The Sleep Apnea-Specific Pulse-Rate Response Predicts Cardiovascular Morbidity and Mortality

Osteoarthritis and the risk of sleep apnea: a general population-based cohort study

OBJECTIVE

Osteoarthritis (OA) is the most common joint disease, leading to pain and inflammation, two risk factors for sleep apnea (SA). We aimed to examine whether OA may increase the risk of incident SA, a common source of mortality and sudden death.

METHOD

Using data from the IQVIA Medical Research Database, we conducted three cohort studies (i.e., knee, hip, and hand cohort) among individuals aged 50 years or older. For each patient with incident OA, up to five non-OA individuals were matched by age, sex, entry-time, and BMI. We calculated the incidence rate of SA for the OA and non-OA cohorts, respectively, and examined the relation of OA to the risk of incident SA using a Cox proportional hazard model adjusting for potential confounders.

RESULTS

During the follow-up, 869 SA cases occurred in 58,674 patients with knee OA and 2,186 in 235,850 non-OA individuals (2.29 vs. 1.41/1000 person-years). Compared with the non-OA cohort, the multivariable-adjusted hazard ratio (HR) of SA in the knee OA cohort was 1.45 (95% confidence interval [CI]: 1.34-1.56). A higher risk of SA was also observed among patients with incident hip OA (adjusted HR: 1.45, 95%CI: 1.28-1.66) and hand OA (adjusted HR: 1.50, 95%CI: 1.26-1.78) than the matched non-OA individuals.

CONCLUSIONS

This general population-based study provides the first evidence that patients with knee, hip, and hand OA may have an increased risk of incident SA. Strategies aimed at screening, prevention, and treatment of SA could be developed to reduce the disease burden in OA patients.

Heart rate response and cardiovascular risk during obstructive sleep apnoea: an easy biomarker derived from pulse oximetry

BACKGROUND

Sleep apnoea-specific heart rate response (ΔHR) has been identified as a promising biomarker for stratifying cardiovascular (CV) risk and predicting positive airway pressure (PAP) benefit in obstructive sleep apnoea (OSA). However, the need for prior manual scoring of respiratory events potentially limits the accessibility and reproducibility of ΔHR. We aimed to evaluate the association of pulse rate response to oxygen desaturations automatically derived from pulse oximetry (ΔHRoxi) with CV risk in OSA.

METHODS

ΔHRoxi and ΔHR were measured in OSA patients from the Institut de Recherche en Santé Respiratoire Pays de la Loire Sleep Cohort (PLSC; n=5002) and the HypnoLaus cohort (n=1307). The primary outcome was major adverse CV events (MACEs), a composite of mortality, stroke and cardiac diseases. Cox regression analyses were conducted to evaluate the association of ΔHRoxi and ΔHR, categorised into low, midrange and high categories, with MACEs.

RESULTS

MACEs occurred in 768 patients from PLSC and 87 patients from HypnoLaus (median follow-up 8.0 and 7.5 years, respectively). Multivariable Cox models showed that subjects with high ΔHRoxi (versus midrange) had higher risk of MACEs in PLSC (hazard ratio (HR) 1.42, 95% CI 1.18-1.71) and HypnoLaus (HR 1.72, 95% CI 1.03-2.87). Similar findings were observed for high ΔHR. Among 2718 patients from PLSC treated with PAP, the association of PAP adherence (PAP use ≥4 h·night-1 versus non-adherent) with MACEs was modified by baseline ΔHR and ΔHRoxi (pinteraction<0.05).

CONCLUSION

ΔHRoxi could constitute a reliable and easy to measure biomarker for stratifying CV risk and predicting CV benefit of PAP in OSA.

The relationship between obesity and obstructive sleep apnea in four community-based cohorts: an individual participant data meta-analysis of 12,860 adults

Background

Obesity is a well-established risk factor for obstructive sleep apnea (OSA). We assessed the reciprocal prevalence of obesity and OSA and how it varies by age and sex.

Methods

Following a systematic review through March 27, 2025, the final sample included four community-based cohort studies in the US and Switzerland. OSA severity was quantified using the apnea-hypopnea index (AHI, all apneas plus hypopneas with ≥4% oxygen desaturation/hour). Random effects individual participant data (IPD) meta-analyses estimated prevalences. Logistic regression compared odds of OSA across weight groups.

Findings

Among 12,860 adults (mean ± SD age: 66.6 ± 7.3 years), 7222 (56.2%) had OSA (AHI ≥5 events/h) and 3309 (25.7%) had obesity (BMI ≥30 kg/m2). IPD meta-analysis showed 31.5% [95% CI: 16.8-48.5] of individuals with OSA had obesity and 44.4% [36.5-52.5] had overweight status (25 ≤ BMI < 30). Among subgroups of individuals with obesity and overweight, 74.3% [63.8-83.5] and 59.8% [46.5-75.7] had any OSA, respectively. Obesity was higher in females than males with OSA, and in younger (<65 years) vs. older individuals. Odds ratios for OSA in subgroups of individuals with overweight and obesity compared to BMI <25 kg/m2 were 2.18 [1.73-2.76] and 4.84 [3.09-6.00], respectively.

Interpretation

Our analyses show that most adults with OSA do not have obesity, with 44.4% having overweight and 23.5% having normal weight or underweight. Obesity was more prevalent among females compared to males and in younger individuals (<65 years) compared to older individuals with OSA. Recognizing OSA is not exclusive to obesity highlights the need for personalized treatment plans.

Funding

American Academy of Sleep Medicine, National Heart, Lung, and Blood Institute, and Apnimed.

A Foundation Model for Sleep-Based Risk Stratification and Clinical Outcomes

Clinical diagnosis of sleep disorders, which are recognized contributors to morbidity and mortality, often relies on polysomnography (PSG) data. However, the vast physiologic data collected during PSG is underutilized, presenting a key opportunity to enhance characterization of sleep dysfunction and predict clinical outcomes. We introduce a sleep foundation model that uniquely integrates PSG time-series signals and electronic medical record data. Using a diverse dataset (n=10,000; mean observation period 14.5±7.1 years), our transformer-based model generates data-driven representations of latent physiological patterns. When clustered, we identified subpopulations with differential health trajectories. The highest risk-group exhibited strong correlations with all-cause mortality (unadjusted hazard ratio [HR] 4.83, 95% confidence interval [CI] 3.60-6.50, p<0.001) as well as cardiovascular outcomes and neurological outcomes, even after accounting for traditional measures. External validation in a National Sleep Research Resource cohort confirmed findings. We created a novel, clinically applicable framework leveraging information-dense PSG data to inform risk stratification and predict health outcomes beyond traditional methods.

Developing a Personalized Approach to Obstructive Sleep Apnea

All areas of medicine are focused on developing a personalized approach to diagnosis and treatment of specific conditions. This is based on the fundamental concept that all subjects with apparently the same disorder are different. There are multiple reasons for these differences. These include differences in the sequence of DNA, differences in the environment, differences in epigenetics, some of which may be driven by environmental differences and differences in the microbiome. These different factors will result in variations in multiple aspects of the phenotype. This includes different pathways to disease, different symptoms, different pattern of comorbidities and risk for adverse outcomes, and different physiological changes during sleep as a result of breathing episodes.

Cardiovascular effects of obstructive sleep apnoea and effects of continuous positive airway pressure therapy: evidence from different study models

Background

Cardiovascular consequences of obstructive sleep apnoea (OSA) and the effects of continuous positive airway pressure (CPAP) therapy on blood pressure, endothelial dysfunction and major adverse cardiovascular events (MACE) have been studied over decades using different study designs. However, clinical findings from different study models on cardiovascular outcomes are sometimes contradictory.

Methods

A literature search was conducted in PubMed for randomised controlled trials, meta-analyses, population-based epidemiological studies and OSA cohort studies up to September 2023 investigating the cardiovascular effects of OSA and CPAP in adults with OSA on the following cardiovascular end-points: blood pressure, arterial hypertension, endothelial function and MACE (myocardial infarction, stroke, transient ischaemic attack or cardiovascular death). The level of evidence for these outcomes was discussed on the basis of different study models.

Results and conclusions

There is high-level evidence of a causal relationship between OSA and arterial hypertension and endothelial dysfunction, as well as on higher MACE incidence among subgroups of patients with untreated OSA. The cardiovascular effects of OSA depend on the severity of OSA, symptoms, phenotype and comorbidities. The blood pressure-lowering effect of CPAP is mainly observed in uncontrolled and treatment-resistant hypertension. The MACE risk reduction in OSA depends on good long-term CPAP adherence. Younger, sleepy patients with more severe OSA, higher hypoxaemic burden and without overt cardiovascular end-organ disease may particularly benefit from CPAP treatment in terms of cardiovascular risk reduction. Randomised controlled trials of CPAP or other effective OSA treatments in primary cardiovascular prevention and in patients at highest risk are lacking.

Power-law properties of nocturnal arrhythmia avalanches: A novel marker for incident cardiovascular events

BACKGROUND

Bursting nonsustained cardiac arrhythmia events are a common observation during sleep.

OBJECTIVES

The purpose of this study was to investigate the hypothesis that nocturnal arrhythmia episode durations could follow a power law, whose exponent could predict long-term clinical outcomes.

METHODS

We defined "nocturnal arrhythmia avalanche" (NAA) as any instance of a drop in electrocardiographic (ECG) template-matched R-R intervals ≥30% of R-R baseline, followed by a return to 90% of baseline. We studied NAA in ECG recordings obtained from the Sleep Heart Health Study (SHHS), Osteoporotic Fractures in Men Study (MrOS) Study, and Multi-Ethnic Study of Atherosclerosis (MESA). The association of nocturnal arrhythmia durations with a power-law distribution was evaluated and the association of derived power-law exponents (α) with major adverse cardiovascular (CV) events and mortality assessed with multivariable Cox regression.

RESULTS

A total of 9176 participants were studied. NAA episodes distribution was consistent with power-law vs comparator distributions in all datasets studied (positive log likelihood ratio of power-law vs exponential in MESA: 83%; SHHS: 69%; MrOS: 81%; power-law vs log-normal in MESA: 95%; SHHS: 35%; MrOS: 64%). The NAA power-law exponent (α) showed a significant association of with adverse CV outcomes (association with CV mortality: SHHS hazard ratio 1.39 [1.07-1.79], P = .012; MrOS hazard ratio 1.42 [1.02-1.94], P = .039; association with CV events: MESA HR 3.46 [1.46-8.21], P = .005) in multivariable Cox regression, after adjusting for conventional CV risk factors and nocturnal ectopic rate.

CONCLUSION

The NAA power-law exponent is a reproducible, predictive marker for incident CV events and mortality.

Multimodal Treatment of Sleep Apnea

Obstructive sleep apnea (OSA) is a common condition linked with multiple comorbidities. Continuous positive airway pressure (CPAP) devices, though the gold standard for OSA treatment, often do not address the entirety of the disorder. Various treatment strategies exist to address OSA beyond CPAP, each targeting different OSA aspects. These include managing comorbid sleep disorders, anatomic considerations, endotype-directed therapy, and lifestyle interventions. These comprehensive approaches aim to improve the benefits of treatment, and reduce the complications associated with OSA.

Evaluation of Sleep Quality in Clinical Practice

A major problem in clinical sleep medicine is that the most comprehensive and sophisticated investigative tool, the polysomnography, fails to provide a reason for the patient's complaints in all but those with sleep apnea and movement disorders. The reasons why conventional metrics of sleep quality are of limited value are discussed in detail. This is followed by description of several well-established features that have not been implemented in clinical practice because of the impracticality of doing the measurements visually. Automation is pending. Finally, several automated features recently derived from spectral analysis of the electroencephalogram were described.

Accessible moderate-to-severe obstructive sleep apnea screening tool using multidimensional obesity indicators as compact representations

Many obesity indicators have been linked to adiposity and its distribution. Utilizing a combination of multidimensional obesity indicators may yield different values to assess the risk of moderate-to-severe obstructive sleep apnea (OSA). We aimed to develop and validate the performances of automated machine-learning models for moderate-to-severe OSA, employing multidimensional obesity indicators as compact representations. We trained, validated, and tested models with logistic regression and other 5 machine learning algorithms on the clinical dataset and a community dataset. Light gradient boosting machine (LGB) had better performance of calibration and clinical utility than other algorithms in both clinical and community datasets. The model with the LGB algorithm demonstrated the feasibility of predicting moderate-to-severe OSA with considerable accuracy using 19 obesity indicators in clinical and community settings. The useable interface with deployment of the best performing model could scale-up well into real-word practice and help effectively detection for undiagnosed moderate-to-severe OSA.

Characterisation of nocturnal arrhythmia avalanche dynamics: Insights from generalised linear model analysis

Nocturnal arrhythmia avalanche (NAA) episodes, characterised by transient non-sustained cardiac arrhythmias during sleep, have been demonstrated as a predictor of adverse cardiovascular events. However, their dynamics and association with sleep architecture and events remain unclear. While generalised linear models (GLM) have captured sleep-disordered breathing (SDB) dynamics, their application to NAA remains underexplored. This study explored whether changes in sleep architecture contribute to nocturnal arrhythmias and if the impact of sleep stages, SDB, and arousal events on these arrhythmias varies by demographic factors. We analysed 7341 ECG recordings from the multi-ethnic study of atherosclerosis (MESA) and the sleep heart health study (SHHS) datasets. R-R intervals were divided into 10-min periods to detect NAA, defined as a 30% drop from baseline followed by recovery to 90% of baseline. A GLM framework was developed to characterise NAA episodes as functions of SDB, sleep arousal events, sleep stages, and prior NAA episodes. The GLM analysis revealed that NAA occurrence was 18% and 30% higher during non-rapid eye movement (NREM) light sleep compared with deep sleep in SHHS (p < 0.001) and MESA (p < 0.001), respectively. SDB events increased the NAA risk in 34% of participants, and arousals in 29%. In SHHS, the impact of SDB on NAA was 5% greater in men (p = 0.018), while the arousal effects were more pronounced in those over 75, highlighting the role of demographic factors in modulating arrhythmia risk. These findings demonstrate the utility of the GLM framework in modelling the dynamics of nocturnal arrhythmias and their associations with sleep disruptions and architecture.

Apnea-Specific Pulse-Rate Response is Associated With Early Subclinical Atherosclerosis in Obstructive Sleep Apnea

INTRODUCTION

In patients with obstructive sleep apnea (OSA), novel metrics such as hypoxic burden (HB) and sleep apnea-specific pulse-rate response (ΔHR) may better correlate with cardiovascular diseases (CVD) than the apnea-hypopnea index (AHI). This manuscript aims to assess the correlation between ΔHR and HB with subclinical atherosclerosis in patients with OSA, testing the hypothesis that elevated ΔHR and HB are associated with subclinical atherosclerosis development.

METHODS

In a prospective study, individuals aged 20-65 years with suspected OSA without known comorbidities were consecutively recruited and defined as OSA (AHI≥5events/h) or healthy controls. Using bilateral carotid ultrasonography, common carotid intima-media thickness (CIMT) was assessed and the identification of at least one atheromatous plaque defined the presence of subclinical atherosclerosis. ΔHR, and HB were derived from pulse-oximetry.

RESULTS

We studied 296 patients of age 45±10 years old, of whom 28% were women, and with a BMI of 30.3±5.3kg/m2. Overall, 245 had OSA and 51 were healthy controls. After controlling for confounding variables higher ΔHR but not HB, was associated with higher CIMT (p=0.006) and higher time spent with oxygen saturation below 90% (T90) was associated with an increase in carotid atheroma plaques (p=0.032). When stratifying OSA based on HB tertiles, we observed that within tertile 2 of HB, an increase in ΔHR was associated with larger CIMT (p=0.017).

CONCLUSION

A higher ΔHR is associated with an increase in CIMT among adult patients with OSA. This study suggests that ΔHR could be a biomarker of risk for CVD in patients with OSA.

Bidirectional interplay of sleep apnea syndrome and cardio-vascular disorders in diabetes

Although often overlooked sleep apnea has emerged as a significant public health concern. Obstructive sleep apnea (OSA) and diabetes commonly co-exist with a vicious cycle worsening the incidence and severity of both conditions. OSA has many implications including cardiometabolic disorders and impaired cardiovascular (CV) prognosis. OSA combined with diabetes generates a cumulative effect on CV outcomes. The association of OSA with several comorbidities including CV disease and heart failure is bi-directional meaning that some of them are likely to contribute to OSA. In patients with diabetes, OSA treatment should be integrated in a holistic strategy of prevention of CV and microvascular complications. This article provides some clues to advance the understanding of the interplay between OSA and CV disorders in diabetes and to consider the role of some CV risk markers like cardiac autonomic neuropathy and artery stiffness and of novel metrics for hypoxic-related events in CV risk stratification, and offers a discussion on the effects of medical approaches including weight loss strategies, GLP1-receptor agonists and sodium-glucose cotransporter 2 inhibitors. It provides a guidance to improve screening and diagnosis of OSA, and adherence to OSA treatment in patients with diabetes.

Improving the cardiovascular outcomes of obstructive sleep apnea: Towards more precise hypoxia-based models of disease severity

Purpose of review

Obstructive sleep apnea (OSA) affects at least 1 billion people worldwide, and its increasing prevalence is alarming considering an association to comorbidities such as cardiovascular disease (CVD) and to demonstrated health disparities. This raises concerns regarding the current diagnostic standards, which are also impacted by disparities. The current review was aimed at identifying limitations in the apnea-hypopnea index (AHI), the primary clinical indicator of OSA severity, and analyzing recent alternatives. In addition, the association between OSA and CVD was discussed, and, considering the role of intermittent hypoxia, solutions were proposed for improving OSA diagnosis.

Recent findings

Based on a review of current literature, alternative metrics to the AHI such as the hypoxia burden, sleep apnea-specific pulse rate, and oxygen desaturation rate were shown to be correlated with indicators of CVD in OSA patients. A recent mathematical study also presents the possibility of a model-based metric to eliminate existing bias in diagnostics and provide a more accurate quantification of tissue hypoxia.

Summary

The analyzed studies give incentive to look beyond current clinical standards in OSA. Through this review, we motivate the use of mathematical modeling as a future avenue to improve OSA diagnosis with a hypoxia-based approach.

Untargeted metabolome atlas for sleep-related phenotypes in the Hispanic community health study/study of Latinos

BACKGROUND

Sleep is essential to maintaining health and wellbeing of individuals, influencing a variety of outcomes from mental health to cardiometabolic disease. This study aims to assess the relationships between various sleep-related phenotypes and blood metabolites.

METHODS

Utilising data from the Hispanic Community Health Study/Study of Latinos, we performed association analyses between 40 sleep-related phenotypes, grouped in several domains (sleep disordered breathing (SDB), sleep duration, sleep timing, self-reported insomnia symptoms, excessive daytime sleepiness (EDS), and heart rate during sleep), and 768 metabolites measured via untargeted metabolomics profiling. Network analysis was employed to visualise and interpret the associations between sleep phenotypes and metabolites.

FINDINGS

The patterns of statistically significant associations between sleep phenotypes and metabolites differed by superpathways, and highlighted subpathways of interest for future studies. For example, primary bile acid metabolism showed the highest cumulative percentage of statistically significant associations across all sleep phenotype domains except for SDB and EDS phenotypes. Several metabolites were associated with multiple sleep phenotypes, from a few domains. Glycochenodeoxycholate, vanillyl mandelate (VMA) and 1-stearoyl-2-oleoyl-GPE (18:0/18:1) were associated with the highest number of sleep phenotypes, while pregnenolone sulfate was associated with all sleep phenotype domains except for sleep duration. N-lactoyl amino acids such as N-lactoyl phenylalanine (lac-Phe), were associated with sleep duration, SDB, sleep timing and heart rate during sleep.

INTERPRETATION

This atlas of sleep-metabolite associations will facilitate hypothesis generation and further study of the metabolic underpinnings of sleep health.

FUNDING

R01HL161012, R35HL135818, R01AG80598.

New management pathways for follow-up of CPAP-treated sleep apnoea patients including digital medicine and multimodal telemonitoring

BACKGROUND

The ever-increasing number of patients diagnosed with obstructive sleep apnoea (OSA) and treated by long-term continuous positive airway pressure (CPAP) overstretches conventional follow-up pathways. New approaches to the management of CPAP-treated patient follow-up are needed to strike a balance between remote monitoring through digital technologies and in-person patient-healthcare-professional contacts. Focusing on the reshaping of the management of care pathways of CPAP-treated patients, with a specific focus on telemonitoring platforms, we aimed to review the evidence on how digital medicine and artificial intelligence (AI) tools are facilitating patient phenotyping and triage, risk stratification and the allocation of resources between the various healthcare professionals for an optimal follow-up of CPAP-treated patients.

PHENOTYPING

OSA is a heterogeneous condition with diverse phenotypes differing in symptoms, comorbidities, demographics, lifestyle and socioeconomic context. Different phenotypes are associated with different CPAP adherence patterns and differing long-term prognosis. This diversity demands greater plurality in management pathways with different types and levels of support to ensure treatment adherence and risk reduction for patients while easing the burden on health services. In multidimensional phenotyping, we discuss alternatives to the apnoea hypopnoea index (AHI) as a measure of OSA severity. Then we consider risk stratification taking advantage of the wealth of CPAP monitoring data already available in databases that can now be exploited using AI and machine learning to direct (stratify) patients into appropriate follow-up management pathways.

INTEGRATED CARE CLINICS FOR HIGH-RISK PATIENTS

We look at the role of integrated OSA care clinics particularly for the management of high-risk patients with low adherence and progression of comorbidities. Here, multidisciplinary teams might propose comorbidity management, and the use of connected wearable devices for long-term monitoring of physical activity, along with remote CPAP monitoring.

REMOTE MANAGEMENT PATHWAYS

The pros and cons of remote management pathways to replace in-person follow-up visits are considered, including the need to re-evaluate CPAP-device reimbursement policies in some countries. While remote CPAP monitoring has become the cornerstone of follow-up providing information on adherence and efficacy, the processing of alerts needs to be improved, particularly regarding mask changes and early detection of CPAP failures.

CHALLENGES

The implementation of CPAP monitoring alone, as well as its extension to multimodal monitoring, can present challenges that remain to be addressed (eg, access to digital care). The extent and components of remote follow-up must be adapted to each specific OSA phenotype. Finally, we give examples of certain patient phenotypes (eg, comorbid insomnia with OSA) with specific follow-up requirements, for which remote (even multimodal) monitoring alone has limitations and the intervention of both sleep specialists and/or their colleagues from other disciplines is needed.

CONCLUSION

Appropriately tailored combined digital and in-person CPAP follow-up pathways would present advantages both for patients with OSA and healthcare services.

Beyond continuous positive airway pressure for cardiovascular risk reduction in patients with obstructive sleep apnea

An accumulating body of evidence suggests a bidirectional relationship between sleep and cardiovascular (CV) health. A high level of evidence has linked obstructive sleep apnea (OSA) with cardiovascular disease (CVD). Accordingly, clinical sleep medicine emphasizes the diagnosis and treatment of OSA in the context of promoting CV health. While continuous positive airway pressure (CPAP), the mainstay treatment for OSA, is effective in improving several sleep-related quality-of-life outcomes and leads to modest reductions in blood pressure, there is currently insufficient evidence to justify using CPAP alone for improving CVD outcomes in OSA. Sleep physicians are uniquely positioned to expand their focus beyond the evaluation of OSA and administering CPAP, in efforts to enhance the CV health of sleep patients. Herein, we suggest the role of sleep physicians as CV preventionists. Key focus areas for managing CV risk beyond CPAP therapy in OSA include identifying comorbid disorders that are vital for optimizing CV health. This involves risk-stratifying patients and providing appropriate counseling, referrals, and treatment as appropriate for comorbid sleep conditions such as insomnia and insufficient sleep, comorbid CV risk factors including hypertension, dyslipidemia, metabolic dysfunction-associated steatohepatitis, as well as counseling for weight management programs, smoking, and alcohol cessation. We urge sleep clinicians to play an active and integral role in optimizing the CV health of patients with sleep disorders.

Sleep apnea-specific hypoxic burden and pulse rate response in children using high flow nasal cannula therapy compared with continuous positive airway pressure

BACKGROUND

Elevated sleep apnea-specific hypoxic burden (HB) and pulse rate response (ΔHR) are associated with a higher cardiovascular risk in adults. The clinical significance of HB and ΔHR in children with obstructive sleep apnea (OSA) and their responses to therapy have not yet been investigated. This study aimed to compare the efficacy of high flow nasal cannula (HFNC) and continuous positive airway pressure (CPAP) in reducing HB and ΔHR in children.

METHODS

This analysis included 17 children (11 males, mean age: 12.6 ± 3.9 years) with obesity and/or medical complexity and moderate-to-severe OSA. Each participant underwent two additional sleep studies: one for HFNC titration and another for CPAP titration. HB and ΔHR were derived from the oximetry and pulse rate signals from overnight sleep studies, respectively.

RESULTS

Both HFNC and CPAP demonstrated significant reductions in HB from baseline, with similar magnitudes [HFNC: -129 (standard error, SE 55) %min/h, p = 0.003; CPAP: -138 (SE 53) %min/h, p = 0.005]. However, for ΔHR, a significant reduction from baseline was observed only in the CPAP group [-2.7 (SE 1.1) beats/min, p = 0.049], not the HFNC group [-1.0 (SE 1.4) beats/min, p = 0.67].

CONCLUSIONS

HFNC is as effective as CPAP in treating hypoxia in children with OSA, but HFNC might be less effective than CPAP in mitigating cardiovascular stress from autonomic disturbances during obstructive events.

The Great Controversy of Obstructive Sleep Apnea Treatment for Cardiovascular Risk Benefit: Advancing the Science Through Expert Consensus. An Official American Thoracic Society Workshop Report

The prevalence of obstructive sleep apnea (OSA) is on the rise, driven by various factors including more sensitive diagnostic criteria, increased awareness, enhanced technology through at-home testing enabling easy and cost-effective diagnosis, and a growing incidence of comorbid conditions such as obesity. Treating symptomatic patients with OSA syndrome to enhance quality of life remains a cornerstone approach. However, there is a lack of consensus regarding treatment to improve cardiovascular disease (CVD) outcomes, particularly in light of overall negative results from several randomized controlled trials (RCT) indicating no benefit of positive airway pressure (PAP) therapy on primary and secondary CVD events. These RCTs were limited by suboptimal PAP adherence, use of composite CVD outcomes, and limited diversity and generalizability to Sleep Clinic patients. As such, this workshop assembled clinical experts, as well as researchers in basic and translational science, epidemiology, clinical trials, and population health to discuss the current state, and future research directions to guide personalized therapeutic strategies and future research directions in OSA. There was overall consensus among workshop participants that OSA represents a heterogeneous disease with variable endotypes and phenotypes, and heterogeneous responses to treatment. Future research should prioritize employing multi-modal therapeutic approaches within innovative and adaptive trial designs, focusing on specific subgroups of OSA patients hypothesized to benefit from a CVD perspective. Future work should also be inclusive of diverse populations and consider the life-course of OSA to better comprehend treatment strategies that can address the disproportionate impact of OSA on racially minoritized groups. Further, a more holistic approach to sleep must be adopted to include broader assessments of symptoms, sleep duration, and comorbid sleep and circadian disorders. Finally, it is imperative to establish a sleep research consortium dedicated to collecting raw data and biospecimens categorized by OSA subtypes. This will facilitate mechanistic determinations, foster collaborative research, and help bolster the pipeline of early-career researchers.

OSA diagnosis goes wearable: are the latest devices ready to shine?

STUDY OBJECTIVES

From 2019-2023, the United States Food and Drug Administration has cleared 9 novel obstructive sleep apnea-detecting wearables for home sleep apnea testing, with many now commercially available for sleep clinicians to integrate into their clinical practices. To help clinicians comprehend these devices and their functionalities, we meticulously reviewed their operating mechanisms, sensors, algorithms, data output, and related performance evaluation literature.

METHODS

We collected information from PubMed, United States Food and Drug Administration clearance documents, ClinicalTrials.gov, and web sources, with direct industry input whenever feasible.

RESULTS

In this "device-centered" review, we broadly categorized these wearables into 2 main groups: those that primarily harness photoplethysmography data and those that do not. The former include the peripheral arterial tonometry-based devices. The latter was further broken down into 2 key subgroups: acoustic-based and respiratory effort-based devices. We provided a performance evaluation literature review and objectively compared device-derived metrics and specifications pertinent to sleep clinicians. Detailed demographics of study populations, exclusion criteria, and pivotal statistical analyses of the key validation studies are summarized.

CONCLUSIONS

In the foreseeable future, these novel obstructive sleep apnea-detecting wearables may emerge as primary diagnostic tools for patients at risk for moderate-to-severe obstructive sleep apnea without significant comorbidities. While more devices are anticipated to join this category, there remains a critical need for cross-device comparison studies as well as independent performance evaluation and outcome research in diverse populations. Now is the moment for sleep clinicians to immerse themselves in understanding these emerging tools to ensure our patient-centered care is improved through the appropriate implementation and utilization of these novel sleep technologies.

CITATION

Chiang AA, Jerkins E, Holfinger S, et al. OSA diagnosis goes wearable: are the latest devices ready to shine? J Clin Sleep Med. 2024;20(11):1823-1838.

The Critical Role of the Adipocytokine NOV in Obstructive Sleep Apnea Induced Cardiometabolic Dysfunction: A Review

Obstructive sleep apnea (OSA) is highly prevalent and associated with oxidative stress, chronic inflammation, and adverse cardiovascular consequences. The comorbid condition of obesity remains epidemic. Both obesity and OSA are highly comorbid in patients with cardiovascular disease including atrial fibrillation, resistant hypertension, congestive heart failure, and coronary artery disease. Patients with these preexisting cardiovascular conditions should be screened for OSA with a low threshold to treat, even if OSA severity is mild. Nephroblastoma overexpressed (NOV/CCN3) protein has been identified in multiple chronic inflammatory states, most notably in obesity and more recently in OSA, even in the absence of obesity. As such, NOV may represent an important biomarker for oxidative stress in OSA and may lead to a deeper understanding of the relationship between OSA and its clinical sequelae.

Influence of sleep on physiological systems in atherosclerosis

Sleep is a fundamental requirement of life and is integral to health. Deviation from optimal sleep associates with numerous diseases including those of the cardiovascular system. Studies, spanning animal models to humans, show that insufficient, disrupted or inconsistent sleep contribute to poor cardiovascular health by disrupting body systems. Fundamental experiments have begun to uncover the molecular and cellular links between sleep and heart health while large-scale human studies have associated sleep with cardiovascular outcomes in diverse populations. Here, we review preclinical and clinical findings that demonstrate how sleep influences the autonomic nervous, metabolic and immune systems to affect atherosclerotic cardiovascular disease.

Physiologic Consequences of Upper Airway Obstruction in Sleep Apnea

OSA is diagnosed and managed by a metric called the apnea-hypopnea index (AHI). The AHI quantifies the number of respiratory events (apnea or hypopnea), disregarding important information on the characteristics and physiologic consequences of respiratory events, including degrees of ventilatory deficit and associated hypoxemia, cardiac autonomic response, and cortical activity. The oversimplification of the disorder by the AHI is considered one of the reasons for divergent findings on the associations of OSA and cardiovascular disease (CVD) in observational and randomized controlled trial studies. Prospective observational cohort studies have demonstrated strong associations of OSA with several cardiovascular diseases, and randomized controlled trials of CPAP intervention have not been able to detect a benefit of CPAP to reduce the risk of CVD. Over the last several years, novel methodologies have been proposed to better quantify the magnitude of OSA-related breathing disturbance and its physiologic consequences. As a result, stronger associations with cardiovascular and neurocognitive outcomes have been observed. In this review, we focus on the methods that capture polysomnographic heterogeneity of OSA.

Sleep timing and the prevalence of hypertension in middle-aged and older populations: the sleep heart health study

OBJECTIVES

Sleep characteristics such as duration, continuity, and irregularity are associated with the risk of hypertension. This study aimed to investigate the association between sleep timing (including bedtime, wake-up time, and sleep midpoint) and the prevalence of hypertension.

METHODS

Participants were selected from the Sleep Heart Health Study (n = 5504). Bedtime and wake-up times were assessed using sleep habit questionnaires. The sleep midpoint was calculated as the halfway point between the bedtime and wake-up time. Restricted cubic splines and logistic regression analyses were performed to explore the association between sleep timing and hypertension.

RESULTS

A significant nonlinear association was observed between bedtime (Poverall<0.001; Pnonlinear<0.001), wake-up time (Poverall=0.024; Pnonlinear=0.076), sleep midpoint (Poverall=0.002; Pnonlinear=0.005), and the prevalence of hypertension after adjusting for potential confounders. Multivariable logistic regression showed that both late (> 12:00AM and 23:01PM to 12:00AM) and early (≤ 22:00PM) bedtimes were associated with an increased risk of hypertension compared to bedtimes between 22:01PM and 23:00PM. In addition, individuals with late (> 7:00AM) and early (≤ 5:00AM) wake-up times had a higher prevalence of hypertension than those with wake-up times ranging between 5:01AM and 6:00AM. Delaying the sleep midpoint (> 3:00AM) was also associated with an increased risk of hypertension. Furthermore, no significant interaction effect was found in the subgroup analyses stratified by age, sex, or apnea-hypopnea index.

CONCLUSIONS

Our findings identified a nonlinear association between sleep timing and hypertension. Individuals with both early and late sleep timing had a high prevalence of hypertension.

Treatment of OSA and its Impact on Cardiovascular Disease, Part 2: JACC State-of-the-Art Review

Many studies have shown an association of obstructive sleep apnea (OSA) with incident cardiovascular diseases, particularly when comorbid with insomnia, excessive sleepiness, obesity hypoventilation syndrome, and chronic obstructive pulmonary disease. Randomized controlled trials (RCTs) have demonstrated that treatment of OSA with positive airway pressure devices (CPAP) improves systemic hypertension, particularly in those with resistant hypertension who are adherent to CPAP. However, large RCTs have not shown long-term benefits of CPAP on hard cardiovascular outcomes, but post hoc analyses of these RCTs have demonstrated improved hard outcomes in those who use CPAP adequately. In theory, low CPAP adherence and patient selection may have contributed to neutral results in intention-to-treat analyses. Only by further research into clinical, translational, and basic underlying mechanisms is major progress likely to continue. This review highlights the various treatment approaches for sleep disorders, particularly OSA comorbid with various other disorders, the potential reasons for null results of RCTs treating OSA with CPAP, and suggested approaches for future trials.

Positive Airway Pressure, Mortality, and Cardiovascular Risk in Older Adults With Sleep Apnea

Importance

Positive airway pressure (PAP) is the first-line treatment for obstructive sleep apnea (OSA), but evidence on its beneficial effect on major adverse cardiovascular events (MACE) and mortality prevention is limited.

Objective

To determine whether PAP initiation and utilization are associated with lower mortality and incidence of MACE among older adults with OSA living in the central US.

Design, Setting, and Participants

This retrospective clinical cohort study included Medicare beneficiaries with 2 or more distinct OSA claims identified from multistate, statewide, multiyear (2011-2020) Medicare fee-for-service claims data. Individuals were followed up until death or censoring on December 31, 2020. Analyses were performed between December 2021 and December 2023.

Exposures

Evidence of PAP initiation and utilization based on PAP claims after OSA diagnosis.

Main Outcomes and Measures

All-cause mortality and MACE, defined as a composite of myocardial infarction, heart failure, stroke, or coronary revascularization. Doubly robust Cox proportional hazards models with inverse probability of treatment weights were used to estimate treatment effect sizes controlling for sociodemographic and clinical factors.

Results

Among 888 835 beneficiaries with OSA included in the analyses (median [IQR] age, 73 [69-78] years; 390 598 women [43.9%]; 8115 Asian [0.9%], 47 122 Black [5.3%], and 760 324 White [85.5%] participants; median [IQR] follow-up, 3.1 [1.5-5.1] years), those with evidence of PAP initiation (290 015 [32.6%]) had significantly lower all-cause mortality (hazard ratio [HR], 0.53; 95% CI, 0.52-0.54) and MACE incidence risk (HR, 0.90; 95% CI, 0.89-0.91). Higher quartiles (Q) of annual PAP claims were progressively associated with lower mortality (Q2 HR, 0.84; 95% CI, 0.81-0.87; Q3 HR, 0.76; 95% CI, 0.74-0.79; Q4 HR, 0.74; 95% CI, 0.72-0.77) and MACE incidence risk (Q2 HR, 0.92; 95% CI, 0.89-0.95; Q3 HR, 0.89; 95% CI, 0.86-0.91; Q4 HR, 0.87; 95% CI, 0.85-0.90).

Conclusions and Relevance

In this cohort study of Medicare beneficiaries with OSA, PAP utilization was associated with lower all-cause mortality and MACE incidence. Results might inform trials assessing the importance of OSA therapy toward minimizing cardiovascular risk and mortality in older adults.

Predictors and markers of the cardiovascular impact of obstructive sleep apnoea

PURPOSE OF REVIEW

Obstructive sleep apnoea (OSA) is the most common form of sleep-disordered breathing and has been linked to cardiovascular health. However, some of the findings supporting this are controversial. These discrepancies might be a result of heterogeneity among OSA patients, and thus, additional information would be required to better stratify OSA patients according to cardiovascular risk. In this review, we aim to discuss the potential of biomarkers to fulfil this role.

RECENT FINDINGS

Randomized controlled trials have been unable to confirm whether OSA treatment with continuous positive airway pressure (CPAP) has a positive effect on cardiovascular outcomes. Emerging physiology-based metrics of OSA seem to be more suitable for identifying patients at higher risk of cardiovascular disease and predicting the effects of CPAP outcomes on cardiovascular health. Similarly, blood-based molecular markers have gained attention in this context over the last few years.

SUMMARY

Accurate cardiovascular risk stratification and appropriate treatment allocation for OSA patients remain challenging. However, significant efforts are being made to develop novel tools to address these important issues.

Obstructive Sleep Apnea and Oxygenation in Very Old Adults: A Propensity-Score Match Study

OBJECTIVES

The prevalence of obstructive sleep apnea (OSA) escalates with advancing age. Although the apnea-hypopnea index (AHI) is the standard measure for assessing OSA severity, it does not account for additional oximetric parameters that may influence disease progression in older adults. This study aimed to evaluate disparities in respiratory polygraphy/polysomnography parameters among patients with OSA, stratified by age and sex.

DESIGN

Retrospective propensity score-matched study.

SETTING AND PARTICIPANTS

Sleep unit of a university hospital; 11,747 participants, 210 aged 80 years or older.

METHODS

Propensity score matching was used to establish 4 age cohorts, with the 210 oldest adults serving as the reference group. Primary outcome variables included the total sleep time with oxygen saturation (SaO2) below 90% (T90), average SaO2, minimum SaO2, and AHI. The association between T90 and AHI, as well as the severity of OSA, was assessed across the 4 age categories.

RESULTS

Despite comparable AHI scores, the oldest patients with OSA exhibited the highest T90 and the lowest SaO2 levels compared to younger counterparts. The proportion of patients with severe OSA and T90 in the highest quartile increased with age: 12.5% in young adults, 14.8% in adults, 21.7% in the old, and 34% in the very old participants (P < .001). old and very old patients had a greater likelihood of being in the most severe OSA category compared to the younger ones, with odds ratios (OR) 2.57 (95% CI 1.42-4.65) and 5.52 (95% CI 3.06-9.97), respectively. These patterns were more pronounced in women of advanced age, indicating a sex-specific variation in disease severity with increasing age.

CONCLUSIONS AND IMPLICATIONS

Old patients with OSA, particularly women, demonstrate elevated T90 and reduced SaO2 levels, irrespective of AHI, indicating a hypoxemia increased risk. The diagnostic criteria, management, and outcomes for OSA may require adaptations to address the unique needs of very old populations.

Heterogeneous Effects of Continuous Positive Airway Pressure in Non-Sleepy Obstructive Sleep Apnea on Cardiovascular Disease Outcomes: Post Hoc Machine Learning Analysis of the ISAACC Trial (ECSACT Study)

Rationale: Randomized controlled trials of continuous positive airway pressure (CPAP) therapy for cardiovascular disease (CVD) prevention among patients with obstructive sleep apnea (OSA) have been largely neutral. However, given that OSA is a heterogeneous disease, there may be unidentified subgroups demonstrating differential treatment effects. Objectives: We sought to apply a novel data-drive approach to identify nonsleepy OSA subgroups with heterogeneous effects of CPAP on CVD outcomes within the Impact of Sleep Apnea Syndrome in the Evolution of Acute Coronary Syndrome (ISAACC) study. Methods: Participants were randomly partitioned into two datasets. One for training (70%) our machine-learning model and a second (30%) for validation of significant findings. Model-based recursive partitioning was applied to identify subgroups with heterogeneous treatment effects. Survival analysis was conducted to compare treatment (CPAP vs. usual care [UC]) outcomes within subgroups. Results: A total of 1,224 nonsleepy OSA participants were included. Of 55 features entered into our model, only two appeared in the final model (i.e., average OSA event duration and hypercholesterolemia). Among participants at or below the model-derived average event duration threshold (19.5 s), CPAP was protective for a composite of CVD events (training hazard ratio [HR], 0.46; P = 0.002). For those with longer event duration (>19.5 s), an additional split occurred by hypercholesterolemia status. Among participants with longer event duration and hypercholesterolemia, CPAP resulted in more CVD events compared with UC (training HR, 2.24; P = 0.011). The point estimate for this harmful signal was also replicated in the testing dataset (HR, 1.83; P = 0.118). Conclusions: We discovered subgroups of nonsleepy OSA participants within the ISAACC study with heterogeneous effects of CPAP. Among the training dataset, those with longer OSA event duration and hypercholesterolemia had nearly 2.5 times more CVD events with CPAP compared with UC, whereas those with shorter OSA event duration had roughly half the rate of CVD events if randomized to CPAP.

The PAP-RES algorithm: Defining who, why and how to use positive airway pressure therapy for OSA

Obstructive sleep apnea (OSA) is a common condition that is increasing in prevalence worldwide. Untreated OSA has a negative impact on health-related quality of life and is an independent risk factor for cardiovascular diseases. Despite available data suggesting that cardiovascular risk might differ according to clinical phenotypes and comorbidities, current approaches to OSA treatment usually take a "one size fits all" approach. Identification of cardiovascular vulnerability biomarkers and clinical phenotypes associated with response to positive airway pressure (PAP) therapy could help to redefine the standard treatment paradigm. The new PAP-RES (PAP-RESponsive) algorithm is based on the identification of OSA phenotypes that are likely to impact therapeutic goals and modalities. The paradigm shift is to propose a simplified approach that defines therapeutic goals based on OSA phenotype: from a predominantly "symptomatic phenotype" (individuals with high symptom burden that negatively impacts on daily life and/or accident risk or clinically significant insomnia) to a "vulnerable cardiovascular phenotype" (individuals with comorbidities [serious cardiovascular or respiratory disease or obesity] that have a negative impact on cardiovascular prognosis or a biomarker of hypoxic burden and/or autonomic nervous system dysfunction). Each phenotype requires a different PAP therapy care pathway based on differing health issues and treatment objectives.

Untargeted Metabolome Atlas for Sleep Phenotypes in the Hispanic Community Health Study/Study of Latinos

Sleep is essential to maintaining health and wellbeing of individuals, influencing a variety of outcomes from mental health to cardiometabolic disease. This study aims to assess the relationships between various sleep phenotypes and blood metabolites. Utilizing data from the Hispanic Community Health Study/Study of Latinos, we performed association analyses between 40 sleep phenotypes, grouped in several domains (i.e., sleep disordered breathing (SDB), sleep duration, timing, insomnia symptoms, and heart rate during sleep), and 768 metabolites measured via untargeted metabolomics profiling. Network analysis was employed to visualize and interpret the associations between sleep phenotypes and metabolites. The patterns of statistically significant associations between sleep phenotypes and metabolites differed by superpathways, and highlighted subpathways of interest for future studies. For example, some xenobiotic metabolites were associated with sleep duration and heart rate phenotypes (e.g. 1H-indole-7-acetic acid, 4-allylphenol sulfate), while ketone bodies and fatty acid metabolism metabolites were associated with sleep timing measures (e.g. 3-hydroxybutyrate (BHBA), 3-hydroxyhexanoylcarnitine (1)). Heart rate phenotypes had the overall largest number of detected metabolite associations. Many of these associations were shared with both SDB and with sleep timing phenotypes, while SDB phenotypes shared relatively few metabolite associations with sleep duration measures. A number of metabolites were associated with multiple sleep phenotypes, from a few domains. The amino acids vanillylmandelate (VMA) and 1-carboxyethylisoleucine were associated with the greatest number of sleep phenotypes, from all domains other than insomnia. This atlas of sleep-metabolite associations will facilitate hypothesis generation and further study of the metabolic underpinnings of sleep health.

Reconsidering screening thresholds in health assessments for obstructive sleep apnea using operational and safety incident data

The rail industry in Australia screens workers for probable obstructive sleep apnea (OSA) due to known safety risks. However, existing criteria to trigger screening only identify a small proportion of workers with OSA. The current study sought to examine the relationship between OSA risk and rail incidents in real-world data from Australian train drivers, and conducted a proof of concept analysis to determine whether more conservative screening criteria are justified. Health assessment (2016-2018) and subsequent rail incident data (2016-2020) were collected from two passenger rail service providers. Predictors included OSA status (confirmed no OSA with a sleep study, controlled OSA, unknown OSA [no recorded sleep assessment data] and confirmed OSA with no indication of treatment); OSA risk according to the current Standard, and OSA risk according to more conservative clinical markers (BMI threshold and cardiometabolic burden). Coded rail safety incidents involving the train driver were included. Data were analysed using zero-inflated negative binomial models to account for over-dispersion with high 0 counts, and rail safety incidents are reported using Incidence Risk Ratios (IRRs). A total of 751 train drivers, typically middle-aged, overweight to obese and mostly men, were included in analyses. There were 43 (5.7%) drivers with confirmed OSA, 62 (8.2%) with controlled OSA, 13 (1.7%) with confirmed no OSA and 633 (84.4%) drivers with unknown OSA. Of the 633 train drivers with unknown OSA status, 21 (3.3%) met 'at risk' criteria for OSA according to the Standard, and incidents were 61% greater (IRR: 1.61, 95% Confidence Interval (CI) 1.02-2.56) in the years following their health assessment compared to drivers who did not meet 'at risk' criteria. A more conservative OSA risk status using lower BMI threshold and cardiometabolic burden identified an additional 30 'at risk' train drivers who had 46% greater incidents compared to drivers who did not meet risk criteria (IRR (95% CI) 1.46 (1.00-2.13)). Our more conservative OSA risk criteria identified more workers, with greater prospective incidents. These findings suggest that existing validated tools could be considered in future iterations of the Standard in order to more sensitively screen for OSA.

Treatment of Sleep Apnea and Reduction in Blood Pressure: The Role of Heart Rate Response and Hypoxic Burden

BACKGROUND

Obstructive sleep apnea is associated with increased blood pressure (BP). Obstructive sleep apnea treatment reduces BP with substantial variability, not explained by the apnea-hypopnea index, partly due to inadequate characterization of obstructive sleep apnea's physiological consequences, such as oxygen desaturation, cardiac autonomic response, and suboptimal treatment efficacy. We sought to examine whether a high baseline heart rate response (ΔHR), a marker of high cardiovascular risk in obstructive sleep apnea, predicts a larger reduction in post-treatment systolic BP (SBP). Furthermore, we aimed to assess the extent to which a reduction in SBP is explained by a treatment-related reduction in hypoxic burden (HB).

METHODS

ΔHR and HB were measured from pretreatment and posttreatment polygraphy, followed by a 24-hour BP assessment in 168 participants treated with continuous positive airway pressure or nocturnal supplemental oxygen from the HeartBEAT study (Heart Biomarker Evaluation in Apnea Treatment). Multiple linear regression models assessed whether high versus mid (reference) ΔHR predicted a larger reduction in SBP (primary outcome) and whether there was an association between treatment-related reductions in SBP and HB.

RESULTS

A high versus mid ΔHR predicted improvement in SBP (adjusted estimate, 5.8 [95% CI, 1.0-10.5] mm Hg). Independently, a greater treatment-related reduction in HB was significantly associated with larger reductions in SBP (4.2 [95% CI, 0.9-7.5] mm Hg per 2 SD treatment-related reduction in HB). Participants with substantial versus minimal treatment-related reductions in HB had a 6.5 (95% CI, 2.5-10.4) mm Hg drop in SBP.

CONCLUSIONS

A high ΔHR predicted a more favorable BP response to therapy. Furthermore, the magnitude of the reduction in BP was partly explained by a greater reduction in HB.

The Hypoxic Burden, Clinical Implication of a New Biomarker in the Cardiovascular Management of Sleep Apnea Patients: A Systematic Review

Background

Obstructive sleep apnea (OSA) is a highly prevalent sleep-disordered breathing. It is associated with adverse co-morbidities, being the most scientific evidence of cardiovascular (CV) disease. Currently, OSA is measured through the apnea-hypopnea index (AHI), the total number of respiratory events per hour of sleep. However, different studies have questioned its utility in OSA management, highlighting the need to search for new parameters that better reflect the heterogeneity of the disease. Hypoxic burden (HB) has emerged as a novel biomarker that informs about the frequency, duration and depth of the desaturation related to the respiratory events. We conducted a systematic review in order to find publications about the heterogeneity of OSA measured by HB and its associations with future disease.

Methods

Systematic review was conducted using PubMed and Web of Science. The terms "sleep apne" and "hypoxic burden" were used to look for publications from the date of inception to August 15, 2023. Inclusion criteria: articles in English published in peer-reviewed journals. Exclusion criteria: (1) not available publications; (2) duplicated articles; (3) letters, editorials, and congress communications; (4) articles not including information about HB as a specific biomarker of OSA.

Results

33 studies were included. The results were classified in 2 main sections: (1) HB implication in the CV sphere: HB showed to be a better predictor of CV risk in OSA patients than traditional measures such as AHI with possible clinical management implication in OSA. (2) HB response to OSA treatment: pharmacological and nonpharmacological treatments have demonstrated to be effective in improving hypoxia measured through the HB.

Conclusions

HB could be a better and more effective parameter than traditional measurements in terms of diagnosis, risk prediction and therapeutic decisions in patients with OSA. This measure could be incorporated in sleep units and could play a role in OSA management, driving the clinic to a more personalized medicine.

Adherence to continuous positive airway pressure therapy in patients with spinal cord injury and obstructive sleep apnea: trajectories and predictors

PURPOSE

To identify specific determinants of non-adherence or cessation of continuous positive airway pressure (CPAP) therapy in a population of patients with spinal cord injuries (SCI).

METHODS

Retrospective analysis of data from patients with SCI who underwent a full night supervised polysomnography between 2015 and 2021 and presented with moderate to severe obstructive sleep apnea (OSA) and for whom CPAP was indicated. Adherence was studied at 1, 6, and 12 months. Univariate and multivariate analyses were performed to identify factors associated with non-adherence (< 4 h per night or CPAP cessation). Factors studied were demographic and disease-related data and both subjective and objective sleep parameters.

RESULTS

A total of 60 patients were included (40% cervical SCI). In univariate analysis, the only predictive parameters of non-adherence observed at 1, 6, and 12 months were the average use of CPAP on the 1st night (p = 0.02) and over the 1st week (p ≤ 0.001). A complete lesion (AIS-A) was predictive of non-adherence at 1 and 6 months (p = 0.02 at 6 months), while mask leakage was associated with non-adherence at 12 months (p = 0.02). Upper limb autonomy and the presence of family caregivers did not appear to be protective. In multivariate analysis, only the average use in the first week remained predictive of adherence (> 4 h) in the short, medium and long term.

CONCLUSION

In patients with SCI and OSA, the 1st week of CPAP treatment seems to be determinant of short-, medium-, and long-term CPAP adherence. Support for SCI patients from the start of treatment is essential and may help avoid treatment failures.

All Obstructive Sleep Apnea Events Are Not Created Equal: The Relationship between Event-related Hypoxemia and Physiologic Response

Rationale: Obstructive sleep apnea (OSA) severity is typically assessed by the apnea-hypopnea index (AHI), a frequency-based metric that allocates equal weight to all respiratory events. However, more severe events may have a greater physiologic impact. Objectives: The purpose of this study was to determine whether the degree of event-related hypoxemia would be associated with the postevent physiologic response. Methods: Patients with OSA (AHI, ⩾5/h) from the multicenter Canadian Sleep and Circadian Network cohort were studied. Using mixed-effect linear regression, we examined associations between event-related hypoxic burden (HBev) assessed by the area under the event-related oxygen saturation recording with heart rate changes (ΔHRev), vasoconstriction (vasoconstriction burden [VCBev] assessed with photoplethysmography), and electroencephalographic responses (power ratio before and after events). Results: Polysomnographic recordings from 658 patients (median [interquartile range] age, 55.00 [45.00, 64.00] yr; AHI, 27.15 [14.90, 64.05] events/h; 42% female) were included in the analyses. HBev was associated with an increase in all physiologic responses after controlling for age, sex, body mass index, sleep stage, total sleep time, and study centers; for example, 1 standard deviation increase in HBev was associated with 0.21 [95% confidence interval, 0.2, 0.22], 0.08 [0.08, 0.09], and 0.22 [0.21, 0.23] standard deviation increases in ΔHRev, VCBev, and β-power ratio, respectively. Conclusions: Increased event-related hypoxic burden was associated with greater responses across a broad range of physiologic signals. Future metrics that incorporate information about the variability of these physiologic responses may have promise in providing a more nuanced assessment of OSA severity.

Identifying clusters of patient comorbidities associated with obstructive sleep apnea using electronic health records

STUDY OBJECTIVES

The objectives of this study were to understand the relative comorbidity burden of obstructive sleep apnea (OSA), determine whether these relationships were modified by sex or age, and identify patient subtypes defined by common comorbidities.

METHODS

Cases with OSA and noncases (controls) were defined using a validated electronic health record (EHR)-based phenotype and matched for age, sex, and time period of follow-up in the EHR. We compared prevalence of the 20 most common comorbidities between matched cases and controls using conditional logistic regression with and without controlling for body mass index. Latent class analysis was used to identify subtypes of OSA cases defined by combinations of these comorbidities.

RESULTS

In total, 60,586 OSA cases were matched to 60,586 controls (from 1,226,755 total controls). Patients with OSA were more likely to have each of the 20 most common comorbidities compared with controls, with odds ratios ranging from 3.1 to 30.8 in the full matched set and 1.3 to 10.2 after body mass index adjustment. Associations between OSA and these comorbidities were generally stronger in females and patients with younger age at diagnosis. We identified 5 distinct subgroups based on EHR-defined comorbidities: High Comorbidity Burden, Low Comorbidity Burden, Cardiovascular Comorbidities, Inflammatory Conditions and Less Obesity, and Inflammatory Conditions and Obesity.

CONCLUSIONS

Our study demonstrates the power of leveraging the EHR to understand the relative health burden of OSA, as well as heterogeneity in these relationships based on age and sex. In addition to enrichment for comorbidities, we identified 5 novel OSA subtypes defined by combinations of comorbidities in the EHR, which may be informative for understanding disease outcomes and improving prevention and clinical care. Overall, this study adds more evidence that OSA is heterogeneous and requires personalized management.

CITATION

Te TT, Keenan BT, Veatch OJ, Boland MR, Hubbard RA, Pack AI. Identifying clusters of patient comorbidities associated with obstructive sleep apnea using electronic health records. J Clin Sleep Med. 2024;20(4):521-533.

Apnea-hypopnea index and the polysomnographic risk factors for predicting 5- to 8-year mortality in patients with OSA

BACKGROUND

The purpose of this study was to investigate the long-term mortality rates of patients with obstructive sleep apnea (OSA) who received an overnight polysomnogram (PSG) for obtaining the diagnosis and to determine the relationship between PSG parameters and overall mortality.

METHODS

Between 2007 and 2013, patients who had overnight PSG and were diagnosed with OSA were included in the study. Factors which are thought to influence mortality were assessed for 5-year and overall survival using the log rank test and Kaplan-Meier survival curves. Using multivariable Cox regression analysis, a model was constructed for factors influencing 5-year and overall survival.

RESULTS

A total of 762 patients with a mean age of 52.7 (±10.8) and a dominance of men (74.7%) were studied. Gender, OSA severity subgroups, and apnea hypopnea index (AHI) were not statistically significantly associated with either 5-year or overall mortality (p<0.05 for both). Age, having a cardiovascular comorbidity, proportion of rapid eye movement (%REM), and total sleep time with an oxyhemoglobin saturation of less than 90% (T90) all showed a significant correlation with overall all-cause mortality in the model. For 5-year mortality and overall mortality, the hazard ration (HR) for T90 was 3.6 (95% CI (1.6-8.0) p=0.001) and 3 (95% CI (1.6-5.7) p=0.001), respectively.

CONCLUSION

The study findings suggest that not AHI but PSG parameters of hypoxia, mainly T90, having cardiovascular comorbidity, and %REM sleep were significant risk factors for all-cause mortality in patients with OSA. The association of OSA, hypoxia, and mortality is an area that deserves further study.

ERS International Congress 2023: highlights from the Sleep Disordered Breathing Assembly

The topic of sleep-related breathing disorders is always evolving, and during the European Respiratory Society (ERS) International Congress 2023 in Milan, Italy, the latest research and clinical topics in respiratory medicine were presented. The most interesting issues included new diagnostic tools, such as cardiovascular parameters and artificial intelligence, pathophysiological traits of sleep disordered breathing from routine polysomnography or polygraphy signals, and new biomarkers and the diagnostic approach in patients with excessive daytime sleepiness. This article summarises the most relevant studies and topics presented at the ERS International Congress 2023. Each section has been written by early career members of ERS Assembly 4.

Is the time below 90% of SpO2 during sleep (T90%) a metric of good health? A longitudinal analysis of two cohorts

BACKGROUND

Novel wireless-based technologies can easily record pulse oximetry at home. One of the main parameters that are recorded in sleep studies is the time under 90% of SpO2 (T90%) and the oxygen desaturation index 3% (ODI-3%). We assessed the association of T90% and/or ODI-3% in two different scenarios (a community-based study and a clinical setting) with all-cause mortality (primary outcome).

METHODS

We included all individuals from the Sleep Heart Health Study (SHHS, community-based cohort) and Santiago Obstructive Sleep Apnea (SantOSA, clinical cohort) with complete data at baseline and follow-up. Two measures of hypoxemia (T90% and ODI-3%) were our primary exposures. The adjusted hazard ratios (HRs) per standard deviation (pSD) between T90% and incident all-cause mortality (primary outcome) were determined by adjusted Cox regression models. In the secondary analysis, to assess whether T90% varies across clinical factors, anthropometrics, abdominal obesity, metabolic rate, and SpO2, we conducted linear regression models. Incremental changes in R2 were conducted to test the hypothesis.

RESULTS

A total of 4323 (56% male, median 64 years old, follow-up: 12 years, 23% events) and 1345 (77% male, median 55 years old, follow-up: 6 years, 11.6% events) patients were included in SHHS and SantOSA, respectively. Every 1 SD increase in T90% was associated with an adjusted HR of 1.18 [95% CI: 1.10-1.26] (p value < 0.001) in SHHS and HR 1.34 [95% CI: 1.04-1.71] (p value = 0.021) for all-cause mortality in SantOSA. Conversely, ODI-3% was not associated with worse outcomes. R2 explains 62% of the variability in T90%. The main contributors were baseline-mean change in SpO2, baseline SpO2, respiratory events, and age.

CONCLUSION

The findings suggest that T90% may be an important marker of wellness in clinical and community-based scenarios. Although this nonspecific metric varies across the populations, ventilatory changes during sleep rather than other physiological or comorbidity variables explain their variability.

Achieving Better Understanding of Obstructive Sleep Apnea Treatment Effects on Cardiovascular Disease Outcomes through Machine Learning Approaches: A Narrative Review

Obstructive sleep apnea (OSA) affects almost a billion people worldwide and is associated with a myriad of adverse health outcomes. Among the most prevalent and morbid are cardiovascular diseases (CVDs). Nonetheless, randomized controlled trials (RCTs) of OSA treatment have failed to show improvements in CVD outcomes. A major limitation in our field is the lack of precision in defining OSA and specifically subgroups with the potential to benefit from therapy. Further, this has called into question the validity of using the time-honored apnea-hypopnea index as the ultimate defining criteria for OSA. Recent applications of advanced statistical methods and machine learning have brought to light a variety of OSA endotypes and phenotypes. These methods also provide an opportunity to understand the interaction between OSA and comorbid diseases for better CVD risk stratification. Lastly, machine learning and specifically heterogeneous treatment effects modeling can help uncover subgroups with differential outcomes after treatment initiation. In an era of data sharing and big data, these techniques will be at the forefront of OSA research. Advanced data science methods, such as machine-learning analyses and artificial intelligence, will improve our ability to determine the unique influence of OSA on CVD outcomes and ultimately allow us to better determine precision medicine approaches in OSA patients for CVD risk reduction. In this narrative review, we will highlight how team science via machine learning and artificial intelligence applied to existing clinical data, polysomnography, proteomics, and imaging can do just that.

Positive Airway Pressure Therapy Predicts Lower Mortality and Major Adverse Cardiovascular Events Incidence in Medicare Beneficiaries with Obstructive Sleep Apnea

Background

Obesity is associated with obstructive sleep apnea (OSA) and cardiovascular risk. Positive airway pressure (PAP) is the first line treatment for OSA, but evidence on its beneficial effect on major adverse cardiovascular events (MACE) prevention is limited. Using claims data, the effects of PAP on mortality and incidence of MACE among Medicare beneficiaries with OSA were examined.

Methods

A cohort of Medicare beneficiaries with ≥2 distinct OSA claims was defined from multi-state, state-wide, multi-year (2011-2020) Medicare fee-for-service claims data. Evidence of PAP initiation and utilization was based on PAP claims after OSA diagnosis. MACE was defined as a composite of myocardial infarction, heart failure, stroke, or coronary revascularization. Doubly robust Cox proportional hazards models with inverse probability of treatment weights estimated treatment effects controlling for sociodemographic and clinical factors.

Results

Among 888,835 beneficiaries with OSA (median age 73 years; 43.9% women; median follow-up 1,141 days), those with evidence of PAP initiation (32.6%) had significantly lower all-cause mortality (HR [95%CI]: 0.53 [0.52-0.54]) and MACE incidence risk (0.90 [0.89-0.91]). Higher quartiles of annual PAP claims were progressively associated with lower mortality (Q2: 0.84 [0.81-0.87], Q3: 0.76 [0.74-0.79], Q4: 0.74 [0.72-0.77]) and MACE incidence risk (Q2: 0.92 [0.89-0.95], Q3: 0.89 [0.86-0.91], Q4: 0.87 [0.85-0.90]).

Conclusion

PAP utilization was associated with lower all-cause mortality and MACE incidence among Medicare beneficiaries with OSA. Results might inform trials assessing the importance of OSA therapy towards minimizing cardiovascular risk and mortality in older adults.

Loop Gain as a Predictor of Blood Pressure Response in Patients Treated for Obstructive Sleep Apnea: Secondary Analysis of a Clinical Trial

Rationale: Randomized trials have shown inconsistent cardiovascular benefits from obstructive sleep apnea (OSA) therapy. Intermittent hypoxemia can increase both sympathetic nerve activity and loop gain ("ventilatory instability"), which may thus herald cardiovascular treatment benefit. Objectives: To test the hypothesis that loop gain predicts changes in 24-hour mean blood pressure (MBP) in response to OSA therapy and compare its predictive value against that of other novel biomarkers. Methods: The HeartBEAT (Heart Biomarker Evaluation in Apnea Treatment) trial assessed the effect of 12 weeks of continuous positive airway pressure (CPAP) versus oxygen versus control on 24-hour MBP. We measured loop gain and hypoxic burden from sleep tests and identified subjects with a sleepy phenotype using cluster analysis. Associations between biomarkers and 24-h MBP were assessed in the CPAP/oxygen arms using linear regression models adjusting for various covariates. Secondary outcomes and predictors were analyzed similarly. Results: We included 93 and 94 participants in the CPAP and oxygen arms, respectively. Overall, changes in 24-hour MBP were small, but interindividual variability was substantial (mean [standard deviation], -2 [8] and 1 [8] mm Hg in the CPAP and oxygen arms, respectively). Higher loop gain was significantly associated with greater reductions in 24-hour MBP independent of covariates in the CPAP arm (-1.5 to -1.9 mm Hg per 1-standard-deviation increase in loop gain; P ⩽ 0.03) but not in the oxygen arm. Other biomarkers were not associated with improved cardiovascular outcomes. Conclusions: To our knowledge, this is the first study suggesting that loop gain predicts blood pressure response to CPAP therapy. Eventually, loop gain estimates may facilitate patient selection for research and clinical practice. Clinical trial registered with www.clinicaltrials.gov (NCT01086800).

Anatomy and physiology of the autonomic nervous system: Implication on the choice of diagnostic/monitoring tools in 2023

The autonomic nervous system (ANS) harmoniously regulates all internal organic functions (heart rate, blood pressure, vasomotion, digestive tract motility, endocrinal secretions) and adapts them to the needs. It's the control of so-called vegetative functions, which allows homeostasis but also allostasis of our body. ANS is divided into two systems often understood as antagonistic and complementary: the sympathetic and the parasympathetic systems. However, we currently know of many situations of co-activation of the two systems. Long seen as acting through "reflex" control loops passing through the integration of peripheral information and the efferent response to the peripheral organ, more recent electrophysiological and brain functional imaging knowledge has been able to identify the essential role of the central autonomic network. This element complicates the understanding of the responses of the reflex loops classically used to identify and quantify dysautonomia. Finding the "ANS" tools best suited for the clinician in their daily practice is a challenge that we will attempt to address in this work.

Long-term health outcomes for patients with obstructive sleep apnea: placing the Agency for Healthcare Research and Quality report in context-a multisociety commentary

This multisociety commentary critically examines the Agency for Healthcare Research and Quality (AHRQ) final report and systematic review on long-term health outcomes in obstructive sleep apnea. The AHRQ report was commissioned by the Centers for Medicare & Medicaid Services and particularly focused on the long-term patient-centered outcomes of continuous positive airway pressure, the variability of sleep-disordered breathing metrics, and the validity of these metrics as surrogate outcomes. This commentary raises concerns regarding the AHRQ report conclusions and their potential implications for policy decisions. A major concern expressed in this commentary is that the AHRQ report inadequately acknowledges the benefits of continuous positive airway pressure for several established, long-term clinically important outcomes including excessive sleepiness, motor vehicle accidents, and blood pressure. While acknowledging the limited evidence for the long-term benefits of continuous positive airway pressure treatment, especially cardiovascular outcomes, as summarized by the AHRQ report, this commentary reviews the limitations of recent randomized controlled trials and nonrandomized controlled studies and the challenges of conducting future randomized controlled trials. A research agenda to address these challenges is proposed including study designs that may include both high quality randomized controlled trials and nonrandomized controlled studies. This commentary concludes by highlighting implications for the safety and quality of life for the millions of people living with obstructive sleep apnea if the AHRQ report alone was used by payers to limit coverage for the treatment of obstructive sleep apnea while not considering the totality of available evidence.

CITATION

Patil SP, Billings ME, Bourjeily G, et al. Long-term health outcomes for patients with obstructive sleep apnea: placing the Agency for Healthcare Research and Quality report in context-a multisociety commentary. J Clin Sleep Med. 2024;20(1):135-149.

Clinical Application of the Multicomponent Grading System for Sleep Apnea Classification and Incident Cardiovascular Mortality

Objective  To evaluate the clinical utility of the Baveno classification in predicting incident cardiovascular mortality after five years of follow-up in a clinic-based cohort of patients with obstructive sleep apnea (OSA). Materials and Methods  We evaluated the reproducibility of the Baveno classification using data from the Santiago Obstructive Sleep Apnea (SantOSA) study. The groups were labeled Baveno A (minor symptoms and comorbidities), B (severe symptoms and minor comorbidities), C (minor symptoms and severe comorbidities), and D (severe symptoms and comorbidities). Within-group comparisons were performed using analysis of variance (ANOVA) and post hoc tests. The associations between groups and incident cardiovascular mortality were determined through the Mantel-Cox and Cox proportional hazard ratios (HRs) adjusted by covariables. Results  A total of 1,300 OSA patients were included (Baveno A: 27.7%; B: 28%; C: 16.8%; and D: 27.5%). The follow-up was of 5.4 years. Compared to Baveno A, the fully-adjusted risk of cardiovascular mortality with Baveno B presented an HR of 1.38 (95% confidence interval [95%CI]: 0.14-13.5; p  = 0.78); with Baveno C, it was of 1.71 (95%CI: 0.18-16.2; p  = 0.63); and, with Baveno D, of 1.04 (95%CI: 0.12-9.2; p  = 0.98). We found no interactions involving Baveno group, sex and OSA severity. Discussion  Among OSA patients, the Baveno classification can describe different subgroups. However, its utility in identifying incident cardiovascular mortality is unclear. Long-term follow-up studies and the inclusion of demographic variables in the classification could improve its ability to detect a high-risk phenotype associated with cardiovascular mortality. Conclusion  The Baveno classification serves as a valuable method for categorizing varying groups of patients afflicted with OSA. Nevertheless, its precision in identifying occurrence of cardiovascular mortality is still unclear.

Ventilatory Burden as a Measure of Obstructive Sleep Apnea Severity Is Predictive of Cardiovascular and All-Cause Mortality

Rationale: The apnea-hypopnea index (AHI), used for the diagnosis of obstructive sleep apnea, captures only the frequency of respiratory events and has demonstrable limitations. Objectives: We propose a novel automated measure, termed "ventilatory burden" (VB), that represents the proportion of overnight breaths with less than 50% normalized amplitude, and we show its ability to overcome limitations of AHI. Methods: Data from two epidemiological cohorts (EPISONO [Sao Paolo Epidemiological Study] and SHHS [Sleep Heart Health Study]) and two retrospective clinical cohorts (DAYFUN; New York University Center for Brain Health) were used in this study to 1) derive the normative range of VB, 2) assess the relationship between degree of upper airway obstruction and VB, and 3) assess the relationship between VB and all-cause and cardiovascular disease (CVD) mortality with and without hypoxic burden that was derived using an in-house automated algorithm. Measurements and Main Results: The 95th percentiles of VB in asymptomatic healthy subjects across the EPISONO and the DAYFUN cohorts were 25.2% and 26.7%, respectively (median [interquartile range], VBEPISONO, 5.5 [3.5-9.7]%; VBDAYFUN, 9.8 [6.4-15.6]%). VB was associated with the degree of upper airway obstruction in a dose-response manner (VBuntreated, 31.6 [27.1]%; VBtreated, 7.2 [4.7]%; VBsuboptimally treated, 17.6 [18.7]%; VBoff-treatment, 41.6 [18.1]%) and exhibited low night-to-night variability (intraclass correlation coefficient [2,1], 0.89). VB was predictive of all-cause and CVD mortality in the SHHS cohort before and after adjusting for covariates including hypoxic burden. Although AHI was predictive of all-cause mortality, it was not associated with CVD mortality in the SHHS cohort. Conclusions: Automated VB can effectively assess obstructive sleep apnea severity, is predictive of all-cause and CVD mortality, and may be a viable alternative to the AHI.