Restless legs syndrome in patients with obstructive sleep apnea: Association between apnea severity and symptoms of depression, insomnia, and daytime sleepiness

OBJECTIVE

To determine if the prevalence and severity of restless legs syndrome (RLS) varies with apnea severity and analyze differences between the sexes in terms of comorbid RLS with symptoms of depression, insomnia, and daytime sleepiness in patients with obstructive sleep apnea (OSA).

METHODS

Symptoms of depression, insomnia, and daytime sleepiness were defined as Patient Health Questionnaire-9 score ≥10, Insomnia Severity Index score ≥15, and Epworth Sleepiness Scale score ≥11. Multivariate logistic and linear regression analyses were conducted.

RESULTS

In 707 adults with OSA (85.1% males), 16.1% (n = 114) had comorbid RLS. The prevalence of RLS was markedly lower in those with moderate and severe OSA than in those with mild OSA. Similarly, the odds of RLS significantly decreased with increasing apnea-hypopnea index. After controlling for age and sex, in patients with comorbid RLS, the International RLS Study Group Rating Scale scores were negatively correlated with apnea-hypopnea index and a nadir peripheral oxygen saturation during sleep. The presence of RLS was more likely to be associated with symptoms of depression, insomnia, and daytime sleepiness after controlling for confounding variables, but only in men.

CONCLUSIONS

RLS is frequently noted in combination with OSA, with a female preponderance. The severities of OSA and RLS may be negatively associated. In patients with OSA, sex-related differences in terms of comorbid RLS with symptoms of depression, insomnia, and daytime sleepiness warrant further investigations.

An association between heart rate variability and pediatric obstructive sleep apnea

BACKGROUND

There are different findings on heart rate variability (HRV) and pediatric obstructive sleep apnea (pOSA) by an overnight HRV or a 1-hr HRV. However, there is limited data of HRV and pOSA diagnosis by using a 24-h HRV test. This study aimed to evaluate if HRV had potential for OSA diagnosis by using a 24-h HRV test.

METHODS

This was a prospective study included children age between 5 and 15 years old, presenting with snoring, underwent polysomnography and a 24-h Holter monitoring. Predictors for pOSA diagnosis were analyzed using logistic regression analysis.

RESULTS

During the study period, there were 81 pediatric patients met the study criteria. Of those, 65 patients (80.25%) were diagnosed as OSA. There were three factors were independently associated with OSA: standard deviation of all normal interval (SDNN), high frequency (HF), and low frequency (LF). The adjusted odds ratios of these factors were 0.949 (95% confidence interval 0.913, 0.985), 0.786 (95% confidence interval 0.624, 0.989), and 1.356 (95% confidence interval 1.075, 1.709).

CONCLUSIONS

HRV parameters including SDNN, HF, and LF were associated with pOSA diagnosis in children by using the 24-h Holter monitoring.

Fine particulate matter and sleep-disordered breathing severity in a large Italian cohort

BACKGROUND

Air pollution and obstructive sleep apnea (OSA) are both linked with cardiovascular co-morbidities and share similar pathophysiological mechanisms. A causal association between the two has been postulated. However, the results of the studies on this topic are conflicting mainly because of the lack of adjustment for important confounders such as seasonality and temperature. We aimed to evaluate if such an association exists in a highly polluted area like Lombardy region (Italy) when accounting for all confounders.

METHODS

Data of adult patients seen at the Sleep Disorder Centre in Milan from 2010 to 2020 were analysed and the main polygraphic data were retrieved. Air pollutant concentrations of the following pollutants NO2, O3, PM2.5, and PM10 were collected through monitoring stations.

RESULTS

A total of 3493 patients were included: males (2358, 67.5%) mean age 60.1 (SD = 14.3) years, BMI 29.2 (6.2) kg/m2, mean AHI 16.5 (18.1) events/h. After adjusting for all confounders, in the multivariable analysis, the only associations that remained significant were long-term exposure to O3 with indexes of OSA severity (AHI and ODI) but only in spring. Furthermore, a positive association was seen between long-term exposure to PM10 and ODI but in springtime only.

CONCLUSION

The findings of the current study does not support an association between fine particulate matter and OSA severity.

Central sleep apnea and exposure to ambient hydrogen sulfide emissions from massive strandings of decomposing sargassum in the Caribbean

BACKGROUND

Sargassum invasion of Caribbean and American shorelines is a recurring environmental hazard. Potential health effects of long-term chronic exposure to sargassum gaseous emissions, notably hydrogen sulfide (H2S), are overlooked. H2S plays an important role in neurotransmission and is involved in generating and transmitting respiratory rhythm. Central sleep apnea (CSA) has been attributed to the depression of respiratory centers.

OBJECTIVE

Evaluate the effects of exposure to sargassum-H2S on CSA.

METHODS

This study, set in the Caribbean, describes the clinical and polysomnographic characteristics of individuals living and/or working in areas impacted by sargassum strandings, in comparison with non-exposed subjects. Environmental exposure was estimated by the closest ground H2S sensor. Multivariate linear regression was applied to analyze CSA changes according to cumulative H2S exposure over time. Effects of air pollution and other sargassum toxic compounds (NH3) on CSA were also controlled.

RESULTS

Among the 685 study patients, 27 % were living and/or working in sargassum impacted areas. Compared with non-exposed patients, exposed ones had similar sleep apnea syndrome risk factors, but had increased levels of CSA events (expressed as absolute number or % of total sleep apnea). Multivariate regression retained only male gender and mean H2S concentration over a 6-month exposure period as independent predictors of an increase in CSA events. A minimal exposure length of 1 month generated a significant rise in CSA events, with the latter increasing proportionally with a cumulative increase in H2S concentration over time.

CONCLUSION

This pioneer work highlights a potential effect of sargassum-H2S on the central nervous system, notably on the modulation of the activity of the brain's respiratory control center. These observations, jointly with previous studies from our group, constitute a body of evidence strongly supporting a deleterious effect of sargassum-H2S on the health of individuals chronically exposed to low to moderate concentration levels over time.

Deep learning of sleep apnea-hypopnea events for accurate classification of obstructive sleep apnea and determination of clinical severity

BACKGROUND

/Objective: Automatic apnea/hypopnea events classification, crucial for clinical applications, often faces challenges, particularly in hypopnea detection. This study aimed to evaluate the efficiency of a combined approach using nasal respiration flow (RF), peripheral oxygen saturation (SpO2), and ECG signals during polysomnography (PSG) for improved sleep apnea/hypopnea detection and obstructive sleep apnea (OSA) severity screening.

METHODS

An Xception network was trained using main features from RF, SpO2, and ECG signals obtained during PSG. In addition, we incorporated demographic data for enhanced performance. The detection of apnea/hypopnea events was based on RF and SpO2 feature sets, while the screening and severity categorization of OSA utilized predicted apnea/hypopnea events in conjunction with demographic data.

RESULTS

Using RF and SpO2 feature sets, our model achieved an accuracy of 94 % in detecting apnea/hypopnea events. For OSA screening, an exceptional accuracy of 99 % and an AUC of 0.99 were achieved. OSA severity categorization yielded an accuracy of 93 % and an AUC of 0.91, with no misclassification between normal and mild OSA versus moderate and severe OSA. However, classification errors predominantly arose in cases with hypopnea-prevalent participants.

CONCLUSIONS

The proposed method offers a robust automatic detection system for apnea/hypopnea events, requiring fewer sensors than traditional PSG, and demonstrates exceptional performance. Additionally, the classification algorithms for OSA screening and severity categorization exhibit significant discriminatory capacity.

Multimodal Prognostic Model for Predicting Chronic Coronary Artery Disease in Patients Without Obstructive Sleep Apnea Syndrome

BACKGROUND

Obstructive sleep apnea syndrome (OSAS), with metabolic disorders as a central feature, is closely correlated with coronary artery disease (CAD). Our goal was to develop a prediction nomogram that integrated multimodal data that could accurately predict the prognosis of patients with chronic coronary disease (CCD).

METHODS

We evaluated 393 patients with CCD with a low-to-intermediate pretest probability of OSAS based on polysomnography. A nomogram was constructed by means of least absolute shrinkage and selection operator (LASSO) and multiple Cox regression analyses to identify independent risk factors for major adverse cardiovascular events (MACEs).

RESULTS

Two hundred seventy-seven patients were randomly assigned to the training set, and 116 to the verification set. The constructed nomogram consisted of seven clinical variables: age, previous CAD, current alcohol consumption, neck circumference, apnea-hypopnea index (AHI), and triglyceride-glucose index (TyG). The nomogram showed good discriminatory power, as evidenced by Harrell's C-index values of 0.79 (95% confidence interval [CI] 0.731-0.849) in the training set and 0.78 (95% CI 0.678-0.882) in the verification set. Moreover, a high correlation was observed between the predicted and actual incidence of MACEs in both the training and verification sets. Decision curve analysis demonstrated excellent clinical utility of the nomogram based on net benefit and threshold probabilities.

CONCLUSIONS

We developed an integrated visualized prognostic nomogram that utilizes multi-modal data, including clinical characteristics, AHI, and TyG index, to predict MACEs in patients with CCD. This approach demonstrated excellent performance, highlighting the potential of combining different data sources to enhance prediction accuracy.

Novel Predictor of the AF Development in Patients with OSAS: Importance of Visceral Adipose Index

Objective

Obstructive sleep apnea syndrome (OSAS) is a sleep disorder whose frequency is increasing daily due to modern lifestyle. Patients with atrial fibrillation (AF), which has the same predisposing factors, frequently visit the outpatient clinic with complaints of palpitation. Existing symptoms are often associated with the course of OSAS, and the development of AF, a disease with high morbidity and mortality, cannot be detected. In our study, we investigated the relationship between the visceral adiposity index (VAI) and AF development in these patients.

Methods

We retrospectively analyzed 207 patients with OSAS who visited the cardiology outpatient clinic. The data of 44 patients with AF and 163 patients without AF were compared.

Results

Demographic characteristics and clinical risk factors were similar between the groups (p>0.05). VAI, apnea-hypopnea index, and inflammatory markers were higher in the AF group, and these risk factors were significant in the multivariate analysis (p<0.05).

Conclusions

Our study is important in terms of showing VAI as one of the most important predictors of AF, which has an impact on mortality and morbidity in patients with OSAS, whose frequency is increasing daily. Further prospective studies are required to confirm our observations and determine their clinical applicability.

Preoperative sleep-disordered breathing and craniofacial abnormalities are risk factors for postoperative sleep-disordered breathing in patients undergoing skin-flap oropharyngeal reconstruction surgery for oral cavity cancer: a prospective case-control study

PURPOSE

After oropharyngeal reconstruction surgery, excessive flap volume within the oral cavity may increase the risk of pharyngeal obstruction during sleep. This prospective observational study aimed to test a hypothesis that the skin-flap oropharyngeal reconstructive surgery increases nocturnal apnea-hypopnea index (nAHI, primary variable) after surgery.

METHODS

Adult patients undergoing oropharyngeal reconstruction surgery participated in this study. The hypothesis was tested by comparing the results of portable type 4 sleep study and craniofacial assessments with lateral head and neck computed tomography scout image before and after surgery. Multiple linear regression analyses were performed to identify predictors for nAHI increase after the surgery.

RESULTS

In 15 patients, a postoperative sleep study was performed at 41 (27, 59) (median (IQR)) days after the surgery. nAHI did not increase after the surgery (mean (95% CI), 13.0 (7.2 to 18.7) to 18.4 (10.2 to 26.6) events.hour-1, p = 0.277), while apnea index significantly increased after the surgery (p = 0.026). Use of the pedicle flap for the oropharyngeal reconstruction (p = 0.051), small mandible (p = 0.008), longer lower face (0.005), and larger tongue size (p = 0.008) were independent predictors for worsening of nAHI after surgery. Hospital stay was significantly longer in patients with the pedicle flap (n = 8) than in those with the free flap (n = 7) (p = 0.014), and the period of hospital stay was directly associated with increase of nAHI after surgery (r = 0.788, p < 0.001, n = 15).

CONCLUSIONS

Oropharyngeal reconstruction surgery worsens sleep-disordered breathing in some patients with craniofacial and surgical risk factors.

TRIAL REGISTRATION

UMIN Clinical Trial Registry (UMIN000036260, March 22, 2019), https://rctportal.niph.go.jp/s/detail/um?trial_id=UMIN000036260.

ECG-based convolutional neural network in pediatric obstructive sleep apnea diagnosis

Obstructive sleep apnea (OSA) is a prevalent respiratory condition in children and is characterized by partial or complete obstruction of the upper airway during sleep. The respiratory events in OSA induce transient alterations of the cardiovascular system that ultimately can lead to increased cardiovascular risk in affected children. Therefore, a timely and accurate diagnosis is of utmost importance. However, polysomnography (PSG), the standard diagnostic test for pediatric OSA, is complex, uncomfortable, costly, and relatively inaccessible, particularly in low-resource environments, thereby resulting in substantial underdiagnosis. Here, we propose a novel deep-learning approach to simplify the diagnosis of pediatric OSA using raw electrocardiogram tracing (ECG). Specifically, a new convolutional neural network (CNN)-based regression model was implemented to automatically predict pediatric OSA by estimating its severity based on the apnea-hypopnea index (AHI) and deriving 4 OSA severity categories. For this purpose, overnight ECGs from 1,610 PSG recordings obtained from the Childhood Adenotonsillectomy Trial (CHAT) database were used. The database was randomly divided into approximately 60%, 20%, and 20% for training, validation, and testing, respectively. The diagnostic performance of the proposed CNN model largely outperformed the most accurate previous algorithms that relied on ECG-derived features (4-class Cohen's kappa coefficient of 0.373 versus 0.166). Specifically, for AHI cutoff values of 1, 5, and 10 events/hour, the binary classification achieved sensitivities of 84.19%, 76.67%, and 53.66%; specificities of 46.15%, 91.39%, and 98.06%; and accuracies of 75.92%, 86.96%, and 91.97%, respectively. Therefore, pediatric OSA can be readily identified by our proposed CNN model, which provides a simpler, faster, and more accessible diagnostic test that can be implemented in clinical practice.

Progression of obstructive sleep apnoea after renal denervation is not associated with hypertension exaggeration

PURPOSE

In a cohort, observational prospective trial, we assessed the long-term dynamics of sleep-disordered breathing in patients with resistant hypertension after renal denervation and their association with blood pressure change at remote follow-up.

MATERIALS AND METHODS

Twenty-eight patients with stable hypertension who were recruited for endovascular radiofrequency renal denervation in 2012-2019 and had valid both baseline and follow-up sleep study, were included in the analysis. All patients underwent physical examination, anthropometry, office and ambulatory blood pressure measurements, blood and urine tests, kidney visualization, and full polysomnography before and within 12-36 months after renal denervation.

RESULTS

The average follow-up comprised 30.1 ± 8.4 months. At long-term follow-up, no significant changes in creatinine level, estimated glomerular filtration rate, body mass index were registered. There was a significant increase in sleep apnea severity indices: the mean change in apnea-hypopnea index comprised 9.0(-21.1;25.2) episodes/h, in oxygen desaturation index 6.5(-16.8;35.9) episodes/h, in the average SpO2 -1.7(-5.6;1.9)%. Over 12-month follow-up, there were no significant differences in blood pressure response in patients with and without sleep apnea. The baseline apnea-hypopnea and oxygen desaturation indices and the mean SpO2 were associated with the circadian blood pressure profile at follow-up, but did not correlate with the blood pressure response.

CONCLUSIONS

Although the severity of sleep apnea worsens at > 12 months follow-up after renal denervation, this is not associated with hypertension exaggeration.

Determinants of apnea-hypopnea index variability during home sleep testing

BACKGROUND

A single-night attended in-laboratory polysomnography or home sleep testing are common approaches for obstructive sleep apnea (OSA) diagnosis. However, internight variability in apnea-hypopnea index value is common, and may result in misclassification of OSA severity and inapropriate treatment decisions.

OBJECTIVE

To investigate factors determining short-term apnea-hypopnea index variability using multi-night automated home sleep testing, and to determine how this variability impacts clinical decisions.

PATIENTS/METHODS

Adults with suspected OSA who successfully performed three home sleep tests using measurements of mandibular jaw movements (Sunrise, Namur, Belgium) combined with automated machine learning analysis were enrolled. Data analysis included principal component analysis, generalized estimating equation regression and qualitative agreement analysis.

RESULTS

160 individuals who performed three sleep tests over a mean of 8.78 ± 8.48 days were included. The apnea-hypopnea index varied by -0.88 events/h (5th-95th percentile range: -14.33 to 9.72 events/h). Based on a single-night recording, rates of overtreatment and undertreatment would have been of 13.5% and 6.0%, respectively. Regression analysis adjusted for age, sex, body mass index, total sleep time, and time between home sleep tests showed that time spent in deep non-rapid eye movement sleep and with head in supine position were independent significant predictors of the apnea-hypopnea index variability.

CONCLUSIONS

At the individual level, short-term internight variability in the apnea-hypopnea index was significantly associated with time spent in deep non-rapid eye movement sleep and head in supine position. Clinical decisions based on a single-night testing may lead to errors in OSA severity classification and incorrect therapeutic decisions.

Association between Obstructive Sleep Apnea and Intracranial Artery Calcification Stratified by Gender and Body Mass Index: A Hospital-Based Observational Study

BACKGROUND AND OBJECTIVES

Obstructive sleep apnea (OSA) is an independent risk factor for stroke. Furthermore, intracranial arterial calcification (IAC) has been validated as a marker for subclinical cerebrovascular disease. However, the relationship between OSA with IAC was less studied compared with its established association with coronary artery calcification. In this study, we aimed to investigate the association between the severity of OSA and the degree of IAC in hospitalized patients without preexisting cardiovascular disease.

METHODS

This hospital-based observational study was conducted from June 1, 2017, to May 1, 2019. In total, 901 consecutive patients who underwent head computed tomography scans and portable sleep monitoring were included. On the basis of the apnea-hypopnea index (AHI), patients were divided into four OSA severity groups (normal: AHI <5/h; mild: 5≤ AHI <15/h; moderate: 15≤ AHI <30/h; severe: AHI ≥30/h). Associations of OSA with IAC scores were assessed by using multivariate logistic regression analysis.

RESULTS

Of the 901 patients, 484 (53.7%) were men; the mean (SD) age was 66.1 (10.0) years. The non-OSA group included 207 (23.0%) patients; mild OSA, 209 (23.2%); moderate OSA, 235 (26.1%); and severe OSA, 169 (18.8%). Mean IAC scores were higher in the severe OSA group compared with non-, mild, and moderate OSA groups (4.79 vs. 2.58; 4.79 vs. 2.94; 4.79 vs. 3.39; p < 0.001). Multivariate analysis adjusted for confounding factors revealed that only severe OSA was associated with a higher IAC score (odds ratio [OR]: 1.65; 95% confidence interval [CI]: 1.43-1.91; p < 0.001). In stratified analyses by BMI, among participants with a BMI <25 kg/m2, the positive association between AHI values and IAC scores was found in the moderate OSA group (OR: 1.23; 95% CI: 1.05, 1.43; p = 0.01) and the severe OSA group (OR: 1.96; 95% CI: 1.55, 2.48; p < 0.001). When stratified by gender, in women, the positive association was found in the moderate OSA group (adjusted OR: 1.21; 95% CI: 1.02-1.51; p = 0.016) and the severe OSA group (adjusted OR: 1.76; 95% CI: 1.36-2.25; p < 0.001). For the men group, a positive association between IAC scores and AHI was only observed in the severe OSA group.

DISCUSSION

These findings suggest that OSA, in particular severe OSA (AHI ≥30), is independently associated with higher IAC scores. Women and no-obesity individuals appeared more susceptible to adverse OSA-related subclinical cerebrovascular disease as measured by IAC scores.

AHI estimation of OSAHS patients based on snoring classification and fusion model

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is a chronic and common sleep-breathing disease that could negatively influence lives of patients and cause serious concomitant diseases. Polysomnography(PSG) is the gold standard for diagnosing OSAHS, but it is expensive and requires overnight hospitalization. Snoring is a typical symptom of OSAHS. This study proposes an effective OSAHS screening method based on snoring sound analysis. Snores were labeled as OSAHS related snoring sounds and simple snoring sounds according to real-time PSG records. Three models were used, including acoustic features combined with XGBoost, Mel-spectrum combined with convolution neural network (CNN), and Mel-spectrum combined with residual neural network (ResNet). Further, the three models were fused by soft voting to detect these two types of snoring sounds. The subject's apnea-hypopnea index (AHI) was estimated according to these recognized snoring sounds. The accuracy and recall of the proposed fusion model achieved 83.44% and 85.27% respectively, and the predicted AHI has a Pearson correlation coefficient of 0.913 (R2 = 0.834, p < 0.001) with PSG. The results demonstrate the validity of predicting AHI based on analysis of snoring sound and show great potential for monitoring OSAHS at home.

Adherence to a "Western-type" dietary pattern is positively associated with the Apnea-Hypopnea Index in adults with obstructive sleep apnea

Dietary habits have been associated with obstructive sleep apnea (OSA); however, the underlying mechanisms remain unclear. We hypothesized that adherence to dietary patterns may be associated with Apnea-Hypopnea Index (AHI) and OSA severity and that insulin resistance, oxidative stress, and inflammation may act as potential mediators of these associations. This was a cross-sectional study among 269 adult participants with polysomnography-diagnosed moderate-to-severe OSA. Dietary and physical activity habits were assessed through validated questionnaires, and biochemical, inflammatory, and oxidative stress markers were measured for all volunteers. Dietary patterns were identified using principal component analysis, and mediation analyses was also performed. A "Western-type" dietary pattern (characterized by high intakes of full-fat dairy, refined grains, potatoes, red meat, sweets, salty snacks, and soft drinks and low intakes of low-fat dairy and whole grains) was positively associated with AHI. Mediation analyses also revealed that insulin resistance partially explained this association. In multivariable models controlling for age, sex, smoking, socioeconomic status, obesity presence, energy intake, and physical activity level, participants in the highest quartile of adherence to the Western-type dietary pattern had ∼3.5 times higher likelihood of suffering from severe OSA, compared with participants in the lowest quartile of adherence (odds ratio [95% confidence interval]: 3.45 [1.21-9.94], P trend across quartiles: 0.024). After further adjustment for Homeostasis Model of Assessment-Insulin Resistance and high-sensitivity C-reactive protein, this association lost significance. Higher adherence to a less healthy, Western-type dietary pattern is positively associated with AHI and OSA severity, which may partially be mediated through insulin resistance.

Effect of phrenic nerve stimulation on patients with central sleep apnea: A meta-analysis

Patients with central sleep apnea (CSA) have a lower quality of life and higher morbidity and mortality. Phrenic nerve stimulation (PNS) is a novel treatment for CSA that has been shown to be safe. However, the effects of PNS on sleep changes are still under debate. This meta-analysis was performed to evaluate the efficacy of PNS in patients with CSA. PubMed, Scopus, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL) and Web of Science databases were searched for relevant studies published. We performed random-effects meta-analyses of the changes in apnea-hypopnea index (AHI), central apnea index (CAI), Arousal Index, percent of sleep with O2 saturation <90% (T90), Epworth Sleepiness Scale (ESS) and sleep efficiency. Ten studies with a total of 580 subjects were analyzed. Overall meta-analysis showed AHI [SMD: -2.24, 95% confidence interval (CI): was -3.11 to -1.36(p＜0.00001)], CAI [SMD: -2.32, 95% CI: -3.17 to -1.47 (p＜0.00001)] and Arousal Index (p = 0.0002, SMD (95% CI) -1.79 (-2.74 to -0.85)) significantly reduced after PNS. No significant changes were observed in T90, ESS and sleep efficiency (p > 0.05). Meta-analysis of observational studies demonstrated AHI, CAI and Arousal Index had a decreasing trend between before and after PNS (all, p＜0.05). However, ESS and T90 did not change significantly after PNS (p > 0.05). Meta-analysis of RCTs showed that CSA patients had trends of a lower AHI (I2 = 0%), CAI (I2 = 74%), Arousal Index (I2 = 0%), T90 (I2 = 0%) and ESS (I2 = 0%) after PNS (all, p＜0.05). The use of PNS appears to be safe and feasible in patients with CSA. However, larger, independent RCTs are required to investigate the efficacy and long-term effect of PNS and more attention should be paid to T90 and ESS.

Belun Ring (Belun Sleep System BLS-100): Deep learning-facilitated wearable enables obstructive sleep apnea detection, apnea severity categorization, and sleep stage classification in patients suspected of obstructive sleep apnea

GOAL AND AIMS

Our objective was to evaluate the performance of Belun Ring with second-generation deep learning algorithms in obstructive sleep apnea (OSA) detection, OSA severity categorization, and sleep stage classification.

FOCUS TECHNOLOGY

Belun Ring with second-generation deep learning algorithms REFERENCE TECHNOLOGY: In-lab polysomnography (PSG) SAMPLE: Eighty-four subjects (M: F = 1:1) referred for an overnight sleep study were eligible. Of these, 26% had PSG-AHI<5; 24% had PSG-AHI 5-15; 23% had PSG-AHI 15-30; 27% had PSG-AHI ≥ 30.

DESIGN

Rigorous performance evaluation by comparing Belun Ring to concurrent in-lab PSG using the 4% rule.

CORE ANALYTICS

Pearson's correlation coefficient, Student's paired t-test, diagnostic accuracy, sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio, Cohen's kappa coefficient (kappa), Bland-Altman plots with bias and limits of agreement, receiver operating characteristics curves with area under the curve, and confusion matrix.

CORE OUTCOMES

The accuracy, sensitivity, specificity, and kappa in categorizing AHI ≥ 5 were 0.85, 0.92, 0.64, and 0.58, respectively. The accuracy, sensitivity, specificity, and Kappa in categorizing AHI ≥ 15 were 0.89, 0.91, 0.88, and 0.79, respectively. The accuracy, sensitivity, specificity, and Kappa in categorizing AHI ≥ 30 were 0.91, 0.83, 0.93, and 0.76, respectively. BSP2 also achieved an accuracy of 0.88 in detecting wake, 0.82 in detecting NREM, and 0.90 in detecting REM sleep.

CORE CONCLUSION

Belun Ring with second-generation algorithms detected OSA with good accuracy and demonstrated a moderate-to-substantial agreement in categorizing OSA severity and classifying sleep stages.

Comparative study of the SleepImage ring device and polysomnography for diagnosing obstructive sleep apnea

Purpose We aim to evaluate the diagnostic performance of the SleepImage Ring device in identifying obstructive sleep apnea (OSA) across different severity in comparison to standard polysomnography (PSG). Methods Thirty-nine patients (mean age, 56.8 ± 15.0 years; 29 [74.3%] males) were measured with the SleepImage Ring and PSG study simultaneously in order to evaluate the diagnostic performance of the SleepImage device for diagnosing OSA. Variables such as sensitivity, specificity, positive and negative likelihood ratio, positive and negative predictive value, and accuracy were calculated with PSG-AHI thresholds of 5, 15, and 30 events/h. Receiver operating characteristic curves were also built according to the above PSG-AHI thresholds. In addition, we analyzed the correlation and agreement between the apnea-hypopnea index (AHI) obtained from the two measurement devices. Results There was a strong correlation (r = 0.89, P < 0.001 and high agreement in AHI between the SleepImage Ring and standard PSG. Also, the SleepImage Ring showed reliable diagnostic capability, with areas under the receiver operating characteristic curve of 1.00 (95% CI, 0.91, 1.00), 0.90 (95% CI, 0.77, 0.97), and 0.98 (95% CI, 0.88, 1.000) for corresponding PSG-AHI of 5, 15 and 30 events/h, respectively. Conclusion The SleepImage Ring could be a clinically reliable and cheaper alternative to the gold standard PSG when aiming to diagnose OSA in adults.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13534-023-00304-9.

The effectiveness of supplemental oxygen and high-flow nasal cannula therapy in patients with obstructive sleep apnea in different clinical settings: A systematic review and meta-analysis

STUDY OBJECTIVE

To evaluate the effectiveness of supplemental oxygen therapy and high-flow nasal cannula (HFNC) therapy in patients with obstructive sleep apnea (OSA) in different clinical settings to assess its application to surgical patients in the postoperative setting.

DESIGN

A systematic search was conducted on MEDLINE and other databases from 1946 to December 16th, 2021. Title and abstract screening were conducted independently, and the lead investigators resolved conflicts. Meta-analyses were performed using a random-effects model and are presented as mean difference and standardized mean difference with 95% confidence intervals. These were calculated using RevMan 5.4.

PATIENTS

1395 and 228 OSA patients underwent oxygen therapy and HFNC therapy respectively.

INTERVENTIONS

Oxygen therapy and HFNC therapy.

MEASUREMENTS

Apnea-hypopnea index (AHI), oxyhemoglobin saturation (SpO₂), cumulative time with SPO₂ < 90% (CT90).

MAIN RESULTS

Twenty-seven oxygen therapy studies were included in the review, with ten randomized controlled trials (RCT), seven randomized crossovers, seven non-randomized crossovers, and three prospective cohorts. Pooled analyses showed that oxygen therapy significantly reduced AHI by 31% and increased SpO₂ by 5% versus baseline, and CPAP significantly reduced AHI by 84%, and increased SpO₂ by 3% versus baseline. CPAP was 53% more effective in reducing AHI than oxygen therapy, but both treatments had similar effectiveness in increasing SpO₂. Nine HFNC studies were included in the review, with five prospective cohorts, three randomized crossovers, and one RCT. Pooled analyses showed that HFNC therapy significantly reduced AHI by 36% but did not substantially increase SpO₂.

CONCLUSIONS

Oxygen therapy effectively reduces AHI and increases SpO₂ in patients with OSA. CPAP is more effective in reducing AHI than oxygen therapy. HFNC therapy is effective in reducing AHI. Although both oxygen therapy and HFNC therapy effectively reduce AHI, more research is needed to draw conclusions on clinical outcomes.

Limitations of the apnea-hypopnea index in children and young adults with neuromuscular disorders

There are no validated criteria to initiate noninvasive ventilation (NIV) in children and young adults with neuromuscular disease (NMD). In order to analyze NIV initiation criteria, we reviewed the polysomnography (PSG) criteria that led to the initiation of NIV in 61 consecutive patients with NMD, median age 4.1 (0.8-21) years, who had a PSG during their routine care. NIV was initiated on abnormal PSG data (apnea-hypopnea index (AHI) > 10 events/h and/or a transcutaneous carbon dioxide pressure > 50 mmHg and/or a pulse oximetry 〈 90%, both during at least 2% sleep time or 〉 5 consecutive minutes) in 11 (18%) patients. Six of these 11 patients had an AHI ≤ 10 events/h and would not have been ventilated if only AHI was retained. However, one of these 6 patients had isolated nocturnal hypoxemia, 3 isolated nocturnal hypercapnia and 2 abnormal respiratory events. Six (10%) patients with a normal PSG were started on NIV on clinical criteria. Our results show the limitation of the AHI when taken as the unique PSG criterion for NIV initiation in young patients with NMD and underline the need to include also abnormalities of overnight gas exchange into the NIV decision-making process.

Management and outcomes of obstructive sleep apnea in infants

OBJECTIVE

To characterize the clinical characteristics of infants with obstructive sleep apnea (OSA), define the resolution rate of infant OSA, and identify factors associated with OSA resolution.

METHODS

We identified infants diagnosed with OSA via retrospective chart review at less than one year of age at a tertiary care center. We identified patient comorbidities, flexible or rigid airway evaluations, surgical procedures, and oxygen/other respiratory support administration. We identified infants as having resolved OSA based on clinical or polysomnogram resolution. We compared the frequency of comorbid diagnoses and receipt of interventions in infants with resolved versus non-resolved OSA by χ² analysis.

RESULTS

83 patients were included. Prematurity was found in 35/83 (42%), hypotonia-related diagnoses in 31/83 (37%), and craniofacial abnormalities in 34/83 (41%). Resolution was observed in 61/83 (74%), either clinically or by polysomnogram, during follow up. On χ² analysis, surgical intervention was not associated with likelihood of resolution (73% versus 74% in those without surgical intervention, p = 0.98). Patients with airway abnormalities on flexible or rigid evaluation were less likely to have OSA resolution than those without (63% versus 100%, p = 0.010), as were patients with hypotonia-related diagnoses (58% versus 83%, p = 0.014). In patients with laryngomalacia, there was no association of supraglottoplasty with increased resolution (88% with supraglottoplasty versus 80% without, p = 1.00).

CONCLUSIONS

We identified a group of infants with OSA with diverse comorbidities. There was a high rate of resolution. This data can assist with treatment planning and family counselling for infants with OSA. A prospective clinical trial is needed to better assess consequences of OSA in this age.

Effect of the Implementation of a Structured Diet Management Plan on the Severity of Obstructive Sleep Apnea: A Systematic Review

PURPOSE OF REVIEW

The prevalence of obstructive sleep apnea (OSA) is increasing worldwide, in line with the increase in obesity prevalence. Taken into consideration the low compliance rates to continuous positive airway pressure (CPAP) treatment, and since obesity is a risk factor for OSA, these patients should receive additional counseling for weight loss through a diet plan. The aim of this review is to examine the role of a structured diet management plan on OSA severity, nocturnal oxygen indices, and subjective sleep parameters.

RECENT FINDINGS

Τhis systematic review of the literature resulted in four studies and demonstrated that severity of OSA, assessed by the apnea-hypopnea index, is reduced by a dietary management plan when delivered through an educational program. Moreover, nocturnal oxygenation is improved, as well as subjective sleep parameters, when initiating a diet on top of CPAP use. In summary, the present systematic review reports on the beneficial effects of a structured diet management plan in patients with OSA. Although CPAP remains the gold standard of OSA treatment, a specific dietary plan should be sought when managing patients with OSA. Nevertheless, still the evidence is low, and further research on this field is needed to reduce the burden of OSA.

Effects of demographic and sleep-related factors on snoring sound parameters

OBJECTIVE

To investigate the effect of frequently reported between-individual (viz., age, gender, body mass index [BMI], and apnea-hypopnea index [AHI]) and within-individual (viz., sleep stage and sleep position) snoring sound-related factors on snoring sound parameters in temporal, intensity, and frequency domains.

METHODS

This study included 83 adult snorers (mean ± SD age: 42.2 ± 11.3 yrs; male gender: 59%) who underwent an overnight polysomnography (PSG) and simultaneous sound recording, from which a total of 131,745 snoring events were extracted and analyzed. Data on both between-individual and within-individual factors were extracted from the participants' PSG reports.

RESULTS

Gender did not have any significant effect on snoring sound parameters. The fundamental frequency (FF; coefficient = -0.31; P = 0.02) and dominant frequency (DF; coefficient = -12.43; P < 0.01) of snoring sounds decreased with the increase of age, and the second formant increased (coefficient = 22.91; P = 0.02) with the increase of BMI. Severe obstructive sleep apnea (OSA; AHI ≥30 events/hour), non-rapid eye movement sleep stage 3 (N3), and supine position were all associated with more, longer, and louder snoring events (P < 0.05). Supine position was associated with higher FF and DF, and lateral decubitus positions were associated with higher formants.

CONCLUSIONS

Within the limitations of the current patient profile and included factors, AHI was found to have greater effects on snoring sound parameters than the other between-individual factors. The included within-individual factors were found to have greater effects on snoring sound parameters than the between-individual factors under study.

Sex differences in polysomnographic findings in patients with obstructive sleep apnea

BACKGROUND AND PURPOSE

Sex differences in the clinical findings and the polysomnographic presentation of patients with obstructive sleep apnea (OSA) are compelling current research issues. For example, patients suffering from obstructive sleep apnea are predominantly male. While women are older than men and tend to have a higher body mass index, men typically present with a more severe form of obstructive sleep apnea. Using polysomnography, we investigated a German cohort, subdivided per severity levels of obstructive sleep apnea (apnea-hypopnea index: ≥5 to < 15/h (mild), ≥15 to < 30/h (moderate), and ≥30/h (severe)) to provide a detailed analysis of breathing and sleep parameters, accounting for body position effects and severity of illness. A deeper understanding of sex differences may allow targeted diagnosis and treatment adjustment.

PATIENTS AND METHODS

This retrospective study included a cohort of 1242 German patients (940 male, 302 female) who underwent overnight polysomnography at the private sleep laboratory "Intersom Köln", Center for Sleep Medicine and Sleep Research. In 1125 subjects (878 male, 247 female), obstructive sleep apnea was diagnosed. All patients were examined between January 01, 2018 and December 31, 2020, comparing anthropometric, sleep morphological, and respiratory polysomnographic findings.

RESULTS

Female patients with obstructive sleep apnea were significantly older than male patients (60.9 ± 12.3 vs. 56.9 ± 12.5 years, P < .001), also among OSA subgroups per OSA severity. The body mass index was similar in male and female patients (29.6 ± 5.1 vs. 29.2 ± 7.3 kg/m², P > .05), including the three subgroups. Men were more likely to have severe obstructive sleep apnea (46.9%) than women (35.2%). Women exhibited a higher proportion of slow-wave sleep than men (129.4 ± 52.8 vs. 104.2 ± 53.2 min; P < .001). The apnea-hypopnea index of total sleep time was significantly greater in male than female patients (32.9 ± 21.2 vs. 27.2 ± 20.2 per hour; P < .001). Female patients had a higher apnea-hypopnea index during rapid-eye-movement (REM) sleep (34.0 ± 23.8 vs. 31.8 ± 22.3 per hour; P = .171). A statistically significant difference in the apnea-hypopnea index during REM sleep between sexes was found when the obstructive sleep apnea severity was considered. Women had a lower apnea-hypopnea index in non-rapid eye-movement (NREM) sleep than men (25.7 ± 21.1 vs. 32.7 ± 22.3 per hour; P < .001). The oxygen desaturation index (29.9 ± 20.3 vs. 22.4 ± 19.4%; P < .001) and an oxygen desaturation below 90% (9.4 ± 14.0 vs. 6.8 ± 11.7%; P = .003) was greater in men than in women. In severe obstructive sleep apnea, the oxygen desaturation index was similar between the sexes (45.0 ± 17.8 vs. 41.1 ± 20.9%; P = .077). Male patients showed a higher supine apnea-hypopnea-index than female patients. (45.7 ± 26.7 vs 36.1 ± 22.7 per hour; P < .001).

CONCLUSION

The present noninvasive, retrospective registry study is the first to examine sex differences in OSA in such a large German population in terms of respiratory and sleep parameters, taking into account the effects of body position and severity of the disease. We could confirm and extend observations from previous studies. Female patients were significantly older than the male patients. The apnea-hypopnea index was higher in male than in female patients. Women showed a higher apnea-hypopnea index in REM sleep and a lower one in NREM sleep. Men were desaturated more often and were more affected by supine-dependent obstructive sleep apnea than women. Contrary to the literature, there were no significant differences in body mass index (BMI) between the sexes. With increasing age and BMI, the gender differences become less significant.

Association between residential greenness and obstructive sleep apnoea among adults in Southern China

BACKGROUND

No previous study has explored the association of residential greenness with obstructive sleep apnoea (OSA) indexes.

OBJECTIVE

To investigate the association of exposure to residential greenness with OSA indexes in adults in Guangdong Province, Southern China.

METHODS

From January 1, 2005 to December 31, 2015, a total of 3925 participants were recruited from the Sleep Center of Guangdong Provincial People's Hospital. Apnea-hypopnea index (AHI) and oxygen desaturation index (ODI) were measured by polysomnography or home sleep test (HST). Participants' daytime sleepiness scores were evaluated using The Epworth Sleeping Scale (ESS). The normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI) were used to assess residential greenness levels. Generalized linear regression models were used to assess the associations of residential greenness with OSA indexes after adjusting for multiple covariates.

RESULTS

The mean (standard deviation) age of the participants was 63.3 (14.4) years. In adjusted models, an interquartile range (IQR) increase in 3-year average NDVI was significantly associated with 9.8 % (95 % confidence interval [95 % CI]: 17.5 %, 2.1 %); 14.5 % (95 % CI: 24.5 %, 4.4 %) and 6.9 % (95 % CI: 13.7 %, 0.0 %) decreases in AHI, ODI and ESS scores, respectively. Furthermore, an IQR increase in 3-year average EVI was significantly associated with 7.8 % (95 % CI: 13.7 %, 1.9 %); 10.8 % (95 % CI: 18.3 %, 3.2 %) and 7.2 % (95 % CI: 12.5 %, 2.0 %) declines in AHI, ODI and ESS scores, respectively. Significant associations were only observed among males, adults aged ≥65 years old, and in the warm season.

CONCLUSIONS

Our study indicates that higher residential greenness was significantly associated with lower OSA indexes in adult population in South China, especially in males, in the elderly, and in the warm season.

Alterations of cholesterol synthesis and absorption in obstructive sleep apnea: Influence of obesity and disease severity

BACKGROUND AND AIMS

Obstructive sleep apnea (OSA) is closely linked to obesity and related adverse metabolic changes, including dyslipidemia. However, it is not clear whether OSA is an independent contributing factor to dyslipidemia, or the observed association is a reflection of a concomitant presence of obesity. Additionally, dyslipidemia is usually evaluated through measurement of parameters of routine lipid status, while more precise evaluation of lipid homeostasis is rarely performed in OSA. In this study, we analyzed markers of cholesterol synthesis and absorption in patients with OSA with respect to the presence of obesity and the disease severity.

METHODS AND RESULTS

This study enrolled 116 OSA patients. Concentrations of non-cholesterol sterols (NCS), measured by LC-MS/MS, were used as markers of cholesterol synthesis and absorption. Apnea-hypopnea index (AHI) and oxygen saturation (SaO₂) were utilized as markers of OSA severity. Serum lipid status parameters were determined by routine enzymatic methods. Markers of cholesterol synthesis were increased (P = 0.005), whilst markers of cholesterol absorption decreased (P = 0.001) in obese OSA patients. Cholesterol synthesis/absorption ratio was elevated in obese subjects (P < 0.001). Concentration of cholesterol synthesis marker lathosterol was significantly higher in subjects with severe OSA (P = 0.014) and we observed a trend of decreased cholesterol absorption in these patients. AHI was revealed as an independent determinant of lathosterol concentration (P = 0.022).

CONCLUSIONS

Our results suggest that the presence of obesity and severe forms of OSA is characterized by elevated endogenous cholesterol synthesis. AHI was singled out as an independent determinant of the serum level of cholesterol synthesis marker lathosterol.

Cardiovascular remodeling in obstructive sleep apnea: focus on arterial stiffness, left ventricular geometry and atrial fibrillation

INTRODUCTION

Obstructive sleep apnea (OSA) is a common sleep-related breathing disorder that is associated with increased risk of cardiovascular disease. The main interest of this clinical review is to discuss the cardiovascular consequences of OSA with a special focus on left ventricular (LV) function and structure, arterial stiffness and atrial fibrillation.

AREA COVERED

We present an overview of the definition, prevalence, and risk factors of OSA and outline the association between OSA and cardiovascular complications. We then briefly discuss echocardiographic assessment in OSA with focus on the left atrium and LV. Finally, we highlight the importance of adherence to continuous positive airway pressure (CPAP) therapy with regard to reducing the risk of cardiovascular disease.

EXPERT COMMENTARY

Although OSA has a strong association with cardiovascular complications, it is often underdiagnosed and undertreated. Patients with resistant hypertension and atrial fibrillation with poor therapeutic success after cardioversion or catheter ablation should be more often screened for OSA. Patients with nocturnal adverse cardiovascular events (stroke, arrhythmias, angina, coronary events) should be closely assessed with regard to OSA, and if confirmed, timely treated by lifestyle modification, CPAP, and aggressive antihypertensive treatment. Adherence to CPAP in OSA patients is essential in terms of reducing the risk of cardiovascular events.

Therapeutic effect of laparoscopic sleeve gastrectomy on obstructive sleep apnea and relationship of type 2 diabetes in Japanese patients with severe obesity

AIMS/INTRODUCTION

Obstructive sleep apnea (OSA) is among the most important obesity-related diseases, and offers the potential for accelerated the early onset and progression of Type 2 diabetes (T2D). The aim of the present study was to clarify the therapeutic effect of laparoscopic sleeve gastrectomy (LSG) on OSA in severely obese Japanese patients and to find correlations between OSA improvements and β cell function (BCF).

MATERIALS AND METHODS

Between September 2013 and December 2019, 61 patients who underwent LSG were enrolled. The apnea-hypopnea index (AHI) was used to diagnose OSA. The tongue area (TA), uvula area (UA), and other parameters were measured using cone-beam computed tomography. Regarding BCF parameters, the homeostasis model assessment of beta-cell function (HOMA-β), insulinogenic, Matsuda, and disposition indexes were used to evaluate the improvement in BCF. Improvement of OSA was defined as AHI < 15.

RESULTS

The improvement rate of OSA was 51.8% (29/56). The change in AHI was significantly correlated with the excess weight-loss percentage (ρ = 0.501), changes in TA (ρ = 0.350), and UA (ρ = 0.341). Multivariate analysis revealed that preoperative AHI and postoperative HbA1c were independent prognostic factors of OSA non-improvement. HOMA-β (P < 0.001), the insulinogenic index (P < 0.001), and the disposition index (P = 0.019) of patients with AHI of < 15 were significantly higher than those in patients with AHI of ≥ 15.

CONCLUSIONS

LSG is a promising procedure for severely obese patients with OSA. BCF recovery was found to be significantly higher in patients with OSA improvement.

Association between the severity of chronic spontaneous urticaria and sleep-disordered breathing

BACKGROUND

Chronic spontaneous urticaria (CSU) is a common mast cell-driven disease, presenting with wheals, angioedema, or both. Sleep-disordered breathing (SDB) is also a common condition and contributes to various diseases by causing chronic inflammation. Recent studies have suggested an association between CSU and SDB.

METHODS

To determine the association between the severity of SDB and that of CSU, we studied consecutive patients with CSU who visited the Sagamihara National Hospital allergy department or dermatology department between April 1 and October 31, 2018. The severity of CSU and SDB was evaluated based on the urticaria activity score 7 (UAS7) and peripheral arterial tone apnea-hypopnea index (pAHI) derived from out-of-center sleep testing (OCST) findings, respectively; their correlation was examined.

RESULTS

Of the 37 patients studied, 19 had symptom-free-to-mild CSU (UAS7 ≤15) and 18 had moderate-to-severe CSU (UAS7 ≥16). The pAHI in the latter group was significantly higher than that in the former group (18 vs. 4.2, p = 0.001). In multivariate logistic analysis, moderate-to-severe SDB (pAHI ≥15) was significantly associated with moderate-to-severe CSU even after adjusting for the BMI (adjusted odds ratio 22 [95% confidence interval, 1.7-285]).

CONCLUSIONS

The severity of SDB is correlated with that of CSU independently of the BMI. Physicians should consider comorbid SDB when treating patients with CSU.

Sleep Apnea and Hypertension

Obstructive sleep apnea is a frequent finding in clinical practice especially with the obesity epidemic and the growing awareness of sleep-disordered breathing as a potential and treatable risk factor for cardiovascular diseases. It frequently coexists undiagnosed activating pathophysiological mechanisms known to participate in development and progression of cardiovascular diseases and resistance to therapeutical strategies. The sympathetic activation and the baroreflex and chemoreflex impairment appear to be the main pathophysiological factors that activating several mechanisms elicit cardiac and vascular damage. Data from cross-sectional population-based studies, prospective studies and meta-analysis have clearly shown the implication of OSA in the development of the hypertensive state and the benefits obtained by continuous positive airway pressure on daytime blood pressure and cardiovascular risk.

Coexistence of cardiovascular risk factors and obstructive sleep apnoea in polysomnography

OBJECTIVES

The objective of the study was to assess the relationship between the coexistence of cardiovascular risk factors (CVRFs) and the incidence and severity of obstructive sleep apnoea (OSA).

METHODS

The study involved 88 people, aged 53.76 ± 12.59 years. A questionnaire, basic anthropometric measurements, blood pressure, standard laboratory tests (total cholesterol, triglycerides and glucose) and polysomnography were performed. Each patient was assessed for the presence of CVRFs: i.e. obesity, arterial hypertension, hypercholesterolemia, hypertriglyceridemia, type 2 diabetes and smoking. OSA was diagnosed based on the apnoea and hypopnea index (AHI) in polysomnography.

RESULTS

It was documented that the mean AHI values were significantly higher in obese patients than in non-obese patients, in patients with arterial hypertension than in patients without hypertension, in patients with hypercholesterolaemia than in patients without hypercholesterolaemia and in patients declaring smoking than in non-smoking patients. The correlation analysis revealed a significant positive linear relationship between the number of CVRFs and the AHI value in polysomnography (r = 0.40, p < 0.05). Based on the regression analysis, it was documented that obesity, arterial hypertension and smoking are independent predictors of higher AHI values.

CONCLUSIONS

In the study group of patients with multiple cardiovascular risk factors, there is a directly proportional relationship between the number of cardiovascular risk factors and the AHI index in polysomnography.

Sleep disordered breathing in patients with Prader willi syndrome: Impact of underlying genetic mechanism

INTRODUCTION

Sleep-disordered breathing (SDB) is common in children with PWS. In the current study, we aimed to evaluate the severity of SDB in patients with PWS using polysomnography (PSG), and assess the effect of the underlying genetic mechanism on PSG parameters.

METHODS

Children with PWS, referred to our sleep laboratory between March 2016 and January 2020 were enrolled. PSG parameters, demographic data, body mass index (BMI), and symptoms related to SDB were recorded. The effect of non-invasive ventilation strategies and the outcome of therapy on PSG parameters were evaluated.

RESULTS

In our study, 64.5% of the patients had severe sleep apnea syndrome (total apnea hypopnea index (AHI) ≥10 events/hour). 22.6% had significantly high (>5 events/hour) central sleep apnea. Patients with a deletion had significantly lower initial and mean SaO₂, longer sleep time SaO₂ under 90%, oxygen desaturation % and total AHI when compared to those with uniparental disomy. PSG parameters were similar between patients who did or didn't receive growth hormone treatment.

CONCLUSION

The majority of the PWS patients had severe sleep apnea syndrome characterized mainly by hypopneas which were accompanied by central apneas. There was a more severe impact on oxygen parameters and total AHI in patients with deletions.

Explainable fuzzy neural network with easy-to-obtain physiological features for screening obstructive sleep apnea-hypopnea syndrome

OBJECTIVE/BACKGROUND

Recently, several tools for screening obstructive sleep apnea-hypopnea syndrome (OSAHS) have been devised with varied shortcomings. To overcome these drawbacks, we aimed to propose a self-estimation method using an explainable prediction model with easy-to-obtain variables and evaluate its performance for predicting OSAHS.

PATIENTS/METHODS

This retrospective, cross-sectional study selected significant easy-to-obtain variables from patients, suspected of having OSAHS by regression analysis, and fed these variables into the proposed explainable fuzzy neural network (EFNN), a back propagation neural network (BPNN) and a stepwise regression model to compare the screening performance for OSAHS.

RESULTS

Of the 300 participants, three easily available features, such as waist circumference, mean blood pressure (BP) at the end of polysomnography and the difference in systolic BP between the end and start of polysomnography, were obtained from regression analysis with a five-fold cross-validation scheme. Feeding these three variables into the prediction models showed that the average prediction differences for apnea-hypopnea index (AHI) when using the EFNN, BPNN, and regression model were respectively 1.5 ± 18.2, 3.5 ± 19.1 and 0.1 ± 19.3, indicating none of the tested methods had good efficacy to predict the AHI values. The performance as determined by the sensitivity + specificity-1 value for screening moderate-to-severe OSAHS of the EFNN, BPNN and regression model were respectively 0.440, 0.414 and 0.380.

CONCLUSIONS

When fed with easy-to-obtain physiological features, the understandable EFNN should be the preferred method to predict moderate-to-severe OSAHS.

Effect of compression stockings on overnight rostral fluid shift and obstructive sleep apnea: A meta-analysis

OBJECTIVE

The overnight rostral fluid shift from the lower limbs is one of the causes of obstructive sleep apnea (OSA). Compression stockings (CS) prevent lower limb fluid retention and have been reported to decrease nighttime fluid shift. The aim of this study is to evaluate the effect of CS on fluid shift and the severity of OSA.

METHODS

A systematic literature search was performed in the PubMed, EMBASE and Cochrane Library databases. The data were analyzed using Comprehensive Meta-Analysis software (Version 3; Biostat, Englewood, NJ). Studies evaluating the effect of CS on the overnight fluid shift and OSA severity were included in the analysis.

RESULTS

A total of 4 studies were included in this meta-analysis. The pooled analysis showed that the apnea-hypopnea index (AHI) of the overall study group was significantly lower after using CS (SMD, -1.08; 95% CI, -1.49 to -0.67). Decreases in the AHI were also observed in the normal fluid status (SMD, -1.05; 95% CI, -1.73 to -0.37) and fluid overload status (SMD, -1.17; 95% CI, -1.76 to -0.58) populations. The overall study group had significant decreases in overnight changes in neck circumference (SMD, -1.05; 95% CI, -2.06 to -0.03) and leg fluid volume (SMD, -1.14; 95% CI, -1.88 to -0.41) after using CS. However, no significant differences in overnight changes in neck circumference and leg fluid volume were observed in normal fluid status patients.

CONCLUSION

CS may help decrease overnight fluid shift and could be a treatment option for OSA.

Obstructive sleep apnea and sudden unexpected death in epilepsy in unselected patients with epilepsy: are they associated?

PURPOSE

We aimed to determine (1) the frequency of high-risk sudden unexpected death in epilepsy (SUDEP) in patients with epilepsy who have had obstructive sleep apnea (OSA) in different stages of sleep using the revised SUDEP risk inventory (rSUDEP-7) score instrument and (2) the factors associated with high risk SUDEP in patients with epilepsy who have had OSA.

METHODS

We conducted a cross-sectional study of consecutive subjects who are more than 15 years old without known sleep disorders, recruited from a single epilepsy clinic in a tertiary care facility. Participants underwent polysomnography. Scoring was performed by two blinded board-certified sleep physicians. The relationships between rSUDEP-7 scores and OSA measures were evaluated using Wilcoxon rank-sum test, chi-squared test, and quantile regression.

RESULTS

Our study population consisted of 95 participants. Overall median (IQR) apnea-hypopnea index (AHI) of our populations was 2.3 (0.7,7.5) events rate per hour; 12 (75%) patients had moderate OSA and 4 (25%) patients had severe OSA. Nine patients had a rSUDEP-7 score of 5 to 7. There was no significant difference between total rSUDEP-7 score or rSUDEP-7 score of > 5 or < 5 and total AHI, supine AHI, non-supine AHI, NREM AHI, or REM AHI; similarly, (2) there was no significant difference in total rSUDEP-7 score between AHI of < 15 or > 15.

CONCLUSION

Our study reveals no association between AHI score, OSA, and total rSUDEP-7 score or rSUDEP-7 score of > 5. The pathophysiology underlying SUDEP appears complex. We need further studies on SUDEP to help elucidate the cardiorespiratory mechanisms and predisposing factors.

Utilization of apnea-hypopnea index as a novel predictive factor for difficult mask ventilation in the Chinese population under general anesthesia

Purpose

Difficult mask ventilation (DMV) is a potentially life-threatening situation that can arise during anesthesia. However, most clinical predictors of DMV are based on European and US populations. On the other hand, most predictive models consist of multiple factors and complicated assessments. Since obstructive sleep apnea (OSA) is among the most important risk factors associated with DMV, the apnea-hypopnea index (AHI) may play an important role in determining patient risk.The purpose of this study was to investigate the relationship between DMV and AHI, and to determine preoperative risk factors for DMV in Chinese patients.

Methods

A prospective cohort trial enrolled patients scheduled for elective surgery. After obtaining informed consent, patient demographic information was collected, and patients were tested with pre-operative polysomnography. The anesthesiologist who managed the airway graded the mask ventilation. The difficult mask ventilation was defined as the mask ventilation provided by an unassisted anesthesiologist without oral airway or other adjuvant. A logistic regression model was used to analyze the association between AHI and DMV.

Results

A total of 159 patients were analyzed. For both primary and secondary outcomes, the unadjusted and adjusted odds ratio for DMV showed significant increases by 5 AHI units. AHI, age, and the Mallampati classification were found to be independent predictive factors for DMV.

Conclusions

AHI is associated with DMV as a novel independent risk factor in Chinese patients. Along with age and Mallampati classification, AHI should be included in establishing a superior predictive strategy for DMV screening.

Trial registration

Chinese Clinical Trial Registry ChiCTR-DDD-17013076

Lipid accumulation product (LAP) was independently associatedwith obstructive sleep apnea in patients with type 2 diabetes mellitus

BACKGROUND

Lipid accumulation product (LAP) is a new index based on a combination of waist circumference (WC) and serum triglycerides (TG) reflecting lipid accumulation. In this cross-sectional study, we aimed to explore whether LAP was independently associated with obstructive sleep apnea (OSA) in Type 2 diabetes mellitus (T2DM) patients.

METHODS

A cross-sectional study of 317 T2DM patients who underwent overnight polysomnography (PSG) tests was conducted. The clinical data between non-OSA group and OSA group were compared. Multivariable linear regression and multivariable logistic regression analyses were performed to determine associations of LAP, with apnea-hypopnea index (AHI) and OSA.

RESULTS

Among 317 patients, 219 (69.1%) were men, and the mean ages (±SD) were 51.4 (±13.5) years for men and 54.6 (±15.1) years for women (p = 0.067). The prevalence rates of OSA were 63.0% for men and 68.4% for women (p = 0.357). LAP (log-transformed) was significantly correlated with AHI (log-transformed), with the Pearson's correlation coefficient of 0.170 (p = 0.002). With adjustment for potential confounding factors, multivariate linear regression analyses showed the association of LAP with AHI was not statistically significant, with the adjusted linear regression coefficients (95% CI) of per SD increase of LAP for AHI (log-transformed) was 0.092 (- 0.011-0.194, p = 0.080). Multivariate logistic regression analyses showed LAP was significantly associated with increased risk of OSA, with the adjusted OR (95%CI) of per SD increase of LAP of 1.639 (1.032-2.604, p = 0.036). However, as constituents of LAP, neither TG nor WC was significantly associated with AHI and OSA.

CONCLUSION

LAP was independently associated with OSA and might be used as a potential OSA risk marker in T2DM patients, beyond the general index of obesity.

Results of coblation midline glossectomy for obstructive sleep apnea

OBJECTIVE

The aim of this study is to determine the effectiveness of coblation midline glossectomy for obstructive sleep apnea (OSA) when used as an isolated procedure. We also aim to compare the effect of this surgical procedure on supine and non-supine apnea.

MATERIALS AND METHODS

The medical records of patients who underwent isolated tongue base surgery as a part of step-wise surgeries between January 2014 and February 2019 are retrospectively reviewed. Pre-operative and post-operative Epworth sleepiness score (ESS), body mass index (BMI), and polysomnographic data, including the apnea-hypopnea index (AHI), oxygen desaturation index (ODI), supine AHI, and non-supine AHI of the patients were compared.

RESULTS

The study included 29 patients (26 male and 3 female). AHI improved significantly, decreasing from 34.9 ± 20.9 to 25.8 ± 17.6. Supine AHI decreased from 62.55 ± 28.23 to 55.18 ± 31.67 post-operatively, but this decrease was not significant. Non-supine AHI decreased significantly from 22.49 ± 24.02 to 14.08 ± 17.46. ESS and ODI also improved significantly.

CONCLUSION

Coblation midline glossectomy is an effective surgical procedure when applied solely, with a success rate of 52%. Non-supine apnea benefits to a greater degree than supine apnea from this surgical procedure.

[Relationship between sleep architecture and severity of obstructive sleep apnea]

OBJECTIVE

To investigate the effect of obstructive sleep apnea (OSA) on different sleep stages, and the relationship between N3 stage of non-rapid eye movement sleep and respiratory abnormal events.

METHODS

A total of 188 adult patients who underwent overnight polysomnography(PSG)monitoring in Sir Run Run shaw Hospital of Zhejiang University from June 24th to December 26th 2019 were enrolled in the study. OSA patients were classified into 3 groups (mild, moderate and severe) according to the apnea-hypopnea index (AHI). PSG data, AHI and the lowest SPO₂ in each stage of sleep were compared among three groups.

RESULTS

There was no significant difference in total sleep time and sleep efficiency among patients with different severity of OSA (all P>0.05). The proportion of N3 stage in moderate and severe OSA groups were significantly smaller than that in mild OSA group (all P<0.05). The proportion of N3 stage in severe OSA group was also smaller than that in moderate OSA group (P<0.05). In addition, severe OSA group had a longer latency of N3 stage than mild and moderate OSA groups (all P<0.05). The latency of N3 stage in moderate OSA group was longer than that in mild OSA group (P<0.05). The AHI in N3 stage was markedly lower than that in other sleep stages (all P<0.01), regardless of the severity of OSA. Supine AHI in N3 stage in mild and moderate groups was significantly lower than that in N1, N2 and rapid eye movement (REM) stages (all P<0.01). Supine AHI in N3 stage in severe group was also lower than that in N2 and REM stages (P<0.05 or P<0.01). The lowest SPO₂ in N3 stage was significantly higher than that in N1, N2 and REM stages (P<0.05 or P<0.01), regardless of the severity of OSA.

CONCLUSIONS

s The proportion of N3 stage is lower in OSA patients, and N3 stage has less sleep respiratory events than non-N3 stages. The results suggest that the increased N3 stage proportion may indicate less severity of OSA.

The correlation between drug-induced sleep endoscopy findings and severity of obstructive sleep apnea

OBJECTIVE

This study aimed to assess the relationship between anthropometric data, drug-induced sleep endoscopy (DISE) findings, and severity of obstructive sleep apnea (OSA).

METHODS

From August 2016 to August 2017, a total of 147 surgically naïve adult patients with OSA underwent DISE. Factors that were analyzed included anthropometric data and DISE findings.

RESULTS

When anthropometric data and DISE findings were analyzed with AHI by univariate analysis, the results showed that Epworth Sleepiness Scale (ESS), body mass index (BMI), neck circumference, concentric collapse of the velum, lateral oropharyngeal collapse, and anterior-posterior collapse of the tongue base were considered potentially independent predictors (p = 0.024, p < 0 .001, p < 0 .001, p < 0.001, p < 0.001, p < 0 .001, respectively, by Spearman correlation). When all important factors were evaluated in a stepwise multiple linear regression analysis, BMI, lateral oropharyngeal collapse, and anterior-posterior collapse of the tongue base were identified as significant predictors for the severity of OSA. The final model was listed as below: AHI score = 2.19 BMI + 7.56 Oropharynx/Lateral degree + 8.23 Tongue base/ Anterior-Posterior degree - 40.59.

CONCLUSION

By analyzing anthropometric data and DISE findings with AHI score, the results indicated that BMI, lateral oropharyngeal collapse, and anterior-posterior collapse of the tongue base were important factors associated with the severity of OSA.

Association between triglyceride glucose index and obstructive sleep apnea risk in Korean adults: a cross-sectional cohort study

Background

Triglyceride glucose (TyG) index is a reliable marker of insulin resistance, which is linked to obstructive sleep apnea (OSA). However, the relationship between TyG index and OSA has not been adequately assessed. This study aimed to evaluate the association between TyG index and OSA.

Methods

TyG index was assessed in 180 (mean age: 48.6 ± 13.8 years; 73.9% male) consecutive Korean adults with suspected OSA admitted to the sleep clinic at St. Paul’s Hospital between 2010 and 2012. The occurrence of more than 5 apnea-hypopnea index (AHI) events/h was used to define OSA. TyG index was calculated using the following equation: In [fasting triglycerides (mg/dL) × fasting glucose (mg/dL)/2]. All participants were grouped according to TyG index tertiles. Multivariate logistic regression analysis was used to determine factors associated with increased OSA risk.

Results

The overall prevalence of OSA in study participants was determined to be 83.9%. The prevalence of OSA increased (I [lowest]: 71.6%; II: 88.7%; III [highest]: 91.4%), and lowest peripheral oxygen saturation (SpO₂) levels decreased (I: 83.3 ± 8.5%; II: 79.9 ± 8.7%; III: 79.0 ± 8.3%), as TyG index tertile increased (P < 0.05). TyG index was correlated with AHI (r = 0.179) and lowest SpO₂ (r = − 0.188) (P < 0.05, respectively). Univariate linear regression analysis revealed an association between TyG and AHI (β = 10.084; P = 0.016). Multivariate logistic regression analysis showed that TyG index (odds ratio [OR]: 3.348; 95% confidence interval [CI]: 1.081–10.372), age ≥ 55 years (OR: 5.426; 95% CI: 1.642–17.935), and obesity (OR: 3.801; 95% CI: 1.468–9.842) were associated with increased OSA risk (all P < 0.05). The optimal TyG index cut-off value for predicting OSA was 8.83 (sensitivity: 61.6%; specificity: 69.0%; area under the curve: 0.688; P = 0.001). The predictive value of the OSA cut-off value improved when age ≥ 55 years and obesity were considered.

Conclusion

Increased TyG index was independently associated with increased OSA risk.

Obstructive sleep apnea syndrome and autonomic dysfunction in Duchenne muscular dystrophy

PURPOSE

Cardiac and respiratory involvement constitutes serious complications of Duchenne muscular dystrophy (DMD). We hypothesized that obstructive sleep apnea syndrome (OSAS) may play a role in cardiac autonomic dysfunction in DMD. We sought to assess the presence of cardiac autonomic function in patients with DMD by analyzing heart rate variability (HRV) during polysomnography (PSG).

METHODS

In a prospective study, all participants had whole-night PSG recorded and scored according to American Academy of Sleep Medicine guidelines. HRV analysis was performed on electrocardiography recordings from PSG recordings.

RESULTS

Twelve consecutive males with DMD (mean age 9.0 ± 3.1 years, mean BMI 20.6 ± 4.8 kg/m2) and eight age-matched healthy males were enrolled. On clinical evaluation, 58% of patients with DMD had at least one symptom related to OSAS, such as snoring, witnessed apnea, or restless sleep. None of the controls had OSAS-related complaints. By PSG none of the controls had OSAS, while 42% of patients with DMD had OSAS (p = 0.004). Average R-R duration and mean percentage of successive R-R intervals > 50 ms values were significantly lower in patients with DMD than those in controls (p < 0.006). In patients with DMD and OSAS, LF/HF (low/high-frequency) ratio was significantly increased in NREM sleep compared with those in controls (p = 0.005). Higher apnea-hypopnea index and lower oxygen saturation showed significant correlations with higher LF power and LF/HF ratio (p < 0.001).

CONCLUSION

Cardiac autonomic dysfunction is present in DMD, being more pronounced in the presence of OSAS.

Weighted Epworth sleepiness scale predicted the apnea-hypopnea index better

Background

The relationship between the Epworth sleepiness scale (ESS) and the apnea-hypopnea index (AHI) is uncertain and even poor. The major problem associated with the ESS might be a lack of consideration of weight in prediction in clinical practice. Would awarding different item-scores to the four scales of ESS items to develop a weighted ESS scoring system improve the accuracy of the AHI prediction? It is warranted to explore the intriguing hypotheses.

Methods

Seven hundred fifty-six adult patients with suspicion of obstructive sleep apnoea syndrome (OSAS) were prospectively recruited to a derivation cohort. This was tested against a prospective validation cohort of 810 adult patients with suspected OSAS. Each ESS item’s increased odds ratio for the corresponding AHI was calculated using univariate logistic regression. The receiver operating characteristic curves were created and the areas under the curves (AUCs) were calculated to illustrate and compare the accuracy of the indices.

Results

The higher the ESS item-score, the closer the relationship with the corresponding AHI. The odds ratios decreased as a result of the increased AHI. The ESS items were of unequal weight in predicting the corresponding AHI and a weighted ESS was developed. The coincidence rates with the corresponding AHI, body mass indices, and neck circumferences rose as the scores increased, whereas nocturnal nadir oxygen saturations decreased, and the weighted ESS was more strongly associated with these indices, compared with the ESS. The capability in predicting the patients without OSAS or with severe OSAS was strong, especially the latter, and the weighted ESS orchestrated manifest improvement in screening the patients with simple snoring. The patterns of sensitivities, specificities, and Youden’s indices of the four ranks of weighted ESS for predicting the corresponding AHI were better than those of the ESS, and the AUCs of weighted ESS were greater than the corresponding areas of ESS in the two cohorts.

Conclusions

The weighted ESS orchestrated significant improvement in predicting the AHI, indicating that the capability in predicting the patients without OSAS or with severe OSAS was strong, which might have implications for clinical triage decisions to prioritize patients for polysomnography.

Evaluation of forced oscilometry technique's parameters in severe obstructive sleep apnea patients without breathing disorder

Background:

Forced oscillometry technique (FOT) is a noninvasive technique that measures reactance and resistance capacity of the lung and is a practical and less time-consuming technique for respiratory effort assessment. Recently, FOT has provided beneficial data regarding the screening of the patients with obstructive sleep apnea (OSA) and assessing the disease progression. The current study aimed to evaluate the correlation of FOT parameters with severity of the apnea-hypnea index (AHI).

Methods:

In the current case series, all patients who had a body mass index ranging between 30 and 35, suffering severe OSA with AHI of more than 30 times per hour, were enrolled. Patients underwent FOT before treatment to measure the following FOT parameters: Respiratory resistance at 5 and 20 Hz (R5 and R20, respectively), resistance difference between R5 and R20, reactance at 5 Hz (X5), and resonant frequency (Fres).

Results:

In the current study, 22 patients were enrolled; whereas 12 (54.5%) were male and 10 (45.5%) were female with a mean age of 5.27 ± 4.34. A statistically significant, strong negative correlation was observed between Fres and AHI, during Pearson correlation analysis (r (20) =0.59, P < 0.0001). However, the relationship between the AHI and R5, R20, R5-R20 and X5 was not statistically significant. Similarly, the multiple regression model showed that, only Fres variable added statistically significantly to the prediction, P = 0.01.

Conclusion:

FOT is a useful tool in evaluation of AHI severity in patients suffering OSA and can be used as a diagnostic material in monitoring and management of these patients.

Does ischemia-modified albumin level predict severity of obstructive sleep apnea?

OBJECTIVE AND AIM

Ischemia-modified albumin (IMA) is a newly recognized marker of chronic inflammation used to evaluate oxidative stress status in patients with various diseases. We explored the possible relationship between IMA levels and obstructive sleep apnea (OSA).

METHODS

In this retrospective study, 169 of 216 sequential patients being evaluated for suspicion of OSAS met inclusion criteria. Polysomnography confirmed OSA in 86 patients (51%) while 81 patients (49%) without OSA were categorized as control subjects. All study participants were tested for blood IMA level, neutrophil/lymphocyte ratio (NLR), C-reactive protein (CRP) level, and red blood cell distribution width (RDW).

RESULTS

The serum IMA level was significantly higher in patients with OSAS than controls (p = 0.008). The serum IMA level increased significantly as OSAS severity increased (r = 0.50, p < 0.001) and was positively correlated with the AHI (r = 0.41, p < 0.001), CRP level (r = 0.31, p = 0.004), body mass index (r = 0.24, p = 0.022), RDW (r = 0.31, p = 0.03), oxygen desaturation index (ODI) (r = 0.22, p = 0.02), and negatively correlated with the hemoglobin concentration (r = - 0.28, p = 0.04) and minimum hemoglobin oxygen saturation (SpO2) (r = - 0.25, p = 0.02). Receiver operator curve (ROC) analysis showed that the optimal serum IMA, CRP, RDW, and NLR values were not different for predicting OSAS diagnosis (areas under the curves (AUC) = 0.62, 0.59, 0.60, and 0.43, respectively). However, the serum IMA level was superior in reflecting OSAS severity (AUC = 0.78) compared to CRP, RDW, and NLR values (AUC = 0.61, 0.53, and 0.51, respectively) (all p < 0.001).

CONCLUSION

Like other markers of inflammation, blood IMA levels were significantly elevated in patients with OSA. However, blood IMA level was a better predictor of disease severity than the other markers.

Demographic, clinical, and biomarker predictors of apnea-hypopnea index from polysomnography in Midwestern sleep clinic patients

BACKGROUND

To examine if selected demographic (age, gender), clinical (diabetes, coronary artery disease, hyperlipidemia, myocardial infarction, stroke, lung disease, smoking history, alcohol intake), and biomarker [blood pressure (BP), heart rate, body mass index (BMI), neck circumference, Mallampati score] variables are predictors of apnea-hypopnea index (AHI) from polysomnography (PSG).

METHODS

This cross-sectional study recruited a sample of adults (N = 170) who were being evaluated for OSA. Participants completed self-reported demographic and clinical questionnaires, and then completed PSG (n = 142). Multi-collinearity was assessed. Confounding factors, correlations, and potential interactions were explored.

RESULTS

The final regression model was performed on 130 participants; 61 (46.9%) had an AHI ≥ 15. Systolic and diastolic BPs were highly correlated. Interactions were tested between gender and other variables (high cholesterol, BMI, neck circumference, systolic BP) and between systolic BP and other variables (high cholesterol, BMI, neck circumference, and lung disease). No interactions occurred between gender or systolic BP and other variables, meaning that the effects of the variables on AHI levels from PSG did not vary depending on gender or systolic BP. BMI, systolic BP, and absence of lung disease were predictors for AHI levels ≥ 15 from PSG.

CONCLUSIONS

BMI and systolic BP were significant predictors of OSA in this study. The absence of lung disease as a significant predictor was unique and may be due to the small number of participants who self-reported lung disease. To our knowledge, this is the first study to report this combination of variables to predict AHI levels ≥ 15 from PSG.

Associations between ankle-brachial index, diabetes, and sleep apnea in the Hispanic community health study/study of Latinos (HCHS/SOL) database

BACKGROUND

Sleep apnea and diabetes mellitus (DM) negatively impact cardiovascular health. One important indicator of cardiovascular health is the Ankle-Brachial Index (ABI). Either low ABI or high ABI are signs of peripheral vascular impairment. Impaired vascular health and DM, together, might provoke sleep apnea; however, information regarding these relationships is limited. Therefore, this study aimed to investigate the association between ABI, DM status, and severity of obstructive sleep apnea in people of Hispanic/Latino descent who are diverse in culture, environmental exposures, nativity, socioeconomic status, and disease burden.

METHODS

A cross sectional analysis from a multi-center epidemiologic study, Hispanic Community Health Study/Study of Latinos, was utilized and included 3779 participants (mean age 55.32 ± 7.67, females 57.9%). The sample was divided into 4 groups based on the American Diabetes Association diagnostic guidelines (no DM or DM), and the ABI status (normal and abnormal). Multiple linear regression analysis was used to determine the association of the four groups and other independent variables with severity of sleep apnea measured by apnea-hypopnea index. Kruskal-Wallis H test was used for comparisons between groups for the apnea-hypopnea index. The significant level was set at 0.01.

RESULTS

There were significant differences between groups in the mean of apnea-hypopnea index (P < 0.001; no DM + normal ABI = 5.42 ± 9.66, no DM + abnormal ABI = 7.11 ± 11.63, DM + normal ABI = 10.99 ± 15.16, DM + abnormal ABI = 12.81 ± 17.80). Linear regression showed that DM and abnormal ABI were significantly associated with severe sleep apnea (β = 3.25, P = 0.001) after controlling for age, sex, BMI, income, education, alcohol use, cigarette use, hypertension or related medication, stroke and statin use.

CONCLUSION

These findings suggest that people with DM and abnormal ABI were more likely to have high apnea-hypopnea index compared to the other groups. We observed gradual increasing in the severity of sleep apnea from low abnormality groups to high abnormality groups for Hispanic/Latino. Further work should elucidate the association of DM, abnormal ABI and sleep apnea with longer term outcomes, and replicate this work in different populations.

Acute stroke and TIA patients have specific polygraphic features of obstructive sleep apnea

Purpose

Obstructive sleep apnea (OSA) is associated with increased risk for stroke, which is known to further impair respiratory functions. However, it is unknown whether the type and severity of respiratory events are linked to stroke or transient ischemic attack (TIA). Thus, we investigate whether the characteristics of individual respiratory events differ between patients experiencing TIA or acute ischemic stroke and matched patients with clinically suspected sleep-disordered breathing.

Methods

Polygraphic data of 77 in-patients with acute ischemic stroke (n = 49) or TIA (n = 28) were compared to age, gender, and BMI-matched patients with suspected sleep-disordered breathing and no cerebrovascular disease. Along with conventional diagnostic parameters (e.g., apnea-hypopnea index), durations and severities of individual apneas, hypopneas and desaturations were compared between the groups separately for ischemic stroke and TIA patients.

Results

Stroke and TIA patients had significantly shorter apneas and hypopneas (p < 0.001) compared to matched reference patients. Furthermore, stroke patients had more central apnea events (p = 0.007) and a trend for higher apnea/hypopnea number ratios (p = 0.091). The prevalence of OSA (apnea-hypopnea index ≥ 5) was 90% in acute stroke patients and 79% in transient ischemic attack patients.

Conclusion

Stroke patients had different characteristics of respiratory events, i.e., their polygraphic phenotype of OSA differs compared to matched reference patients. The observed differences in polygraphic features might indicate that stroke and TIA patients suffer from OSA phenotype recently associated with increased cardiovascular mortality. Therefore, optimal diagnostics and treatment require routine OSA screening in patients with acute cerebrovascular disease, even without previous suspicion of OSA.

Electronic supplementary material

The online version of this article (10.1007/s11325-019-02010-2) contains supplementary material, which is available to authorized users.

Dissociation between objectively quantified snoring and sleep quality

BACKGROUND

The impact of simple snoring on sleep structure and sleepiness has not been well described. In several studies, self-reported snoring was associated with increased daytime sleepiness. However, most studies did not distinguish patients with simple snoring from those with coexisting obstructive sleep apnea (OSA) using objective measures. We therefore evaluated the relationship between objectively measured snoring and both sleep structure and daytime sleepiness in patients with no or mild OSA.

METHODS

Subjects referred for suspected sleep disorders underwent polysomnography (PSG) during which breath sounds were recorded by a microphone. Those with an apnea-hypopnea index (AHI) <15/h were analyzed. Individual snores were identified by a computer algorithm, from which the snore index (SI) was calculated as the number of snores/h of sleep. Sleep stages and arousals were quantified. Daytime sleepiness was evaluated using the Epworth Sleepiness Scale (ESS) score.

RESULTS

74 (35 males) subjects were included (age, mean ± SD: 46.4 ± 15.3 years and body mass index: 29.8 ± 7.0 kg/m²). The mean SI was 266 ± 243 snores/h. Subjects were categorized according to their SI into 3 tertiles: SI < 100, between 100-350, and >350. No sleep structure indeces, arousals, or ESS score differed among SI tertiles (p > 0.13). There was no correlation between SI and any of these variables (p > 0.29). In contrast, the AHI was significantly related to frequency of arousals (r = 0.23, p = 0.048).

CONCLUSIONS

These findings suggest that simple snoring assessed objectively is not related to indices of sleep structure or subjective sleepiness.

Circulating P-Selectin and Its Glycoprotein Ligand in Nondiabetic Obstructive Sleep Apnea Patients

Selectins and their ligands play an important role in atherosclerosis. The role of these adhesion molecules in the pathogenesis of obstructive sleep apnea (OSA) may be of clinical relevance. Therefore, the aim of this study was to assess the serum content of platelet P-selectin (P-SEL) and P-selectin glycoprotein ligand 1 (PSGL-1) in different OSA stages. The study was performed in nondiabetic patients, aged 32-71, in whom OSA was verified by polysomnography. The apnea/hypopnea index (AHI) was used to stratify OSA stages: AHI <5, no sleep pathology (OSA-0); AHI 5-15, (OSA-1); AHI 16-30, (OSA-2); and AHI >30, (OSA-3). There were 16 patients in each group. P-SEL and PSGL-1 were assessed by ELISA kits. There were no appreciable differences in the patients' glucose or high-specificity C-reactive protein content. We found that P-SEL and PSGL-1 significantly increased from OSA-0 to OSA-3. There were the following positive associations in all OSA patients: P-SEL vs. AHI, PSGL-1 vs. AHI, and P-SEL vs. PSGL-1. In addition, the adhesion molecules are associated with the anthropometric parameters, oxygen saturation, and sleep architecture in the OSA-1 group. We conclude that the adhesion molecules consistently increase in the blood of nondiabetic OSA patients, along with progression of disorder severity.

Prevalence of Sleep Apnea in Patients with Carotid Artery Stenosis

Obstructive sleep apnea (OSA) is a common disease affecting about 13% of men and 6% of women, usually having severe cardiovascular sequalae. OSA is responsible for the systemic inflammatory response and oxidative stress and results in endothelial injury being a risk factor for atherosclerosis. The aim of this study was to estimate the prevalence of OSA among patients with severe carotid artery stenosis. Fifty-five patients (F/M-24/31, mean age 70 ± 7 years, body mass index 28.3 ± 6.3 kg/m²) were enrolled into the study. The patients were qualified for elective surgical treatment of carotid artery stenosis. Polysomnography was performed in all patients the night before surgery. Thirty-six patients underwent surgical endarterectomy and nineteen patients underwent carotid artery stenting. Sleep apnea was diagnosed in 44 (80%) of all patients. The mean apnea-hypopnea index (AHI) was 14.5 ± 12.9. The OSA severity distribution was as follows: 22 mild, 16 moderate, and 6 severe cases. We found that the percentage of carotid endarterectomies was the greatest in mild and moderate OSA. It was approximately twofold greater than that in non-OSA patients. Carotid artery stenting was performed in nearly half of the patients in each of these groups. We conclude that OSA is highly prevalent in patients with carotid artery stenosis scheduled for carotid surgery. Nonetheless, the exact pathogenetic mechanisms underlying mutual interaction between OSA and vascular wall damage remain elusive. OSA is not routinely diagnosed among patients with advanced atherosclerosis. The study results might be an argument for performing polysomnography in patients with carotid artery stenosis.