Sleepiness, quality of life, and sleep maintenance in REM versus non-REM sleep-disordered breathing

REM sleep obstructive sleep apnoea

Obstructive sleep apnoea (OSA) can occur in both rapid eye movement (REM) and non-REM sleep or be limited to REM sleep, when the upper airway is most prone to collapse due to REM sleep atonia. Respiratory events are usually longer and more desaturating in REM than in NREM sleep. The prevalence of REM OSA is higher in women than in men and REM OSA usually occurs in the context of mild-moderate OSA based on the apnoea-hypopnoea index calculated for the entire sleep study. Studies have highlighted some detrimental consequences of REM OSA; for example, its frequent association with systemic hypertension and a degree of excessive daytime sleepiness similar to that found in nonsleep-stage-dependent OSA. Moreover, REM OSA could increase cardiometabolic risk. Continuous positive airway pressure (CPAP) treatment aimed at preventing REM OSA should be longer than the 4 h usually considered as good compliance, since REM sleep occurs mostly during the second half of the night. Unfortunately, patients with REM OSA show poor adherence to CPAP. Alternative non-CPAP treatments might be a good choice for REM OSA, but data are lacking. This review summarises the available data on REM OSA and critically examines the weaknesses and strengths of existing literature.

REM-OSA as a Tool to Understand Both the Architecture of Sleep and Pathogenesis of Sleep Apnea-Literature Review

Sleep is a complex physiological state, which can be divided into the non-rapid eye movement (NREM) phase and the REM phase. Both have some unique features and functions. This difference is best visible in electroencephalography recordings, respiratory system activity, arousals, autonomic nervous system activity, or metabolism. Obstructive sleep apnea (OSA) is a common condition characterized by recurrent episodes of pauses in breathing during sleep caused by blockage of the upper airways. This common condition has multifactorial ethiopathogenesis (e.g., anatomical predisposition, sex, obesity, and age). Within this heterogenous syndrome, some distinctive phenotypes sharing similar clinical features can be recognized, one of them being REM sleep predominant OSA (REM-OSA). The aim of this review was to describe the pathomechanism of REM-OSA phenotype, its specific clinical presentation, and its consequences. Available data suggest that in this group of patients, the severity of specific cardiovascular and metabolic complications is increased. Due to the impact of apneas and hypopneas predominance during REM sleep, patients are more prone to develop hypertension or glucose metabolism impairment. Additionally, due to the specific function of REM sleep, which is predominantly fragmented in the REM-OSA, this group presents with decreased neurocognitive performance, reflected in memory deterioration, and mood changes including depression. REM-OSA clinical diagnosis and treatment can alleviate these outcomes, surpassing the traditional treatment and focusing on a more personalized approach, such as using longer therapy of continuous positive airway pressure or oral appliance use.

International Consensus Statement on Obstructive Sleep Apnea

BACKGROUND

Evaluation and interpretation of the literature on obstructive sleep apnea (OSA) allows for consolidation and determination of the key factors important for clinical management of the adult OSA patient. Toward this goal, an international collaborative of multidisciplinary experts in sleep apnea evaluation and treatment have produced the International Consensus statement on Obstructive Sleep Apnea (ICS:OSA).

METHODS

Using previously defined methodology, focal topics in OSA were assigned as literature review (LR), evidence-based review (EBR), or evidence-based review with recommendations (EBR-R) formats. Each topic incorporated the available and relevant evidence which was summarized and graded on study quality. Each topic and section underwent iterative review and the ICS:OSA was created and reviewed by all authors for consensus.

RESULTS

The ICS:OSA addresses OSA syndrome definitions, pathophysiology, epidemiology, risk factors for disease, screening methods, diagnostic testing types, multiple treatment modalities, and effects of OSA treatment on multiple OSA-associated comorbidities. Specific focus on outcomes with positive airway pressure (PAP) and surgical treatments were evaluated.

CONCLUSION

This review of the literature consolidates the available knowledge and identifies the limitations of the current evidence on OSA. This effort aims to create a resource for OSA evidence-based practice and identify future research needs. Knowledge gaps and research opportunities include improving the metrics of OSA disease, determining the optimal OSA screening paradigms, developing strategies for PAP adherence and longitudinal care, enhancing selection of PAP alternatives and surgery, understanding health risk outcomes, and translating evidence into individualized approaches to therapy.

Acute and long-term effects of acetazolamide in presumed high loop gain sleep apnea

BACKGROUND

The acute effect during positive pressure titration and long term efficacy of acetazolamide (AZT) in high loop gain sleep apnea (HLGSA) is inadequately assessed. We predicted that AZT may improve HLGSA in both conditions.

METHODS

A retrospective analysis of polysomnograms from patients with presumed HLGSA and residual respiratory instability administered AZT (125 or 250 mg) about 3 h into an initially drug-free positive pressure titration. A responder was defined as ≥ 50% reduction of the apnea hypopnea index(AHI 3% or arousal) before and after AZT. A multivariable logistic regression model estimated responder predictors. Long term efficacy of AZT was assessed by comparing both auto-machine (aREI_FLOW) and manually scored respiratory events (sREI_FLOW) extracted from the ventilator, prior to and after 3 months of AZT, in a subset.

RESULTS

Of the 231 participants (median age of 61[51-68] years) and 184 (80%) males in the acute effect testing: 77 and 154 patients were given 125 mg and 250 mg AZT. Compared to PAP alone, PAP plus AZT was associated with a lower breathing related arousal index (8 [3-16] vs. 5 [2-10], p < 0.001), and AHI3% (19 [7-37] vs. 11 [5-21], p < 0.001); 98 patients were responders. The non-rapid eye movement sleep (NREM) AHI3% (OR 1.031, 95%CI [1.016-1.046], p < 0.001) was a strong predictor for responder status with AZT exposure. In the 109 participants with 3-month data, both aREI_FLOW and sREI_FLOWwere significantly reduced after AZT.

CONCLUSIONS

AZT acutely and chronically reduced residual sleep apnea in presumed HLGSA; NREM AHI3% is a response predictor. AZT was well tolerated and beneficial for at least 3 months.

Neurocognitive, mood changes, and sleepiness in patients with REM-predominant obstructive sleep apnea

PURPOSE

This article focuses on recent evidence linking rapid eye movement (REM) obstructive sleep apnea (OSA) (REM-OSA) to neurocognitive dysfunction and mood changes; the proposed mechanisms for increased risk of neurocognitive dysfunction in REM-OSA, and future research prospects.

METHODS

PubMed and Google Scholar records were examined for articles utilizing pre-defined keywords. In this work, we mainly included studies published after 2017; nevertheless, critical studies published prior to 2017 were considered.

RESULTS

REM-OSA is an under-recognized stage-related sleep-disordered breathing in which obstructive respiratory events happen chiefly in stage REM. The disorder is commonly seen amongst younger patients and females and has recently been linked to cardiometabolic complications. Although less symptomatic than non-REM-OSA and non-stage-specific OSA, current findings indicate that REM-OSA may have neurocognitive repercussions and mood changes and could be linked to insomnia, increased dreams, and nightmares.

CONCLUSION

Currently available evidence indicates that REM-OSA may present with insomnia and nightmares and could affect cognitive function and mood.

Sleep fragmentation during rapid eye movement sleep and hypertension in obstructive sleep apnea

OBJECTIVE

Sleep fragmentation determined by repetitive arousals from sleep in obstructive sleep apnea (OSA) is associated with hypertension. We aimed to quantify the independent association of arousals during rapid eye movement (REM)/non-rapid eye movement (NREM) sleep with prevalent hypertension.

METHODS

We included adults with 4 h of total sleep time and at least 30 min of REM sleep obtained from overnight in-laboratory polysomnography. Logistic regression models were fitted to explore the association between arousals during REM/NREM sleep and prevalent hypertension. All models controlled for OSA metrics and arousals during NREM/REM sleep, either by statistical adjustment or by stratification.

RESULTS

The sample comprised of 11 643 patients, of which 10 055 were OSA patients. Fully adjusted models demonstrated significant dose-relationships between arousal index during REM sleep (AI-REM) and prevalent hypertension (P trend = 0.002). The higher relative odds of prevalent hypertension were most evident with AI-REM > 40 events/h. In OSA patients with arousal index during NREM sleep (AI-NREM) <15 events/h, every10-unit increase in the AI-REM was associated with 18% higher odds of hypertension (odds ratio, 1.18; 95% confidence interval, 1.11-1.27) in OSA. On the contrary, AI-NREM was not a significant predictor of hypertension in any of the models.

CONCLUSIONS

Our findings indicate that arousals during REM sleep are associated with prevalent hypertension. This is clinically relevant because treatment of OSA is often limited to the first half of the sleep period leaving most of sleep fragmentation during REM sleep untreated.

Does REM Sleep-Dependent Obstructive Sleep Apnea Have Clinical Significance?

(1) Background: The clinical significance of rapid eye movement (REM) sleep-dependent obstructive sleep apnea (OSA) remains controversial because various criteria have been used to describe it. This study determined the clinical significance of REM-OSA in Koreans using data from patients with sufficient total sleep time (TST) and REM sleep duration. (2) Methods: We investigated 1824 patients with OSA who were diagnosed by polysomnography (PSG). REM-OSA was defined as an overall apnea-hypopnea index (AHI) ≥ 5, NREM-AHI < 15, and REM-AHI/NREM-AHI ≥ 2. Demographic and medical data were collected from digital medical records and sleep questionnaires. We compared clinical and PSG data between REM-OSA and REM sleep-nondependent OSA (nREM-OSA). (3) Results: In total, 140 patients (20.2%) were categorized as REM-OSA. Those patients were predominantly female (53.6% vs. 21.7% of the overall cohort, p < 0.001). REM-OSA is frequent in the mild (69.3% vs. 18.8%) to moderate (30% vs. 27.9%) range of OSA (p < 0.001). (4) Conclusions: The prevalence of REM-OSA was similar to that in previous study findings: frequent in mild to moderate OSA and females, which is consistent with results in Western populations. Our findings suggest that REM-OSA does not have clinical significance as a subtype of OSA.

REM-Predominant Obstructive Sleep Apnea in Patients with Coronary Artery Disease

Obstructive sleep apnea (OSA) is common in adults with coronary artery disease (CAD). OSA that occurs predominantly during rapid-eye movement (REM) sleep has been identified as a specific phenotype (REM-predominant OSA) in sleep clinic cohorts. We aimed to examine the association of REM-predominant OSA with excessive sleepiness, functional outcomes, mood, and quality of life in a CAD cohort, of whom 286 OSA patients with total sleep time ≥ 240 min, and REM sleep ≥ 30 min, were included. REM-predominant OSA was defined as a REM-apnea-hypopnea-index (AHI) /non-REM (NREM) AHI ≥ 2. In all, 73 (25.5%) had REM-predominant OSA. They were more likely to be female (26.0% vs. 9.9%; p = 0.001), and more obese (42.5% vs. 24.4%; p = 0.003) but had less severe OSA in terms of AHI (median 22.6/h vs. 36.6/h; p < 0.001) compared to the patients with non-stage specific OSA. In adjusted logistic regression models, female sex (odds ratio [OR] 4.64, 95% confidence interval [CI] 1.85−11.64), body-mass-index (BMI; OR 1.17; 95% CI 1.07−1.28) and AHI (OR 0.93, 95% CI 0.91−0.95) were associated with REM-predominant OSA. In univariate linear regression models, there was a dose-response relationship between REM-AHI and Zung Self-rated Depression Scale but not excessive sleepiness, functional outcomes, and anxiety scores. Among the Short Form-36 subdomains, Vitality, Mental Health, and Mental Component Summary (MCS) scores were inversely correlated with REM-AHI. In multivariate linear models, only MCS remained significantly associated with REM-AHI after adjustment for age, BMI, and sex (β-coefficient −2.20, %95 CI [−0.56, −0.03]; p = 0.028). To conclude, female sex and BMI were related to REM-predominant OSA in this revascularized cohort. MCS was inversely associated with REM-AHI in the multivariate model.

Clinical Characteristics of Rapid Eye Movement-Related Obstructive Sleep Apnea: An Experience in a Tertiary Medical Center of Taiwan

PURPOSE

Obstructive sleep apnea (OSA) is characterized by intermittent hypoxemia and sleep fragmentation. While apnea is pronounced with severe desaturation during rapid eye movement (REM) sleep, REM-related OSA is a distinct phenotype of OSA associated with respiratory disturbances predominantly during REM sleep. In this study, we investigated the clinical features of REM-related OSA in Taiwan.

PATIENTS AND METHODS

All patients diagnosed with OSA in the Taipei Veterans General Hospital from 2015 to 2017 were analyzed retrospectively and classified into REM-related OSA (REM-OSA) group, non-REM related OSA (NREM-OSA) group, and non-stage specific-OSA group. The clinical demographics, OSA-related symptoms, polysomnography results, and medical comorbidities of the three groups were analyzed.

RESULTS

Among 1331 patients with OSA, 414 (31.1%) were classified as REM-OSA, 808 (60.7%) as NREM-OSA, and 109 (8.2%) as non-stage specific-OSA. After being adjusted for OSA severity, the REM-OSA group was associated with less portion of males, longer desaturation duration, and lower nadir oxygen saturation (SpO₂) compared with the NREM-OSA group in mild and moderate OSA. In moderate OSA, the non-stage specific-OSA group featured more OSA severity and more desaturation compared with the other groups. The Epworth Sleepiness Scale scores and the prevalence of comorbidities did not vary among the REM-OSA, NREM-OSA, and non-stage specific-OSA groups. High REM-AHI/NREM-AHI ratio was associated with young age, female gender, high BMI, and low AHI.

CONCLUSION

OSA patients with high REM-AHI/NREM-AHI ratio are related to young age, female gender, high BMI, and low AHI. Patients with REM-related OSA presented with longer desaturation duration and lower nadir SpO2 after being adjusted for OSA severity.

Proportion of rapid eye movement sleep related obstructive sleep apnea (REM related OSA) in patients with sleep disordered breathing: A cross sectional study

Background and Objectives:

Obstructive sleep apnea (OSA) during rapid eye movement (REM) stage of sleep is gaining importance in recent years. This study was done to determine the proportion of REM-related OSA and its associated polysomnographic features.

Methods:

One hundred forty-two patients were included in the study. REM-related OSA was defined based on previously established broad and strict criteria (REM apnea–hypopnea index [AHI]/non-REM [NREM] AHI ratio ≥2 and REM AHI >5 with NREM AHI <5, respectively), and its association with polysomnographic features was studied using appropriate statistical tools.

Results:

The proportion of REM-related OSA in the study was 56.3% and 25.3% as per broad and strict criterion, respectively. The REM-related OSA group had a mean younger age (47.4 ± 13.2 years) as compared to NREM-related OSA group (52.6 ± 15.8 years). Females (34 out of 45; 75.6%) were more likely to have REM-related OSA as compared to males (46 out of 107; 47.4%). Supine AHI, arousal index, oxygen desaturation index, length of the longest event, and the lowest oxygen saturation recorded during sleep had a significant association with REM-related OSA. 74% of patients with overall AHI <5 and 87% patients with overall AHI 5 to 15 satisfied the criteria for REM-related OSA as per broad criterion.

Conclusion:

REM-related OSA was quite prevalent in the study population (56.3%) and was more common in the mild and moderate severity subgroups of OSA.

Prevalence and Risk Factors for Rapid Eye Movement-Related Obstructive Sleep Apnea in Children

OBJECTIVES

Different pathophysiological mechanisms and the distribution of respiratory events among rapid eye movement (REM) and non-rapid eye movement (NREM) sleep modulate the effect of obstructive sleep apnea (OSA). We aimed to study the prevalence and risk factors for REM-related OSA in children.

STUDY DESIGN

Retrospective, cross-sectional study.

METHODS

We recruited 366 children with OSA confirmed by polysomnography (PSG) over a 5-year period. REM-related OSA is defined by an obstructive apnea-hypopnea index (OAHI) in the REM sleep ≥2× than during NREM sleep.

RESULTS

The prevalence of REM-related OSA in children was 50.3%. Children with REM-related OSA were more likely to be female (P = 0.042), and had lower prevalence of adenotonsillar hypertrophy (P = 0.043) compared with children with other OSA subtypes. Children with REM-related OSA slept longer in the supine position (P = 0.003), had shorter duration of NREM1 sleep (P = 0.018), lower nadir SpO₂ (P = 0.005), and a higher oxygen desaturation index 3% (ODI3%) (P = 0.014), and lower arousal index (P = 0.034) compared with other OSA subtypes. Female gender and supine sleep was the independent risk factors for REM-related OSA.

CONCLUSION

The prevalence of REM-related OSA was 50.3%. OAHI_REM should be considered as an important parameter in future clinical research studies done in children with OSA.

Rapid eye movement related obstructive sleep apnea: Where do we stand?

Rapid eye movement (REM) related obstructive sleep apnea (OSA) is defined by the presence of episodes of apnea or hypopnea predominantly or exclusively during REM sleep. Epidemiology of this disorder shows a complex interaction with age, sex, and body mass index. The prevalence is variable and depends on the criteria used to define this disorder. Moreover, the clinical significance of this entity remains poorly defined. However, episodes of apnea or hypopnea encountered during REM sleep are longer and are associated with a more profound drop in oxygen saturation than non-REM sleep. Likewise, this disorder may be independently associated with hypertension and poor glycemic control. More importantly, positive airway pressure therapy as currently prescribed may not treat the majority of apnea episodes during REM sleep. The treatment is further complicated by the different definitions used for the diagnosis of this disorder and the lack of consensus if patients with this diagnosis should be treated if their overall apnea-hypopnea index does not meet the threshold for the clinical diagnosis of OSA. The definition and treatment used for the diagnosis and management of REM-related OSA needs to be standardized. Moreover, a consensus needs to be developed as to whether patients with this disorder should be treated if their overall apnea-hypopnea index does not meet the threshold for the clinical diagnosis of OSA. Further investigation may help answer if this disorder is independently associated with neurocognitive and cardiometabolic adverse outcomes and help guide the therapeutic approach.

Natural History of Sleep-disordered Breathing during Rapid Eye Movement Sleep. Relevance for Incident Cardiovascular Disease

Rationale: Sleep-disordered breathing (SDB) occurring primarily during rapid eye movement (REM) sleep is a common clinical problem. The natural history of REM-related SDB and the associated cardiovascular sequelae of disease progression remain to be determined.Objectives: The objective of the current study was to describe the natural history of REM-related SDB, ascertain predictors of progression, and determine whether the evolution of REM-related SDB into non-REM (NREM) sleep is associated with incident cardiovascular events.Methods: Participants from the Sleep Heart Health Study with a baseline NREM apnea-hypopnea index (NREM-AHI) of <5 events/h and data from a follow-up sleep study along with information on incident cardiovascular disease were included in the study. Bivariate logistic regression was used to jointly model the predictors of disease progression based on the presence or absence of SDB during NREM and REM sleep using a cut-point of 5 events/h. Explanatory variables such as age, race, body mass index (BMI), change in BMI, and baseline REM-AHI were considered. Proportional hazards regression was then used to establish whether the development of SDB during NREM sleep was associated with incident cardiovascular disease.Results: The majority of the 1,908 participants included in the study did not develop SDB during NREM sleep. The likelihood of progression of SDB into NREM sleep did increase with higher baseline REM-AHI. BMI and an increase in BMI predicted progression of SDB in both NREM and REM sleep in men but not in women. There was a strong interdependence between developing a NREM-AHI of ≥5 events/h and worsening REM-AHI at follow-up with odds ratios of 6.01 and 4.47, in women and men, respectively. Moreover, the relative risk for incident cardiovascular events among those who developed a NREM-AHI of ≥5 events/h at the follow-up visit was elevated only in women with REM-related SDB at baseline.Conclusions: SDB during REM sleep is a relatively stable condition and does not progress in the majority of individuals. Progression of SDB into NREM sleep is associated with sex, weight, and age. SDB during REM and NREM sleep tends to develop concurrently. Finally, the development of SDB during NREM sleep is associated with incident cardiovascular events, but only in women with REM-related SDB at baseline.

Total durations of respiratory events are modulated within REM and NREM sleep by sleeping position and obesity in OSA patients

BACKGROUND

Supine sleeping position and obesity are well-known risk factors for obstructive sleep apnea (OSA) and modulate the risk for OSA-related daytime symptoms. Although respiratory event durations are associated with OSA-related severe health consequences, it is unclear how sleeping position, obesity, and daytime sleepiness are associated with respiratory event durations during REM and NREM sleep. We hypothesize that irrespective of the apnea-hypopnea index (AHI), respiratory event durations differ significantly between various OSA subgroups during REM and NREM sleep.

METHODS

One night in-lab polysomnographic recordings were retrospectively analyzed from 1910 untreated suspected OSA patients. 599 patients (AHI ≥ 5) were included in study and divided into subgroups based on positional dependency, BMI, and daytime sleepiness (Epworth Sleepiness Scale and Multiple Sleep Latency Test). Differences in total hypopnea time (THT), total apnea time (TAT), and total apnea-hypopnea time (TAHT) within REM and NREM sleep between the subgroups were evaluated.

RESULTS

During REM sleep, positional OSA patients had lower THT (OR = 0.952, p < 0.001) and TAHT (OR = 0.943, p < 0.001) than their non-positional counterparts. Compared to normal-weight patients (BMI < 25 kg/m²), obese patients (BMI ≥ 30 kg/m²) had lower THT, TAT, and TAHT (ORs = 0.942-0.971, p ≤ 0.009) during NREM sleep but higher THT (OR = 1.057, p = 0.001) and TAHT (OR = 1.052, p = 0.001) during REM sleep. No significant differences were observed in THT, TAT, and TAHT between patients with and without daytime sleepiness.

CONCLUSION

Regardless of the AHI, respiratory event durations vary significantly between OSA sub-groups during REM and NREM sleep. Therefore, to personalize OSA severity estimation the diagnosis should be tailored based on patient's demographics, clinical phenotype, and PSG characteristics.

CPAP treatment in REM-related obstructive sleep apnea: a distinct clinical phenotype of sleep disordered breathing

PURPOSE

REM-related obstructive sleep apnea (REM-OSA), as defined using revised apnea-hypopnea index (AHI) criteria, might represent a specific OSA phenotype. However, there is a lack of data on outcomes of treatment in this population. This study evaluated the effects of CPAP treatment over 12 months on clinical outcomes for patients with the polysomnography phenotype of REM-OSA.

METHODS

We conducted a prospective observational study with the following inclusion criteria: subjective sleepiness and diagnostic polysomnography demonstrating AHI_REM≥15 events/h, AHI_NREM<5 events/h, and ≥ 30 min of REM sleep. Clinical outcomes assessed included Epworth Sleepiness Scale (ESS), psychomotor vigilanc test reaction time (PVT-RT), and CPAP adherence at baseline, 1, 3, 6, and 12 months; Functional Outcomes of Sleep Questionnaire (FOSQ) and Depression Anxiety Stress Scales (DASS-21) at baseline, 1, 3 and 12 months. The reason is the first 3 outcomes (ESS, PVT, adherence) were assessed at baseline, 1, 3, 6, and 12 months, while the next 2 outcomes (FOSQ, DASS) were assessed at baseline, 1, 3, and 12 months. The edited version is not as clear in separating these outcomes into 2 groups; Functional Outcomes of Sleep Questionnaire (FOSQ); and Depression Anxiety Stress Scales (DASS-21) at baseline, 1, 3, and 12 months. Linear mixed effects models were used to investigate the joint effects of time and average CPAP adherence on our outcomes of interest.

RESULTS

Twenty participants completed a minimum of 1 month of CPAP treatment and were included for analysis. During the trial, 8 participants discontinued CPAP (4 before 3 months, 1 before 6 months, 3 before 12 months), and 19 participants completed 12 months of treatment. Baseline ESS was elevated at 12.6 units. Average CPAP usage for all 27 participants over 12 months was 2.9 ± 2.4 h. There was a significant decrease in ESS and increase in FOSQ at all time points, and the decrease in ESS was only seen in the CPAP-adherent subgroup. Decreases in DASS-21 and PVT-RT were not sustained.

CONCLUSIONS

CPAP treatment in sleepy patients with moderate to severe REM-OSA is associated with reduced sleepiness and improved quality of life.

TRIAL REGISTRATION

The trial was registered in the Australian New Zealand Clinical Trials Registry: ACTRN12620000576921, 18/05/2020 (retrospectively registered).

Natural History of REM-OSA in Children and Its Associations with Adverse Blood Pressure Outcomes: A Longitudinal Follow-Up Study

PURPOSE

Most respiratory events in childhood obstructive sleep apnea (OSA) take place during rapid-eye-movement (REM) sleep. This study aimed to describe the characteristics and natural history of childhood REM-OSA and to evaluate the associations between OSA subtypes and blood pressure (BP) outcomes.

PARTICIPANTS AND METHODS

This was a prospective 10-year follow-up study of a cohort established for a childhood OSA epidemiologic study. All subjects from the original cohort were invited to undergo a polysomnography (PSG) and 24-hour ambulatory blood pressure (ABP) monitoring. REM-OSA was defined with a ratio of obstructive apnea hypopnea index (OAHI) during REM sleep (OAHI_REM) to OAHI during non-REM sleep (OAHI_NREM) ≥ 2. Natural history was observed and linear mixed models were used to assess the associations between OSA subtypes and BP outcomes.

RESULTS

A total of 610 participants from baseline were included to study the epidemiology of REM-OSA in childhood. Among children with OSA, 65% had REM-OSA. At 10-year follow-up, 234 were included in the analysis. REM-OSA was more common at both baseline (58/92, 63%) and 10-year follow-up (34/58, 59%). For those with REM-OSA at baseline and persistent OSA at follow-up, the majority (72%) remained to have REM-OSA. Compared to those without OSA, subjects with REM-OSA had significantly higher nocturnal SBP (mean difference 2.19 mmHg, 95% confidence interval (CI): 0.12, 4.26; p = 0.039) and DBP (mean difference 1.58 mmHg, 95% confidence interval (CI): 0.11, 3.04; p = 0.035), and less nocturnal SBP dipping (mean difference -1.84%, 95% CI: -3.25, -0.43; p = 0.011), after adjusting for potential confounders. This significant association between REM-OSA and nocturnal SBP dipping was observed at baseline visit only.

CONCLUSION

REM-OSA was found to be a stable phenotype through childhood to young adulthood, and REM-OSA was associated with higher nocturnal BP and a lesser degree of nocturnal SBP dipping in children.

Insomnia as a Symptom of Rapid Eye Movement-Related Obstructive Sleep Apnea

Rapid eye movement (REM)-related obstructive sleep apnea (OSA), a polysomnographic phenotype that affects 12–36% of OSA patients, is defined by apnea and hypopnea events that predominantly or exclusively occur during REM sleep. Recent studies indicated that REM-related OSA was associated with the development of nocturnal non-dipping of systolic and diastolic blood pressure, metabolic syndrome, diabetes, and depressive symptoms. However, to date, the association between REM-related OSA and insomnia still remains unclear. We investigated whether there was a difference between REM- and non-REM-related OSA in terms of insomnia-related sleep disturbance as measured by the Pittsburgh Sleep Quality Index (PSQI) in 1736 patients with OSA. REM-related OSA showed a significant association with increased PSQI in all adjusted models. In the subgroup analysis, the coefficients of all models were higher in female than in male patients with REM-related OSA. Insomnia should be considered an important complaint in patients with REM-related OSA, and its indicators, such as the PSQI, should be included in routine diagnostic testing.

Obstructive sleep apnea during REM sleep and daytime cerebral functioning: A regional cerebral blood flow study using high-resolution SPECT

Obstructive sleep apnea (OSA) predominantly during rapid eye movement (REM) sleep may have impacts on brain health, even in milder OSA cases. Here, we evaluated whether REM sleep OSA is associated with abnormal daytime cerebral functioning using high-resolution single-photon emission computed tomography (SPECT). We tested 96 subjects (25 F, age: 65.2 ± 6.4) with a wide range of OSA severity from no OSA to severe OSA (apnea-hypopnea index: 0-97 events/h). More respiratory events during REM sleep were associated with reduced daytime regional cerebral blood flow (rCBF) in the bilateral ventromedial prefrontal cortex and in the right insula extending to the frontal cortex. More respiratory events during non-REM (NREM) sleep were associated with reduced daytime rCBF in the left sensorimotor and temporal cortex. In subjects with a lower overall OSA severity (apnea-hypopnea index<15), more respiratory events during REM sleep were also associated with reduced daytime rCBF in the insula and extending to the frontal cortex. Respiratory events that characterized OSA during NREM versus REM sleep are associated with distinct patterns of daytime cerebral perfusion. REM sleep OSA could be more detrimental to brain health, as evidenced by reduced daytime rCBF in milder forms of OSA.

Effectiveness of pediatric drug-induced sleep endoscopy for REM-predominant obstructive sleep apnea

STUDY OBJECTIVES

Because dexmedetomidine (DEX)-induced sedation mimics non-rapid eye movement (NREM) sleep, its utility in sedating children with REM-predominant disease is unclear. We sought to determine the effectiveness of pediatric drug-induced sleep endoscopy (DISE) using DEX and ketamine for children with REM-predominant OSA, specifically whether or not at least one site of obstruction could be identified.

METHODS

A retrospective case series of children without tonsillar hypertrophy undergoing DISE at a tertiary pediatric hospital from 10/2013 through 9/2015 who underwent subsequent surgery to address OSA with polysomnography (PSG) before and after.

RESULTS

We included 56 children, mean age 5.6±5.4 years, age range 0.1-17.4 years, mean BMI 20.3±7.4 kg/m2 (76±29 percentile). At least one site of obstruction was identified in all patients, regardless of REM- or NREM-predominance. The mean obstructive apnea-hypopnea index (oAHI) improved (12.6 ± 10.7 to 9.0 ± 14.0 events/h) in children with REM-predominant (P = 0.013) and NREM-predominant disease (21.3 ± 18.9 to 10.3 ± 16.2 events/h) (P = 0.008). The proportion of children with a postoperative oAHI < 5 was 53% and 55% for REM- and NREMpredominant OSA, respectively. Unlike children with NREM-predominant disease, children with REM-predominant disease had significant improvement in the mean saturation nadir (P < 0.001), total sleep time (P = 0.006), and sleep efficiency (P = 0.015).

CONCLUSIONS

For children with OSA without tonsillar hypertrophy, DISE using DEX/ketamine was useful to predict at least one site of obstruction, even for those with REM-predominant OSA. DISE-directed outcomes resulted in significant improvements in mean oAHI, total sleep time, sleep efficiency, saturation nadir, and the proportion with oAHI < 5, after surgery for some children with REM-predominant disease.

Sleep problems in active duty military personnel seeking treatment for posttraumatic stress disorder: presence, change, and impact on outcomes

Study Objectives

To examine sleep disorder symptom reports at baseline and posttreatment in a sample of active duty U.S. Army Soldiers receiving treatment for posttraumatic stress disorder (PTSD). Explore sleep-related predictors of outcomes.

Methods

Sleep was evaluated in 128 participants in a parent randomized clinical trial comparing Spaced formats of Prolonged Exposure (PE) or Present Centered Therapy and a Massed format of PE. In the current study, Spaced formats were combined and evaluated separately from Massed.

Results

At baseline, the average sleep duration was &lt; 5 h per night on weekdays/workdays and &lt; 6 h per night on weekends/off days. The majority of participants reported clinically significant insomnia, clinically significant nightmares, and probable sleep apnea and approximately half reported excessive daytime sleepiness at baseline. Insomnia and nightmares improved significantly from baseline to posttreatment in all groups, but many patients reported clinically significant insomnia (&gt;70%) and nightmares (&gt;38%) posttreatment. Excessive daytime sleepiness significantly improved only in the Massed group, but 40% continued to report clinically significant levels at posttreatment. Short sleep (Spaced only), clinically significant insomnia and nightmares, excessive daytime sleepiness, and probable sleep apnea (Massed only) at baseline predicted higher PTSD symptoms across treatment course. Short weekends/off days sleep predicted lower PTSD symptom improvement in the Spaced treatments.

Conclusions

Various sleep disorder symptoms were high at baseline, were largely unchanged with PTSD treatment, and were related to worse PTSD treatment outcomes. Studies are needed with objective sleep assessments and targeted sleep disorders treatments in PTSD patients.

Clinical Trial Registration

NCT01049516.

The association between sleep efficiency and diabetes mellitus in community-dwelling individuals with or without sleep-disordered breathing

BACKGROUND

Sleeping habits have been reported to be associated with diabetes mellitus. This study aimed to explore the relationship of sleep efficiency with diabetes mellitus in individuals with or without sleep-disordered breathing based on polysomnography records.

METHODS

We enrolled participants from the Sleep Heart Health Study. Objective indicators of sleep characteristics including sleep efficiency, sleep latency, slow-wave sleep, wake after sleep onset, and total arousal index were monitored via in-home polysomnography. Sleep efficiency was divided into grade 1 (≥85%), grade 2 (80%-84.9%), and grade 3 (<80%). Multivariate logistic regression models were utilized to investigate the association between sleep quality and diabetes mellitus.

RESULTS

The present study comprised 4737 participants with a mean age of 63.6 ± 11.0 years. The prevalence of diabetes mellitus was higher in those with grade 3 sleep efficiency than that in those with grade 1 and grade 2 sleep efficiency in participants with (10.9% vs 8.5% vs 8.3%, respectively; P =.134) or without (9.5% vs 5.6% vs 3.5%, respectively; P <.001) sleep-disordered breathing. After adjusting for potential confounding factors, sleep efficiency <80% was associated with the prevalence of diabetes mellitus only in participants without sleep-disordered breathing (odds ratio, 1.894; 95% confidence interval, 1.187-3.022, P =.007).

CONCLUSION

Poor sleep efficiency is associated with diabetes mellitus in those without sleep-disordered breathing. Therefore, the relationship between sleep efficiency and diabetes mellitus is worth further investigation.

REM-related obstructive sleep apnea: when does it matter? Effect on motor memory consolidation versus emotional health

STUDY OBJECTIVES

The clinical importance of obstructive sleep apnea, which can be prevalent during rapid eye movement (REM) sleep, is unclear. The current study examines the effect of REM-related obstructive sleep apnea on motor memory consolidation as well as on mood states.

METHODS

We compared performance on the motor sequence task (MST), psychomotor vigilance test (PVT), Functional Outcomes of Sleep Questionnaire, and the Profile of Mood State (POMS) survey between 3 groups: healthy controls (n = 18), REM-exclusive OSA (n = 17), and patients with OSA with respiratory events throughout REM and non-rapid eye movement (NREM) sleep (n = 18).

RESULTS

As expected, performance on the MST improved overnight in the healthy control group. An improvement which was similar in magnitude was also observed in the REM-exclusive OSA group whereas patients with similar OSA during REM and NREM sleep showed reduced overnight memory consolidation. Consistent with these results, we found a correlation between overnight MST improvement and the apnea hypopnea index during NREM sleep (P = .041), but not during REM sleep (P = .424). However, patients with REM-exclusive apnea demonstrated the most negative emotions based on scoring highest on the POMS survey (P = .019).

CONCLUSIONS

Our results provide evidence that although apneas occurring only during REM sleep do not have an effect on the encoding and stabilization of motor sequence memories, they are deleterious for emotional health.

The Associations of Gender, Menopause, Age, and Asthma with REM-Predominant Obstructive Sleep Apnea: A Prospective Observational Study

PURPOSE

The study sought to assess demographics, clinical features, comorbidities, and polysomnographic features of a large cohort of clinic-based patients with rapid eye movement-predominant obstructive sleep apnea (REM-predominant-OSA) in both genders, while assessing the relationship between REM-predominant OSA in one hand and menopausal status and age on the other.

METHODS

This prospective observational study was conducted between January 2003 and December 2017. REM-predominant OSA diagnostic criteria included an AHI of ≥5/h, with REM-AHI/non-REM-AHI of >2, a non-REM-AHI of <15/h, and a minimum of 15 min of REM sleep. Patients who had an AHI>5 events/h and did not meet the criteria for REM-predominant OSA were included in the non-stage-specific OSA group (NSS).

RESULTS

The study consisted of 1346 men and 823 women (total=2169). REM-predominant OSA was diagnosed in 17% (n=369). The prevalence of REM-predominant OSA in women was 25% compared with 12% in men. Several independent associations of REM-predominant OSA were identified in the whole group, including age (OR: 0.97 [0.95-0.98], p<0.01), female sex (OR: 6.95 [4.86-9.93], p>0.01), REM sleep duration (min) (OR: 1.02 [1.02-1.03], < 0.01), and time with SpO2 <90% (mins) (OR: 0.97 [0.95-0.99], < 0.01), hypertension (OR:0.67 [0.45-0.99], 0.04) and asthma (OR: 2.19 [1.56-3.07], < 0.01). The prevalence of REM-predominant OSA in premenopausal and postmenopausal women was 35% and 18.6% (p< 0.01), respectively. Among women, age was an independent correlate (OR: 0.97 [0.94-0.99], p=0.03; however, menopausal status was not.

CONCLUSION

REM-predominant OSA is prevalent among clinic-based patients with OSA. A younger age and female sex were independent correlates of REM-predominant OSA. Among women, a younger age but not menopausal status was a correlate of REM-predominant OSA. Asthma was independently associated with REM-predominant OSA.

Obstructive Sleep Apnea during REM Sleep and Cardiovascular Disease

RATIONALE

Obstructive sleep apnea (OSA) during REM sleep is a common disorder. Data on whether OSA that occurs predominantly during REM sleep is associated with health outcomes are limited.

OBJECTIVES

The present study examined the association between OSA during REM sleep and a composite cardiovascular endpoint in a community sample with and without prevalent cardiovascular disease.

METHODS

Full-montage home polysomnography was conducted as part of the Sleep Heart Health Study. The study cohort was followed for an average of 9.5 years, during which time cardiovascular events were assessed. Only participants with a non-REM apnea-hypopnea index (AHI) of less than 5 events/h were included. A composite cardiovascular endpoint was determined as the occurrence of nonfatal or fatal events, including myocardial infarction, coronary artery revascularization, congestive heart failure, and stroke. Proportional hazards regression was used to derive the adjusted hazards ratios for the composite cardiovascular endpoint.

MEASUREMENTS AND MAIN RESULTS

The sample consisted of 3,265 subjects with a non-REM AHI of less than 5.0 events/h. Using a REM AHI of less than 5.0 events/h as the reference group (n = 1,758), the adjusted hazards ratios for the composite cardiovascular endpoint in those with severe REM OSA (≥30 events/h; n = 180) was 1.35 (95% confidence interval, 0.98-1.85). Stratified analyses demonstrated that the association was most notable in those with prevalent cardiovascular disease and severe OSA during REM sleep with an adjusted hazards ratio of 2.56 (95% confidence interval, 1.46-4.47).

CONCLUSIONS

Severe OSA that occurs primarily during REM sleep is associated with higher incidence of a composite cardiovascular endpoint, but in only those with prevalent cardiovascular disease.

Associations Between Characteristics of Obstructive Sleep Apnea and Nocturnal Blood Pressure Surge

Research suggests that oxygen desaturation and sleep stage during obstructive sleep apnea (OSA) are related to the magnitude of high blood pressure (BP) in a laboratory setting. However, in a clinical setting, these associations have not been well studied. We used a noninvasive oscillometric BP measurement device to investigate the association between oxygen-triggered BP levels at the end of each OSA episode and the characteristics of the preceding OSA episode. In 42 newly diagnosed OSA patients (average age, 63.5±12.5 years; average apnea-hypopnea index, 32.6±18.2 per hour), 258 BP measurements were obtained at the end of OSA episodes. Hypoxia-peak systolic BP (SBP), defined as the maximum oxygen-triggered SBP value, was significantly higher in rapid eye movement sleep (144.9±19.9 mm Hg) than in non-rapid eye movement stage 1 sleep (129.5±15.1 mm Hg; P<0.001) and non-rapid eye movement stage 2 sleep (129.4±14.7 mm Hg; P<0.001). In a multivariate-linear mixed model, the lowest oxygen saturation percentage during each OSA episode was associated with increased hypoxia-peak SBP (-0.501 mm Hg; P<0.001), nocturnal SBP surge (-0.395 mm Hg; P<0.001), defined as the difference between the hypoxia-peak SBP and the mean nocturnal SBP, and maximum value of SBP surge (-0.468 mm Hg; P<0.001), defined as the difference between the hypoxia-peak SBP and the minimum nocturnal SBP independent of sleep stage. These values were not associated with the duration of each OSA episode. The contribution of rapid eye movement sleep and severe oxygen desaturation to OSA-related BP elevation measured with a noninvasive oscillometric method was determined in a clinical setting.

Research Priorities in Pathophysiology for Sleep-disordered Breathing in Patients with Chronic Obstructive Pulmonary Disease. An Official American Thoracic Society Research Statement

BACKGROUND

Obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD) are common conditions; the co-occurrence of these diseases, called the overlap syndrome (OVS), has been associated with poor health outcomes.

PURPOSE

The purpose of this Official American Thoracic Society Research Statement is to describe pathophysiology, epidemiology, outcomes, diagnostic metrics, and treatment of OVS, as well as to identify important gaps in knowledge and make recommendations for future research.

METHODS

Clinicians and researchers with expertise in sleep medicine, pulmonary medicine, or both were invited to participate. Topics were divided among the participants according to their interest and expertise. A literature search was conducted; the search was not a formal systematic review. Evidence was considered and supplemented with the panelists' nonsystematic clinical observations. Important knowledge gaps were identified.

RESULTS

Recommendations for research to fill existing knowledge gaps were made. The recommendations were formulated by discussion and consensus.

CONCLUSIONS

Many important questions about OVS exist. This American Thoracic Society Research Statement highlights the types of research that leading clinicians and researchers believe will have the greatest impact on better understanding the spectrum of disease, improving diagnosis, and optimizing therapy.

The relationship between anxiety, depression, daytime sleepiness in the REM-related mild OSAS and the NREM-related mild OSAS

INTRODUCTION

Obstructive sleep apnea syndrome (OSAS) is a common form of sleep-related respiratory disease characterized by recurrent blockages in the upper airway. Rapid eye movement (REM)-related OSAS is a condition in which apneas and hypopneas are more common during REM sleep. We investigated whether there was any difference between REM-related mild OSAS group and NREM-related mild OSAS group in terms of anxiety, depression, and daytime sleepiness.

METHODS

A total of 166 patients with mild OSAS (72 patients with REM-related and 94 NREM-related OSAS) participated in the study. Hospital Anxiety-Depression Scale (HADS) and Epworth Sleepiness Scale (ESS) questionnaires were completed by both groups.

RESULTS

Anxiety and depression scores were significantly higher in patients with REM-related OSAS in comparison to the NREM-related OSAS group (p = 0.01, p = 0.02 respectively). There was no statistically significant difference between the two groups in terms of ESS scores (p = 0.60).

CONCLUSION

The results of our study suggest that patients with REM-related OSAS have higher rates of depression and anxiety compared to non-REM-related OSAS patients and this may adversely affect quality of life. It may be possible to prevent psychiatric complications, such as depression and anxiety, by administering treatments that reduce REM sleep duration and intensity in patients with REM-related OSAS.

Implication of mixed sleep apnea events in adult patients with obstructive sleep apnea-hypopnea syndrome

PURPOSE

Although mixed sleep apnea (MSA) is one of the three types of sleep apnea, it is not considered a separate disease entity. It is generally seen as a part of obstructive sleep apnea-hypopnea syndrome (OSAHS), but its implications are often ignored. In this study, we examined its features and the potential impact on OSAHS patients.

METHODS

Subjects diagnosed with OSAHS by polysomnography (PSG) were enrolled. All participants underwent physical checkups and tests of blood biochemistry. They were anthropometrically, clinically, and polysomnographically studied.

RESULTS

MSA events were common in patients with severe OSAHS patients. There were significant differences between the pure OSAHS group and its mixed counterpart in apnea-hypopnea indices during REM (AHI_REM) and non-REM (AHI_NREM) and in percentages of N2 or N3 sleep. Logistic regression analysis showed that, after adjustment of other parameters, patients with MSA events were mostly male, had higher body mass index (BMI), higher scores on Epworth Sleepiness Scales (ESS), higher triglyceride (TG) levels, and higher apnea-hypopnea index (AHI). The combined predictive probability of the aforementioned variables was 0.766 (95% CI = 0.725~0.806; sensitivity 61.6%, specificity 82.1%).

CONCLUSIONS

Our study suggested that MSA was related to the stability of the ventilatory control in OSAHS patients. MSA events occur more frequently in patients with severe OSAHS, and male gender, obesity, daytime sleepiness, and elevated TG levels were risk factors for the mixed OSAHS.

REM obstructive sleep apnea: risk for adverse health outcomes and novel treatments

Rapid eye movement (REM) sleep was discovered nearly 60 years ago. This stage of sleep accounts for approximately a quarter of total sleep time in healthy adults, and it is mostly concentrated in the second half of the sleep period. The majority of research on REM sleep has focused on neurocognition. More recently, however, there has been a growing interest in understanding whether obstructive sleep apnea (OSA) during the two main stages of sleep (REM and non-REM sleep) leads to different cardiometabolic and neurocognitive risk. In this review, we discuss the growing evidence indicating that OSA during REM sleep is a prevalent disorder that is independently associated with adverse cardiovascular, metabolic, and neurocognitive outcomes. From a therapeutic standpoint, we discuss limitations of continuous positive airway pressure (CPAP) therapy given that 3 or 4 h of CPAP use from the beginning of the sleep period would leave 75% or 60% of obstructive events during REM sleep untreated. We also review potential pharmacologic approaches to treating OSA during REM sleep. Undoubtedly, further research is needed to establish best treatment strategies in order to effectively treat REM OSA. Moreover, it is critical to understand whether treatment of REM OSA will translate into better patient outcomes.

REM-associated sleep apnoea: prevalence and clinical significance in the HypnoLaus cohort

This study determined the prevalence of rapid eye movement (REM) related sleep-disordered breathing (REM-SDB) in the general population and investigated the associations of REM-SDB with hypertension, metabolic syndrome, diabetes and depression.Home polysomnography (PSG) recordings (n=2074) from the population-based HypnoLaus Sleep Cohort (48.3% men, 57±11 years old) were analysed. The apnoea-hypopnoea index was measured during REM and non-REM sleep (as REM-AHI and NREM-AHI, respectively). Regression models were used to explore the associations between REM-SDB and hypertension, diabetes, metabolic syndrome and depression in the entire cohort and in subgroups with NREM-AHI <10 events·h^-1 and total AHI <10 events·h^-1The prevalence of REM-AHI ≥20 events·h^-1 was 40.8% in the entire cohort. An association between increasing REM-AHI and metabolic syndrome was found in the entire cohort and in both the NREM-AHI and AHI subgroups (p-trend=0.014, <0.0001 and 0.015, respectively). An association was also found between REM-AHI ≥20 events·h^-1 and diabetes in both the NREM-AHI <10 events·h^-1 (odds ratio (OR) 3.12 (95% CI 1.35-7.20)) and AHI <10 events·h^-1 (OR 2.92 (95% CI 1.12-7.63)) subgroups. Systolic and diastolic blood pressure were positively associated with REM-AHI ≥20 events·h^-1REM-SDB is highly prevalent in our middle-to-older age sample and is independently associated with metabolic syndrome and diabetes. These findings suggest that an increase in REM-AHI could be clinically relevant.

Comparing REM- and NREM-Related Obstructive Sleep Apnea in Jordan: A Cross-Sectional Study

Obstructive sleep apnea (OSA) is a common disorder that includes an intermittent mechanical obstruction of the upper airway during sleep, which can occur either during rapid eye movement (REM) phase or non-REM (NREM) phase. In this study, we aim to evaluate the differences in demographic and polysomnographic features between REM- and NREM-related OSA in a Jordanian sample, using both the broad and the restricted definitions of REM-related OSA. All patients who were referred due to clinical suspicion of OSA and underwent sleep study were screened. We included patients with a diagnosis of OSA who had Apnea-Hypopnea Index (AHI) greater than or equal to five. We classified patients into REM-related OSA according to either the broad definition (AHI_REM/AHI_NREM ≥ 2) or the strict definition (AHI_REM > 5 and AHI_NREM < 5 with a total REM sleep duration of at least 30 minutes), and patients with AHI_REM/AHI_NREM less than two were classified as NREM-related OSA. A total of 478 patients were included in this study with a mean age of 55.3 years (±12.6). According to the broad definition of REM-related OSA, 86 (18%) of OSA patients were classified as having REM-related OSA compared to only 13 (2.7%) patients according to the strict definition. Significant differences were found between both NREM-related OSA and REM-related OSA according to the broad and to the strict definitions for arousal index (p < 0.001 and p < 0.032), respectively, duration of saturation below 90% (p < 0.001 for both), and saturation nadir (p < 0.036 and p < 0.013), respectively. No significant differences were found between this group and other OSA patients regarding age, BMI, ESS, and snoring. Our study showed that the stricter the definition for REM-related OSA, the milder the associated clinical changes.

Obstructive sleep apnea during rapid eye movement sleep: clinical relevance and therapeutic implications

PURPOSE OF REVIEW

Obstructive sleep apnea (OSA) is a highly prevalent condition that has been associated with cardiovascular morbidity and mortality, impaired glucose metabolism and daytime functional impairment. Compared with nonrapid eye movement sleep, rapid eye movement (REM) sleep is associated with higher sympathetic activity and cardiovascular instability in healthy individuals and more so in patients with OSA.

RECENT FINDINGS

Recent studies have indicated that REM OSA is independently associated with prevalent and incident hypertension, nondipping of nocturnal blood pressure, increased insulin resistance and impairment of human spatial navigational memory.

SUMMARY

These findings have significant clinical implications for the duration of continuous positive airway pressure (CPAP) use that is needed to decrease the health risks associated with OSA. Further research is needed to establish the duration of CPAP needed to effectively treat REM OSA and to evaluate patients with REM OSA with an overall normal apnea-hypopnea index.

Comparison of positional and rapid eye movement-dependent sleep apnea syndromes

AIM

We aimed to compare the clinical, epidemiological, and polysomnographic features of rapid eye movement (REM)-dependent obstructive sleep apnea syndrome (OSAS) and positional OSAS which are two separate clinical entities.

METHODS

Between January 2014 and December 2015, at the Akdeniz University Medical Faculty Hospital, patients who were diagnosed REM-dependent and positional OSAS with polysomnography were retrospectively studied.

RESULTS

In this study, 1727 patients were screened consecutively. Five hundred and eighty-four patients were included in the study. Of the patients, 24.6% (140) were diagnosed with REM-dependent OSAS and 75.4% (444) were diagnosed as positional OSAS. Female predominance was found in REM-dependent OSAS (P < 0.001). The mean total apnea-hypopnea index (AHI), non-REM AHI, and supine AHI in REM-dependent OSAS were 14.73, 9.24, and 17.73, respectively, and these values were significantly lower when compared with positional OSAS (P < 0.001). Patients diagnosed with REM-dependent OSAS had a statistically significant tendency to be overweight (P < 0.001). For REM-dependent OSAS, total pulse rate, supine pulse rate, and REM pulse rate were statistically higher than positional OSAS (P < 0.001).

CONCLUSION

Positional OSAS is a clinical entity that is more common than REM-dependent OSAS. OSAS severity is higher in positional OSAS than REM-dependent OSAS. REM-dependent OSAS is observed more commonly in women.

Long-term adherence to continuous positive airway pressure in patients with rapid eye movement-only obstructive sleep apnea: a prospective cohort study

Background

Obstructive sleep apnea (OSA) during rapid eye movement (REM) sleep is a special form of OSA that occurs predominantly during REM sleep. No study has assessed the long-term adherence to continuous positive airway pressure (CPAP) among patients with REM-only OSA. To objectively assess the long-term adherence to CPAP therapy among patients with REM-predominant (REM-only) OSA.

Methods

This was a prospective observational cohort study that included consecutive patients who were diagnosed with OSA. Patients were divided into the following two groups: (I) REM-only OSA [an apnea hypopnea index (AHI) of ≥5, with a REM-AHI/NREM-AHI of >2, an NREM-AHI of <15, and a minimum of 15 min of REM-sleep duration], and (II) non-stage specific OSA. Follow-up was performed at 1, 6 and 12 months after the initiation of CPAP-therapy.

Results

The study included 175 patients; 30 met the criteria for REM-only OSA, and the remaining patients constituted the non-stage specific OSA group. The number of hours of CPAP use per day was significantly lower in the REM-only OSA group at 1, 6 and 12 months compared to the non-stage specific OSA group. At 12 months, the number of hours used per day was 3.8±1.8 and 5.1±2.1 hours in the REM-only and non-stage specific OSA groups, respectively (P=0.003). Approximately 80% of the enrolled participants in both groups were still using CPAP at the end of the study; 23.3% of REM-only OSA patients met the criteria for good adherence (>4 hours/day), and 56.7% met the criteria for partial adherence.

Conclusions

CPAP adherence is lower among patients with REM-only OSA compared to patients with non-stage specific OSA.

Non-REM sleep-disordered breathing affects performance on the psychomotor vigilance task

PURPOSE

Although many studies have investigated the clinical importance of sleep apnea on rapid eye movement (REM) and non-REM (NREM) sleep, the relationship between behavioral performance and apneic events during different sleep phases remains unclear. In the present study, we sought to investigate the effect of sleep phase fragmentation due to sleep-disordered breathing (SDB) during REM and NREM on the vigilance and sustainability of attention based on psychomotor vigilance task (PVT) performance.

METHODS

From a pool of subjects who underwent consecutive diagnostic polysomnography (PSG) for obstructive sleep apnea, 163 adult subjects with both REM and NREM sleep ≥ 30 min were enrolled for our study and performed a standardized 10-min PVT. The main outcome variables of the PVT were mean reaction time (RT), PVT Lapse count, and the slope of the reciprocal RT. Subjective sleepiness was measured using the Epworth Sleepiness Scale (ESS).

RESULTS

After multivariate linear regression analysis with adjustment for age, sex, body mass index, and the apnea-hypopnea index (AHI) of the counterpart sleep phase, we found that AHI during NREM (AHI_NREM) compared to AHI during REM (AHI_REM) was significantly associated with PVT lapses.

CONCLUSIONS

Our results suggest that SDB during NREM has a significant impact on vigilance lapses compared to that of REM.

The prevalence of REM-related obstructive sleep apnoea is reduced by the AASM 2012 hypopnoea criteria

PURPOSE

The variations in reported prevalence of rapid eye movement-related obstructive sleep apnoea (REM-OSA) have been attributed to different definitions, although the effect of hypopnoea criteria has not been previously investigated.

METHODS

Within this retrospective study, 134 of 382 consecutive patients undertaking polysomnography (PSG) for the suspicion of OSA met the inclusion criteria. PSGs were scored using both the 2007 AASM recommended hypopnoea criteria (AASM_2007Rec) and the 2012 AASM recommended hypopnoea criteria (AASM_2012Rec). For each hypopnoea criteria, REM-OSA patients were grouped as REM-related [either as REM-predominant OSA (rpOSA) or REM-isolated OSA (riOSA)] or non-stage-specific OSA (nssOSA). Outcome measures (SF-36, FOSQ and DASS-21) were also compared between groups.

RESULTS

Incorporation of the AASM_2012Rec criteria compared to the AASM_2007Rec criteria increased the apnoea-hypopnoea index (AHI) for NREM and REM sleep but decreased the AHI_REM/AHI_NREM ratio from 1.9 to 1.3 (p < 0.001). It also decreased the prevalence of riOSA [15.7 vs 2.2% (p < 0.001) for AASM_2007Rec and AASM_2012Rec, respectively]. The prevalence of rpOSA remained the same for each hypopnoea criteria although the prevalence of nssOSA increased with the AASM_2012Rec hypopnoea criteria [53.0 vs 66.4% (p < 0.006) for AASM_2007Rec and AASM_2012Rec, respectively]. There were no differences in clinical symptoms between the groups, irrespective of hypopnoea criteria used.

CONCLUSIONS

This study demonstrates that in comparison with AASM_2007Rec, the AASM_2012Rec hypopnoea criteria reduce the prevalence of riOSA but not rpOSA by reducing the ratio of REM respiratory events and NREM respiratory events.

Associations between cystatin C-based eGFR, ambulatory blood pressure parameters, and in-clinic versus ambulatory blood pressure agreement in older community-living adults

OBJECTIVES

The objective of this study was to determine the relationship between chronic kidney disease [CKD; measured using cystatin C-based estimated glomerular filtration rate (eGFR)] and abnormal ambulatory blood pressure (including nocturnal dipping) in healthy older adults. Further, this study aimed to assess the agreement between clinic and ambulatory blood pressure monitoring.

METHODS

Serum cystatin C levels were measured to calculate eGFR. Participants underwent clinic and 24-h ambulatory blood pressure measurements. Multiple linear regression was performed to examine the association between reduced cystatin C-based eGFR (CKDcys) and blood pressure parameters. Bland-Altman analysis was carried out to evaluate the agreement between clinic and ambulatory measurements.

RESULTS

The average age was 72 years. There were 60 individuals with CKDcys (eGFR<60 ml/min/1.73 m). Compared with those without CKDcys, individuals with CKDcys were older, more likely to have hypertension, and less likely to have normal dipping patterns. On multivariate analysis, the presence of CKDcys was found to be significantly associated with a lower mean ambulatory diastolic blood pressure (-2 mmHg, P=0.048), but not with nocturnal dipping or other blood pressure parameters. Clinic systolic blood pressure (SBP) significantly overestimated the mean wake-time ambulatory SBP; the mean difference was 11 mmHg for those without CKDcys (95% limits of agreement -14 to 35 mmHg) and 14 mmHg for those with CKDcys (95% limits of agreement -13 to 41 mmHg); there was no statistically significant effect modification by CKD status.

CONCLUSION

In older, seemingly healthy adults, mild CKD was associated with lower ambulatory diastolic blood pressure. The presence of CKD did not affect interpretation of clinic versus ambulatory blood pressure monitoring, although the accuracy of clinic SBP was poor.

Phenotypes in obstructive sleep apnea: A definition, examples and evolution of approaches

Obstructive sleep apnea (OSA) is a complex and heterogeneous disorder and the apnea hypopnea index alone can not capture the diverse spectrum of the condition. Enhanced phenotyping can improve prognostication, patient selection for clinical trials, understanding of mechanisms, and personalized treatments. In OSA, multiple condition characteristics have been termed "phenotypes." To help classify patients into relevant prognostic and therapeutic categories, an OSA phenotype can be operationally defined as: "A category of patients with OSA distinguished from others by a single or combination of disease features, in relation to clinically meaningful attributes (symptoms, response to therapy, health outcomes, quality of life)." We review approaches to clinical phenotyping in OSA, citing examples of increasing analytic complexity. Although clinical feature based OSA phenotypes with significant prognostic and treatment implications have been identified (e.g., excessive daytime sleepiness OSA), many current categorizations lack association with meaningful outcomes. Recent work focused on pathophysiologic risk factors for OSA (e.g., arousal threshold, craniofacial morphology, chemoreflex sensitivity) appears to capture heterogeneity in OSA, but requires clinical validation. Lastly, we discuss the use of machine learning as a promising phenotyping strategy that can integrate multiple types of data (genomic, molecular, cellular, clinical) to identify unique, meaningful OSA phenotypes.

Hypertension Is Associated With Undiagnosed OSA During Rapid Eye Movement Sleep

BACKGROUND

Evidence linking OSA with hypertension in population studies is conflicting. We examined longitudinal and cross-sectional associations of previously unrecognized OSA, including OSA occurring in rapid eye movement (REM) sleep, with hypertension.

METHODS

The Men Androgens Inflammation Lifestyle Environment and Stress (MAILES) study is a longitudinal study of community-dwelling men in Adelaide, South Australia. Biomedical assessments at baseline (2002-2006) and follow-up (2007-2010) identified hypertension (systolic ≥ 140 mm Hg and/or diastolic ≥ 90 mm Hg, or medication) and risk factors. In 2010 to 2011, 837 men without a prior diagnosis of OSA underwent full in-home unattended polysomnography of whom 739 recorded ≥ 30 min of REM sleep. Hypertension at follow-up (concomitant with OSA status) was defined as prevalent hypertension. Recent-onset hypertension was defined as hypertension at biomedical follow-up (56 months mean follow-up [range, 48-74]) in men free of hypertension at baseline.

RESULTS

Severe REM OSA (apnea hypopnea index ≥30/h) showed independent adjusted associations with prevalent (OR, 2.40, 95% CI, 1.42-4.06), and recent-onset hypertension (2.24 [1.04-4.81]). Significant associations with non-REM AHI were not seen. In men with AHI < 10, REM OSA (apnea hypopnea index) ≥ 20/h was significantly associated with prevalent hypertension (2.67 [1.33-5.38]) and the relationship with recent-onset hypertension was positive but not statistically significant (2.32 [0.79-6.84]). Similar results were seen when analyses were confined to men with non-REM AHI < 10.

CONCLUSIONS

In men not considered to have OSA (AHI < 10), hypertension was associated with OSA during REM sleep. REM OSA may need consideration as an important clinical entity requiring treatment but further systematic assessment and evidence is needed.

Development of the National Healthy Sleep Awareness Project Sleep Health Surveillance Questions

OBJECTIVES

For the first time ever, as emphasized by inclusion in the Healthy People 2020 goals, sleep health is an emphasis of national health aims. The National Healthy Sleep Awareness Project (NHSAP) was tasked to propose questions for inclusion in the next Behavioral Risk Factor Surveillance System (BRFSS), a survey that includes a number of questions that target behaviors thought to impact health, as a means to measure community sleep health. The total number of questions could not exceed five, and had to include an assessment of the risk for obstructive sleep apnea (OSA).

METHODS

An appointed workgroup met via teleconference and face-to-face venues to develop an inventory of published survey questions being used to identify sleep health, to develop a framework on which to analyze the strengths and weaknesses of current survey questions concerning sleep, and to develop recommendations for sleep health and disease surveillance questions going forward.

RESULTS

The recommendation was to focus on certain existing BRFSS questions pertaining to sleep duration, quality, satisfaction, daytime alertness, and to add to these other BRFSS existing questions to make a modified STOP-BANG questionnaire (minus the N for neck circumference) to assess for risk of OSA.

CONCLUSIONS

Sleep health is an important dimension of health that has previously received less attention in national health surveys. We believe that 5 questions recommended for the upcoming BRFSS question banks will assist as important measures of sleep health, and may help to evaluate the effectiveness of interventions to improve sleep health in our nation.

Obstructive sleep apnoea during REM sleep and incident non-dipping of nocturnal blood pressure: a longitudinal analysis of the Wisconsin Sleep Cohort

BACKGROUND

Non-dipping of nocturnal blood pressure (BP) is associated with target organ damage and cardiovascular disease. Obstructive sleep apnoea (OSA) is associated with incident non-dipping. However, the relationship between disordered breathing during rapid eye movement (REM) sleep and the risk of developing non-dipping has not been examined. This study investigates whether OSA during REM sleep is associated with incident non-dipping.

METHODS

Our sample included 269 adults enrolled in the Wisconsin Sleep Cohort Study who completed two or more 24 h ambulatory BP studies over an average of 6.6 years of follow-up. After excluding participants with prevalent non-dipping BP or antihypertensive use at baseline, there were 199 and 215 participants available for longitudinal analysis of systolic and diastolic non-dipping, respectively. OSA in REM and non-REM sleep were defined by apnoea hypopnoea index (AHI) from baseline in-laboratory polysomnograms. Systolic and diastolic non-dipping were defined by systolic and diastolic sleep/wake BP ratios >0.9. Modified Poisson regression models estimated the relative risks for the relationship between REM AHI and incident non-dipping, adjusting for non-REM AHI and other covariates.

RESULTS

There was a dose-response greater risk of developing systolic and diastolic non-dipping BP with greater severity of OSA in REM sleep (p-trend=0.021 for systolic and 0.024 for diastolic non-dipping). Relative to those with REM AHI<1 event/h, those with REM AHI≥15 had higher relative risk of incident systolic non-dipping (2.84, 95% CI 1.10 to 7.29) and incident diastolic non-dipping (4.27, 95% CI 1.20 to 15.13).

CONCLUSIONS

Our findings indicate that in a population-based sample, REM OSA is independently associated with incident non-dipping of BP.

Clinical effectiveness and cost-effectiveness results from the randomised controlled Trial of Oral Mandibular Advancement Devices for Obstructive sleep apnoea-hypopnoea (TOMADO) and long-term economic analysis of oral devices and continuous positive airway pressure

BACKGROUND

Obstructive sleep apnoea-hypopnoea (OSAH) causes excessive daytime sleepiness (EDS), impairs quality of life (QoL) and increases cardiovascular disease and road traffic accident risks. Continuous positive airway pressure (CPAP) treatment is clinically effective but undermined by intolerance, and its cost-effectiveness is borderline in milder cases. Mandibular advancement devices (MADs) are another option, but evidence is lacking regarding their clinical effectiveness and cost-effectiveness in milder disease.

OBJECTIVES

(1) Conduct a randomised controlled trial (RCT) examining the clinical effectiveness and cost-effectiveness of MADs against no treatment in mild to moderate OSAH. (2) Update systematic reviews and an existing health economic decision model with data from the Trial of Oral Mandibular Advancement Devices for Obstructive sleep apnoea-hypopnoea (TOMADO) and newly published results to better inform long-term clinical effectiveness and cost-effectiveness of MADs and CPAP in mild to moderate OSAH.

TOMADO

A crossover RCT comparing clinical effectiveness and cost-effectiveness of three MADs: self-moulded [SleepPro 1™ (SP1); Meditas Ltd, Winchester, UK]; semibespoke [SleepPro 2™ (SP2); Meditas Ltd, Winchester, UK]; and fully bespoke [bespoke MAD (bMAD); NHS Oral-Maxillofacial Laboratory, Addenbrooke's Hospital, Cambridge, UK] against no treatment, in 90 adults with mild to moderate OSAH. All devices improved primary outcome [apnoea-hypopnoea index (AHI)] compared with no treatment: relative risk 0.74 [95% confidence interval (CI) 0.62 to 0.89] for SP1; relative risk 0.67 (95% CI 0.59 to 0.76) for SP2; and relative risk 0.64 (95% CI 0.55 to 0.76) for bMAD (p < 0.001). Differences between MADs were not significant. Sleepiness [as measured by the Epworth Sleepiness Scale (ESS)] was scored 1.51 [95% CI 0.73 to 2.29 (SP1)] to 2.37 [95% CI 1.53 to 3.22 (bMAD)] lower than no treatment (p < 0.001), with SP2 and bMAD significantly better than SP1. All MADs improved disease-specific QoL. Compliance was lower for SP1, which was unpopular at trial exit. At 4 weeks, all devices were cost-effective at £20,000/quality-adjusted life-year (QALY), with SP2 the best value below £39,800/QALY.

META-ANALYSIS

A MEDLINE, EMBASE and Science Citation Index search updating two existing systematic reviews (one from November 2006 and the other from June 2008) to August 2013 identified 77 RCTs in adult OSAH patients comparing MAD with conservative management (CM), MADs with CPAP or CPAP with CM. MADs and CPAP significantly improved AHI [MAD -9.3/hour (p < 0.001); CPAP -25.4/hour (p < 0.001)]. Effect difference between CPAP and MADs was 7.0/hour (p < 0.001), favouring CPAP. No trials compared CPAP with MADs in mild OSAH. MAD and CPAP reduced the ESS score similarly [MAD 1.6 (p < 0.001); CPAP 1.6 (p < 0.001)].

LONG-TERM COST-EFFECTIVENESS

An existing model assessed lifetime cost-utility of MAD and CPAP in mild to moderate OSAH, using the revised meta-analysis to update input values. The TOMADO provided utility estimates, mapping ESS score to European Quality of Life-5 Dimensions three-level version for device cost-utility. Using SP2 as the standard device, MADs produced higher mean costs and mean QALYs than CM [incremental cost-effectiveness ratio (ICER) £6687/QALY]. From a willingness to pay (WTP) of £15,367/QALY, CPAP is cost-effective, although the likelihood of MADs (p = 0.48) and CPAP (p = 0.49) being cost-effective is very similar. Both were better than CM, but there was much uncertainty in the choice between CPAP and MAD (at a WTP £20,000/QALY, the probability of being the most cost-effective was 47% for MAD and 52% for CPAP). When SP2 lifespan increased to 18 months, the ICER for CPAP compared with MAD became £44,066. The ICER for SP1 compared with CM was £1552, and for bMAD compared with CM the ICER was £13,836. The ICER for CPAP compared with SP1 was £89,182, but CPAP produced lower mean costs and higher mean QALYs than bMAD. Differential compliance rates for CPAP reduces cost-effectiveness so MADs become less costly and more clinically effective with CPAP compliance 90% of SP2.

CONCLUSIONS

Mandibular advancement devices are clinically effective and cost-effective in mild to moderate OSAH. A semi-bespoke MAD is the appropriate first choice in most patients in the short term. Future work should explore whether or not adjustable MADs give additional clinical and cost benefits. Further data on longer-term cardiovascular risk and its risk factors would reduce uncertainty in the health economic model and improve precision of effectiveness estimates.

TRIAL REGISTRATION

This trial is registered as ISRCTN02309506.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 18, No. 67. See the NIHR Journals Library website for further project information.

On the cutting edge of obstructive sleep apnoea: where next?

Obstructive sleep apnoea is a common disease that is now more widely recognised because of the rise in prevalence and the increasingly compelling data that shows major neurocognitive and cardiovascular sequelae. At the same time, the clinical practice of sleep medicine is changing rapidly, with novel diagnostics and treatments that have established a home-based (rather than laboratory-based) management approach. We review the most recent insights and discoveries in obstructive sleep apnoea, with a focus on diagnostics and therapeutics. As will be discussed, management of obstructive sleep apnoea could soon transition from a so-called one size fits all approach to an individualised approach.

Obstructive sleep apnea during REM sleep and hypertension. results of the Wisconsin Sleep Cohort

RATIONALE

Obstructive sleep apnea (OSA) is associated with hypertension.

OBJECTIVES

We aimed to quantify the independent association of OSA during REM sleep with prevalent and incident hypertension.

METHODS

We included adults enrolled in the longitudinal community-based Wisconsin Sleep Cohort Study with at least 30 minutes of REM sleep obtained from overnight in-laboratory polysomnography. Studies were repeated at 4-year intervals to quantify OSA. Repeated measures logistic regression models were fitted to explore the association between REM sleep OSA and prevalent hypertension in the entire cohort (n = 4,385 sleep studies on 1,451 individuals) and additionally in a subset with ambulatory blood pressure data (n = 1,085 sleep studies on 742 individuals). Conditional logistic regression models were fitted to longitudinally explore the association between REM OSA and development of hypertension. All models controlled for OSA events during non-REM sleep, either by statistical adjustment or by stratification.

MEASUREMENTS AND MAIN RESULTS

Fully adjusted models demonstrated significant dose-relationships between REM apnea-hypopnea index (AHI) and prevalent hypertension. The higher relative odds of prevalent hypertension were most evident with REM AHI greater than or equal to 15. In individuals with non-REM AHI less than or equal to 5, a twofold increase in REM AHI was associated with 24% higher odds of hypertension (odds ratio, 1.24; 95% confidence interval, 1.08-1.41). Longitudinal analysis revealed a significant association between REM AHI categories and the development of hypertension (P trend = 0.017). Non-REM AHI was not a significant predictor of hypertension in any of the models.

CONCLUSIONS

Our findings indicate that REM OSA is cross-sectionally and longitudinally associated with hypertension. This is clinically relevant because treatment of OSA is often limited to the first half of the sleep period leaving most of REM sleep untreated.

Relationship of heart rate variability to sleepiness in patients with obstructive sleep apnea with and without heart failure

BACKGROUND

Many patients with severe obstructive sleep apnea (OSA) do not complain of excessive daytime sleepiness (EDS), possibly due to increased sympathetic nervous activity (SNA) and accompanying heightened alertness. We hypothesized that in patients with OSA, those without subjective EDS (Epworth Sleepiness Scale, ESS score < 11) would have higher very low frequency (VLF) heart rate variability (HRV) during sleep, reflecting greater sympathetic heart rate modulation than patients with an ESS score ≥ 11.

METHODS

Patients with severe OSA (AHI ≥ 30: 26 with and 65 without heart failure) were divided into those with and without EDS. Heart rate (HR) signals were acquired in stage 2 sleep during periods of recurrent apneas and hypopneas and submitted to coarse graining spectral analysis, which extracts harmonic, neurally mediated contributions to HRV from total spectral power. Because the apnea-hyperpnea cycle entrains muscle SNA at VLF (0 to 0.04 Hz), VLF power was our principal between-group comparison.

RESULTS

Subjects without EDS had higher harmonic VLF power (944 ± 839 vs 447 ± 461 msec(2), p = 0.003) than those with EDS, irrespective of the presence or absence of heart failure (1218 ± 944 vs 426 ± 299 msec(2), p = 0.043, and 1029 ± 873 vs 503 ± 533 msec(2), p = 0.003, respectively). ESS scores correlated inversely with VLF power in all (r = -0.294, p = 0.005) and in heart failure subjects (r = -0.468, p = 0.016).

CONCLUSIONS

Patients with severe OSA but without EDS have higher VLF-HRV than those with EDS. This finding suggests that patients with severe OSA but without EDS have greater sympathetic modulation of HRV than those with EDS that may reflect elevated adrenergically mediated alertness.

CITATION

Taranto Montemurro L; Floras JS; Picton P; Kasai T; Alshaer H; Gabriel JM; Bradley TD. Relationship of heart rate variability to sleepiness in patients with obstructive sleep apnea with and without heart failure.