Interaction Between Slow Wave Sleep and Obstructive Sleep Apnea in Prevalent Hypertension

A Systematic Review of Sleep Disturbance in Idiopathic Intracranial Hypertension

Purpose of Review

Sleep disturbances, particularly obstructive sleep apnea (OSA), may have a significant impact on the outcomes of patients with idiopathic intracranial hypertension (IIH). We conducted a PRISMA-compliant systematic literature review to study sleep disturbance in adult patients with IIH.

Recent Findings

The current literature on the relationship between IIH and sleep is quite limited. Research has found that sleep disturbances are associated with lower quality of life and may worsen several symptoms associated with IIH, such as headache, cognitive deficits, and neuropsychiatric issues.

Summary

OSA was more prevalent in patients with IIH than in healthy controls. Several studies found that OSA was associated with worse IIH symptoms and treatment of OSA helped improve these parameters. Limitations included available literature and heterogeneity in sleep metrics and OSA diagnostic criteria between studies. Overall, further study of sleep disturbances in patients with IIH may encourage earlier screening, improved treatment options, and long-term improvements in quality of life.

The pulse of sleep: novel interventions in understanding the sleep-cardiovascular connection: a literature review

Introduction

Sleep disorders represent common complaints in different medical illnesses. They encompass a risk for diverse inflammatory, metabolic, and cardiovascular diseases. Sleep disorders include disorders of hypersomnolence, insomnia, parasomnias, sleep-related movement disorders, circadian rhythm sleep-wake-disorders, and sleep-related breathing disorders, each one of which was associated with increased cardiovascular disease risk in a different mechanism. In this review, the authors address the most recent research on the correlation between sleep and CVD.

Methods

The literature on sleep disorders and their potential links to various cardiovascular diseases was reviewed in narrative form. For the published papers up to June 2023, the authors searched the databases of PubMed and Google Scholar. Literature demonstrating the relationship between these illnesses, pathophysiological mechanisms, diagnosis, and various therapeutic approaches was included.

Results

Sleep disorders were significantly linked to heart rate variability, hypertension, and obesity, which can eventually result in cardiovascular consequences and affect mortality and morbidity. The disruption in sleep cycles, which can be noticed in different sleep disorders, can obviously result in blood pressure, heart rate, and other cardiac functions. The clinical assessment acts as the cornerstone in the diagnosis of different spectrums of sleep disorders. The management of sleep disorders ranges from cognitive-behavioral therapy to continuous positive airway pressure (CPAP).

Conclusion

Additional research on the topic is needed to pinpoint any potential links and pathological processes. To improve clinical treatment and preventive measures, further observational studies should emphasize the reliability of early diagnostic signs.

Symptom and comorbidity burden in hypertensive patients with obstructive sleep apnea

Background

Obstructive sleep apnea (OSA) is an important but frequently overlooked risk factor for hypertension (HTN). The prevalence of hypertension is high in patients with OSA, but the differences in clinical symptoms and comorbidities between patients with OSA with hypertension and those with normal blood pressure have not been fully defined.

Methods

This study retrospectively analyzed OSA patients diagnosed for the first time in Lihuili Hospital Affiliated to Ningbo University from 2016 to 2020. Patients were divided into an OSA group with hypertension and an OSA group without hypertension. The sociodemographic information, clinical symptoms, comorbidities, and polysomnography results of the two groups were compared. The independent risk factors associated with hypertension in patients with OSA were explored.

Results

A total of 1108 patients with OSA initially diagnosed were included in the study, including 387 with hypertension and 721 without. Compared with OSA patients without hypertension, OSA patients with hypertension were older; had a higher body mass index (BMI) and Epworth sleepiness score (ESS); a higher incidence of nocturia; and a higher proportion of diabetes mellitus, coronary heart disease, and cerebrovascular disease. Multivariate analysis showed age (odds ratio [OR]:1.06, 95% confidence interval [CI]:1.04-1.08), BMI (OR:1.17, 95% CI:1.11-1.23), ESS score (OR:0.97, 95%CI: 0.94-1.00) and nocturia symptoms (OR:1.64, 95% CI:1.19-2.27) was independently associated with hypertension in OSA patients, and comorbid diabetes (OR: 3.86, 95% CI: 2.31-6.45), coronary heart disease (OR: 1.90, 95% CI:1.15-3.16), and ischemic stroke (OR: 3.69,95% CI:1.31-10.40) was independently associated with hypertension in OSA patients.

Conclusion

Compared to OSA patients with normal blood pressure, OSA patients with hypertension had more significant daytime sleepiness, more frequent nocturnal urination, and a higher risk of diabetes, coronary heart disease, and cerebrovascular disease.

Relationship between ODI and sleep structure of obstructive sleep apnea and cardiac remodeling

PURPOSE

The purpose of the study was to evaluate the quantitative relationship between Oxygen Desaturation Index (ODI) and sleep structure of obstructive sleep apnea (OSA) and cardiac remodeling.

METHODS

In this study, patients were enrolled from January 2015 to October 2022, and were divided into 3 groups according to AHI: patients with AHI < 15, patients with 15 ≤ AHI < 30, and 260 patients with AHI ≥ 30. Stratified linear regression was used to analyze independent risk factors for cardiac remodeling in OSA.

RESULTS

A total of 479 patients were enrolled. We found that compared with AHI < 15 group (n = 120), the group with AHI > 30 (n = 260) had increased left atrial anteroposterior diameter, left ventricular end-diastolic internal diameter, left ventricular posterior wall thickness, right ventricular anteroposterior diameter, and interventricular septal thickness (P < 0.05). The group with 15 ≤ AHI ≤ 30 (n = 99) had increased left atrial anteroposterior diameter (P < 0.05). Multivariate linear regression revealed that N2 sleep was an independent risk factor for left ventricular posterior wall thickness, with positive correlation (p < 0.05). N3 sleep was an independent risk factor for transverse right atrial diameter and right ventricular anteroposterior diameter, with negative correlation (P < 0.05). ODI was an independent risk factor for interventricular septal thickness, with positive correlation (P < 0.05). The arousal index was an independent risk factor for increased left atrial anteroposterior diameter, with positive correlation (P < 0.05).

CONCLUSIONS

Increased ODI is an independent risk factor for interventricular septal thickness, while decreased slow wave sleep is an independent risk factor for right heart remodeling in OSA.

Obstructive sleep apnea: Beyond the dogma of obesity!

Obstructive sleep apnea (OSA) has long been studied in patients with obesity and type 2 diabetes mellitus (T2DM), due to the fact that both disorders are commonly associated with an increased body mass index (BMI). However, a link between OSA and non-obese diabetic patients is still not very elaborated, nor heavily explored. In this review, we elucidate some proposed mechanisms for the link between OSA and diabetic patients both with and beyond obesity, shedding the light on the latter case. One such mechanism is oxidative stress, a phenomenon of reactive oxygen species (ROS) imbalance seen in both of the previously mentioned disorders. A plausible explanation for the OSA-induced ROS production is the repeating episodes of hypoxia and reperfusion and their effect on the mitochondrial electron transport chain. This paper explores the literature regarding ROS imbalance as the possible missing link between OSA and Diabetes Mellitus beyond obesity, while still mentioning other possible proposed mechanisms such as a dysregulated autonomic nervous system (ANS), as well as mechanical and craniofacial abnormalities. This paper also suggests a link between OSA and diabetic complications, while exploring the clinical progress made in treating the former disorder with anti-oxidant and hypo-glycemic drugs. If further investigated, these findings could help identify novel therapeutic interventions for the treatment of OSA and Diabetic patients.

The Relationship Between Slow Wave Sleep and Blood Oxygen Saturation Among Patients With Apnea: Retrospective Study

Background and Objective Prior research suggests that slow wave sleep (SWS) is disrupted in people with obstructive sleep apnea (OSA). However, it was not clear whether the reduction in SWS is related to abnormal breathing or the extent of OSA as determined by the minimum oxygen saturation. Further, there is limited research on the relationship between oxygen saturation and SWS. The present study examined the relationship between SWS and minimum oxygen saturation levels in patients with OSA.Methods The sample consisted of 589 patients with OSA (mean age: 48.54 years) who completed full-night polysomnography.Results Results showed that there was a significant difference in SWS scores across three apnea-hypopnea index (AHI) groups (AHI score 5–15 for mild apnea, 16–30 for moderate apnea, and >30 for severe apnea). Lower SWS scores were observed in the severe apnea group. Additionally, results indicated that as oxygen saturation decreased, the SWS scores decreased.Conclusions Results from this study indicate that oxygen saturation significantly predicts SWS amounts. These findings suggest that interventions for low oxygen saturation could enhance the amounts of SWS. The clinical ramifications of these findings are worthy of consideration.

Comorbidity Profile and Predictors of Obstructive Sleep Apnea Severity and Mortality in Non-Obese Obstructive Sleep Apnea Patients

Backgrounds and Objectives: Obstructive sleep apnea (OSA) is associated with increased morbidity and mortality. OSA is an independent risk factor for many different conditions, especially cardiovascular diseases. The purpose of this study was to ascertain the comorbidity profile of non-obese patients with newly diagnosed OSA and evaluate the risk for cardiovascular disease and mortality. The present study also aimed to establish predictors for OSA severity. Materials and Methods: This study included 138 newly diagnosed patients who underwent polysomnographic analysis. The 10-year risk for cardiovascular disease was assessed using a newly validated prediction model: Systematic Coronary Risk Evaluation (SCORE-2). In addition, the Charlson Comorbidity Index (CCI) was assessed as a widely-used example of a mortality comorbidity index. Results: The study population included 138 patients: 86 males and 52 females. Patients were stratified, according to AHI (apnea/hypopnea index), into four groups: 33 patients had mild OSA (5 ≤ AHI < 15), 33 patients had moderate OSA (15 ≤ AHI < 30), 31 patients had severe OSA (AHI ≥ 30), and 41 individuals had AHI < 5, which were a part of the control group. SCORE-2 increased in line with OSA severity and was higher in OSA groups compared to the control group (H = 29.913; DF = 3; p < 0.001). Charlson Index was significantly higher in OSA patients compared to controls (p = 0.001), with a higher prevalence of total comorbidities in the OSA group of patients. Furthermore, CCI 10-year survival score was significantly lower in the OSA group, suggesting a shorter survival of those patients with a more severe form of OSA. We also examined the prediction model for OSA severity. Conclusions: Determining the comorbidity profile and estimation of the 10-year risk score of OSA patients could be used to classify these patients into various mortality risk categories and, according to that, provide them with adequate treatment.

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.

Effectiveness and safety of (adeno) tonsillectomy for pediatric obstructive sleep apnea in different age groups: A systematic review and meta-analysis

This meta-analysis aimed to assess the effectiveness and safety of (adeno)tonsillectomy (AT) for uncomplicated pediatric obstructive sleep apnea (OSA) across different age groups. Four electronic databases were searched until April 2022, and 93 studies (9087 participants) were selected, including before-after studies, cohort studies, and randomized controlled trials. It has been suggested that age, disease severity, and length of follow-up are associated with surgical effects. Compared with older children (>7 years), patients receiving AT surgery before the age of 7 exhibited a significantly greater release of disease severity, as well as a greater decrease in hypoxemic burden, improvement in sleep quality, and better cardiovascular function. Cognitive/behavioral performance also improved after AT, although it was more related to the length of follow-up than the age at surgery. Notably, the surgical complication rate was considerably higher in patients younger than 3 years old. Overall, we suggest that the age of 3-7 years might be optimal for AT in polysomnography-diagnosed uncomplicated OSA to maximize potential benefits for both disease and comorbidities and balance the risks of surgery.

The long-term and short-term effects of ambient air pollutants on sleep characteristics in the Chinese population: big data analysis from real world by sleep records of consumer wearable devices

Several studies on long-term air pollution exposure and sleep have reported inconsistent results. Large-scale studies on short-term air pollution exposures and sleep have not been conducted. We investigated the associations of long- and short-term exposure to ambient air pollutants with sleep in a Chinese population based on over 1 million nights of sleep data from consumer wearable devices. Air pollution data including particulate matter (PM2.5, PM10), nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO), and ozone (O3) were collected from the Ministry of Ecology and Environment. Short-term exposure was defined as a moving average of the exposure level for different lag days from Lag0 to Lag0-6. A 365-day moving average of air pollution was regarded as long-term exposure. Sleep data were recorded using wearable devices from 2017 to 2019. The mixed-effects model was used to evaluate the associations. We observed that sleep parameters were associated with long-term exposure to all air pollutants. Higher levels of air pollutant concentrations were associated with longer total sleep and light sleep duration, shorter deep sleep duration, and decreases in wake after sleep onset (WASO), with stronger associations of exposures to NO2 and CO [a 1-interquartile range (IQR) increased NO2 (10.3 μg/m3) was associated with 8.7 min (95% CI: 8.08 to 9.32) longer sleep duration, a 1-IQR increased CO (0.3 mg/m3) was associated with 5.0 min (95% CI: - 5.13 to - 4.89) shorter deep sleep duration, 7.7 min (95% CI: 7.46 to 7.85) longer light sleep duration, and 0.5% (95% CI: - 0.5 to - 0.4%) lower proportion of WASO duration to total sleep]. The cumulative effect of short-term exposure on Lag0-6 is similar to long-term exposure but relatively less. Subgroup analyses indicated generally greater effects on individuals who were female, younger (< 45 years), slept longer (≥ 7 h), and during cold seasons, but the pattern of effects was mixed. We supplemented two additional types of stratified analyses to reduce repeated measures of outcomes and exposures while accounting for individual variation. The results were consistent with the overall results, proving the robustness of the overall results. In summary, both short- and long-term exposure to air pollution affect sleep, and the effects are comparable. Although people tend to have prolonged total sleep duration with increasing air pollutant concentrations, their sleep quality might remain poor because of the reduction in deep sleep.

The association between sleep architecture, quality of life, and hypertension in patients with obstructive sleep apnea

OBJECTIVE

The aim of this study was to investigate the association between hypertension and overnight polysomnography measures of sleep duration, sleep architecture, and quality of life (QoL) in patients with obstructive sleep apnea (OSA).

METHODS

Participants were patients suspected of having OSA with or without hypertension. All patients underwent overnight polysomnography and completed the Epworth Sleepiness Scale (ESS), Self-Rating Anxiety Scale, Self-Rating Depression Scale, and 12-item Short-Form Health Survey.

RESULTS

Of 128 patients (mean age 46.2 ± 12.5 years), 53% had hypertension. The average total sleep duration was 344 min (standard deviation 90) or 5.7 h and sleep efficiency was < 70%. There was no significant difference between patients with OSA with/without hypertension in total sleep duration, sleep architecture, anxiety, depression, ESS scores, or QoL. In patients with OSA, nocturnal minimum oxygen saturation was significantly negatively correlated with bodily pain and physical component summary (PCS) scores; mean nocturnal saturation was negatively correlated with bodily pain and social function; anxiety showed a significant negative correlation with role emotional; and depression was significantly negatively correlated with physical function, role physical, general health, role emotional, PCS, and mental component summary (MCS) scores. In the group with OSA and hypertension, N3 duration was negatively correlated with social function, mental health, and MCS scores. Anxiety was significantly negatively correlated with physical function, role physical, vitality, mental health, role emotional, PCS, and MCS scores. Depression was significantly negatively correlated with physical function, role physical, vitality, mental health, role emotional, PCS, and MCS scores. In patients with mild, moderate, and severe OSA, QoL was associated with depression. In mild OSA, PCS was correlated with ESS and anxiety. In moderate OSA, MCS was correlated with apnea-hypopnea index scores. In severe OSA, MCS and PCS were correlated with anxiety.

CONCLUSIONS

There were no significant associations between the presence of hypertension and total sleep duration, sleep architecture, or QoL in patients with OSA. However, hypertension may affect the influencing factors of QoL in patients with OSA. Further cohort studies are needed to confirm these findings.

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.

Association Between Sleep Efficiency and Hypertension in Chinese Obstructive Sleep Apnea Patients

Objective

We aimed to explore the relationship of sleep efficiency (SE) with the prevalence of hypertension in Chinese obstructive sleep apnea (OSA) patients based on polysomnography (PSG) records.

Methods

We studied 2360 patients with OSA and 764 primary snorers who underwent PSG in our hospital. SE was divided into three grades, including ≥85%, 80%~84.9%, and <80%. Hypertension was defined based either on direct blood pressure measurements, under anti-hypertensive treatments or on physician diagnosis. Multivariate logistic regression models were conducted to investigate the association between SE and hypertension.

Results

After adjusting for potential confounding factors, OSA patients with <80% SE and those with 80% to 84.9% SE were significantly associated with the prevalence of hypertension (OR = 1.248, 95% CI 1.018~1.531, P=0.033; OR = 1.380, 95% CI 1.040~1.832, P=0.026). Compared to primary snorers, OSA combined with <85% SE increased the odds of hypertension. In stratified analysis by SE, risk of hypertension only in those with <80% SE was significantly different between OSA and primary snorers. Furthermore, this relationship between reduced SE and hypertension was evident especially in female, younger ages, obese, moderate and severe OSA patients. No significant relationship between reduced SE and hypertension was found in primary snores group.

Conclusion

We found that poor SE was correlated with the prevalence of hypertension in Chinese OSA patients, but not in those with primary snoring. Moreover, this relationship was evident especially in female, younger ages, obese, moderate and severe OSA patients.

Distinct phenotypic clusters of sleep‐disordered breathing and their association with medical care‐seeking behaviour and sleep habits: the Guangdong Sleep Health Study

Sleep-disordered breathing (SDB) is highly prevalent, but its rates of diagnosis and treatment are low. As a heterogeneous condition, it is associated with delayed diagnosis and/or suboptimal treatment. We aimed to determine distinct SDB clusters and examine their association with medical care-seeking behaviour and sleep habits in a community-dwelling population in South China. Participants were enrolled in the 'Guangdong Sleep Health Study'. Five distinct community sites were investigated. Participant information was collected, and overnight sleep monitoring was performed. Latent class analysis was performed to classify patients with SDB based on patterns of SDB-related symptoms and signs. Overall, 1,524 patients with SDB were evaluated. Four distinct clusters were identified: 'minimally symptomatic' (Cluster 2), which was the most dominant subtype (41.6%), followed by 'pure insomnia/fewer daytime symptoms' (Cluster 4; 24.7%), 'insomnia/multiple daytime symptoms' (Cluster 3; 17.8%), and 'upper airway symptoms with sleepiness' (Cluster 1; 15.9%). The overall medical care-seeking rate attributable to sleep and breathing disorders was only 3.3%: 10.3% in Cluster 3, 2.5% in Cluster 1, 2.1% in Cluster 4, and 1.3% in Cluster 2, in which Cluster 3 was the highest and Cluster 2 was the lowest (adjusted p < 0.05). Regarding the sleep habit of going to bed and waking up at a consistent time, Cluster 3 exhibited the worst performance and Cluster 2 the best. In conclusion, distinct phenotypic subtypes were identified in community-dwelling patients with SDB. Tailored strategies to encourage medical care-seeking, early identification, and optimisation of treatment are necessary considering the different subtypes.

Associations between common sleep disturbances and cardiovascular risk in patients with obstructive sleep apnea: A large-scale cross-sectional study

Objectives

Studies have shown that obstructive sleep apnea (OSA) is inextricably linked with cardiovascular diseases (CVD). However, the roles of certain common sleep disturbances, such as low slow-wave sleep, excessive daytime sleepiness and short sleep duration, in the pathogenesis and progression of CVD in patients with OSA have not been determined. Therefore, we conducted a large cross-sectional study to explore the effect of low slow-wave sleep, excessive daytime sleepiness and short sleep duration on the risk of CVD in patients with OSA.

Methods

Subjects were consecutively enrolled to participate in the sleep center of Shanghai Jiao Tong University Affiliated Sixth People’s Hospital. All OSA patients were diagnosed by standard polysomnography, while controls were all simple snorers. A total of 4,475 participants were strictly recruited. The Framingham Risk Score were employed to assess the 10-year risk of CVD, and logistic regression was used to measure the association between sleep disturbances and the moderate-to-high CVD risk.

Results

In the whole cohort, OSA, excessive daytime sleepiness, and low slow-wave sleep were all risk factors for the moderate-to-high 10-year CVD risk (odds ratio [OR] = 3.012, 95% confidence interval [CI] 2.418–3.751; OR = 1.407, 95% CI: 1.228–1.613, and OR = 0.973,95% CI: 0.967–0.980), but sleep duration did not contribute significantly to that risk. Whether in patients with OSA and controls, low SWS (<12.8%) could increase the risk of CVD. Subjective excessive daytime sleepiness would significantly increase the risk of CVD only in patients with severe OSA.

Conclusion

It is important to pay more attention to the impact of sleep on cardiovascular health. Patients with sleep disturbances should adopt a healthy lifestyle and undergo regular follow-up of cardiovascular indicators to prevent cardiovascular complications.

Trial registration

[http://www.chictr.org.cn/showproj.aspx?proj=43057], identifier [ChiCTr1900025714].

An Attention-Guided Spatiotemporal Graph Convolutional Network for Sleep Stage Classification

Sleep staging has been widely used as an approach in sleep diagnoses at sleep clinics. Graph neural network (GNN)-based methods have been extensively applied for automatic sleep stage classifications with significant results. However, the existing GNN-based methods rely on a static adjacency matrix to capture the features of the different electroencephalogram (EEG) channels, which cannot grasp the information of each electrode. Meanwhile, these methods ignore the importance of spatiotemporal relations in classifying sleep stages. In this work, we propose a combination of a dynamic and static spatiotemporal graph convolutional network (ST-GCN) with inter-temporal attention blocks to overcome two shortcomings. The proposed method consists of a GCN with a CNN that takes into account the intra-frame dependency of each electrode in the brain region to extract spatial and temporal features separately. In addition, the attention block was used to capture the long-range dependencies between the different electrodes in the brain region, which helps the model to classify the dynamics of each sleep stage more accurately. In our experiments, we used the sleep-EDF and the subgroup III of the ISRUC-SLEEP dataset to compare with the most current methods. The results show that our method performs better in accuracy from 4.6% to 5.3%, in Kappa from 0.06 to 0.07, and in macro-F score from 4.9% to 5.7%. The proposed method has the potential to be an effective tool for improving sleep disorders.

[A long-term ischemic stroke risk score model in patients aged 60 years and older with obstructive sleep apnea: a multicenter prospective cohort study]

OBJECTIVE

To analyze the independent risk factors of long-term ischemic stroke and establish a nomogram for predicting the long-term risks in elderly patients with obstructive sleep apnea (OSA).

METHODS

This multicenter prospective cohort study was conducted from January, 2015 to October, 2017 among consecutive elderly patients (≥60 years) with newly diagnosed OSA without a history of cardio-cerebrovascular diseases and loss of important clinical indicators. The follow-up outcome was the occurrence of ischemic stroke. The baseline demographic and clinical data, sleep parameters, laboratory and ultrasound results were collected from all the patients, who were randomized into the modeling group (n=856) and validation group (n=258) at a 3∶1 ratio. LASSO regression was used for variable reduction and dimension screening, and the risk score prediction model of ischemic stroke was established based on Cox proportional hazard regression.

RESULTS

In the total of 1141 patients enrolled in this study, 58 (5.08%) patients experienced ischemic stroke during the median follow-up of 42 months (range 41-54 months). The cumulative incidence of ischemic stroke was 5.14% in the model group and 4.91% in the verification group (P < 0.05). Age (HR=3.44, 95% CI: 2.38- 7.77), fasting blood glucose (FPG) (HR=2.13, 95% CI: 1.22-3.72), internal diameter of the ascending aorta (HR=2.60, 95% CI: 1.0- 4.47), left atrial anteroposterior diameter (HR=1.98, 95% CI: 1.75-2.25) and minimum oxygen saturation (LSpO₂) (HR=1.57, 95% CI: 1.20-1.93) were identified as independent risk factors for ischemic stroke (P < 0.05 or 0.01). A long-term ischemic stroke risk score model was constructed based the regression coefficient ratios of these 5 risk variables. Before and after the application of the Bootstrap method, the AUC of the cohort risk score model was 0.84 (95% CI: 0.78- 0.90) and 0.85 (95% CI: 0.78- 0.89) in the model group and was 0.83 (95% CI: 0.73-0.93) and 0.82 (95%CI: 0.72-0.90) in the verification group, respectively, suggesting a good prediction efficiency and high robustness of the model. At the best clinical cutoff point, the cumulative incidence of ischemic stroke was significantly higher in the high-risk group than in the low-risk group (P=0.021).

CONCLUSION

This model can help to identify high-risk OSA patients for early interventions of the risks of ischemic stroke associated with OSA.

Cardiorespiratory Fitness May Protect Memory for Poorer Sleepers

OBJECTIVES

Physical activity has been shown to protect executive functions against the deleterious effects of poorer sleep among older adults (OA); however, it is unknown whether memory is protected too, and if this relationship differs by age. The present study investigated the relationship between cardiorespiratory fitness, sleep, and memory in both older and young adults (YA).

METHODS

This observational study recruited 26 OA (70.7 ± 2.8 years) and 35 YA (21.0 ± 3.1 years). Participants completed the Rockport 1-mile walk test to evaluate cardiorespiratory fitness. Participants wore an actigraph for 1 week to measure habitual sleep and returned for a second visit to perform the memory tests. The interaction between cardiorespiratory fitness and sleep to predict memory was assessed separately in OA and YA.

RESULTS

In OA, cardiorespiratory fitness significantly moderated the relationship between memory and sleep quality, specifically number of nighttime awakenings, sleep efficiency, and wake after sleep onset. Further analyses reveal that a high number of nighttime awakenings and low sleep efficiency significantly predicted worse memory performance in the low fit OA, but high fit OA. Notably, every nighttime awakening was associated with a nearly 4% decrease in memory in low fit OA, but not high fit OA. Wake after sleep onset did not significantly predict memory in either fitness group. No interaction was found when looking at sleep duration or self-report sleep quality in OA and no significant interactions were observed between fitness, sleep, and memory in YA.

CONCLUSION

Overall, the results suggest that cardiorespiratory fitness may act as a protective buffer for memory in OA with poor sleep quality. These same was not true for YA suggesting that the protective effects of cardiorespiratory fitness on sleep-related memory impairments may be age specific.

Association Between Arousals During Sleep and Hypertension Among Patients With Obstructive Sleep Apnea

Background

Sleep fragmentation induced by repetitive arousals is a hallmark of obstructive sleep apnea (OSA). Sleep fragmentation has been linked to hypertension in community‐based studies, but it is unclear if this association is manifest in OSA. We aimed to explore whether frequent arousals from sleep modify the relationship between OSA and prevalent hypertension.

Methods and Results

A total of 10 102 patients with OSA and 1614 primary snorers were included in the study. Hypertension was defined on either direct blood pressure measures or diagnosis by a physician. Spontaneous, respiratory, and movement arousals were derived by polysomnography. Logistic regression models were used to estimate the associations between arousals and prevalent hypertension in patients with OSA and primary snorers. For every 10‐unit increase of total arousal index, odds of hypertension significantly increased in both the total sample (odds ratio [OR], 1.08; 95% CI, 1.03–1.14; P=0.002) and patients with OSA (OR, 1.10; 95% CI, 1.04–1.16; P<0.001), but not in the primary snoring group. Total arousal index was significantly associated with systolic blood pressure and diastolic blood pressure in the total sample (β=0.05 and β=0.06; P<0.001) and in patients with (β=0.05 and β=0.06; P<0.01), but not in primary snorers. In addition, a greater influence of respiratory events with arousals than respiratory events without arousals on blood pressure in OSA was also noted. Results were independent of confounders, including apnea‐hypopnea index and nocturnal hypoxemia.

Conclusions

We conclude that repetitive arousals from sleep are independently associated with prevalent hypertension in patients with OSA.

Association between self-reported snoring and hypertension: a systematic review and meta-analysis

OBJECTIVES

The purpose of this study is to summarize the evidence for the association between snoring and hypertension and the effect of snoring on hypertension in men and/or women.

METHODS

We searched the articles in the Cochrane Library, PubMed, Scopus, Web of Science and Embase published up to 12 November 2020 to evaluate the association between snoring and hypertension. Studies were selected according to the predefined screening criteria and their qualities were assessed by Newcastle-Ottawa Quality Evaluation Scale. The odds ratio and 95% confidence interval were used as effective indicators. It was registered in PROSPERO with the number: CRD42021224912.

RESULTS

According to the inclusion/exclusion criteria, 11 studies including eight prospective cohort studies and three cross-sectional studies were included. The results showed that compared with non-snoring participants, snoring significantly increased the risk of hypertension in both men and women [odds ratio (OR) = 1.32, 95% confidence interval (CI), 1.23-1.42; men: odds ratio (OR) = 1.32; 95% confidence interval (CI), 1.18-1.49; women: odds ratio (OR) = 1.26; 95% confidence interval (CI), 1.14-1.40]. Besides, the risk of hypertension was significantly increased when the snoring frequency was ≥4 nights/week [frequency≥4 nights/week: odds ratio (OR) = 1.42; 95% confidence interval (CI), 1.21-1.66; 4 nights/week >frequency>0: odds ratio (OR) = 1.23; 95% confidence interval (CI),1.13-1.34].

CONCLUSIONS

Snoring is considered as an independent predictor of hypertension in both men and women, which may play a role in the prevention and control of hypertension. People who snore frequently should pay close attention to their blood pressure levels to prevent hypertension.

Sleep and Cardiovascular Risk

Sleep is essential for healthy being and healthy functioning of human body as a whole, as well as each organ and system. Sleep disorders, such as sleep-disordered breathing, insomnia, sleep fragmentation, and sleep deprivation are associated with the deterioration in human body functioning and increased cardiovascular risks. However, owing to the complex regulation and heterogeneous state sleep per se can be associated with cardiovascular dysfunction in susceptible subjects. The understanding of sleep as a multidimensional concept is important for better prevention and treatment of cardiovascular diseases.

Association between comorbid sleep apnoea-hypopnoea syndrome and prognosis of intensive care patients: a retrospective cohort study

OBJECTIVE

In this study, we investigated the association between comorbid sleep apnoea-hypopnoea syndrome (SAHS) and the prognosis of patients in an intensive care unit (ICU) to determine whether this relationship varies between different disease subgroups.

METHODS

We conducted a retrospective cohort study using publicly available information from the critical care database Medical Information Mart for Intensive Care III. Adults (≥18 years of age) who attended the ICU for the first time were enrolled. Demographic information and clinical data were obtained from each patient. The primary outcome was 30-day mortality after ICU admission, and the secondary outcomes were in-hospital and ICU mortality. Multivariate logistic regression and Cox regression analyses were used to examine the associations between SAHS comorbidities and the research outcomes. Propensity score matching was used to adjust for potential confounding variables.

RESULTS

Of the 32 989 patients enrolled, 1918 (5.81%) were diagnosed with SAHS as a comorbid condition. Patients with SAHS had a significantly lower 30-day mortality rate compared with those without SAHS (5.27% vs 13.65%, respectively; p<0.001). The frequency of chronic obstructive pulmonary disease, cerebral disease, cardiovascular disease, hypertension, diabetes mellitus and renal failure was significantly different between the two groups. Patients with SAHS demonstrated significantly longer survival compared with patients without SAHS. Multivariate Cox proportional hazards regression identified a significant relationship between SAHS and mortality within 30 days (adjusted HR=0.610, 95% CI 0.499 to 0.747, p<0.0001).

CONCLUSION

SAHS as a comorbid condition decreases the risk of 30-day mortality, in-hospital mortality and ICU mortality among ICU patients.

Obstructive Sleep Apnea and Cognitive Decline: A Review of Potential Vulnerability and Protective Factors

Around 40% of dementia risk is attributable to modifiable risk factors such as physical inactivity, hypertension, diabetes and obesity. Recently, sleep disorders, including obstructive sleep apnea (OSA), have also been considered among these factors. However, despite several epidemiological studies investigating the link between OSA and cognitive decline, there is still no consensus on whether OSA increases the risk of dementia or not. Part of the heterogeneity observed in previous studies might be related to some individual characteristics that modulate the association between OSA and cognitive decline. In this narrative review, we present these individual characteristics, namely, age, sex, menopause, obesity, diabetes mellitus, hypertension, cardiovascular diseases, smoking, excessive alcohol consumption, depression, air pollution, Apolipoprotein E ε4 allele, physical activity, and cognitive reserve. To date, large cohort studies of OSA and cognitive decline tended to statistically control for the effects of these variables, but whether they interact with OSA to predict cognitive decline remains to be elucidated. Being able to better predict who is at risk of cognitive decline when they have OSA would improve clinical management and treatment decisions, particularly when patients present relatively mild OSA.

Endotypes and phenotypes in obstructive sleep apnea

PURPOSE OF REVIEW

The purpose of this review is to describe the variability of obstructive sleep apnea (OSA), both from a standpoint of underlying mechanisms and in terms of clinical manifestations.

RECENT FINDINGS

Recent data suggest that not all patients with sleep apnea get their disease for the same reason. As such, no one variable is effective at defining which patients do or do not have sleep apnea. Identifying the mechanism(s) underlying OSA for an individual is helpful as it can help to determine whether personalized therapy could be developed based on an individual's characteristics. In addition, these underlying mechanisms may be helpful in predicting response to therapy and prognosticating regarding future complications.

SUMMARY

OSA is a heterogeneous disease with highly varying underlying mechanisms. OSA has variable clinical manifestations with definable subsets having risk of particular complications. Future studies will be helpful to identify mechanisms underlying OSA using clinically accessible tools and then using these data to focus individualized treatment approaches.

Proteomic biomarkers of sleep apnea

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is characterized by recurrent partial to complete upper airway obstructions during sleep, leading to repetitive arousals and oxygen desaturations. Although many OSA biomarkers have been reported individually, only a small subset have been validated through both cross-sectional and intervention studies. We sought to profile serum protein biomarkers in OSA in unbiased high throughput assay.

METHODS

A highly multiplexed aptamer array (SomaScan) was used to profile 1300 proteins in serum samples from 713 individuals in the Stanford Sleep Cohort, a patient-based registry. Outcome measures derived from overnight polysomnography included Obstructive Apnea Hypopnea Index (OAHI), Central Apnea Index (CAI), 2% Oxygen Desaturation index, mean and minimum oxygen saturation indices during sleep. Additionally, a separate intervention-based cohort of 16 individuals was used to assess proteomic profiles pre- and post-intervention with positive airway pressure.

RESULTS

OAHI was associated with 65 proteins, predominantly pathways of complement, coagulation, cytokine signaling, and hemostasis which were upregulated. CAI was associated with two proteins including Roundabout homolog 3 (ROBO3), a protein involved in bilateral synchronization of the pre-Bötzinger complex and cystatin F. Analysis of pre- and post intervention samples revealed IGFBP-3 protein to be increased while LEAP1 (Hepicidin) to be decreased with intervention. An OAHI machine learning classifier (OAHI >=15 vs OAHI<15) trained on SomaScan protein measures alone performed robustly, achieving 76% accuracy in a validation dataset.

CONCLUSIONS

Multiplex protein assays offer diagnostic potential and provide new insights into the biological basis of sleep disordered breathing.

The Associations Between Sleep Architecture and Metabolic Parameters in Patients With Obstructive Sleep Apnea: A Hospital-Based Cohort Study

Background and Objectives: The associations between objective sleep architecture and metabolic parameters have been rarely studied in patients with obstructive sleep apnea (OSA). Here, we evaluated the associations between objective sleep measures derived via polysomnography (PSG) and metabolic parameters.

Methods: A total of 2,308 subjects with suspected OSA were included. We measured common metabolic parameters such as body mass index (BMI) and glucose, insulin, blood pressure, total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) levels. All subjects underwent full-night PSG. PSG sleep parameters included total sleep time (TST), time spent in slow-wave sleep (SWS) and rapid eye movement (REM) sleep, sleep efficiency, and the microarousal index (MAI).

Results: The TST correlated with the BMI, glucose level, and systolic blood pressure. The SWS/TST ratio correlated with BMI and glucose, TC, and TG levels. The REM/TST ratio correlated with BMI, glucose, insulin, and TG levels, and diastolic blood pressure. We found significant relationships between sleep efficiency and BMI, glucose levels, and TG levels. The MAI was significantly correlated with all metabolic parameters. After adjustment for age, gender, smoking status, alcohol use, apnea hypopnea index, and oxygen desaturation index (ODI), multiple linear regression analysis showed that the MAI was independently associated with glucose level, TC, HDL, and LDL. REM/TST ratio was positively associated with diastolic blood pressure but negatively associated with glucose metabolism.

Conclusions: Though some independent correlation between sleep and metabolic parameters was confirmed, only weak associations were observed, suggesting a clinically negligible influence of sleep structure. Further prospective studies are warranted to confirm our findings.

Slow-wave sleep is associated with incident hypertension in patients with obstructive sleep apnea: a cross-sectional study

OBJECTIVE

This study aimed to examine the association between slow-wave sleep ([SWS] N3 stage) and the risk of hypertension in patients with obstructive sleep apnea (OSA) or primary snorers.

METHODS

A retrospective cross-sectional study of 1145 participants who were evaluated for suspected OSA at our Sleep Medical Center were included. Among these participants, 1022 had OSA and 123 were primary snorers. Logistic regression modeling was performed to evaluate the association between the prevalence of hypertension and combined OSA and SWS based on polysomnographic measurements.

RESULTS

Patients with OSA in the lowest SWS quartile (quartile 1,  < 2.0%) showed a two-fold increased risk of hypertension after adjustment for confounding factors compared with primary snorers (odds ratio, 2.13 [95% confidence interval 1.54-2.06]). In logistic analysis stratified according to SWS quartiles, there was no significant difference in the risk of hypertension between patients with OSA and primary snorers in quartile 1. However, in the highest quartile (quartile 4), SWS was significantly associated with incident hypertension in patients with OSA rather than primary snorers.

CONCLUSION

SWS is associated with prevalent hypertension in patients with OSA. Notably, a low proportion of SWS confers a stronger association with incident hypertension than OSA.