Evaluation of a single-channel nasal pressure device to assess obstructive sleep apnea risk in laboratory and home environments

Mandibular Jaw Movement Automated Analysis for Oral Appliance Monitoring in Obstructive Sleep Apnea: A Prospective Cohort Study

Rationale: Oral appliances are second-line treatments after continuous positive airway pressure for obstructive sleep apnea (OSA) management. However, the need for oral appliance titration limits their use as a result of monitoring challenges to assess the treatment effect on OSA. Objectives: To assess the validity of mandibular jaw movement (MJM) automated analysis compared with polysomnography (PSG) and polygraphy (PG) in evaluating the effect of oral appliance treatment and the effectiveness of MJM monitoring for oral appliance titration at home in patients with OSA. Methods: This observational, prospective study included 135 patients with OSA eligible for oral appliance therapy. The primary outcome was the apnea-hypopnea index (AHI), measured through in-laboratory PSG/PG and MJM-based technology. Additionally, MJM monitoring at home was conducted at regular intervals during the titration process. The agreement between PSG/PG and MJM automated analysis was revaluated using Bland-Altman analysis. Changes in AHI during the home-based oral appliance titration process were evaluated using a generalized linear mixed model and a generalized estimating equation model. Results: The automated MJM analysis demonstrated strong agreement with PG in assessing AHI at the end of titration, with a median bias of 0.24/h (limits of agreement, -11.2 to 12.8/h). The improvement of AHI from baseline in response to oral appliance treatment was consistent across three evaluation conditions: in-laboratory PG (-59.6%; 95% confidence interval, -59.8% to -59.5%), in-laboratory automated MJM analysis (-59.2%; -65.2% to -52.2%), and at-home automated MJM analysis (-59.7%; -67.4% to -50.2%). Conclusions: Incorporating MJM automated analysis into the oral appliance titration process has the potential to optimize oral appliance therapy outcomes for OSA.

Algorithmic detection of sleep-disordered breathing using respiratory signals: a systematic review

Background and Objective. Sleep-disordered breathing (SDB) poses health risks linked to hypertension, cardiovascular disease, and diabetes. However, the time-consuming and costly standard diagnostic method, polysomnography (PSG), limits its wide adoption and leads to underdiagnosis. To tackle this, cost-effective algorithms using single-lead signals (like respiratory, blood oxygen, and electrocardiogram) have emerged. Despite respiratory signals being preferred for SDB assessment, a lack of comprehensive reviews addressing their algorithmic scope and performance persists. This paper systematically reviews 2012-2022 literature, covering signal sources, processing, feature extraction, classification, and application, aiming to bridge this gap and provide future research references.Methods. This systematic review followed the registered PROSPERO protocol (CRD42022385130), initially screening 342 papers, with 32 studies meeting data extraction criteria.Results. Respiratory signal sources include nasal airflow (NAF), oronasal airflow (OAF), and respiratory movement-related signals such as thoracic respiratory effort (TRE) and abdominal respiratory effort (ARE). Classification techniques include threshold rule-based methods (8), machine learning models (13), and deep learning models (11). The NAF-based algorithm achieved the highest average accuracy at 94.11%, surpassing 78.19% for other signals. Hypopnea detection sensitivity with single-source respiratory signals remained modest, peaking at 73.34%. The TRE and ARE signals proved to be reliable in identifying different types of SDB because distinct respiratory disorders exhibited different patterns of chest and abdominal motion.Conclusions. Multiple detection algorithms have been widely applied for SDB detection, and their accuracy is closely related to factors such as signal source, signal processing, feature selection, and model selection.

Heart Rate During Sleep in PTSD Patients: Moderation by Contact with a Service Dog

There is growing interest in the potential health benefits of dog ownership in both the lay and scientific communities. Large reductions in risk for cardiovascular disease and all-cause mortality in dog owners relative to non-owners have been observed in epidemiological samples. Persons diagnosed with posttraumatic stress disorder exhibit elevated risk for cardiovascular disease. The current study tested a sample of 45 U.S. military veterans with deployment-related posttraumatic stress disorder employing an intensive, longitudinal, within-subjects design contrasting sleep heart rate on nights with and without a service dog. As participants were engaged in residential psychiatric treatment, sleep opportunities, waking activities, meals, and medications, were consistently scheduled. The primary recording methodology, mattress actigraphy, enabled passive quantification of heart rate over a total sample of 1097 nights. Service dog contact was associated with reduced sleep heart rate especially in participants with more severe PTSD. Longer-term longitudinal studies will be needed to assess the durability and asymptotic magnitude of this effect. An unexpected effect of nights in study was associated with increased heart rate consistent with hospitalization-associated deconditioning.

Screening for obstructive sleep apnoea in post-treatment cancer patients

BACKGROUND AND AIMS

For cancer patients, comorbid obstructive sleep apnea (OSA) poses additional risk to their surgical/anaesthetic outcomes, quality of life, and survival. However, OSA screening is not well-established in oncology settings. We tested two screening tools (STOP-Bang questionnaire [SBQ] and the at-home monitoring device, ApneaLink™Air), for predicting polysomnography (PSG) confirmed OSA in post-treatment cancer patients.

METHODS

Breast (n = 56), endometrial (n = 37) and melanoma patients (n = 50) were recruited from follow-up clinics at Westmead Hospital (Sydney, Australia). All underwent overnight PSG, 137 completed SBQ, and 99 completed ApneaLink™Air. Positive (PPV) and negative (NPV) predictive values for PSG-determined moderate-to-severe OSA and severe OSA, were calculated using an SBQ threshold ≥3 au and ApneaLink™Air apnoea-hypopnea index thresholds of ≥10, ≥15 and ≥30 events/h.

RESULTS

Both SBQ and ApneaLink™Air had high NPVs (92.7% and 85.2%-95.6% respectively) for severe OSA, but NPVs were lower for moderate-to-severe OSA (69.1% and 59.1%-75.5%, respectively). PPV for both tools were relatively low (all <73%). Combining both tools did not improve screening performance.

CONCLUSIONS

These screening tools may help identify cancer patients without severe OSA, but both are limited in identifying those with moderate-to-severe or severe OSA. PSG remains optimal for adequately identifying and managing comorbid OSA in cancer patients.

Portable evaluation of obstructive sleep apnea in adults: A systematic review

Obstructive sleep apnea (OSA) is a significant healthcare burden affecting approximately one billion people worldwide. The prevalence of OSA is rising with the ongoing obesity epidemic, a key risk factor for its development. While in-laboratory polysomnography (PSG) is the gold standard for diagnosing OSA, it has significant drawbacks that prevent widespread use. Portable devices with different levels of monitoring are available to allow remote assessment for OSA. To better inform clinical practice and research, this comprehensive systematic review evaluated diagnostic performances, study cost and patients' experience of different levels of portable sleep studies (type 2, 3, and 4), as well as wearable devices and non-contact systems, in adults. Despite varying study designs and devices used, portable diagnostic tests are found to be sufficient for initial screening of patients at risk of OSA. Future studies are needed to evaluate cost effectiveness with the incorporation of portable diagnostic tests into the diagnostic pathway for OSA, as well as their application in patients with chronic respiratory diseases and other comorbidities that may affect test performance.

Impact of transcatheter edge-to-edge mitral valve repair on central sleep apnoea

Aims

Sleep-disordered breathing (SDB) and its subtype central sleep apnoea (CSA) are highly prevalent in patients with heart failure and associated with worse prognosis. Whereas pharmacological therapy of heart failure has been shown to ameliorate CSA, results from previous studies on the effect of mitral regurgitation therapy on SDB are contradicting. The aim of this study was to assess the impact of transcatheter edge-to-edge mitral valve repair (TEER) on prevalence and severity of CSA.

Methods and results

We enrolled 47 patients undergoing TEER for symptomatic mitral regurgitation in a prospective study. Secondary mitral regurgitation and left ventricular ejection fraction < 50% were present in 79% and 68% of patients, respectively. Respiratory polygraphy was performed before TEER in a compensated condition and four weeks after the procedure. 34 patients completed the follow-up. At baseline, 19 (56%) patients showed moderate-to-severe SDB, of whom 13 (68%) were classified as CSA. Both apnoea-hypopnoea index and percentage of recorded time spent in Cheyne-Stokes respiration strongly decreased from baseline to follow-up (median [IQR] 16 [7–30] vs. 7 [4–15] /h, p = 0.007; 6 [0–34] vs. 0 [0–8] %, p = 0.008). Median relative reduction of central apnoea index was 75% (p = 0.023), while obstructive apnoea index did not change significantly. Increase in stroke volume after TEER and high systolic pulmonary artery pressure at baseline predicted a > 50% reduction of both Apnoea-hypopnoea index and Cheyne-Stokes respiration.

Conclusion

TEER is associated with a significant short-term reduction of CSA and Cheyne-Stokes respiration in high-risk patients, strengthening its value as an effective treatment option for advanced heart failure.

Graphical abstract

A generalized algorithm for the automatic diagnosis of sleep apnea from per-sample encoding of airflow and oximetry

OBJECTIVE

Sleep apnea is a common sleep breathing disorder that can significantly decrease sleep quality and have major health consequences. It is diagnosed based on the apnea hypopnea index (AHI). This study explored a novel, generalized algorithm for the automatic diagnosis of sleep apnea employing airflow (AF) and oximetry (SpO2) signals.

APPROACH

Of the 988 polysomnography records, 45 were randomly selected for developing the automatic algorithm and the remainder 943 for validating purposes. The algorithm detects apnea events by a per-sample encoding process applied to the peak excursion of AF signal. Hypopnea events were detected from the per-sample encoding of AF and SpO2 with an adjustment to time lag in SpO2. Total recording time was automatically processed and optimized for computation of total sleep time (TST). Total number of detected events and computed TST were used to estimate AHI. The estimated AHI was validated against the scored data from the Sleep Heart Health Study.

MAIN RESULTS

Intraclass correlation coefficient of 0.94 was obtained between estimated and scored AHIs. The diagnostic accuracies were 93.5%, 92.4%, and 96.6% for AHI cut-off values of ≥5, ≥15, and ≥30 respectively. The overall accuracy for the combined severity categories (normal, mild, moderate, and severe) and kappa were 83.4% and 0.77 respectively.

SIGNIFICANCE

This new automatic technique was found to be superior to the other existing methods and can be applied to any portable sleep devices especially for home sleep apnea tests.

Home Sleep Testing of Sleep Apnea

Measurement methods with graded complexity for use in the lab as well as for home sleep testing (HST) are available for the diagnosis of sleep apnea, and there are different classification systems in existence. Simplified HST measurements, which record fewer parameters than traditional four- to six-channel devices, can indicate sleep apnea and can be used as screening tool in high-prevalence patient groups. Peripheral arterial tonometry (PAT) is a technique which can be suitable for the diagnosis of sleep apnea in certain cases. Different measurement methods are used, which has an influence on the significance of the results. New minimal-contact and non-contact technologies of recording and analysis of surrogate parameters are under development. If they are validated by clinical studies, it will be possible to detect sleep apnea in need of treatment more effectively. In addition, this could become a solution to monitor the effectiveness of such treatment.

Sleep-Disordered Breathing in Pregnancy

Sleep-disordered breathing (SDB) is a spectrum of abnormal respiratory events including habitual snoring and increased upper airway resistance and obstructive episodes. The uncertainties concerning the incidence and recognition of SDB during pregnancy and the importance of the issue for fetal and maternal health prompted us to screen pregnant women for SDB. The study included 312 women in the third trimester of pregnancy aged 17-46 of whom 51 were preselected, based on the results of SDB questionnaires, for a nighttime home screening using a portable ApneaLink Air device. We found that single or multiple episodes of apnea were present in 35 (69%) women. The mean apnea/hypopnea index (AHI) was 1.8 ± 1.8 episodes/h of sleep, which did not exceed the prevalence in the general young-adult female population. However, we noticed a substantial number of inspiratory airflow limitation (IFL) episodes most often accompanied by snoring and more frequent in pregnant women with a greater weight gain. IFLs, although not fulfilling the quantifiable criteria of hypopnea, raise the possibility of hardly recognizable oxygenation and cardiovascular disturbances in pregnancy, reflected in an increased risk index for SDB. We conclude that pregnancy encompasses the risk of revealing or intensifying pre-existing SDB which can jeopardize maternal and fetal health. The risk particularly applies to overweight women. We submit that women in late pregnancy should be carefully screened for possible SDB.

Diagnostic approaches to respiratory abnormalities in craniofacial syndromes

Craniofacial syndromes are a complex cluster of genetic conditions characterized by embryonic perturbations in the developmental trajectory of the upper airway and related structures. The presence of reduced airway size and maladaptive neuromuscular responses, particularly during sleep, leads to significant alterations in sleep architecture and overall detrimental gas exchange abnormalities that can be life-threatening. The common need for multi-stage therapeutic interventions for these craniofacial problems requires careful titration of anatomy and function, and the latter is currently evaluated by overnight polysomnography in sleep laboratories. The cost, inconvenience, and scarcity of pediatric sleep laboratories preclude the frequent evaluations that could optimize the overall process of treatment and corresponding outcomes. Here, we critically examine reductionist approaches to polysomnography in children to establish the parallel approximation of such techniques to infant with craniofacial disorders. The need for prospective longitudinal multicenter studies with side-by-side comparisons aimed at identifying an optimal diagnostic and long-term monitoring paradigm for these potentially life-threatening conditions is emphasized.

Validity and Cost-Effectiveness of Pediatric Home Respiratory Polygraphy for the Diagnosis of Obstructive Sleep Apnea in Children: Rationale, Study Design, and Methodology

Obstructive sleep apnea (OSA) in children is a prevalent, albeit largely undiagnosed disease associated with a large spectrum of morbidities. Overnight in-lab polysomnography remains the gold standard diagnostic approach, but is time-consuming, inconvenient, and expensive, and not readily available in many places. Simplified Home Respiratory Polygraphy (HRP) approaches have been proposed to reduce costs and facilitate the diagnostic process. However, evidence supporting the validity of HRP is still scarce, hampering its implementation in routine clinical use. The objectives were: Primary; to establish the diagnostic and therapeutic decision validity of a simplified HRP approach compared to PSG among children at risk of OSA. Secondary: (a) Analyze the cost-effectiveness of the HRP versus in-lab PSG in evaluation and treatment of pediatric OSA; (b) Evaluate the impact of therapeutic interventions based on HRP versus PSG findings six months after treatment using sleep and health parameters and quality of life instruments; (c) Discovery and validity of the urine biomarkers to establish the diagnosis of OSA and changes after treatment.

Cognitive profiles in obstructive sleep apnea: a cluster analysis in sleep clinic and community samples

STUDY OBJECTIVES

Although cognitive dysfunction is a recognized consequence of untreated obstructive sleep apnea (OSA), the deficit pattern is heterogeneous. Understanding this heterogeneity may identify those at risk of cognitive deficits and guide intervention strategies. To facilitate understanding, we examined whether distinct profiles of neuropsychological performance were present in OSA and, if so, how they are related to other OSA features.

METHODS

We studied sleep clinic (n = 121) and community (n = 398) samples with moderate-severe OSA (apnea-hypopnea index ≥ 15 events/h). Attention and memory were assessed using the Cognitive Drug Research system. Sleep was assessed using polysomnography in the clinic sample and dual channel (flow, oximetry) portable monitoring in the community sample. Latent profile analysis was used to determine structure of cognitive clusters. Discriminant function analysis was used to examine associations between nocturnal and diurnal features of OSA and profile membership.

RESULTS

Both samples were best characterized by a 3-profile solution: (1) strong thinkers (performed well across most domains and showed greater cognitive reserve); (2) inattentive fast thinkers (strong processing speed but poor ability to maintain attention); and (3) accurate slow thinkers (strengths in maintaining attention but poor processing speed). Profile membership was associated with mean overnight oxygen saturation and cognitive reserve in the clinic sample and the presence of cardiovascular disease and/or diabetes in the community sample.

CONCLUSIONS

These findings help explain the diversity of outcomes in previous studies of cognitive dysfunction in OSA by demonstrating that individual differences in cognitive reserve, nocturnal oxygen saturation, and comorbidities affect how cognition is impacted by OSA.

The implementation of a physical activity intervention in adults with Obstructive Sleep Apnoea over the age of 50 years: a feasibility uncontrolled clinical trial

Background

Obstructive Sleep Apnoea (OSA) is a risk factor for cardiovascular disease (CVD) and Type 2 diabetes (T2D). Observational studies suggested that OSA treatment might reduce CVD and T2D but RCTs failed to support these observations in part due to poor adherence to continuous positive airway pressure (CPAP). Physical activity (PA) has been shown to have favourable impact on CVD and the risk of T2D independent of its impact on weight and therefore might provide additional health gains to patients with OSA, whether or not adherent to CPAP.

Methods

The main aim of this study was to explore the feasibility of providing a 12-week PA intervention to adults aged over 50 with OSA. The secondary aim was to assess the impact of the PA intervention on OSA severity. Patients with moderate-severe OSA (apnoea hypopnea index (AHI) ≥ 15 events/hour (based on overnight ApneaLink™) were recruited in response to posters displayed in workplaces. A 12-week daily PA intervention was delivered in participant’s home setting and PA was monitored via text and validated by objective PA measures (GT3X accelerometers).

Results

The intervention was feasible as all 10 patients (8 males, mean (SD) age 57.3 (6.01)) completed the intervention and PA increased across the 12-weeks. The duration of PA increased from baseline (113.1 min (64.69) per week to study-end following the intervention (248.4 min (148.31) (p = 0.02). Perceived Exertion (RPE) (physical effort) increased significantly between baseline (M = 10.7 (1.94)) to end of intervention (M = 13.8, (1.56) (p < 0.001). The intervention had no significant impact on weight or composition. Following the intervention, there was a statistically non-significant a reduction in AHI from baseline to study end (22.3 (7.35) vs. 15.8 (7.48); p = 0.09).

Conclusion

It is feasible to deliver a PA intervention to adults aged over 50 with OSA. The intervention resulted in improved PA and AHI levels somewhat and seemingly independent of weight changes. Future trials need to examine whether PA can reduce the burden of OSA associated comorbidities.

Trial registration

CTN: ISRCTN11016312 Retrospectively Registered 21/07/20.

A machine learning-based test for adult sleep apnoea screening at home using oximetry and airflow

The most appropriate physiological signals to develop simplified as well as accurate screening tests for obstructive sleep apnoea (OSA) remain unknown. This study aimed at assessing whether joint analysis of at-home oximetry and airflow recordings by means of machine-learning algorithms leads to a significant diagnostic performance increase compared to single-channel approaches. Consecutive patients showing moderate-to-high clinical suspicion of OSA were involved. The apnoea-hypopnoea index (AHI) from unsupervised polysomnography was the gold standard. Oximetry and airflow from at-home polysomnography were parameterised by means of 38 time, frequency, and non-linear variables. Complementarity between both signals was exhaustively inspected via automated feature selection. Regression support vector machines were used to estimate the AHI from single-channel and dual-channel approaches. A total of 239 patients successfully completed at-home polysomnography. The optimum joint model reached 0.93 (95%CI 0.90–0.95) intra-class correlation coefficient between estimated and actual AHI. Overall performance of the dual-channel approach (kappa: 0.71; 4-class accuracy: 81.3%) significantly outperformed individual oximetry (kappa: 0.61; 4-class accuracy: 75.0%) and airflow (kappa: 0.42; 4-class accuracy: 61.5%). According to our findings, oximetry alone was able to reach notably high accuracy, particularly to confirm severe cases of the disease. Nevertheless, oximetry and airflow showed high complementarity leading to a remarkable performance increase compared to single-channel approaches. Consequently, their joint analysis via machine learning enables accurate abbreviated screening of OSA at home.

SIESTA - Home sleep study with BresoDx for obstructive sleep apnea: a randomized controlled trial

STUDY OBJECTIVES

The objectives of this study were to evaluate (1) the accuracy of the clinical diagnosis of obstructive sleep apnea (OSA) informed by the home sleep study with a Type 4 portable monitor BresoDx® versus Type 1 polysomnography (PSG); and (2) agreement of the apnea-hypopnea index (AHI) compared between BresoDx and PSG.

MATERIAL AND METHODS

This was a randomized, parallel, multicentre, single-blind, pragmatic controlled trial enrolling adults referred to three Ontario sleep clinics for suspected OSA. Participants were randomized to BresoDx followed by PSG (one-night apart) or PSG followed by BresoDx sleep testing sequence arms. The primary outcomes included the accuracy of clinical diagnosis and OSA severity measured by AHI between tests.

RESULTS

In sum, 233 participants completed both sleep studies and 206 completed physician consultation visits. The agreement between clinical diagnosis informed by PSG versus BresoDx was fair (Cohen's kappa coefficient = 0.28). The sensitivity of BresoDx-informed clinical diagnosis against PSG was between 0.86 and 0.89, and the specificity between 0.38 and 0.44. For AHI cut-off of ≥5 events/hour the sensitivity, specificity and positive and negative predictive values were 0.85, 0.48, 0.81 and 0.54.

CONCLUSIONS

Home sleep apnea testing with BresoDx can be used in a referral population with a high pretest probability of OSA similar to other Type IV devices. This study complements the existing body of evidence suggesting that home testing with portable devices plays a valuable role for diagnosing of OSA in a variety of settings. SIESTA TRIAL REGISTRATION: www.clinicaltrials.gov (Identifier: NCT02003729).

Undiagnosed Obstructive Sleep Apnea and Physical Activity in Older Manual Workers

Cardiovascular disease is a negative health outcome of obstructive sleep apnea (OSA). Risk factors associated with OSA development include low physical activity (PA), high body mass index (BMI), and increasing age (>50 years), and weight loss is usually recommended as treatment. This cross-sectional study examined the association between PA, BMI, and OSA severity in manual workers. Fifty-five participants (23 females and 32 males; mean age 55.2 years), were examined for OSA and completed a PA and anthropometric assessment. On average, OSA severity was mild, PA levels were moderate, and 32% of the sample was classified as obese. PA was negatively associated with OSA severity, but BMI strongly independently predicted OSA severity, with no evidence of mediation. As both PA and BMI were significantly associated with OSA in older manual workers, increasing PA should also be a focus of treatment for OSA.

Two Independent Predictors of Nightmares in Posttraumatic Stress Disorder

STUDY OBJECTIVES

Understanding nightmares (NM) and disturbing dreams (DD) in posttraumatic stress disorder (PTSD) has been limited by the unpredictability of these events and their nonappearance in the sleep laboratory. This study used intensive, longitudinal, ambulatory methods to predict morning reports of NM/DD in veterans in whom chronic, severe PTSD was diagnosed.

METHODS

Participants were 31 male United States military veterans engaged in residential treatment for PTSD and participating in a service animal training intervention. Participants slept on mattress actigraphs and provided reports of momentary mood, as well as morning NM/DD reports, for up to 6 weeks. Mattress actigraphy provided sleep-period heart rate and respiratory sinus arrhythmia (RSA), and an actigraphic estimate of sleep efficiency. On one night, a respiratory event index (REI) was obtained using an ambulatory system.

RESULTS

A total of 468 morning reports were obtained, of which 282 endorsed NM/DD during the prior night, and 186 did not. After accounting for multiple predictors, only elevated REI and lower prior-night sleep RSA predicted morning endorsement of NM/DD. These two predictors did not interact.

CONCLUSIONS

Elevated REI and lower sleep period RSA were independently predictive of NM/DD. The former result is consistent with studies showing that sleep-disordered breathing (SDB) is a factor in NM/DD, and that continuous positive airway pressure (CPAP) can reduce these symptoms in patients with comorbid PTSD and SDB. The latter result implicates dysregulated arousal modulation during sleep in trauma-related NM/DD. It is consistent with findings that NM/DD are reported in patients without SDB and can persist in patients with comorbid PTSD and SDB even when CPAP successfully remediates SDB.

Investigation of Obstructive Sleep Apnea Using Portable Monitors and Health Check Data in Japanese Drivers

AIMS

The identification and appropriate management of commercial motor vehicle (CMV) drivers with unrecognized obstructive sleep apnea (OSA) is a major public health concern and priority; OSA among drivers has not been fully investigated in Japan, and a better understanding of this undiagnosed disease is warranted. Therefore, we evaluated the prevalence of OSA and the factors related to apnea-hypopnea index (AHI) in Japanese CMV drivers.

METHODS

This retrospective study included 1309 Japanese CMV drivers aged 40-69 years. All the subjects received type Ⅳ portable sleep monitors (PMs) with Epworth Sleepiness Scale (ESS) and a periodic health check including anthropometrical and laboratory measurements, and a questionnaire of medical history, smoking status, and life style, following which variables related to AHI were analyzed.

RESULTS

Of all the subjects, 23.9% had moderate to severe OSA (AHI ≥15). Age, body mass index (BMI), LogeHbA1c and diastolic blood pressure (DBP) showed significance with AHI in 1309 subjects. The following factors were found to have significant odds ratio (OR) for AHI of ≥15 in 1309 subjects: age, ESS, DBP, and LogeHbA1c.

CONCLUSION

Notably, drivers with undiagnosed OSA exist. In these subjects, AHI was related to obesity, hypertension, and diabetes. For the early diagnosis and intervention of OSA, BMI, blood pressure, and HbA1c measurements may be helpful, particularly for drivers. Furthermore, when performing an objective assessment of the suspected OSA, evaluating these parameters during routine medical check-ups may be useful and feasible in the detection of drivers with latent OSA.

Screening for obstructive sleep apnea among hospital outpatients

Background

Obstructive sleep apnea syndrome (OSAS) is common in adults. People with OSAS have a higher risk of experiencing traffic accidents and occupational injuries (OIs). We aimed to clarify the diagnostic performance of a three-channel screening device (ApneaLink^TM) compared with the gold standard of full-night attended polysomnography (PSG) among hospital outpatients not referred for sleep-related symptoms. Furthermore, we aimed to determine whether manual revision of the ApneaLink^TM autoscore enhanced diagnostic performance.

Methods

We investigated 68 patients with OI and 44 without OI recruited from the University Hospital Basel emergency room, using a cross-sectional study design. Participating patients spent one night at home with ApneaLink^TM and within 2 weeks slept for one night at the sleep laboratory. We reanalyzed all ApneaLink^TM data after manual revision.

Results

We identified significant correlations between the ApneaLink^TM apnea-hypopnea index (AHI) autoscore and the AHI derived by PSG (r = 0.525; p <0.001) and between the ApneaLink^TM oxygen desaturation index (ODI) autoscore and that derived by PSG (r = 0.722; p <0.001). The ApneaLink^TM autoscore showed a sensitivity and specificity of 82% when comparing AHI ≥5 with the cutoff for AHI and/or ODI ≥15 from PSG. In Bland Altman plots the mean difference between ApneaLink^TM AHI autoscore and PSG was 2.75 with SD ± 8.80 (β = 0.034), and between ApneaLink^TM AHI revised score and PSG -1.50 with SD ± 9.28 (β = 0.060).

Conclusions

The ApneaLink^TM autoscore demonstrated good sensitivity and specificity compared with the gold standard (full-night attended PSG). However, Bland Altman plots revealed substantial fluctuations between PSG and ApneaLink^TM AHI autoscore respectively manually revised score. This spread for the AHI from a clinical perspective is large, and therefore the results have to be interpreted with caution. Furthermore, our findings suggest that there is no clinical benefit in manually revising the ApneaLinkTM autoscore.

Diagnosis of sleep apnea in patients with stable chronic heart failure using a portable sleep test diagnostic device

PURPOSE

ApneaLink is a portable device for the screening of sleep apnea, a prevalent and underdiagnosed comorbidity in heart failure patients. A prospective cross-sectional study in patients with chronic heart failure was carried out to assess the sensitivity and specificity of apnea-hypopnea index (AHI) measurements using ApneaLink against the standard polysomnography test.

METHODS

Adult patients with a prior hospitalization in an acute heart failure hospital unit were recruited for the study. All participants were tested for sleep apnea using ApneaLink and polysomnography simultaneously during an overnight stay at a sleep laboratory. Global sleep apnea was evaluated according to the AHI, which was analyzed and compared. Subpopulation comparison based on ejection fraction was not realized due to population size.

RESULTS

Thirty-five patients with stable chronic heart failure completed the study (mean age 70.9 ± 10.5 years and body mass index 30.0 ± 4.7 kg/m²). Two patients were excluded due to insufficient study duration. ApneaLink had a sensitivity greater than 80% for all AHI measurements, and a specificity greater than 80% for all AHI measurements, except for AHI ≥ 5 events/h (61.5%). The results showed higher sensitivities and specificities at AHI values of ≥ 10 events/h (sensitivity 81.3% and specificity 84.2%) and ≥ 15 events/h (sensitivity 83.3% and specificity 91.3%). Correlation analysis showed that AHI measurements using ApneaLink and polysomnography had a strong and significant correlation (r = 0.794; P < 0.001).

CONCLUSIONS

Our results suggest that ApneaLink could be used in clinical practice to identify heart failure patients with high (AHI ≥ 15 events/h) and low (AHI < 5 events/h) probability of having sleep apnea, sparing the need for a diagnostic polysomnography and thus potentially impacting prognosis by providing a more cost-effective and timely diagnosis of this non-cardiac comorbidity.

Diagnostic accuracy of level IV portable sleep monitors versus polysomnography for obstructive sleep apnea: a systematic review and meta-analysis

PURPOSE

Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder. In-laboratory, overnight type I polysomnography (PSG) is the current "gold standard" for diagnosing OSA. Home sleep apnea testing (HSAT) using portable monitors (PMs) is an alternative testing method offering better comfort and lower costs. We aimed to systematically review the evidence on diagnostic ability of type IV PMs compared to PSG in diagnosing OSA.

METHODS

Participants: patients ≥16 years old with symptoms suggestive of OSA;intervention: type IV PMs (devices with < 2 respiratory channels); comparator: in-laboratory PSG; outcomes: diagnostic accuracy measures;studies: cross-sectional, prospective observational/experimental/quasi-experimental studies; information sources: MEDLINE and Cochrane Library from January 1, 2010 to May 10, 2016. All stages of review were conducted independently by two investigators.

RESULTS

We screened 6054 abstracts and 117 full-text articles to select 24 full-text articles for final review. These 24 studies enrolled a total of 2068 patients with suspected OSA and evaluated 10 different PMs with one to six channels. Only seven (29%) studies tested PMs in the home setting. The mean difference (bias) between PSG-measured and PM-measured apnea-hypopnea index (AHI) ranged from - 14.8 to 10.6 events/h. At AHI ≥ 5 events/h, the sensitivity of type IV PMs ranged from 67.5-100% and specificity ranged from 25 to 100%.

CONCLUSION

While current evidence is not very strong for the stand-alone use of level IV PMs in clinical practice, they can potentially widen access to diagnosis and treatment of OSA. Policy recommendations regarding HSAT use should also consider the health and broader social implications of false positive and false negative diagnoses.

Short Sleep Duration, Obstructive Sleep Apnea, Shiftwork, and the Risk of Adverse Cardiovascular Events in Patients After an Acute Coronary Syndrome

BACKGROUND

It is unknown whether short sleep duration, obstructive sleep apnea, and overnight shift work are associated with the risk of recurrent cardiovascular events in patients after an acute coronary syndrome.

METHODS AND RESULTS

SOLID-TIMI 52 (The Stabilization of PLaques UsIng Darapladib-Thrombolysis in Myocardial Infarction 52 Trial) was a multinational, double-blind, placebo-controlled trial that enrolled 13 026 patients ≤30 days of acute coronary syndrome. At baseline, all patients were to complete the Berlin questionnaire to assess risk of obstructive sleep apnea and a sleep and shift work survey. Median follow-up was 2.5 years. The primary outcome was major coronary events (MCE; coronary heart disease death, myocardial infarction, or urgent revascularization). Cox models were adjusted for clinical predictors. Patients who reported <6 hours sleep per night had a 29% higher risk of MCE (adjusted hazard ratio, 1.29; 95% confidence interval, 1.12-1.49; P<0.001) compared with those with longer sleep. Patients who screened positive for obstructive sleep apnea had a 12% higher risk of MCE (1.12; 1.00-1.24; P=0.04) than those who did not screen positive. Overnight shift work (≥3 night shifts/week for ≥1 year) was associated with a 15% higher risk of MCE (1.15; 1.03-1.29; P=0.01). A step-wise increase in cardiovascular risk was observed for individuals with more than 1 sleep-related risk factor. Individuals with all 3 sleep-related risk factors had a 2-fold higher risk of MCE (2.01; 1.49-2.71; P<0.0001).

CONCLUSIONS

Short sleep duration, obstructive sleep apnea, and overnight shift work are under-recognized as predictors of adverse outcomes after acute coronary syndrome. Increased efforts should be made to identify, treat, and educate patients about the importance of sleep for the potential prevention of cardiovascular events.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01000727.

[Diagnostic accuracy of outpatient polygraphy devices : A comparison with inpatient polysomnography in clinical routine]

BACKGROUND

Cardiorespiratory polysomnography (PSG) is considered the reference method for diagnosis of obstructive sleep apnea (OSA). Due to waiting times and high costs, payers increasingly request outpatient polygraphy (PG) as an alternative to inpatient PSG. The aim of the present study was to evaluate the diagnostic accuracy of different outpatient PG devices compared to stationary PSG in clinical practice.

MATERIALS AND METHODS

Externally collected outpatient PG findings of 406 patients were retrospectively compared with the corresponding PSG findings.

RESULTS

Among the 406 patients were 343 men (85%) and 63 women (15%), with mean age 50 years. Mean body mass index (BMI) was 30 kg/m². The rank correlation coefficient for PG- and PSG- derived apnea-hypopnea index (AHI) values was r = 0.574. On average, PG underestimated the AHI by 6.4 (±20.5) events/h. OSAS severity was determined correctly by PG in only 43% of cases. Sensitivity (90.7%) and specificity (45.2%) of ambulatory PG was calculated for the threshold value AHI ≥ 5/h. Based on the results of PG, an indicated therapy would have been omitted in 35 cases (9%) and unnecessary treatment initiated in 17 cases (4%). The PG devices used showed a comparable diagnostic accuracy (r = 0.513-0.657), with a sensitivity of 81.3-96.9% and a specificity of 33.3-50.0%.

CONCLUSION

Outpatient PG cannot reliably assess OSA severity in clinical routine. Confirmation by PSG in a sleep lab in symptomatic patients is obligatory. Outpatient PG devices should only be used as an upstream screening method. The automatic evaluation of the PG should always be proofed.

Association of Diabetic Microvascular Complications and Parameters of Obstructive Sleep Apnea in Patients with Type 2 Diabetes

BACKGROUND

Obstructive sleep apnea (OSA) is prevalent in patients with type 2 diabetes, but the influence of OSA on diabetes complications is not clear. We aimed to investigate the association of OSA with chronic diabetes complications in Chinese patients with type 2 diabetes.

SUBJECTS AND METHODS

In total, 880 hospitalized patients were enrolled in a multicenter, cross-sectional study that involved 12 hospitals from six cities in the People's Republic of China. Overnight sleep monitoring with a portable monitor was used to record respiratory parameters, including the apnea-hypopnea index (AHI), the oxygen desaturation index (ODI), the oxygen saturation (SPO2), and the cumulative time of SPO2 below 90% or 85% (CT90% and CT85%, respectively). Chronic diabetes complications were recorded from medical charts.

RESULTS

CT90% was independently associated with diabetic nephropathy (DN) after adjusting for age, sex, diabetes duration, glycosylated hemoglobin, body mass index, hypertension, and the use of angiotensin converting enzyme inhibitor/angiotensin receptor blocker drugs within 1 week. The associated parameters increased from two (the average SPO2 and CT90%) to three (ODI, the lowest SPO2, and CT85%) when the severity of DN increased from microalbuminuria to renal insufficiency. The estimated glomerular filtration rate was independently correlated with ODI (β = -0.172, P = 0.029) and the lowest SPO2 (β = 0.354, P = 0.004) after adjustments. The lowest SPO2 was associated with proliferative diabetic retinopathy by univariate logistic regression but was not significant in multivariate regression after adjustment.

CONCLUSIONS

Parameters of nocturnal hypoxemia are associated with DN and renal function of patients with type 2 diabetes. The parameters of hypoxemia may more sensitively reflect the association of OSA and diabetic microvascular complications than AHI.

Validity and Predictive Value of a Portable Two-Channel Sleep-Screening Tool in the Identification of Sleep Apnea in Patients With Heart Failure

BACKGROUND

Sleep apnea is an important comorbidity in heart failure (HF) and is associated with an adverse outcome. Diagnosing sleep apnea is difficult, and polysomnography, considered to be the criterion standard, is not widely available. We assessed the validity of a portable 2-channel sleep-screening tool for the identification of sleep apnea in patients with HF.

METHODS AND RESULTS

One hundred patients with stable HF had simultaneous recordings of home-based polysomnography and the screening tool (Apnealink). To compare the apnea-hypopnea index of the screening tool with polysomnography, intraclass correlation (ICC), sensitivity, and specificity were calculated, and a Bland-Altman plot and receiver operating characteristic (ROC) curves were constructed. Ninety valid measurements with the screening tool were obtained (mean age 65.5 ± 11.0 y, 72% male, mean left ventricular ejection fraction 34.6 ± 11.0%). Agreement between the screening tool and polysomnography was high (ICC 0.85). The optimal cutoff value was apnea-hypopnea index ≥15/h (area under the ROC curve 0.94). Sensitivity and specificity were 92.9% and 91.9%, respectively.

CONCLUSIONS

The screening tool is useful in excluding the presence of sleep apnea in HF patients to refer only high-risk patients for more extensive polysomnography. This method may potentially reduce the need for the more expensive polysomnography.

Misclassification of OSA severity with automated scoring of home sleep recordings

BACKGROUND

The advent of home sleep testing has allowed for the development of an ambulatory care model for OSA that most health-care providers can easily deploy. Although automated algorithms that accompany home sleep monitors can identify and classify disordered breathing events, it is unclear whether manual scoring followed by expert review of home sleep recordings is of any value. Thus, this study examined the agreement between automated and manual scoring of home sleep recordings.

METHODS

Two type 3 monitors (ApneaLink Plus [ResMed] and Embletta [Embla Systems]) were examined in distinct study samples. Data from manual and automated scoring were available for 200 subjects. Two thresholds for oxygen desaturation (≥ 3% and ≥ 4%) were used to define disordered breathing events. Agreement between manual and automated scoring was examined using Pearson correlation coefficients and Bland-Altman analyses.

RESULTS

Automated scoring consistently underscored disordered breathing events compared with manual scoring for both sleep monitors irrespective of whether a ≥ 3% or ≥ 4% oxygen desaturation threshold was used to define the apnea-hypopnea index (AHI). For the ApneaLink Plus monitor, Bland-Altman analyses revealed an average AHI difference between manual and automated scoring of 6.1 (95% CI, 4.9-7.3) and 4.6 (95% CI, 3.5-5.6) events/h for the ≥ 3% and ≥ 4% oxygen desaturation thresholds, respectively. Similarly for the Embletta monitor, the average difference between manual and automated scoring was 5.3 (95% CI, 3.2-7.3) and 8.4 (95% CI, 7.2-9.6) events/h, respectively.

CONCLUSIONS

Although agreement between automated and manual scoring of home sleep recordings varies based on the device used, modest agreement was observed between the two approaches. However, manual review of home sleep test recordings can decrease the misclassification of OSA severity, particularly for those with mild disease.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT01503164; www.clinicaltrials.gov.

A Comprehensive Evaluation of a Two-Channel Portable Monitor to "Rule in" Obstructive Sleep Apnea

STUDY OBJECTIVES

We hypothesized that a dual-channel portable monitor (PM) device could accurately identify patients who have a high pretest probability of obstructive sleep apnea (OSA), and we evaluated factors that may contribute to variability between PM and polysomnography (PSG) results.

METHODS

Consecutive clinic patients (N = 104) with possible OSA completed a home PM study, a PM study simultaneous with laboratory PSG, and a second home PM study. Uniform data analysis methods were applied to both PM and PSG data. Primary outcomes of interest were the positive likelihood ratio (LR+) and sensitivity of the PM device to "rule-in" OSA, defined as an apnea-hypopnea index (AHI) ≥ 5 events/h on PSG. Effects of different test environment and study nights, and order of study and analysis methods (manual compared to automated) on PM diagnostic accuracy were assessed.

RESULTS

The PM has adequate LR+ (4.8), sensitivity (80%), and specificity (83%) for detecting OSA in the unattended home setting when benchmarked against laboratory PSG, with better LR+ (> 5) and specificity (100%) and unchanged sensitivity (80%) in the simultaneous laboratory comparison. There were no significant night-night (all p > 0.10) or study order effects (home or laboratory first, p = 0.08) on AHI measures. Manual PM data review improved case finding accuracy, although this was not statistically significant (all p > 0.07). Misclassification was more frequent where OSA was mild.

CONCLUSIONS

Overall performance of the PM device is consistent with current recommended criteria for an "acceptable" device to confidently "rule-in" OSA (AHI ≥ 5 events/h) in a high pretest probability clinic population. Our data support the utility of simple two-channel diagnostic devices to confirm the diagnosis of OSA in the home environment.

COMMENTARY

A commentary on this article appears in this issue on page 411.

Sleep efficiency and nocturnal hemodynamic dipping in young, normotensive adults

Blunted dipping of nocturnal systolic arterial pressure (SAP) and heart rate (HR) are independent risk factors for hypertension and all-cause mortality. While several epidemiological studies report a significant association between short sleep duration and hypertension, associations between sleep efficiency and the nocturnal drop of SAP remain controversial. Moreover, relations between sleep efficiency and HR diurnal patterns have been overlooked. We hypothesized that low sleep efficiency (<85%) would be associated with blunted nocturnal SAP and HR dipping. Twenty-two normotensive subjects (13 men, 9 women; age: 18–28 yr) wore an actigraphy watch for 7 days and nights, and an ambulatory blood pressure monitor for 24 h on a nonactigraph night. There were no differences in age, sex, body mass index, mean sleep time, number of awakenings, or 24-h blood pressure between the low ( n = 12) and high ( n = 10) sleep efficiency groups. However, the low sleep efficiency subjects demonstrated a blunted dip of nocturnal SAP (10 ± 1% vs. 14 ± 1%, P = 0.04) and HR (12 ± 3% vs. 21 ± 3%, P = 0.03) compared with the high sleep efficiency group. The low sleep efficiency group also demonstrated a higher mean nocturnal HR (63 ± 2 vs. 55 ± 2 beats/min; P = 0.02). These findings support growing evidence that sleep efficiency, independent of total sleep time, may be an important cardiovascular risk factor.

Endoscopic assessment of reflux esophagitis concurrent with hiatal hernia in male Japanese patients with obstructive sleep apnea

OBJECTIVE

The pathogenetic relationship underlying the high prevalence of gastroesophageal reflux disease (GERD) in patients with obstructive sleep apnea (OSA) remains unclear. In addition, GERD has not been adequately assessed by endoscopy in patients with OSA. The purpose of this study was to use endoscopy to investigate potential interactions among reflux esophagitis, hiatal hernia (HH) and OSA.

MATERIAL AND METHODS

A total of 243 consecutive male Japanese participants who underwent both overnight ambulatory polygraphic monitoring and esophagogastroduodenoscopy were retrospectively evaluated in a cross-sectional study. The prevalence and severity of HH and reflux esophagitis were assessed according to the Los Angeles classification and the Makuuchi classification, respectively. Associations among reflux esophagitis, HH and OSA were examined by univariate and multivariate analyses.

RESULTS

OSA was diagnosed in 98 individuals (40.3%). Endoscopy-confirmed esophagitis (p = 0.027) and HH (p < 0.001) were significantly more prevalent among patients with OSA. Multivariate regression model analysis adjusted for age, body mass index, visceral obesity represented by waist circumference, presence of OSA, concurrence of OSA and HH, smoking, and alcohol consumption yielded OSA as the only variable significantly associated with HH (odds ratio [OR], 2.60; 95% confidence interval [CI], 1.35-4.99; p = 0.004), while concurrence of OSA and HH was related to reflux esophagitis (OR, 3.59; CI, 1.87-6.92; p < 0.001).

CONCLUSIONS

OSA was associated with HH and concurrent OSA and HH with reflux esophagitis in male Japanese patients with OSA. Our results support the hypothesis that complicating HH may link reflux esophagitis to OSA.

Capability of a neck worn device to measure sleep/wake, airway position, and differentiate benign snoring from obstructive sleep apnea

To evaluate the accuracy of a neck-worn device in measuring sleep/wake, detecting supine airway position, and using loud snoring to screen for obstructive sleep apnea. Study A included 20 subjects who wore the neck-device during polysomnography (PSG), with 31 records obtained from diagnostic and split-night studies. Study B included 24 community-based snorers studied in-home for up to three-nights with obstructive sleep apnea (OSA) severity measured with a validated Level III recorder. The accuracy of neck actigraphy-based sleep/wake was measured by assessing sleep efficiency (SE). Differences in sleep position measured at the chest and neck during PSG were compared to video-editing. Loud snoring acquired with an acoustic microphone was compared to the apnea-hypopnea index (AHI) by- and acrosspositions. Over-reported SE by neck actigraphy was inversely related to OSA severity. Measurement of neck and chest supine position were highly correlated with video-edits (r = 0.93, 0.78). Chest was bias toward over-estimating supine time while the majority of neck-device supine position errors occurred during CPAP titrations. Snoring was highly correlated with the overall, supine, and non-supine PSG-AHI (r = 0.79, 0.74, 0.83) and was both sensitive and specific in detecting overall, supine, and non-supine PSGAHI >10 (sensitivity = 81, 88, 82 %; specificity = 87, 79, 100 %). At home sleep testing-AHI > 10, the sensitivity and specificity of loud snoring was superior when users were predominantly non-supine as compared to baseline (sensitivity = 100, 92 %; specificity = 88, 77 %). Neck actigraphy appears capable of estimating sleep/wake. The accuracy of supine airway detection with the neck-device warrants further investigation. Measurement of loud snoring appears to provide a screening tool for differentiating positional apneic and benign snorers.

Postoperative vascular complications in unrecognised Obstructive Sleep apnoea (POSA) study protocol: an observational cohort study in moderate-to-high risk patients undergoing non-cardiac surgery

INTRODUCTION

Emerging epidemiological data suggest that obstructive sleep apnoea (OSA) is common in the general surgical population. Unfortunately, the majority of these patients are unrecognised and untreated at the time of surgery. There is substantial biological rationale to indicate that patients with unrecognised OSA are at a higher risk of postoperative vascular events. However, the extent of this morbidity is currently unknown. We have initated the postoperative vascular complications in the unrecognised obstructive sleep apnoea (POSA) study to determine the associations between OSA, nocturnal hypoxia and major postoperative vascular events in 1200 moderate-to-high risk patients undergoing major non-cardiac surgery.

METHODS AND ANALYSIS

The POSA study is an international prospective observational cohort study. Using a type 3 portable sleep monitoring device and ambulatory oximetry, we will quantify the severity of OSA. The primary outcome is a composite of vascular death, myocardial infarction; non-fatal cardiac arrest; stroke; pulmonary embolism; congestive heart failure and new arrhythmia within 30 days of surgery. As of November 2013, we have recruited over 700 patients from nine centres in six countries. The mean age is 68 years, the mean body mass index is 27 kg/m(2) and 55% of patients are men. 27.9% of patients have known coronary artery disease, over 76% have diabetes. The majority of patients underwent orthopaedic surgery (28%) and colorectal resection (18.5%).

ETHICS AND DISSEMINATION

The POSA study has received ethics approval from all study sites before patient recruitment. Informed consent will be obtained from all patients. The POSA study will determine the risk of unrecognised OSA in major non-cardiac surgery. We will publish these findings in peer-reviewed journals.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01494181.

Apnea-hypopnea index: time to wake up

Despite the widespread use of the apnea-hypopnea index in research, its scientific and statistical properties have not been examined thoroughly. The index may be viewed either as a rate (number of events per hour of sleep) or as a ratio of two variables (number of events/number of hours of sleep). When considered as a rate, the apnea-hypopnea index may be modeled as the dependent variable, provided that researchers explicitly state which physical property they assume to be measuring. On the other hand, the index is rarely, if ever, the preferred model of exposure to sleep-disordered breathing (an independent variable), regardless of whether it is considered a rate or a ratio variable. Continued indiscriminate use of the apnea-hypopnea index in sleep research should be discouraged.