea hypopnea syndrome: a systematic review and updated meta-analysis

Objective

This study aimed to distinguish between healthy controls and patients with OSAHS regarding homocysteine (HCY) levels and investigate how individuals with OSAHS respond to continuous positive airway pressure ventilation (CPAP) in terms of serum and plasma HCY levels.

Methods

To ascertain published articles about OSAHS, an exhaustive search was performed across medical databases, encompassing PubMed, Web of Science, EMBASE, CNKI, and Cochrane Library, until January 2, 2024. This study reviewed the literature regarding HCY levels in individuals with OSAHS and control groups, HCY levels under pre- and post-CPAP treatment, the Pearson/Spearman correlation coefficients between HCY levels and apnea-hypopnea index (AHI), and the hazard ratio (HR) of HCY levels concerning the occurrence of major adverse cerebrocardiovascular events (MACCEs) in patients with OSAHS. Meta-analyses were performed using weighted mean difference (WMD), correlation coefficients, and HR as effect variables. The statistical analysis was conducted using the R 4.1.2 and STATA 11.0 software packages.

Results

In total, 33 articles were selected for the final analysis. The OSAHS group exhibited significantly higher serum/plasma HCY levels than the control group (WMD = 4.25 μmol/L, 95% CI: 2.60-5.91, P< 0.001), particularly among individuals with moderate and severe OSAHS. Additionally, subgroup analysis using mean age, ethnicity, mean body mass index, and study design type unveiled significantly elevated levels of HCY in the serum/plasma of the OSAHS group compared to the control group. CPAP treatment can significantly decrease serum/plasma HCY levels in patients with OSAHS. Moreover, elevated HCY levels in individuals with OSAHS could be one of the risk factors for MACCEs (adjusted HR = 1.68, 95% CI = 1.10-2.58, P = 0.017). AHI scores show a positive correlation with serum/plasma HCY levels.

Conclusion

Patients with OSAHS had elevated serum/plasma HCY levels compared to healthy controls; however, CPAP therapy dramatically decreased HCY levels in patients with OSAHS. In patients with OSAHS, elevated HCY levels were linked with an increased risk of MACCEs, and HCY was positively connected with AHI values. HCY levels may serve as a useful clinical indicator for determining the severity and efficacy of OSAHS treatments.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42024498806.

Mandibular advancement devices decrease systolic pressure during the day and night in patients with obstructive sleep apnea: A systematic review and meta-analysis

The aim of this systematic review and meta-analysis was to analyze whether or not mandibular advancement devices (MADs) produce changes in blood pressure in patients with obstructive sleep apnea (OSA) in relation to use time and if the device is used at night or day.

MATERIALS AND METHOD

A systematic review of the literature and meta-analysis was carried out in accordance with PRISMA guidelines. In the bibliographic search, a total of four databases were consulted: PubMed-Medline, Scopus, Web of Science, and Cochrane. Of the 622 articles initially revealed, 160 duplicates were eliminated. After applying the selection criteria, 17 articles were included for the qualitative analysis and 4 for the meta-analysis. The studies were combined using a random effects model with the inverse method of variance, determining the mean differences in systolic and diastolic pressure before and after treatment using the MAD splint as the effect size. Day/night circadian effect and treatment time were analyzed using meta-regression with a mixed-effects model.

RESULTS

MAD treatment was not found to affect diastolic pressure. By combining the four studies with the control group in a meta-analysis (I2 = 75%; z =  - 0.15; p-value = 0.882), the mean difference in diastolic pressure between the MAD group and the control group was estimated at - 0.06 (- 0.86; 0.74). The meta-regression also showed no significant effect of day/night (p = 0.560) or treatment time (p = 0.854) on diastolic pressure. When combining the four studies with the control group (I2 = 84%%; z =  - 1.47; p-value = 0.142), a non-significant mean difference in systolic pressure between the MAD group and the control group of - 0.99 (- 2.31; 0.33) was estimated in the meta-analysis. However, when assessing the effect of day/night or treatment time on systolic blood pressure using a meta-regression, the latter showed significant covariates that reduce systolic blood pressure values in the model at night (p < 0.001) and in relation to treatment time (p < 0.001).

CONCLUSIONS

Only systolic pressure appears to be affected by the use of the MAD in patients with OSA, and this decrease in systolic pressure is greater at night and when treatment time is longer.

Mandibular Advancement vs CPAP for Blood Pressure Reduction in Patients With Obstructive Sleep Apnea

BACKGROUND

Hypertension guidelines recommend diagnosis and treatment of obstructive sleep apnea (OSA) in patients with hypertension. The mandibular advancement device (MAD) is an oral appliance therapy for patients who decline or cannot tolerate continuous positive airway pressure (CPAP).

OBJECTIVES

We compared the relative effectiveness of MAD vs CPAP in reducing 24-hour ambulatory blood pressure (BP).

METHODS

In an investigator-initiated, randomized, noninferiority trial (prespecified margin 1.5 mm Hg), 321 participants aged ≥40 years with hypertension and increased cardiovascular risk were recruited at 3 public hospitals for polysomnography. Of these, 220 participants with moderate-to-severe OSA (apnea-hypopnea index ≥15 events per hour) were randomized to either MAD or CPAP (1:1). The primary outcome was the difference between the 24-hour mean arterial BP at baseline and 6 months.

RESULTS

Compared with baseline, the 24-hour mean arterial BP decreased by 2.5 mm Hg (P = 0.003) at 6 months in the MAD group, whereas no change was observed in the CPAP group (P = 0.374). The between-group difference was -1.6 mm Hg (95% CI: -3.51 to 0.24, noninferiority P < 0.001). The MAD group demonstrated 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. Both the MAD and CPAP improved daytime sleepiness, with the between-group difference similar (P = 0.384). There were no between-group differences in cardiovascular biomarkers.

CONCLUSIONS

MAD is noninferior to CPAP for reducing 24-hour mean arterial BP in participants with hypertension and increased cardiovascular risk. (Cardiosleep Research Program on Obstructive Sleep Apnea, Blood Pressure Control and Maladaptive Myocardial Remodeling-Non-inferiority Trial [CRESCENT]; NCT04119999).

Effect of mandibular advancement splint therapy on cardiac autonomic function in obstructive sleep apnoea

PURPOSE

This study aimed to evaluate the effect of mandibular advancement splint (MAS) therapy on cardiac autonomic function in patients with obstructive sleep apnoea (OSA) using heart rate variability (HRV) analysis.

METHODS

Electrocardiograms (ECG) derived from polysomnograms (PSG) of three prospective studies were used to study HRV of patients with OSA before and after MAS treatment. HRV parameters were averaged across the entire ECG signal during N2 sleep using 2-min epochs shifted by 30 s. Paired t-tests were used to compare PSG and HRV measures before and after treatment, and the percent change in HRV measures was regressed on the percent change in apnoea-hypopnea index (AHI).

RESULTS

In 101 patients with OSA, 72% were Caucasian, 54% men, the mean age was 56 ± 11 years, BMI 29.8 ± 5.3 kg/m2, and treatment duration was 4.0 ± 3.2 months. After MAS therapy, there was a significant reduction in OSA severity (AHI, - 18 ± 16 events per hour, p < 0.001) and trends towards increased low-frequency to high-frequency ratio, low-frequency power, and reduced high-frequency power (LF:HF, - 0.4 ± 1.5, p = 0.01; LF, - 3 ± 16 nu, p = 0.02, HF, 3.5 ± 13.7 nu, p = 0.01). Change in NN intervals correlated with the change in AHI (β(SE) =  - 2.21 (0.01), t =  - 2.85, p = 0.005). No significant changes were observed in the time-domain HRV markers with MAS treatment.

CONCLUSION

The study findings suggest that successful MAS treatment correlates with changes in HRV, specifically the lengthening of NN intervals, a marker for improved cardiac autonomic adaptability.

Obstructive sleep apnea heterogeneity and autonomic function: a role for heart rate variability in therapy selection and efficacy monitoring

Obstructive sleep apnea is a highly prevalent sleep-related breathing disorder, resulting in a disturbed breathing pattern, changes in blood gases, abnormal autonomic regulation, metabolic fluctuation, poor neurocognitive performance, and increased cardiovascular risk. With broad inter-individual differences recognised in risk factors, clinical symptoms, gene expression, physiological characteristics, and health outcomes, various obstructive sleep apnea subtypes have been identified. Therapeutic efficacy and its impact on outcomes, particularly for cardiovascular consequences, may also vary depending on these features in obstructive sleep apnea. A number of interventions such as positive airway pressure therapies, oral appliance, surgical treatment, and pharmaceutical options are available in clinical practice. Selecting an effective obstructive sleep apnea treatment and therapy is a challenging medical decision due to obstructive sleep apnea heterogeneity and numerous treatment modalities. Thus, an objective marker for clinical evaluation is warranted to estimate the treatment response in patients with obstructive sleep apnea. Currently, while the Apnea-Hypopnea Index is used for severity assessment of obstructive sleep apnea and still considered a major guide to diagnosis and managements of obstructive sleep apnea, the Apnea-Hypopnea Index is not a robust marker of symptoms, function, or outcome improvement. Abnormal cardiac autonomic modulation can provide additional insight to better understand obstructive sleep apnea phenotyping. Heart rate variability is a reliable neurocardiac tool to assess altered autonomic function and can also provide cardiovascular information in obstructive sleep apnea. Beyond the Apnea-Hypopnea Index, this review aims to discuss the role of heart rate variability as an indicator and predictor of therapeutic efficacy to different modalities in order to optimise tailored treatment for obstructive sleep apnea.

Acute Effect of Positive Airway Pressure on Heart Rate Variability in Obstructive Sleep Apnea

Autonomic dysregulation is associated with cardiovascular consequences in obstructive sleep apnea (OSA). This study aimed to investigate the effect of acute continuous positive airway pressure (CPAP) treatment on autonomic activity and to identify factors contributing to heart rate variability (HRV) changes in OSA. Frequency domain HRV parameters were calculated and compared between the baseline polysomnography and during the CPAP titration in 402 patients with moderate to severe OSA. There were significant reductions in total power, very low-frequency band power, low-frequency band power, and high-frequency band power during the CPAP titration as compared to the baseline polysomnography. This tendency was pronounced in male patients with severe OSA. Multivariate analysis found that changes in the apnea-hypopnea index and oxygen saturation were significantly associated with changes in sympathetic and parasympathetic activity, respectively. This study demonstrated that HRV parameters significantly changed during the CPAP titration, indicating a beneficial effect of CPAP in the restoration of sympathetic and parasympathetic hyperactivity in OSA. Prospective longitudinal studies should determine whether long-term CPAP treatment aids in maintaining the long-lasting improvement of the autonomic functions, thereby contributing to the prevention of cardiovascular and cerebrovascular diseases in patients with OSA.

Efficacy of titratable mandibular advancement device versus continuous positive airway pressure therapy in the treatment of obstructive sleep apnea: A clinical crossover trial

Background

To compare efficacy of continuous positive airway pressure (CPAP) and oral appliance (OA) in management of various grades of obstructive sleep apnea (OSA).

Methods

Thirty polysomnography diagnosed cases of OSA were divided into three groups based on baseline apnea hypopnea index (AHI) as follows: group 1: mild OSA (AHI = 5-14.9), group 2: moderate OSA (AHI = 15-29.9), and group 3: severe OSA (AHI >30) with 10 patients in each group. Half of the patients in each group were randomly allocated to CPAP or OA therapy, and crossover of therapy was performed after two months. AHI, Epworth's Sleepiness Scale (ESS), and mean oxygen saturation (SPO2) were measured at baseline, after each arm of treatment and after the crossover. A questionnaire survey including information regarding pretreatment sleep symptoms and improvement after therapy was performed at above time frames. At the end of therapy, the patients were surveyed regarding satisfaction and perceived effectiveness with both modalities.

Results

CPAP was more efficacious in reducing AHI and SPO2 as compared with OA across the three study groups. The improvement in most sleep-related symptoms was higher with CPAP. The satisfaction and perception on effectiveness of treatment were higher with OA than CPAP across three study groups (P-value<0.05 for all).

Conclusions

OA is an effective alternative to CPAP across all grades of OSA in selected cases, which is more preferred owing to higher effectiveness and satisfaction among the patients.

Appliances Therapy in Obstructive Sleep Apnoea: A Systematic Review and Meta-Analysis

Obstructive sleep apnea (OSA) is a recurrent partial or complete obstruction of the upper airway during sleep caused by narrowing or collapse of the pharyngeal wall. It leads to microstimulation and oxyhemoglobin desaturation, resulting in sleepiness and loud snoring. OSA negatively affects the cardiovascular system and may contribute to neurocognitive impairment. The aim of this systematic review is to evaluate the effectiveness and efficacy of appliance therapy in obstructive sleep apnea. The effectiveness was assessed by using the Apnea Hypopnea Index (AHI). An electronic search of the Cochrane Library, PubMed, and Google Scholar was conducted between 1998 and 2021. Articles were independently assessed by three reviewers. The quality of a randomised control trial (RCT) is assessed using the Cochrane risk of bias method. The tool GRADE was used to achieve the desired level of confidence for each outcome reported. Several studies used continuous positive airway pressure (CPAP), mandibular advancement devices (MAD), and tongue retention devices (TRD). The meta-analysis included a total of six papers that met the inclusion criteria. Results showed that CPAP significantly improved AHI compared with an oral appliance (random effects: difference in means = 8.40, 95% CI = 7.21 to 9.60). It was also found that oral appliance (OA) therapy significantly improved AHI compared with baseline before appliance therapy (random effects: mean difference = 13.40, 95% CI = 10.87 to 15.93; p.00001). For mild to moderate OSA, CPAP is considered the gold standard. Our meta-analysis of six RCTs found favorable evidence for OSA patients receiving oral devices; however, they were less effective than CPAP. A subgroup analysis found that MAD may be a beneficial treatment for mild to moderate OSA patients who do not respond to CPAP. The findings suggest that oral appliances may be an effective treatment for OSA, especially in patients with mild to moderate OSA.

The role of oral appliance therapy in obstructive sleep apnoea

There is now widespread recognition within the world of sleep medicine of the increasing importance of dental sleep medicine and, in particular, the role of oral appliance therapy (OAT) in the management of adults with obstructive sleep apnoea (OSA). For the purpose of this review, the term OAT refers to a custom-made intra-oral appliance, which acts to posture the mandible in a forward and downward direction, away from its natural resting position. Whilst nasally applied continuous positive airway pressure remains the "gold standard" in nonsurgical OSA management, OAT remains the recognised alternative treatment.This review of OAT aims to provide an evidence-based update on our current understanding of their mode of action, exploring the potential anatomical and physiological impact of their use in preventing collapse of the upper airway; the current clinical practice guidelines, including the recently published National Institute of Clinical Excellence 2021 guidance, in conjunction with the American Academy of Sleep Medicine and American Academy of Dental Sleep Medicine; optimal design features, comparing the role of custom-made versus noncustom OAT devices and the importance of titration in achieving a dose-dependent effect; patient predictors, preference and adherence to OAT; its impact on a range of both patient- and clinician-centred health outcomes, with a comparison with CPAP; the limitations and side-effects of providing OAT; and, finally, a look at future considerations to help optimise the delivery and outcomes of OAT.

Homocysteine Levels in Severe OSA Patients Before and After TORS-OSA Surgery

OBJECTIVE

The increased risk of cardiovascular diseases owing to a high level of serum homocysteine has been widely reported. Literature has demonstrated that patients with obstructive sleep apnea/hypopnea syndrome (OSA) had a higher homocysteine level than control group. This study aimed to investigate the alteration of serum homocysteine levels in severe OSA patients receiving transoral robotic surgery (TORS).

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary academic medical center.

METHODS

Data of polysomnography (PSG) and serum homocysteine levels before and at least 3 months after the surgery were collected and analyzed via paired t tests. A subgroup analysis based on the preoperative homocysteine level (≥15 mcmol/L, as hyperhomocysteinemia group) was conducted to compare the intergroup differences of homocysteine decrease. Pearson's correlation was used to survey the relationships between the changes of major PSG parameters and the levels of homocysteine decrease at baseline and after TORS-OSA surgery.

RESULTS

Two hundred sixty-one patients with severe OSA were enrolled. There were significant improvements in major PSG parameters after TORS-OSA surgery. Homocysteine levels significantly decreased from 12.1 ± 3.9 to 11.4 ± 3.7 mcmol/L (difference = -0.7 ± 2.8 mcmol/L, p = .001) postoperatively, which was shown in the hyperhomocysteinemia group (difference = -2.9 ± 4.7 mcmol/L, p = .007) to a greater extent. Pearson's correlation revealed that ΔODI (oxygen desaturation index/h) was the predominant estimate with a positive association with Δhomocysteine (r = 0.525, p = .012).

CONCLUSION

TORS-OSA surgery could decrease homocysteine levels in OSA patients. The effects were more relevant in severe OSA patients with abnormal preoperative homocysteine levels.

Patients with Obstructive Sleep Apnea and Cardiovascular Diseases: What, When, and Why Is Mandibular Advancement Device Treatment Required? A Short Review

Obstructive sleep apnea is a potentially dangerous condition with significant risks of comorbidities if left untreated. It represents a cardiovascular risk factor in the general population, and a higher prevalence is observed in patients already suffering from cardiovascular diseases. The gold standard treatment, continuous positive airway pressure, is not always accepted or tolerated. The mandibular advancement device represents an alternative treatment that we propose to implement in our study. The objective here is to first present a brief review of the topic. Due to poor evidence in the field, we propose a pilot study to evaluate the effect of a mandibular advancement device in patients with cardiovascular disease who are not treated for their sleep pathology in order to improve their therapeutic management.

To compare different non-surgical treatment modalities on treatment of obstructive sleep apnea: A systematic review and meta-analysis

The study aimed to assess the effect of mandibular advancement device (MAD) in patients with obstructive sleep apnea for reduction in 24-h mean blood pressure, sleep quality, Apnea Hypopnea Index (AHI), and patient compliance, compared to continuous positive airway pressure (CPAP), other interventions, or no treatment. Three different databases such as PubMed, EMBASE, and CENTRAL were searched using different search terms till July 2021 as per the inclusion and exclusion criteria. After inclusion of studies, data extraction including risk of bias assessment was done. For each study, we used odds ratio, mean difference, and 95% confidence interval to assess and synthesize the outcomes. The quality of evidence was evaluated as per the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE). Twenty-one randomized controlled trials were included: 497 patients in the MAD group, 239 patients in the CPAP group, and 274 patients in the sham group. In MAD-CPAP comparison, the results favored CPAP in the reduction of AHI of 3.48 (1.76-5.19). However, unclear results were found for sleep quality measured as Epworth Sleepiness Scale (ESS), patient compliance, and 24-h mean blood pressure. In MAD-sham comparison, the results favored MAD in the reduction of AHI of - 8.39 (-10.90--5.88] and ESS of - 0.91 (-1.70--0.12) and favored sham in terms of patient compliance while, unclear results for 24-h mean blood pressure. The GRADE score indicated that the quality of evidence is very low, low, and moderate for different outcomes. CPAP in comparison to MAD and MAD in comparison to sham showed a significant AHI reduction. However, patient compliance and 24-h mean blood pressure were not significantly different in MAD-CPAP or MAD-sham. Quality of evidence is very low and low when MAD was compared with CPAP and sham, respectively, for AHI.

The effect of obstructive sleep apnea therapy on cardiovascular autonomic function: a systematic review and meta-analysis

STUDY OBJECTIVES

Autonomic function is impaired in obstructive sleep apnea (OSA) and may mediate the association between OSA and cardiovascular risk. We investigated the effect of OSA therapy on autonomic function through a systematic review and meta-analysis of intervention studies.

METHODS

A systematic search using three databases (Medline, Embase, and Scopus) was performed up to December 9, 2020. Studies of OSA patients ≥ 18 years with autonomic function assessed before and after treatment with positive airway pressure, oral appliance, positional therapy, weight loss, or surgical intervention were included for review. Random effects meta-analysis was carried out for five groups of autonomic function indices. Risk of bias was assessed using the Cochrane Collaboration tool.

RESULTS

Forty-three eligible studies were reviewed with 39 included in the meta-analysis. OSA treatment led to large decreases in muscle sympathetic nerve activity (Hedges' g = -1.08; 95% CI -1.50, -0.65, n = 8) and moderate decreases in catecholamines (-0.60; -0.94, -0.27, n = 3) and radio nucleotide imaging (-0.61; -0.99, -0.24, n = 2). OSA therapy had no significant effect on baroreflex function (Hedges' g = 0.15; 95% CI -0.09, 0.39, n = 6) or heart rate variability (0.02; -0.32, 0.36, n = 14). There was a significant risk of bias due to studies being primarily non-randomized trials.

CONCLUSIONS

OSA therapy selectively improves autonomic function measures. The strongest evidence for the effect of OSA therapy on autonomic function was seen in reduced sympathetic activity as assessed by microneurography, but without increased improvement in parasympathetic function. OSA therapy may reduce the risk of cardiovascular disease in OSA through reduced sympathetic activity.

The multisystemic effects of oral appliance therapy for obstructive sleep apnea: A narrative review

Obstructive sleep apnea (OSA) is a chronic condition accompanied by repeated obstruction of the upper airway during sleep despite respiratory efforts, resulting in intermittent hypoxemia, altered sleep structure, and sympathetic activation. Previous studies have shown a significant association between OSA and general health issues such as cardiovascular diseases, endocrine disorders, neurocognitive function decline, and poor quality of life. Continuous positive airway pressure (CPAP) has been considered as the first line treatment for OSA. However, accumulating evidence supports the role of oral appliance (OA) therapy, including mandibular advancement devices, as an alternative option for snoring and OSA patients who do not comply with or refuse CPAP usage. Despite a generally favorable outcome of OA therapy for OSA related respiratory indices, studies focusing on the impact of systemic effects of OA therapy in OSA patients are relatively scarce compared with the extensive literature focusing on the systemic effects of CPAP. Therefore, this article aimed to provide an overview of the current evidence regarding the multisystemic effects of OA therapy for OSA.

Mandibular Advancement Splint Therapy

Mandibular advancement splint (MAS) therapy is the leading alternative to continuous positive airway pressure (CPAP) therapy for the treatment of obstructive sleep apnoea. A MAS is an oral appliance which advances the mandible in relation to the maxilla, thus increasing airway calibre and reducing collapsibility. Although it is less effective than CPAP in reducing the apnoea-hypopnoea index (AHI), it has demonstrated equivalence to CPAP in a number of key neurobehavioural and cardiovascular health outcomes, perhaps due to increased tolerability and patient adherence when compared to CPAP. However, response to MAS is variable, and reliable prediction tools for patients who respond best to MAS therapy have thus far been elusive; this is one of the key clinical barriers to wider uptake of MAS therapy. In addition, the most effective MAS devices are custom-made by a dentist specialising in the treatment of sleep disorders, which may present financial or accessibility barriers for some patients. MAS devices are generally well tolerated but may have side effects including temporomandibular joint (TMJ) dysfunction, hypersalivation, tooth pain and migration as well as occlusal changes. A patient-centred approach to treatment from a multidisciplinary team perspective is recommended. Evidence-based clinical practice points and areas of future research are summarised at the conclusion of the chapter.

European Respiratory Society guideline on non-CPAP therapies for obstructive sleep apnoea

Treatment of obstructive sleep apnoea (OSA) in adults is evolving, as new therapies have been explored and introduced in clinical practice, while other approaches have been refined or reconsidered. In this European Respiratory Society (ERS) guideline on non-continuous positive airway pressure (CPAP) therapies for OSA, we present recommendations determined by a systematic review of the literature. It is an update of the 2011 ERS statement on non-CPAP therapies, advanced into a clinical guideline. A multidisciplinary group of experts, including pulmonary, surgical, dentistry and ear–nose–throat specialists, methodologists and patient representatives considered the most relevant clinical questions (for both clinicians and patients) relating to the management of OSA. Eight key clinical questions were generated and a systematic review was conducted to identify published randomised clinical trials that answered these questions. We used the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach to assess the quality of the evidence and the strength of recommendations. The resulting guideline addresses gastric bypass surgery, custom-made dual-block mandibular advancement devices, hypoglossal nerve stimulation, myofunctional therapy, maxillo-mandibular osteotomy, carbonic anhydrase inhibitors and positional therapy. These recommendations can be used to benchmark quality of care for people with OSA across Europe and to improve outcomes.

OSA-patients who refuse/don't adhere to CPAP can profit from established/emerging treatment options. High scientific evidence is lacking. Patients’ values/preference may weigh heavy in the decision for non-CPAP options, while health inequity is a concern.https://bit.ly/3o0tJeP

Correlation between Polysomnographic Parameters and Tridimensional Changes in the Upper Airway of Obstructive Sleep Apnea Patients Treated with Mandibular Advancement Devices

BACKGROUND

The effectiveness of mandibular advancement devices has been solidly demonstrated in the past. They are considered a valid alternative treatment to continuous positive airway pressure for patients with obstructive sleep apnea. Nevertheless, the relationship between polysomnographic parameters and the increase in the volume of the upper airway in patients with obstructive sleep apnea syndrome has not been clearly established so far. This study aimed to determine the impact of these oral appliances upon the volume of the airway after the device titration phase and correlate it with the degree of mandibular advancement and the improvement of polysomnographic parameters.

METHODS

All patients were diagnosed by polysomnography and were treated with a customized, titratable mandibular advancement device. Three-dimensional volumetric measurements were performed using cone beam computed tomography.

RESULTS

The present study included 45 patients diagnosed with obstructive sleep apnea hypopnea syndrome (mild in 23 patients, moderate in 11 and severe in 11). Forty-four percent of the patients presented with an apnea hypopnea index <5/h at the end of treatment. The volume of the upper airway increased an average of 4.3 ± 5.9 cm3, this represents a percentage increase of 20.9%, which was significantly correlated with an apnea hypopnea index and a minimum oxygen saturation improvement.

CONCLUSIONS

The mandibular advancement device used was found to be effective in improving polysomnographic parameters. Moreover, the oral appliance was able to significantly increase the tridimensional dimensions of the upper airway. Moreover, this finding was correlated with a reduction in the apnea hypopnea index (p = 0.007) and an increase on minimum oxygen saturation (p = 0.033).

Circadian blood pressure profile and blood pressure changes following oral appliance therapy for obstructive sleep apnoea

OBJECTIVES

Oral appliance therapy for obstructive sleep apnoea (OSA) reduces blood pressure (BP) but there is little information on relationship to circadian BP pattern (nocturnal BP dipping or non-dipping). The aims of this study were to determine whether nocturnal dipping pattern influences BP changes following oral appliance therapy, and to determine the effect of oral appliance therapy on circadian BP pattern.

METHODS

Participants in two randomized trials of oral appliance therapy (1-2 months) with 24-h ambulatory BP monitoring (ABPM) data were included (N = 152). Nocturnal BP Dippers (nocturnal/diurnal SBP ratio <0.9) and non-dippers were compared for BP changes following oral appliance therapy and the effect of oral appliance therapy on nocturnal BP dipping was assessed.

RESULTS

Of 152 participants, 64.5% were dippers. Dippers were on average younger and less likely to be hypertensive (42 vs. 82.7%, P < 0.001). Nondippers showed greater reduction in nocturnal BP measures, related to higher BP measures at baseline. There was no difference in the relationship between treatment effectiveness and BP changes between groups. Oral appliance therapy converted only 23% of baseline non-dippers to a nocturnal dipping profile.

CONCLUSION

Baseline circadian BP profile influenced the BP response to oral appliance therapy, largely because of higher baseline BP in the non-dipper subgroup. Oral appliance therapy did not convert OSA patients to a more favourable circadian BP profile. Further work is required to understand the effect of oral appliance therapy on circadian BP profile and of the individuals who will receive cardiovascular benefit from oral appliance therapy.

Current Management of Residual Excessive Daytime Sleepiness Due to Obstructive Sleep Apnea: Insights for Optimizing Patient Outcomes

Although excessive daytime sleepiness (EDS) attributable to obstructive sleep apnea (OSA) can be resolved by consistent usage of and effective treatment (often with the use of continuous positive airway pressure therapy), 12–58% of patients report residual EDS (REDS). While REDS is difficult to treat, a proportion of cases are possibly due to reversible issues, and wake-promoting medications can prove useful for the remaining cases. Given the challenges associated with effective management of REDS and its relationship to multiple comorbidities, multidisciplinary management of patients with REDS is often recommended. Here we aim to bridge the knowledge gap on the burden, risk factors, prevalence, and potential pathophysiologic mechanisms of REDS in patients with OSA after first-line treatment. The roles of primary care physicians and sleep specialists, as well as the importance of the use of objective assessment tools for the evaluation of REDS and the effective management of comorbidities, are discussed. An update of approved treatments and emerging candidate treatments is also presented.

Health outcomes of continuous positive airway pressure versus mandibular advancement device for the treatment of severe obstructive sleep apnea: an individual participant data meta-analysis

STUDY OBJECTIVES

The impact of therapy with continuous positive airway pressure (CPAP) and mandibular advancement device (MAD) has not been directly compared in patients with severe obstructive sleep apnea (OSA). The purpose of this individual participant data meta-analysis was to compare the treatment effects of CPAP and titratable MAD on sleepiness, quality of life, sleep-disordered breathing severity, and sleep structure in patients with severe OSA.

METHODS

Randomized controlled trials (RCTs) that included severe OSA patients were identified in order to compare the impact of the two treatments. Individual data from severe OSA patients were extracted from the databases and pooled for analysis.

RESULTS

Of the seven studies identified, three crossover RCT and one parallel-group RCT corresponding to 151 patients and 249 observations (125 in the CPAP treatment arm and 124 in the MAD treatment arm) were included in the analysis. Titratable MAD had a similar impact to CPAP on major patient-centered outcomes (sleepiness and quality of life). CPAP was more effective in reducing AHI and ODI. However, the two treatments had a similar impact on sleep structure with an increase of N3 and REM sleep. Finally, treatment adherence and preference were largely in favor of MAD.

CONCLUSION

This meta-analysis suggests that MAD represents an effective alternative treatment in severe OSA patients intolerant to CPAP or who prefer alternate therapy.

Factors influencing adherence to oral appliance therapy in adults with obstructive sleep apnea: a systematic review and meta-analysis

STUDY OBJECTIVES

The review aimed to identify the factors influencing adherence to oral appliance therapy in adults with obstructive sleep apnea.

METHODS

The protocol was initially registered with the International Register of Systematic Reviews (Prospero: CRD42019122615) prior to undertaking a comprehensive electronic search of databases and references without language and date restrictions. Quality assessment was undertaken using the Cochrane Collaboration's risk of bias tool and Quality in Prognosis Studies (QUIPS) tool.

RESULTS

Studies exhibited low or unclear risk of bias for the domains assessed by the respective quality assessment tools. The influence of independent variables such as disease characteristics, patient characteristics, appliance features, and psychological and social factors on adherence levels was also assessed. There was a total of 31 included studies, which consisted of 8 randomized controlled trials, 2 controlled clinical trial, 7 prospective cohorts, 11 retrospective cohorts, and the remaining 3 studies were a case-series, case-control, and a mixed-methods. All 31 included studies were subject to qualitative analysis, with only 4 studies included in the quantitative analysis. Results of the meta-analysis demonstrated increased adherence with custom-made appliances, with a pooled mean difference of -1.34 (-2.02 to -0.66) and low levels of heterogeneity (I² = 0%).

CONCLUSIONS

A weak relationship was observed between objective adherence and patient and disease characteristics, such as age, sex, obesity, apnea-hypopnea index, and daytime sleepiness, to oral appliance therapy. Nonadherent patients reported more side effects with oral appliance therapy than users and tended to discontinue the treatment within the first 3 months. Custom-made oral appliances were preferred and increased adherence reported in comparison to ready-made appliances. Further research is imperative to examine the relationship between psychosocial factors and adherence to oral appliance therapy.

Heart rate variability and obstructive sleep apnea: Current perspectives and novel technologies

Obstructive sleep apnea (OSA) is a highly prevalent condition, resulting in recurrent hypoxic events, sleep arousal, and daytime sleepiness. Patients with OSA are at an increased risk of cardiovascular morbidity and mortality. The mechanisms underlying the development of cardiovascular disease in OSA are multifactorial and cause a cascade of events. The primary contributing factor is sympathetic overactivity. Heart rate variability (HRV) can be used to evaluate shifts in the autonomic nervous system, during sleep and in response to treatment in patients with OSA. Newer technologies are aimed at improving HRV analysis to accelerate processing time, improve the diagnosis of OSA, and detection of cardiovascular risk. The present review will present contemporary understandings and uses for HRV, specifically in the realms of physiology, technology, and clinical management.

The effects of continuous positive airway pressure and mandibular advancement therapy on metabolic outcomes of patients with mild obstructive sleep apnea: a randomized controlled study

BACKGROUND

Moderate and severe obstructive sleep apnea (OSA) have been independently associated with dyslipidemia. The results of metabolic improvement with continuous positive airway pressure (CPAP) have been controversial. Less evidence exists regarding this issue in mild OSA. A current treatment for mild OSA is mandibular advancement device (MAD) therapy, but its effectiveness on the metabolic profile needs to be compared with CPAP. The purpose of this study was to compare MAD vs CPAP vs no treatment on the metabolic profile during 6 and 12 months of follow-up in patients with mild OSA.

METHODS

The inclusion criteria were patients with mild OSA, both genders, ages 18 to 65 years, and body mass index (BMI) of < 35 Kg/m². Patients were randomized in 3 groups (CPAP, MAD, and control). The evaluations included physical examination, metabolic profile, and full polysomnography at baseline, 6 months, and 12 months of follow-up.

RESULTS

Seventy-nine patients with mild OSA were randomized in three treatment groups, with mean age (± SD) of 47 ± 9 years, 54% men, and AHI 9.5 ± 2.9 events/h. MAD and CPAP reduced AHI at 6 and 12 months compared to the control group. MAD adherence was higher than CPAP at 6 and 12 months. Despite lower adherence compared to MAD, CPAP was more effective in reducing total cholesterol over 12 months (baseline 189.3 ± 60.2 mg/dl to 173.4 ± 74.3 mg/dl) and low-density lipoprotein cholesterol (LDL-c, baseline 112.8 ± 54.9 mg/dl to 94.5 ± 67.4 mg/dl).

CONCLUSIONS

After 1 year of treatment, CPAP was superior to MAD in reducing total cholesterol and LDL-c in patients with mild OSA.

Cardiovascular changes in children with obstructive sleep apnea and obesity after treatment with noninvasive ventilation

STUDY OBJECTIVES

Adults with obesity and obstructive sleep apnea (OSA) are at risk for cardiometabolic disease, and this risk likely extends to children with both conditions. Noninvasive ventilation (NIV; including continuous and bilevel positive airway pressure) is often used to treat OSA in children with obesity. The aim of this study was to examine the impact of NIV treatment on heart rate variability (HRV), as a marker of cardiovascular risk, in children with obesity and newly diagnosed OSA.

METHODS

A prospective multicenter cohort study was conducted in children with obesity prescribed NIV therapy for newly diagnosed moderate-severe OSA. Measurements of HRV were derived from polysomnography recordings at baseline and after 12 months of treatment. HRV parameters were examined by sleep stage, before and after arousal and oxygen desaturation events. HRV parameters were compared between time points using pair t tests as well as mixed model analysis.

RESULTS

Twelve children had appropriate data for analysis at baseline and 12 months. Heart rate decreased by 4.5 beats/min after NIV treatment, with no change in HRV parameters. HRV parameters differed by sleep stage and showed an increase in arousal-related sympathetic-parasympathetic balance after 12 months of NIV treatment. HRV parameters did not differ before and after oxygen desaturation events.

CONCLUSIONS

NIV for the treatment in children with obesity and OSA resulted in a small decrease in heart rate and an increase in arousal-related sympathetic-parasympathetic balance. These findings suggest small, potentially positive impacts of NIV on cardiovascular risk in children with concurrent obesity and OSA.

Obstructive sleep apnoea treatment and blood pressure: which phenotypes predict a response? A systematic review and meta-analysis

The treatment for obstructive sleep apnoea (OSA) with continuous positive airway pressure (CPAP) or mandibular advancement devices (MADs) is associated with blood pressure (BP) reduction; however, the overall effect is modest. The aim of this systematic review and meta-analysis of randomised controlled trials (RCTs) comparing the effect of such treatments on BP was to identify subgroups of patients who respond best to treatment.The article search was performed in three different databases with specific search terms and selection criteria. From 2289 articles, we included 68 RCTs that compared CPAP or MADs with either passive or active treatment. When all the studies were pooled together, CPAP and MADs were associated with a mean BP reduction of -2.09 (95% CI -2.78- -1.40) mmHg for systolic BP and -1.92 (95% CI -2.40- -1.43) mmHg for diastolic BP and -1.27 (95% CI -2.34- -0.20) mmHg for systolic BP and -1.11 (95% CI -1.82- -0.41) mmHg for diastolic BP, respectively. The subgroups of patients who showed a greater response were those aged <60 years (systolic BP -2.93 mmHg), with uncontrolled BP at baseline (systolic BP -4.14 mmHg) and with severe oxygen desaturations (minimum arterial oxygen saturation measured by pulse oximetry <77%) at baseline (24-h systolic BP -7.57 mmHg).Although this meta-analysis shows that the expected reduction of BP by CPAP/MADs is modest, it identifies specific characteristics that may predict a pronounced benefit from CPAP in terms of BP control. These findings should be interpreted with caution; however, they are particularly important in identifying potential phenotypes associated with BP reduction in patients treated for OSA.

Effectiveness of sleep surgery versus a mandibular advancement device for obstructive sleep apnea in terms of nocturnal cardiac autonomic activity

PURPOSE

Sleep surgery and mandibular advancement devices (MAD) are treatments for obstructive sleep apnea (OSA), but their comparative efficacy remains unclear. We compared their efficacy using various parameters.

METHODS

Subjects treated for OSA with sleep surgery or MAD (n = 30/group)-matched for sex, body mass index (BMI), and baseline apnea-hypopnea index (AHI)-were enrolled. The efficacy of these treatments according to polysomnographic parameters, sleep quality questionnaires, and heart rate variability (HRV) time- and frequency-domain parameters were compared between pre-treatment and 3-month post-treatment.

RESULTS

Polysomnographic and sleep quality questionnaire parameters improved significantly in both groups. In time-domain HRV analysis, average normal-to-normal intervals increased significantly in the surgery (942.2 ± 140.8 to 994.6 ± 143.1, P = 0.008) and MAD (901.1 ± 131.7 to 953.7 ± 123.1, P = 0.002) groups. Low frequency (LF) decreased significantly in the surgery group (P = 0.012); high frequency (HF) remained unchanged in both groups. The LF/HF ratio decreased in both groups (2.9 ± 1.8 to 2.3 ± 1.7, P = 0.017, vs. 3.0 ± 1.8 to 2.4 ± 1.4, P = 0.025). Normalized high frequency increased significantly in both groups (31.0 ± 13.2 to 36.8 ± 13.7, P = 0.009, vs. 29.1 ± 10.7 to 33.7 ± 12.5, P = 0.024), in contrast to normalized low frequency. However, no HRV parameter changes differed significantly between the groups after adjusting for age, BMI, and AHI.

CONCLUSION

Sleep surgery and MAD are equally effective treatments for OSA according to cardiac autonomic activity.

The impact of continuous positive airway pressure therapy on circulating levels of malondialdehyde: a systematic review and meta-analysis

BACKGROUND

Obstructive sleep apnea (OSA) is a highly prevalent sleep disorder which associated with increased oxidative stress and cardiovascular diseases. Malondialdehyde (MDA) is a reliable marker of lipid peroxidation and is elevated in patients with OSA. Studies reported inconsistent findings on the effect of continuous positive airway pressure (CPAP) therapy on MDA levels. As the study power maybe a reason for the inconsistent findings, we aimed to use meta-analysis to assess effect of CPAP therapy on MDA in patients with OSA.

METHOD

Electronic search was performed to find out studies on the effect of CAPA on MDA levels in OSA patients. Search carried out in databases of PubMed, EMBASE, Scopus, Cochrane library and web of science.

RESULTS

Search resulted in 161 records of which 83 remained after removing duplicated records. Further, 51 articles were removed by title and abstract and 22 records evaluated by full text. Finally 13 articles were included in the intended meta-analysis. Pooled analysis demonstrated that CPAP therapy reduced MDA levels significantly [SMD (-1.51) (95% CI, -2.06 to -0.97) p < 0.05]. Subgroup analyses showed that CPAP therapy was effective in categories of age (≤50 and > 50 years), BMI (≤30 and > 30 kg/m²) and therapy duration (≤12 week and >12 week).

CONCLUSION

the results of the present study demonstrated considerable effect of CPAP therapy on MDA as independent risk factor for cardiovascular diseases and robust marker of lipid peroxidation.

Nocturnal heart rate variability may be useful for determining the efficacy of mandibular advancement devices for obstructive sleep apnea

A mandibular advancement device (MAD) is recommended as an alternative therapy for obstructive sleep apnea (OSA), which effectively reduces the collapsibility of the upper airway during sleep by advancing the mandible. However, the effects of MAD therapy on cardiac autonomic modulation remain unclear. We evaluated the effects of MAD on nocturnal heart rate variability (HRV) in OSA. Anthropometric data, questionnaire results, and HRV parameters (evaluated using time domain and frequency domain methods) of 58 adult patients with OSA treated with MAD therapy were retrospectively reviewed. All patients underwent polysomnography at baseline and 3-month follow-up. The average normal-to-normal (NN) interval, standard deviation of the NN interval, low-frequency power in normalized units (LFnu), and high-frequency power in normalized units (HFnu) showed significant changes with MAD therapy. Based on the criteria for success (decrease in the apnea-hypopnea index by >50% and value <20/h), 34 and 24 patients were classified into the response and nonresponse groups, respectively. No differences in baseline characteristics were detected between groups, except for higher body mass index and lower minimal oxygen saturation in the nonresponse group. A subgroup analysis indicated that the average NN interval and HFnu significantly increased, and that Total power (TP), very low frequency, low frequency(LF), low frequency/high frequency and LFnu significantly decreased compared to baseline in the response group; however, no HRV changes were found in the nonresponse group. After adjusting for age, sex, and body mass index, the response group showed significant changes from baseline in TP and LF compared to the nonresponse group. Therefore, HRV may be useful for determining the efficacy of MAD therapy in OSA.

The effect of continuous positive airway pressure on circulating malondialdehyde among obstructive sleep apnea patients: a meta-analysis

BACKGROUND

Obstructive sleep apnea (OSA) has been demonstrated to be associated with an increase of oxidative stress. However, whether circulating malondialdehyde (MDA), a widely used biomarker of oxidative stress, could be reduced by the treatment of OSA by continuous positive airway pressure (CPAP) is debated. The present meta-analysis was performed to determine the effect of CPAP treatment on circulating MDA among patients with OSA.

METHODS

A systematic search of PubMed, Embase, and Web of Science was performed for literature covering the period between 1967 and August 2019. Standardized mean difference (SMD) was calculated to estimate the treatment effects of pre- and post-CPAP therapy.

RESULTS

A total of 10 studies with 220 patients were included in this meta-analysis. A significant decrease in circulating MDA was observed after CPAP treatment (SMD = 1.164, 95% CI = 0.443 to 1.885, z = 3.16, p = 0.002) in OSA patients. Subgroup analyses revealed that CPAP therapy was associated with a significant decrease of circulating MDA in elder (SMD = 1.629, 95% CI = 0.265 to 2.994, z = 2.34, p = 0.019), more obese patients (SMD = 0.954, 95% CI = 0.435 to 1.473, z = 3.61, p = 0.000), more severe OSA patients (SMD = 0.879, 95% CI = 0.421 to 1.336, z = 3.76, p = 0.000), patients with therapeutic duration ≥ 3 months (SMD = 1.867, 95% CI = 0.563 to 3.172, z = 2.80, p = 0.005), and patients with good compliance (SMD = 1.004, 95% CI = 0.703 to 1.305, z = 6.54, p = 0.000).

CONCLUSIONS

This meta-analysis suggested that CPAP therapy exerted significant lowering effects on circulating MDA, especially in elder, more obese, and more severe OSA patients and patients with good compliance as well as longer duration of CPAP application.

[OSA in adults: Role of the mandibular advancement device (MAD)]

Mandibular advancement devices are an alternative to continuous positive airway pressure for patients with mild or moderate obstructive sleep apnea/ hypopnea syndrome (OSA). Oral appliances advance the mandible and tongue, enlarge and stabilize the upper airways during sleep. Clinical examination is used to select candidates for oral appliances and a particular appliance for a given patient. Titration of the advancement will optimize its effectiveness by resolving subjective clinical symptoms. Polygraphic or ventilatory polysomnography controls the effectiveness of the treatment (IAH reduction, increase of oxygen saturation and improvement of the main symptoms). Clinical follow-up is required to assess longterm outcomes, side effects and treatment adherence. Oral appliances are effective in the short-term provided they achieved a 50% reduction in IAH and complete symptom resolution.

Critical Issues in Dental and Medical Management of Obstructive Sleep Apnea

This critical review focuses on obstructive sleep apnea (OSA) and its management from a dental medicine perspective. OSA is characterized by ≥10-s cessation of breathing (apnea) or reduction in airflow (hypopnea) ≥5 times per hour with a drop in oxygen and/or rise in carbon dioxide. It can be associated with sleepiness and fatigue, impaired mood and cognition, cardiometabolic complications, and risk for transportation and work accidents. Although sleep apnea is diagnosed by a sleep physician, its management is interdisciplinary. The dentist’s role includes 1) screening patients for OSA risk factors (e.g., retrognathia, high arched palate, enlarged tonsils or tongue, enlarged tori, high Mallampati score, poor sleep, supine sleep position, obesity, hypertension, morning headache or orofacial pain, bruxism); 2) referring to an appropriate health professional as indicated; and 3) providing oral appliance therapy followed by regular dental and sleep medical follow-up. In addition to the device features and provider expertise, anatomic, behavioral, demographic, and neurophysiologic characteristics can influence oral appliance effectiveness in managing OSA. Therefore, OSA treatment should be tailored to each patient individually. This review highlights some of the putative action mechanisms related to oral appliance effectiveness and proposes future research directions.

Repercussion of medium and long treatment period with continuous positive airways pressure therapy in heart rate variability of obstructive sleep apnea

INTRODUCTION

Obstructive sleep apnea (OSA) is a respiratory sleep disorder. Many of these patients also exhibit autonomic alterations which can be observed through heart rate variability (HRV). Currently, one of the treatments for apnea is continuous positive airway pressure (CPAP).

OBJECTIVE

To observe OSA patients treated with CPAP exhibit HRV changes at medium and long treatment period.

METHODS

This is an integrative literature review conducted in May of 2018. The databases used for this research were PubMed, Scopus, Scielo and Pedro, the keywords used were "heart rate variability", "obstructive sleep apnea" and "CPAP". In this review was included original, published, randomized and non-randomized articles, released in the English language, before and up to April 2018, which specified the effects of CPAP therapy in autonomic dysfunction through the analysis of the HRV of patients diagnosed with OSA after at least one month of therapy.

RESULTS

The research of the literature produced 113 articles. After excluding duplicates and applying the inclusion and exclusion criteria, 8 articles were selected for this review.

CONCLUSION

It was concluded that CPAP therapy is related to change in heart rate variability in patients with obstructive sleep apnea.

Ready-made versus custom-made mandibular advancement appliances in obstructive sleep apnea: A systematic review and meta-analysis

Mandibular advancement appliances (MAAs) are an increasingly accepted treatment choice in obstructive sleep apnea management. The ready-made MAAs has questioned the need for a customised MAAs, given the former is more accessible and considerably cheaper. We conducted a systematic review and meta-analysis to evaluate both objective and patient-centred outcomes in relation to ready-made and custom-made MAAs s. Biomedical electronic databases, clinical trials registers and Grey literature were searched to January 2017, for randomised controlled trials. Meta-analyses of clinical trials were conducted for a range of objective (apnea-hypopnea index, treatment response) and subjective scales (daytime sleepiness; quality of life; patient preference and adherence). The review included three randomised controlled trials, which revealed low risk of bias. Custom-made MAAs s achieved a significant mean difference in the apnea-hypopnea index (-3.2; 95% confidence interval -5.18, -1.22; p = .004), daytime sleepiness (-0.98; 95% confidence interval -1.97, 0.01; p = .05), observed mean difference in Functional Outcomes of Sleep Questionnaire scores (0.76; 95% confidence interval 0.14, 1.38; p = .02), self-reported adherence (6.4-7 nights per week and 5-6.3 hr per night) and expressed preference (p ≤ .001) when compared with the ready-made MAAs s. Custom-made MAAs s offer clear definable advantages, demonstrating significant clinical effectiveness, patient preference and adherence.

Association of allergic rhinitis with obstructive sleep apnea: A meta-analysis

BACKGROUND

The co-existence of allergic rhinitis (AR) and obstructive sleep apnea (OSA) is a common phenomenon in clinical practice. AR has long been considered a risk factor for OSA. However, the relationship is not completely clear. Therefore, we conducted a meta-analysis to evaluate the prevalence of AR in sleep-disordered breathing (SDB) /OSA and their relationship.

METHODS

A comprehensive literature search was performed in PubMed/Medline, Google Scholar, Wiley Online Library, EMBASE, and Web of Science. Data were analyzed and pooled to estimate effect size (ES) /odds ratio (OR) with 95% confidence intervals (95%CI). Heterogeneity was quantified and evaluated by chi-squared-based Q-test and I2 test, with P < .05 and I > 50% indicating evidence of heterogeneity.

RESULTS

44 studies contained 6086 participants were included in this meta-analysis. For adults, the prevalence of AR was 22.8 (95% CI, 15.0-30.6) % in SDB and 35.2 (95% CI, 25.6-44.7) % in OSA. In children with SDB and OSA, the prevalence of AR was 40.8 (95% CI, 24.3-57.2) %, and 45.2 (95% CI, 25.4-65.0) % respectively. The odds ratios of prevalence of the SDB pediatric patients with AR was 2.12 (95%CI, 1.75, 2.57; P < .0001) times higher than that of non-SDB pediatric patients. There were no significant differences between OSA adults with or without AR in BMI (Body Mass Index), neck circumference, apnea hypopnea index (AHI) and epworth sleep scale score (ESS).

CONCLUSION

The prevalence of AR in OSA/SDB is considerably high and children with SDB suffering from a higher incidence of AR than non-SDB. OSA adults accompanied with AR do not have any influences on sleep parameters.

Difficult-to-treat OSAS: Combined continuous positive airway pressure (CPAP) and mandibular advancement devices (MADs) therapy. A case report

Background: Obstructive sleep apnea syndrome and is characterized by recurrent episodes of partial or complete upper airway collapse during sleep with consequent oxygen desaturations and cardiovascular, neurological, and metabolic impairment. Clinical presentation: The authors report the case of a 66-year-old male presenting "metabolic syndrome" (obesity, impaired glucose tolerance, dyslipidemia, multi-drug treated arterial hypertension), atopy, mouth breathing due to turbinate hypertrophy, and pathological daytime sleepiness. As patient's compliance to standard continuous positive airway pressure (CPAP) therapy was poor, he was treated using low-pressure CPAP combined with a mandibular advancement device (MAD). Conclusion: In selected patients, a treatment combining CPAP and MAD might be a more tolerable alternative to CPAP alone. The improved pharyngeal patency, promoted by mandibular advancement and stretching of the pharyngeal muscles, allows operating the CPAP at lower pressures when the MAD alone is not sufficient to induce a safe sleep profile.

Nocturnal Blood Pressure Is Reduced by a Mandibular Advancement Device for Sleep Apnea in Women: Findings From Secondary Analyses of a Randomized Trial

BACKGROUND

Obstructive sleep apnea is associated with high blood pressure. The magnitude of blood pressure effects from sleep apnea treatment is unclear. We aimed to determine the effect of mandibular advancement device therapy on ambulatory nighttime and daytime blood pressure in women and men with daytime sleepiness and snoring or mild to moderate sleep apnea (apnea-hypopnea index, <30).

METHODS AND RESULTS

In this 4-month, double-blind, randomized controlled trial comprising 96 untreated patients, 27 women and 58 men, aged 31 to 70 years, completed the study. The active group received individually made adjustable mandibular advancement devices, and the control group was given individually made sham devices, to be used during sleep. Polysomnographic sleep recordings and ambulatory 24-hour blood pressure measurements were performed at baseline and at follow-up. In women with mandibular advancement devices, the mean nighttime systolic blood pressure was 10.8 mm Hg (95% confidence interval, 4.0-17.7 mm Hg; P=0.004) lower than in the women in the sham group, adjusted for baseline blood pressure, age, body mass index, and the apnea-hypopnea index. The mean nighttime adjusted diastolic blood pressure was 6.6 mm Hg (95% confidence interval, 2.7-10.4 mm Hg; P=0.002) lower in the mandibular advancement device group. In men, there were no significant differences in blood pressure at night or during the daytime between the intervention groups.

CONCLUSIONS

A mandibular advancement device for obstructive sleep apnea reduces nocturnal blood pressure in women.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT00477009.

Effectiveness of oral appliances versus continuous positive airway pressure in treatment of OSA patients: An updated meta-analysis

Objective: To update the meta-analysis comparing the effectiveness of oral appliance (OA) with continuous positive airway pressure (CPAP) in treating patients with obstructive sleep apnea (OSA). Methods: PubMed, ISI Web of Knowledge, Ovid, EBSCO Dentistry & Oral Science Source, The Cochrane Library, and Embase database were searched for RCTs until 23 May 2017. Meta-analyses were performed using RevMan 5.3. Results: Sixteen RCTs were included. Compared with OA, CPAP significantly decreased AHI, min SaO2, ARI, ESS (p < 0.05), with no significant difference in REM%, FOSQ, BP (p ≥ 0.05). OA significantly improved REM% in the severe groups and ESS in the adjustable OA group (p < 0.05). OA shared greater preference. Conclusion: Even though CPAP can better decrease the severity of OSA, more patients opted for OA, which showed better results in severe patients, especially adjustable OA.

Effects of CPAP and mandibular advancement device treatment in obstructive sleep apnea patients: a systematic review and meta-analysis

The purpose of this review is to conduct a systematic review and meta-analysis comparing the effects of continuous positive airway pressure (CPAP) with a mandibular advancement device (MAD) in improving the quality of life (sleepiness, cognitive, and functional outcomes) in patients diagnosed with obstructive sleep apnea (OSA). Authors identified randomized, placebo-controlled studies from MEDLINE through PubMed, Web of Science, and the Cochrane Library. Studies were assessed for inclusion and exclusion criteria, as well as risk of bias. Initial search yielded 240 unduplicated references, which the authors reduced to 12 relevant studies. Patients with CPAP therapy showed no statistically significant difference in the post-treatment quality of life measured with the SF-36 mental health component (p = .994), or the SF-36 physical functioning component (p = .827). There was no significant improvement in neither Functional Outcomes of Sleep Questionnaire (p = .788) nor cognitive performance (p = .395) compared to patients treated with oral appliances. However, the meta-analyses' overall results showed a significant improvement in the post-treatment apnea-hypopnea index (AHI) in favor of CPAP therapy as compared with the oral appliance group (p < .001). Meta-analyses showed unclear results for sleepiness with no significant differences in average post-treatment Epworth Sleepiness Scale [ESS] (p = .203), but significant differences in change in ESS from baseline favorable to CPAP treatment (p = .047). Further studies are needed. Compliance with treatment was 1.1 h per night significantly lower with CPAP than MAD (p = .004), which could explain why though efficacy (AHI) is better with CPAP, no significant results are shown for quality of life, cognitive, and functional outcomes. Though CPAP is significantly more efficient in reducing AHI (moderate quality of evidence), it has a significantly lower compliance resulting in no differences with MAD in quality of life, cognitive, or functional outcomes. Sleep medicine professionals should monitor treatment compliance and offer patients non-compliant with CPAP an oral appliance for treatment of OSA.

Cardiovascular effects of oral appliance therapy in obstructive sleep apnea: A systematic review and meta-analysis

Obstructive sleep apnea (OSA) is associated with increased cardiovascular morbidity and mortality. This study systematically reviews the effects of oral appliance therapy (OAT) on a broad spectrum of cardiovascular outcomes. A literature search was performed up to December 31st 2016. Twenty-five relevant full-text articles were retrieved. Sixteen articles were considered methodologically sufficient, including 11 randomized controlled trials. Pooled data of the RCTs showed significant reductions in daytime systolic and diastolic blood pressure compared to baseline, but no significant reductions in heart rate, except for daytime heart rate when compared to inactive/placebo OAT. OAT and continuous positive airway pressure (CPAP) were equally effective in reducing blood pressure. Studies assessing the effect of OAT on heart rate variability, circulating cardiovascular biomarkers, and endothelial function and arterial stiffness, generally involved small numbers of patients, and were heterogeneous and inconclusive. Studies assessing the effect of OAT on cardiac function showed no effects on echocardiographic outcomes. One observational study showed that OAT was as effective as CPAP in reducing cardiovascular death. It could be speculated that OAT may lead to a reduction in long-term cardiovascular morbidity and mortality in OSA patients. However, further methodologically high quality, longitudinal studies are warranted to address this key question.

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.

Update on Oral Appliance Therapy for OSA

Purpose of Review

The majority of the adult population is affected by obstructive sleep apnea (OSA), according to recent epidemiological research. Oral appliance (OA) therapy is increasingly recommended, particularly for patients with milder OSA. This review updates the evidence in favor of OA therapy.

Recent Findings

A high level of evidence shows that OA is effective in the treatment of OSA, but continuous positive airway pressure (CPAP) is more efficient. Higher adherence with OAs may compensate for this difference. Daytime sleepiness is better treated with CPAP than with OA in patients with severe OSA. In patients with milder OSA, it is unclear whether sleepiness is significantly reduced. The long-term effectiveness of OAs is uncertain because of side-effects and the risk of OSA deterioration.

Summary

OAs are effective, but their efficacy is more variable than that of CPAP. More research is needed about the mechanism of action of OA, subjective effects and long-term health outcomes.

Effects of positive airway pressure therapy on cardiovascular and metabolic markers in males with obstructive sleep apnea

INTRODUCTION

Obstructive sleep apnea syndrome (OSAS) is associated with cardiovascular/metabolic complications. Some analytical parameters (homocysteine, glycemic and lipidic profiles) are recognized markers of these consequences. Limited data is available on the association of these markers and OSAS's severity/response to positive airway pressure therapy (PAP).

MATERIAL AND METHODS

In this prospective study we analyzed polysomnographic and analytical data of male patients admitted to sleep laboratory. The aim was to evaluate metabolic/cardiovascular markers in snorers and OSAS patients, to relate with sleep parameters and PAP response. One-hundred and three patients were included, and 73 (71%) were OSAS patients. OSAS patients were similar to snorers except for higher body mass index (BMI) and dyslipidemia. Severe OSAS patients showed higher glycemia, HbA1c, insulin, and insulin resistance, and lower HDL cholesterol in comparison to mild-moderate (p<0.05, p<0.05, p<0.001, p<0.001, p<0.05, respectively). Glycemic profile and triglycerides were slightly correlated with OSAS severity. 46 OSAS patients were submitted to 6 months of PAP, with a statistical decrease in mean values of homocysteine, glycemia, total and LDL cholesterol (p<0.05, p<0.05, p<0.05, respectively), and in glycemia and LDL cholesterol in severe group only (p<0.05, p<0.05, respectively).

RESULTS

This study demonstrated an association between glucose metabolism parameters and triglycerides with OSAS severity underlying the complexity of the process leading to cardiovascular/metabolic complications in this disorder. Moreover, homocysteine, glycemic and lipidic profiles changed significantly after 6 months of PAP therapy in OSAS, supporting its cardiovascular and metabolic protective effect.

CONCLUSION

Our study has reinforced the importance of analytical cardiovascular/metabolic evaluation as complementary tool of diagnosis/treatment response in OSAS.

Evening and morning peroxiredoxin-2 redox/oligomeric state changes in obstructive sleep apnea red blood cells: Correlation with polysomnographic and metabolic parameters

We have examined the effects of Obstructive Sleep Apnea (OSA) on red blood cell (RBC) proteome variation at evening/morning day time to uncover new insights into OSA-induced RBC dysfunction that may lead to OSA manifestations. Dysregulated proteins mainly fall in the group of catalytic enzymes, stress response and redox regulators such as peroxiredoxin 2 (PRDX2). Validation assays confirmed that at morning the monomeric/dimeric forms of PRDX2 were more overoxidized in OSA RBC compared to evening samples. Six month of positive airway pressure (PAP) treatment decreased this overoxidation and generated multimeric overoxidized forms associated with chaperone/transduction signaling activity of PRDX2. Morning levels of overoxidized PRDX2 correlated with polysomnographic (PSG)-arousal index and metabolic parameters whereas the evening level of disulfide-linked dimer (associated with peroxidase activity of PRDX2) correlated with PSG parameters. After treatment, morning overoxidized multimer of PRDX2 negatively correlated with fasting glucose and dopamine levels. Overall, these data point toward severe oxidative stress and altered antioxidant homeostasis in OSA RBC occurring mainly at morning time but with consequences till evening. The beneficial effect of PAP involves modulation of the redox/oligomeric state of PRDX2, whose mechanism and associated chaperone/transduction signaling functions deserves further investigation. RBC PRDX2 is a promising candidate biomarker for OSA severity and treatment monitoring, warranting further investigation and validation.