The impact of obesity on oxygen desaturation during sleep-disordered breathing

Nocturia and obstructive sleep apnoea

Nocturia, the need to urinate at night, is a common symptom in patients with obstructive sleep apnoea (OSA). Continuous positive airway pressure treatment can reduce nocturia in some patients, but the underlying mechanisms are complex and not fully understood. OSA affects the autonomic nervous system, oxidative stress and endothelial damage. Furthermore, the commonly held theory attributing polyuria to a false signal of cardiac overload and response natriuresis has limitations. A comprehensive approach to the management of nocturia in OSA, considering factors such as comorbidities, medication use, alcohol consumption and lifestyle, is needed. Effective management of nocturia in OSA requires a multidisciplinary approach, and urologists should be aware of the potential effect of OSA on physiology and refer patients for further testing at a sleep centre. In addition to continuous positive airway pressure, other interventions such as oral appliances and surgical obstruction treatment could be beneficial for some patients. Overall, understanding the complex interplay between OSA and nocturia is crucial for optimizing patient outcomes.

A comparison of two obesity-related hypoventilation disorders: Impact on sleep, quality of life and neurocognitive outcomes and the effects of positive airway pressure therapy

Study Objectives

Symptom impact and neurocognitive function have not been previously compared between patients with obesity-associated hypoventilation disorders (obesity hypoventilation syndrome [OHS]) and hypoventilation in the setting of obesity and obstructive airways disease (OHAD). The aim of this study is to compare baseline sleep-related symptoms, health-related quality of life, and neurocognitive function between OHS and OHAD and the impact of PAP therapy on these outcomes.

Methods

Epworth Sleepiness Scale (ESS), Pittsburgh Sleepiness Quality Index (PSQI), SF36, and various neurocognitive tests, in addition to anthropometric, polysomnography, lung function, and blood gas data from participants with OHS and participants with OHAD, were included in the analysis. These data were originally collected in their respective randomized clinical trials, comparing the efficacy of different PAP modes (bilevel PAP vs. CPAP) in resolving hypercapnia. Between groups (OHS vs OHAD), pre- and post-treatment (with 3 months of positive airway pressure) comparisons were made using linear mixed modeling.

Results

45 OHS participants (mean age 51 years old, 33% female, BMI 52 kg/m2, FER 0.81, PaCO2 54 mmHg, AHI 87/h) and 32 OHAD participants (mean age 61years old, 31% female, BMI 43kg/m2, FER 0.60, PaCO2 54 mmHg, AHI 59/h) were included in the analysis. Both OHS and OHAD had similar baseline ESS (14(5.6) vs. 12(5.4)), Global PSQI (10(3.2) vs. 11(4.8)), SF36 and neurocognitive test performances (other than OHAD had lower digit symbol substitution test performance). Treatment with PAP therapy resulted in similar ESS, Global PSQI, and SF36 improvements in both groups. Neurocognitive performance did not significantly improve after PAP therapy in either group.

Conclusions

The symptom impact between two separate hypoventilation disorders (OHS and OHAD), in terms of sleepiness, sleep quality, quality of life, and cognitive function, were similar. OHS and OHAD had similar treatment responses in these parameters after 3 months of PAP therapy.Nocturnal ventilatory support in OHS.

Obstructive sleep apnea and cognitive functioning in the older general population: The moderating effect of age, sex, ApoE4, and obesity

Research on the relationship between obstructive sleep apnea and cognitive functioning has yielded conflicting results, particularly in the older population, and moderators of this association have rarely been studied. Here we investigated the cross-sectional association between obstructive sleep apnea and cognitive functioning as well as the moderating effect of age, sex, apolipoprotein E4, and obesity on this association among community-dwelling older people. We analysed data from 496 participants (71.4 ± 4.4 years; 45.6% men) of the HypnoLaus study who underwent polysomnography and a battery of neuropsychological tests. The sample was categorised as no-to-mild obstructive sleep apnea (apnea-hypopnea index 0-14.9/h; reference), moderate obstructive sleep apnea (apnea-hypopnea index 15.0-29.9/h), or severe obstructive sleep apnea (apnea-hypopnea index ≥30/h). Regression and moderation analyses were performed with adjustment for confounders. Apolipoprotein E4 and obesity moderated the association between severe obstructive sleep apnea and processing speed, whereas no moderating effects were found for age and sex. In apolipoprotein E4 carriers only, severe obstructive sleep apnea was associated with lower performance in Stroop condition 1 (B = 3.13, p = 0.024). In obese participants only, severe obstructive sleep apnea was associated with lower performance in Stroop condition 1 (B = 3.02, p = 0.025) and Stroop condition 2 (B = 3.30, p = 0.034). Severe obstructive sleep apnea was also associated with lower executive function in the whole sample according to Stroop condition 3 (B = 3.44, p = 0.020) and Stroop interference score (B = 0.24, p = 0.006). Our findings support associations of severe obstructive sleep apnea (but not moderate obstructive sleep apnea) with lower performance in processing speed and executive function in the older general population. Apolipoprotein E4 and obesity appear to be vulnerability factors that strengthen the association between severe obstructive sleep apnea and lower performance in processing speed.

REM sleep obstructive sleep apnoea

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

Association between REM-related mild obstructive sleep apnea and common cardiometabolic diseases

PURPOSE

To explore the association between rapid eye movement-related obstructive sleep apnea (REM-OSA) and common cardiometabolic diseases (CMDs) in patients with mild OSA.

METHODS

This retrospective study was conducted by reviewing the medical records and polysomnograms (PSGs) of patients at Siriraj Hospital. The PSGs of patients diagnosed with mild OSA who had ≥ 15 min of REM sleep were included. REM-OSA was defined if the apnea-hypopnea index (AHI) in REM was ≥ 2 times that of non-REM. Common CMDs included coronary artery disease, stroke, heart failure, diabetes mellitus, and hypertension.

RESULTS

The data of 518 patients with a mean age of 48.3 years, 198 males, and mean AHI of 9.8 events/h were analyzed in this study. When compared with the control group, the REM-OSA group (308 patients) were predominantly female (72%), overweight (62%), and had more severe oxygen desaturation, p-value < 0.001. CMDs were significantly more common in the REM-OSA group than in the controls [odds ratio (OR) 1.52, 95% confidence interval 1.04-2.21, p-value = 0.029]. Patients with a REM AHI of ≥ 20 events/h were significantly associated with hypertension compared to those with a REM AHI of < 20 events/h, p-value = 0.001. However, these associations were found not to be statistically significant after controlling for age, sex, BMI, and prevalent coexisting CMD (OR = 1.13, 95% CI: 0.72-1.76, p-value = 0.605).

CONCLUSION

Common CMDs, particularly HT, tend to show an association with REM-OSA in patients with mild OSA, but this association did not reach statistically significant levels.

Overall Obesity Not Abdominal Obesity Has a Causal Relationship with Obstructive Sleep Apnea in Individual Level Data

Objective

Both obstructive sleep apnea (OSA) and obesity are highly prevalent worldwide, and are intrinsically linked. Previous studies showed that obesity is one of the major risk factors for OSA, but the causality of the relationship is still unclear. The study was to investigate the causal relationships of overall obesity and abdominal obesity with OSA and its quantitative traits.

Methods

In this case-control study, a total of 7134 participants, including 4335 moderate-to-severe OSA diagnosed by standard polysomnography and 2799 community-based controls were enrolled. Anthropometric and biochemical data were collected. Mendelian randomization (MR) analyses were performed using the genetic risk score, based on 29 body mass index (BMI)- and 11 waist-hip-ratio (WHR)-associated single nucleotide polymorphisms as instrumental variables. The causal associations of these genetic scores with OSA and its quantitative phenotypes were analyzed.

Results

Obesity was strongly correlated with OSA in observational analysis (β= 0.055, P = 3.7 × 10-5). In MR analysis, each increase by one standard deviation in BMI was associated with increased OSA risk [odds ratio (OR): 2.21, 95% confidence interval (CI): 1.62-3.02, P = 5.57 × 10-7] and with 2.72-, 4.68-, and 3.25-fold increases in AHI, ODI, and MAI, respectively (all P < 0.05) in men. However, no causal associations were found between WHR and OSA risk or OSA quantitative traits in men and women.

Conclusion

Compared to abdominal obesity, overall obesity showed a causal relationship with OSA and its quantitative traits, especially in men.

How does obstructive sleep apnea alter cerebral hemodynamics?

STUDY OBJECTIVES

We aimed to characterize the cerebral hemodynamic response to obstructive sleep apnea/hypopnea events, and evaluate their association to polysomnographic parameters. The characterization of the cerebral hemodynamics in obstructive sleep apnea (OSA) may add complementary information to further the understanding of the severity of the syndrome beyond the conventional polysomnography.

METHODS

Severe OSA patients were studied during night sleep while monitored by polysomnography. Transcranial, bed-side diffuse correlation spectroscopy (DCS) and frequency-domain near-infrared diffuse correlation spectroscopy (NIRS-DOS) were used to follow microvascular cerebral hemodynamics in the frontal lobes of the cerebral cortex. Changes in cerebral blood flow (CBF), total hemoglobin concentration (THC), and cerebral blood oxygen saturation (StO2) were analyzed.

RESULTS

We considered 3283 obstructive apnea/hypopnea events from sixteen OSA patients (Age (median, interquartile range) 57 (52-64.5); females 25%; AHI (apnea-hypopnea index) 84.4 (76.1-93.7)). A biphasic response (maximum/minimum followed by a minimum/maximum) was observed for each cerebral hemodynamic variable (CBF, THC, StO2), heart rate and peripheral arterial oxygen saturation (SpO2). Changes of the StO2 followed the dynamics of the SpO2, and were out of phase from the THC and CBF. Longer events were associated with larger CBF changes, faster responses and slower recoveries. Moreover, the extrema of the response to obstructive hypopneas were lower compared to apneas (p < .001).

CONCLUSIONS

Obstructive apneas/hypopneas cause profound, periodic changes in cerebral hemodynamics, including periods of hyper- and hypo-perfusion and intermittent cerebral hypoxia. The duration of the events is a strong determinant of the cerebral hemodynamic response, which is more pronounced in apnea than hypopnea events.

International Consensus Statement on Obstructive Sleep Apnea

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Oxygen resaturation rate is significantly associated with objectively assessed excessive daytime sleepiness in suspected obstructive sleep apnoea patients

INTRODUCTION

Commonly utilised metrics such as the apnoea-hypopnoea index show limited correlation to excessive daytime sleepiness (EDS). Oxygen desaturation parameters show better predictive power, however oxygen resaturation parameters have not yet been investigated. Oxygen resaturation may represent increased cardiovascular fitness and thus we hypothesized that a higher resaturation rate would be protective against EDS.

METHODS

Oxygen saturation parameters were computed via ABOSA software for adult patients referred for polysomnography and multiple sleep latency test in Israel Loewenstein hospital 2001-2011. EDS was defined as a mean sleep latency (MSL) below 8 min.

RESULTS

1629 patients (75% male, 53% obese, median age of 54 years) were included for analysis. The average desaturation event nadir was 90.4% and resaturation rate 0.59%/second. Median MSL was 9.6 min, and 606 patients met criteria for EDS. Patients who were younger, female, and with larger desaturations had significantly higher resaturation rates (p < 0.001). In multivariate models, adjusted for age, sex, body mass index, and average desaturation depth, resaturation rate showed a significant negative correlation with MSL (z-score standardised beta, -1 (95%CI -0.49, -1.52)), and significantly increased odds ratio (OR) of EDS (OR, 1.28 (95%CI 1.07, 1.53)). The beta associated with resaturation rate was larger, though non-significantly, than that of desaturation depth (difference 0.36 (95% CI -1.34, 0.62), p = 0.470).

CONCLUSION

Oxygen resaturation parameters show significant associations with objectively assessed EDS independent of desaturation parameters. Thus, resaturation and desaturation parameters may reflect differing underlying mechanistic pathways and both be considered novel and appropriate markers for assessing sleep-disordered breathing and associated outcomes.

Investigating the Relationship between Obstructive Sleep Apnoea, Inflammation and Cardio-Metabolic Diseases

Obstructive sleep apnoea (OSA) is a prevalent underdiagnosed disorder whose incidence increases with age and weight. Uniquely characterised by frequent breathing interruptions during sleep-known as intermittent hypoxia (IH)-OSA disrupts the circadian rhythm. Patients with OSA have repeated episodes of hypoxia and reoxygenation, leading to systemic consequences. OSA consequences range from apparent symptoms like excessive daytime sleepiness, neurocognitive deterioration and decreased quality of life to pathological complications characterised by elevated biomarkers linked to endocrine-metabolic and cardiovascular changes. OSA is a well-recognized risk factor for cardiovascular and cerebrovascular diseases. Furthermore, OSA is linked to other conditions that worsen cardiovascular outcomes, such as obesity. The relationship between OSA and obesity is complex and reciprocal, involving interaction between biological and lifestyle factors. The pathogenesis of both OSA and obesity involve oxidative stress, inflammation and metabolic dysregulation. The current medical practice uses continuous positive airway pressure (CPAP) as the gold standard tool to manage OSA. It has been shown to improve symptoms and cardiac function, reduce cardiovascular risk and normalise biomarkers. Nonetheless, a full understanding of the factors involved in the deleterious effects of OSA and the best methods to eliminate their occurrence are still poorly understood. In this review, we present the factors and evidence linking OSA to increased risk of cardiovascular conditions.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Effects of Acute Exposure and Acclimatization to High-Altitude on Oxygen Saturation and Related Cardiorespiratory Fitness in Health and Disease

Maximal values of aerobic power (VO₂max) and peripheral oxygen saturation (SpO₂max) decline in parallel with gain in altitude. Whereas this relationship has been well investigated when acutely exposed to high altitude, potential benefits of acclimatization on SpO₂ and related VO₂max in healthy and diseased individuals have been much less considered. Therefore, this narrative review was primarily aimed to identify relevant literature reporting altitude-dependent changes in determinants, in particular SpO₂, of VO₂max and effects of acclimatization in athletes, healthy non-athletes, and patients suffering from cardiovascular, respiratory and/or metabolic diseases. Moreover, focus was set on potential differences with regard to baseline exercise performance, age and sex. Main findings of this review emphasize the close association between individual SpO₂ and VO₂max, and demonstrate similar altitude effects (acute and during acclimatization) in healthy people and those suffering from cardiovascular and metabolic diseases. However, in patients with ventilatory constrains, i.e., chronic obstructive pulmonary disease, steep decline in SpO₂ and V̇O₂max and reduced potential to acclimatize stress the already low exercise performance. Finally, implications for prevention and therapy are briefly discussed.

Clinical and Polysomnographic Characteristics of Nonobese and Obese Chinese Patients With Obstructive Sleep Apnea

PURPOSE

Obesity is a risk factor associated with the onset and exacerbation of obstructive sleep apnea (OSA). However, the majority of OSA patients in Asian populations are nonobese. To date, there have been insufficient large-scale studies of the differences in the clinical and polysomnographic features of obese and nonobese OSA patients in this population, and few studies have sought to identify predictors of OSA severity in affected obese and nonobese patients.

METHODS

We conducted a case-matched retrospective study, including 652 consecutive Chinese OSA patients (326 nonobese and 326 obese) to assess differences in demographic, clinical, and polysomnographic data between these two groups. Independent predictors of OSA severity were identified through multivariate linear regression analysis.

RESULTS

The age and gender distributions of our obese and nonobese OSA patient cohorts did not differ significantly ( P > 0.05), and rates of comorbidities were comparable in these two patient groups ( P > 0.05). Nonobese patients were more likely to report atypical symptoms of OSA, including insomnia ( P < 0.001), irritability ( P < 0.05), and depressive symptoms ( P < 0.01), whereas obese patients were more likely to report typical symptoms of OSA, such as habitual snoring ( P < 0.001), witnessed apnea ( P < 0.05), and daytime sleepiness ( P < 0.001). Relative to nonobese patients, those who were obese exhibited significantly higher apnea-hypopnea index during total sleep time ( P < 0.001), apnea-hypopnea index during nonrapid eye movement sleep ( P < 0.001), and apnea-hypopnea index during rapid eye movement sleep ( P < 0.001), in addition to lower average oxygen saturation ( P < 0.001), minimal oxygen saturation ( P < 0.001), and a higher oxygen desaturation index ( P < 0.001) and arousal index ( P < 0.001). Total sleep time was, on average, shorter for nonobese patients ( P < 0.05), who also exhibited decreased sleep efficiency and more frequent awakening relative to obese patients ( P < 0.05). A multivariate linear regression analysis revealed that neck circumference and waist circumference were independent predictors of OSA severity in obese patients ( P < 0.05).

CONCLUSIONS

On average, OSA was typically less severe in nonobese patients, who were also more likely to experience atypical OSA symptoms relative to obese patients. These results also suggest that the differential contributions of body fat accumulation and distribution to OSA severity may offer insights into the pathogenesis, clinical manifestations, and optimal management of this condition in nonobese and obese patient populations. It is vital that clinicians consider these differences to properly diagnose and treat this debilitating condition.

Accuracy of Oxygen Saturation Measurements in Patients with Obesity Undergoing Bariatric Surgery

BACKGROUND

We aimed to determine the magnitude, direction, and influencing factors of the concordance between arterial oxygen saturation (SaO₂) and peripheral capillary oxygen saturation (SpO₂) in patients with obesity undergoing bariatric surgery, supporting the measurement of SaO₂ and SpO₂ in key populations.

METHODS

Patients with obesity undergoing bariatric surgery from 2017 to 2020 were included. Preoperative SpO₂ and SaO₂ were collected. Linear correlation and multiple linear regression analyses were performed to characterize the relationships between body mass index (BMI), age, and sex with pulse oximetry and arterial blood gas (ABG) parameters. Bland-Altman analysis was applied to determine the concordance between SpO₂ and SaO₂ and the limits of this concordance.

RESULTS

A total of 134 patients with obesity undergoing bariatric surgery were enrolled. SaO₂ was negatively associated with BMI (p < 0.0001) and age (p = 0.006), and SpO₂ was negatively associated with BMI (p = 0.021) but not with age. SpO₂ overestimated SaO₂ in 91% of patients with a bias of 2.05%. This bias increased by 203% in hypoxemic patients compared with nonhypoxemic patients (p < 0.0001). The bias was 1.3-fold higher (p = 0.023) in patients with a high obesity surgery mortality risk score (OS-MRS) than in those with low or intermediate scores.

CONCLUSION

Compared with SpO₂, preoperative SaO₂ can more accurately reflect the real oxygen saturation in patients with obesity undergoing bariatric surgery, especially for those with BMI ≥ 40 kg/m², age ≥ 40 years, and high OS-MRS. ABG analysis can provide a more reliable basis for accurate and timely monitoring, ensuring the perioperative safety of susceptible patients.

Association of self-reported snoring and hyperuricaemia: a large cross-sectional study in Chongqing, China

OBJECTIVE

To examine the relationship between self-reported snoring and hyperuricaemia in a large-scale population in Chongqing, China.

SETTING

Face-to-face electronic questionnaire survey, physical examination and biological sample testing were conducted in 13 districts of Chongqing. Chongqing is a municipality in southwest China.

PARTICIPANTS

In this study, 23 308 Han ethnicity permanent residents aged 30-79 years were recruited. Individuals missing data were excluded, 22 389 subjects were included in final analysis.

PRIMARY AND SECONDARY OUTCOME MEASURES

Serum uric acid (UA) was measured using an oxidase method. Hyperuricaemia was defined as serum UA >420 µmol/L in men and >360 µmol/L in women. Information about self-reported snoring was obtained by questionnaire survey. All participants were divided into 'no snoring' 'snoring occasionally' and 'snoring frequently'. Multivariable logistic regression analysis was performed to assess the relationship between self-reported snoring and hyperuricaemia.

RESULTS

The prevalence of hyperuricaemia was 14.43%, and snorers were more likely to have hyperuricaemia than non-snorer in different age and gender groups. For the total population, those who snore occasionally or frequently were more likely to be hyperuricaemia (OR 1.19, 95% CI 1.07 to 1.31; OR 1.33, 95% CI 1.19 to 1.47) compared with no snoring people. Stratification by age, gender and body mass index (BMI), we found that the positive association between snoring frequently and hyperuricaemia was insisted in different age, gender and high BMI groups, and the strength of association varied with different age, gender and BMI category.

CONCLUSION

Snoring frequency was positively associated with higher risk of hyperuricaemia. Snoring frequently may be a signal for hyperuricaemia, especially for women, those over 59 years of age, or those who are overweight or obese.

The effects of exercise training on vascular function among overweight adults with obstructive sleep apnea

Obstructive sleep apnea (OSA) is associated with increased cardiovascular morbidity due, in part, to impaired vascular function. Exercise confers cardioprotection by improving vascular health. Yet, whether OSA severity affects the vascular improvements conferred with exercise training is not known. Overweight (body mass index (BMI) >27 kg/m²) adults were evaluated for OSA and enrolled in a six-week exercise intervention. Baseline assessments of brachial artery flow-mediated dilation (BAFMD), central augmentation index (AIx) and pulse wave velocity (PWV) were repeated post training. Fifty-one participants (25 men; 26 women) completed the study. Despite improved aerobic capacity (p=0.0005) and total fat mass (p=0.0005), no change in vascular function was observed. Participants were divided into two severity groups according to their baseline total apnea-hypopnea index (AHI) as either 5 to 14.9 events•hr^-1 (n= 21; Age=48 ± 7 yrs; BMI=33.7 ± 4.6kg•m^-2) or 15 ≥events•hr^-1 (n=30; Age=56 ± 13 yrs; BMI = 34.3 ± 4.2 kg•m^-2). No effect of OSA group was observed for BAFMD (p=0.82), AIx (p=0.37) or PWV (p=0.44), suggesting that OSA severity does not influence the effect of exercise on vascular function. The vascular effects of extended exercise programs of greater intensity in overweight OSA patients should be examined.

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

PURPOSE

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

Automated Scoring of Sleep and Associated Events

Conventionally, sleep and associated events are scored visually by trained technologists according to the rules summarized in the American Academy of Sleep Medicine Manual. Since its first publication in 2007, the manual was continuously updated; the most recent version as of this writing was published in 2020. Human expert scoring is considered as gold standard, even though there is increasing evidence of limited interrater reliability between human scorers. Significant advances in machine learning have resulted in powerful methods for addressing complex classification problems such as automated scoring of sleep and associated events. Evidence is increasing that these autoscoring systems deliver performance comparable to manual scoring and offer several advantages to visual scoring: (1) avoidance of the rather expensive, time-consuming, and difficult visual scoring task that can be performed only by well-trained and experienced human scorers, (2) attainment of consistent scoring results, and (3) proposition of added value such as scoring in real time, sleep stage probabilities per epoch (hypnodensity), estimates of signal quality and sleep/wake-related features, identifications of periods with clinically relevant ambiguities (confidence trends), configurable sensitivity and rule settings, as well as cardiorespiratory sleep staging for home sleep apnea testing. This chapter describes the development of autoscoring systems since the first attempts in the 1970s up to the most recent solutions based on deep neural network approaches which achieve an accuracy that allows to use the autoscoring results directly for review and interpretation by a physician.

High Rapid Eye Movement Sleep Apnea Hypopnea Index is Associated with Hypertension in Patients with Obstructive Sleep Apnea

PURPOSE

Obstructive sleep apnea (OSA) plays an important role in the pathogenesis of hypertension. The aim of this cross-sectional study was to explore the clinical and polysomnographic characteristics of OSA patients with hypertension and to explore the gender differences in the relationship between rapid eye movement (REM) OSA and hypertension.

PATIENTS AND METHODS

A total of 808 patients with OSA at a tertiary hospital were enrolled in this study, and OSA patients were divided into groups presenting with or without hypertension. The clinical and polysomnographic characteristics were compared between the groups. Multivariate binary logistic analysis was performed to assess the association between REM OSA and hypertension.

RESULTS

After adjustment for potential confounders, the risk of hypertension in patients with OSA increased with severity categories of apnea hypopnea index during rapid eye movement sleep stage (REM AHI) (OR = 1.61 for REM AHI ≥58.87 events/h relative to REM AHI <30.50 events/h, 95% CI 1.07-2.42, P = 0.022). Consistent with this, when taken as a continuous variable, this association still remains significant (OR = 1.007, 95% CI 1.001-1.014, P < 0.05). This effect was more pronounced in women patients, the OR for REM AHI ≥57.24 events/h relative to REM AHI <30.36 events/h was 2.79 (95% CI, 1.16-6.73; P = 0.022); however, there was no significant difference in male patients.

CONCLUSION

REM AHI was significantly and positively associated with hypertension in patients with OSA, and the effect was more pronounced in female patients.

Waist-To-Hip Ratio Predicts Abnormal Overnight Oximetry in Men Independent of Body Mass Index

Background: Ambulatory overnight oximetry (OXI) has emerged as a cost-effective initial test for sleep disordered breathing. Obesity is closely associated with obstructive sleep apnea (OSA); however, whether body mass index (BMI) or waist-to-hip ratio (WHR) predicts abnormal overnight OXI remains unknown. Methods: We performed a retrospective cross-sectional study of 393 men seen in the Executive Health Program at Mayo Clinic in Rochester, Minnesota who underwent ambulatory overnight OXI ordered by preventive medicine physicians between January 1, 2004 through December 31, 2010. We compared participant/spouse-reported symptoms (sleepiness, snoring), physician indications for OXI (obesity, fatigue), Epworth Sleepiness Scale scores, anthropomorphic measurements (WHR, BMI), and comorbid medical conditions (hypertension, diabetes) with OXI results. Results: 295 of the 393 men who completed OXI had abnormal results. During multivariate analysis, the strongest independent predictor of abnormal OXI for men was WHR (≥1.0, OR = 5.59) followed by BMI (≥30.0 kg/m2, OR = 2.75), age (≥55 yrs, OR = 2.06), and the presence of snoring (OR = 1.91, P < 0.05 for all). A strong association was observed between WHR and abnormal OXI in obese (BMI ≥ 30.0 kg/m2, OR = 6.28) and non-obese (BMI < 29.9 kg/m2, OR = 6.42, P < 0.01 for both) men. Furthermore, 88 men with abnormal OXI underwent polysomnography with 91% being subsequently diagnosed with OSA. Conclusions: In ambulatory, predominantly middle-aged men undergoing preventive services evaluation many physician indications for OXI were not predictors of abnormal results; however, WHR strongly predicted abnormal OXI in obese and non-obese men. As such, we suggest middle-aged men who snore and have a WHR ≥1.0 should be directly referred to a sleep clinic for polysomnography.

Prediction of Oxygen Desaturation by Using Sound Data From a Noncontact Device: A Proof-of-Concept Study

OBJECTIVES/HYPOTHESIS

Prediction of the apnea-hypopnea index (AHI) from breathing sounds during sleep could be used to prescreen for obstructive sleep apnea (OSA). In addition, the oxygen desaturation index (ODI) is a known risk factor for developing cardiovascular disease in OSA patients. This study focused on estimation of ODI from a noncontact manner from sleep breathing sounds.

STUDY DESIGN

Retrospective study.

METHODS

Patients who visited the sleep center due to snoring or sleep apnea underwent polysomnography in lab overnight. Sound recordings were made during polysomnography using a microphone. After noise reduction, the sound data were segmented into 5 seconds windows and features were extracted. Binary classification and regression analyses were performed to estimate the ODI during sleep (model 1). This was re-tested after inclusion of body mass index (BMI) and age as additional features (model 2: BMI only, model 3: BMI and age).

RESULTS

We included 116 patients. The mean age and AHI of all patients were 50.4 ± 16.7 years and 23.0 ± 24.0 events/hr. In binary classification, for ODI cutoff values of 5, 15, and 30 events/hr, the areas under the curve were 0.88, 0.93, 0.91, respectively, and accuracies were 85.34, 86.21, and 87.07, respectively. In regression analysis, the correlation coefficient and mean absolute error were 0.80 and 9.60 events/hr, respectively. In models 2 and 3, the correlation coefficient and mean absolute error were 0.82, 9.44 events/hr and 0.81, 9.6 events/hr, respectively.

CONCLUSION

Prediction of ODI from sleep sound seems to be feasible. Additional clinical feature such as BMI may increase overall predictability.

LEVEL OF EVIDENCE

IV Laryngoscope, 2021.

Nocturnal Blood Pressure Fluctuations in Patients with Rapid Eye Movement-Related Obstructive Sleep Apnea

Rapid eye movement-related obstructive sleep apnea (REM-related OSA) is a polysomnographic phenotype. Nocturnal blood pressure (BP) fluctuations remain unclear in patients with REM-related OSA. We studied 27 patients with REM-related OSA, categorized as having REM-apnea-hypopnea index (REM-AHI) ≥ 5/h, REM-AHI/non-REM-AHI ≥ 2, and non-REM-AHI < 15/h. Beat-to-beat systolic BP (SBP) variability and nocturnal SBP fluctuation patterns using pulse transit time (PTT) were investigated. The maximum increase and average nocturnal SBP were significantly higher in males than in females (p = 0.003 and p = 0.008, respectively). The rate of non-dipping patterns in nocturnal SBP fluctuations was 63% in all patients (males, 70%; females, 50%). Epworth Sleepiness Scale (ESS) and Self-rating Depression Scale (SDS) scores in females were higher than those in males (8.4 ± 6.1 vs. 13.4 ± 5.4 points, p = 0.04; 43.8 ± 7.9 vs. 52 ± 11.6 points, p = 0.04, respectively). A high proportion of patients with REM-related OSA had a non-dipping pattern. Using PPT, we observed that in patients with REM-related OSA, SBP variability was greater in males. Despite clinical symptoms being slightly more severe in females, nocturnal SBP fluctuations should be considered in male patients with REM-related OSA.

Prevalence of obstructive sleep apnea among patients with chronic obstructive pulmonary disease

Background

The conjunction of chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) is known as overlap syndrome (OS). The coexistence of these diseases has cardiovascular morbidity and mortality. The aim of this study is to assess the prevalence of OSA in COPD patients. One hundred COPD patients (obese and non-obese) performed sleep questionnaires and polysomnograms.

Results

OSA prevalence in COPD was 50% and it increases with increasing disease severity (P < 0.001). The highest prevalence of OSA was found in obese patients with severe COPD; 90.5% of these patients have OSA. In the OSA group, obese patients were found to have significantly higher STOP-Bang Questionnaire (SBQ), Epworth Sleep Scale (ESS), modified medical research council (mMRC) dyspnea scale, apnea-hypopnea index (AHI), respiratory disturbance index (RDI), and oxygen desaturation index (ODI). Both obese and non-obese COPD patients showed significant positive correlations between AHI and smoking index (SI), SBQ, ESS, mMRC, ODI, and neck circumference (NC).

Conclusions

From this study, it can be concluded that moderate and severe COPD patients had a higher diagnosis of sleep-disordered breathing. Also, obese-COPD patients are more susceptible to develop OSA.

Trial registration

Name of the registry: Benha University Protocol Record Benha U123, Obstructive Sleep Apnea Prevalence in Patients With Chronic Obstructive Pulmonary Diseases. Trial registration number: NCT04903639. Date of registry: 5/22/2021 (retrospective study).

Comparison of Intra-operative Pressure-Controlled Ventilation and Volume-Controlled Ventilation in Bariatric Surgery: A Prospective Randomized Study

Background: Mechanical ventilation may be particularly challenging in obese patients undergoing laparoscopic bariatric surgery. The present study aimed to compare the effects of pressure-controlled ventilation (PCV) with those of volume-controlled ventilation (VCV) on peripheral tissue oxygenation (PTO), respiratory function, hemodynamic status, and ventilation-related complications in patients undergoing laparoscopic bariatric surgery.

Methods: A total of 100 patients with obesity who underwent gastric plication or sleeve gastrectomy were recruited for the study, and 60 patients (n=32, in group PCV; n=28, in group VCV) were ultimately enrolled. Data on peri-operative PTO (arterial blood gas [ABG] analysis and tissue oxygen saturation [StO₂]) and respiratory functions were recorded for each patient, along with post-operative hemodynamic status, fluid intake, urinary output, Numeric Pain Rating Scale (NPRS) score , and complications.

Results: The two groups were similar in pH, partial pressure of oxygen, partial pressure of carbon dioxide, oxygen saturation, and lactate values at baseline, intra-operative and post-operative periods. The peri-operative StO₂ values were also similar between the two groups at all times. The two groups were identical in terms of preoperative values for respiratory function tests and post-operative hemodynamic status, fluid intake, urinary output, pain scores, and complication rates.

Conclusions: In conclusion, the choice of the mechanical ventilation mode did not appear to influence oxygen delivery, respiratory function, hemodynamic status, post-operative pain, or ventilation-related complications in obese patients undergoing laparoscopic bariatric surgery.

Nocturnal oximetry in bariatric surgery patients referred to overnight in-lab polysomnography

OBJECTIVE

This study aimed to evaluate nocturnal oximetry approaches in identifying obstructive sleep apnea (OSA) among bariatric surgical candidates.

METHODS

This was a cross-sectional study involving adult bariatric patients who were undergoing in-lab polysomnography and who were previously screened with the GOAL questionnaire. OSA severity was established as any OSA, moderate/severe OSA, and severe OSA. Oximetry data were evaluated as oxygen saturation (average and nadir), oxygen desaturation index (ODI) at 3%, and proportion of time spent with oxygen saturation <90%. Associations between oximetry data and the apnea-hypopnea index (AHI) were assessed by Spearman correlation index (r), linear regression, logistic regression, and discrimination.

RESULTS

All oximetry values were significantly correlated with the AHI among 1,178 individuals, with the ODI emerging as the better parameter (r = 0.911, p < 0.001). Using linear regression, the ODI was the only predictor of the AHI (β = 0.952, p < 0.001). In the multivariate analysis, the ODI was the only independent parameter predicting OSA at all severity levels. In addition, the ODI exhibited excellent discrimination to predict OSA and displayed improved performance among individuals screened as being at high risk versus those at low risk with the GOAL instrument.

CONCLUSIONS

The ODI emerges as a valid surrogate predictor of the AHI, particularly among those screened as being at high risk for OSA.

Association between obstructive sleep apnea and lipid metabolism during REM and NREM sleep

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is thought to be associated with dyslipidemia. However, differences concerning dyslipidemia during rapid eye movement (REM) and non-REM (NREM) sleep have yet to be determined. This study was designed to explore the association between lipid profiles and OSA during REM or NREM sleep.

METHODS

This is a clinical cohort. A total of 2,619 participants with at least 30 minutes of REM sleep were included. Sleep variables and fasting lipid profiles [total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), apolipoprotein (apo)A-I, apoB, apoE, and lipoprotein(a) (Lp(a))] were obtained from each participant. Apnea-hypopnea indices in REM and NREM sleep (AHI_REM and AHI_NREM, respectively) were recorded. Linear regression analysis was used to assess the associations of AHI_REM and AHI_NREM with lipid profiles.

RESULTS

When stratified by the AHI_REM severity of OSA, all demographics, clinical variables, and sleep parameters differed between the groups except for apoA-I. In fully-adjusted multivariate linear regression models, AHI_REM was independently associated with increasing levels of TG, HDL-C, and apoE (P = .04, P = .01 and P = .01, respectively). AHI_NREM was independently associated with increasing levels of TC, TG, LDL, and apoB, and lower level of HDL-C (all P < .05). In sensitivity analyses by only exploring associations in patients who had an AHI_NREM or AHI_REM < 5 events/h in separate regression models, AHI_REM was not associated with all-lipid profile in almost all adjusted models (all P > .05), whereas AHI_NREM was associated with elevated TC, LDL-C, and apoB (P = .03, P = .01 and P = .01, respectively).

CONCLUSIONS

AHI_NREM was independently associated with the greatest alterations in serum lipids, including TC, LDL-C, and apoB.

Primary care provider evaluation and management of insomnia

STUDY OBJECTIVES

To evaluate the type and extent of information collected from patients with insomnia during their first office encounter for insomnia and the prescribing therapies of primary care providers during this initial encounter.

METHODS

This study was a retrospective chart review of randomly selected patients who had a primary care provider office visit at any clinic affiliated with a university medical system between March 1, 2013, and March 1, 2016. Demographic and clinical information was abstracted for analysis.

RESULTS

Our sample (n = 200) was primarily female (63.5%), White (69%), middle-aged (ages 44.6 ± 15.1 years) adults. Most (68.5%) encounter notes did not have significant information related to insomnia risk factors and symptoms (< 50% of the notes). When examining comorbidities, we found that younger patients (<45 years old) were more likely to have anxiety linked to insomnia (P = .025), whereas older patients (≥45) were less likely to have any identified comorbidities associated with insomnia (P = .009). Only 5.0% of patients with insomnia were referred for cognitive-behavioral therapy for insomnia, whereas 51.5% of patients were prescribed sleep medications. The younger cohort was statistically more likely to receive sleep hygiene or cognitive-behavioral therapy for insomnia as a treatment option in comparison to the older cohort (P = .01 and P = .04, respectively).

CONCLUSIONS

Progress notes from primary care providers tend to have a paucity of information on insomnia symptoms and related comorbidities. Medications are often prescribed as the first-line treatment for insomnia. Cognitive-behavioral therapy for insomnia remains underutilized despite robust evidence suggesting that cognitive-behavioral therapy for insomnia is a safe and effective treatment for insomnia.

Longer and Deeper Desaturations Are Associated With the Worsening of Mild Sleep Apnea: The Sleep Heart Health Study

Study Objectives

Obesity, older age, and male sex are recognized risk factors for sleep apnea. However, it is unclear whether the severity of hypoxic burden, an essential feature of sleep apnea, is associated with the risk of sleep apnea worsening. Thus, we investigated our hypothesis that the worsening of sleep apnea is expedited in individuals with more severe desaturations.

Methods

The blood oxygen saturation (SpO₂) signals of 805 Sleep Heart Health Study participants with mild sleep apnea [5 ≤ oxygen desaturation index (ODI) < 15] were analyzed at baseline and after a mean follow-up time of 5.2 years. Linear regression analysis, adjusted for relevant covariates, was utilized to study the association between baseline SpO₂-derived parameters and change in sleep apnea severity, determined by a change in ODI. SpO₂-derived parameters, consisting of ODI, desaturation severity (DesSev), desaturation duration (DesDur), average desaturation area (avg. DesArea), and average desaturation duration (avg. DesDur), were standardized to enable comparisons between the parameters.

Results

In the group consisting of both men and women, avg. DesDur (β = 1.594, p = 0.001), avg. DesArea (β = 1.316, p = 0.004), DesDur (β = 0.998, p = 0.028), and DesSev (β = 0.928, p = 0.040) were significantly associated with sleep apnea worsening, whereas ODI was not (β = -0.029, p = 0.950). In sex-stratified analysis, avg. DesDur (β = 1.987, p = 0.003), avg. DesArea (β = 1.502, p = 0.024), and DesDur (β = 1.374, p = 0.033) were significantly associated with sleep apnea worsening in men.

Conclusion

Longer and deeper desaturations are more likely to expose a patient to the worsening of sleep apnea. This information could be useful in the planning of follow-up monitoring or lifestyle counseling in the early stage of the disease.

Prevalence, clinical symptoms and polysomnographic findings of REM-related sleep disordered breathing in Japanese population

BACKGROUND

Rapid eye movement sleep -predominant sleep-disordered breathing (REM-SDB) is a condition in which sleep apneas or hypopneas predominantly occur during REM sleep. This study aimed to investigate the prevalence, clinical findings including daytime sleepiness or comorbid cardio-metabolic diseases, and detailed polysomnographic features of REM-SDB in Japanese population.

METHODS

Total of 1458 patients diagnosed as SDB were selected for this study. Prevalence of REM-SDB was estimated in the groups of mild, moderate and severe SDB. Polysomnographic findings, daytime sleepiness self-measured with Epworth Sleepiness Scale (ESS) and history of comorbid cardio-metabolic diseases were obtained and compared between the groups with REM-SDB and non-stage specific SDB.

RESULTS

Prevalence of REM-SDB according to the criteria #2 was 22.1% in total SDB subjects, 46,1% in mild SDB and 18.9% in moderate SDB. None was found in severe SDB. Patients with REM-SDB showed milder SDB, higher BMI and higher female predominance than those with non-stage specific SDB. They also showed lower arousal index, respiratory arousal index per total AHI, percentage of N1 sleep, total AHI, ODI, and higher sleep efficiency. Meanwhile, maximum event durations of obstructive apnea and hypopnea were significantly longer, and the nadir SpO₂ was lower in REM-SDB. The ESS score and percentages of comorbid cardio-metabolic diseases were roughly equivalent between REM-SDB and non-stage specific SDB.

CONCLUSION

REM-SDB was associated with high obesity, female gender, and mild severity of SDB. They showed daytime sleepiness and comorbid cardio-metabolic diseases quite equally to patients with non-stage specific SDB in spite of their lower AHI and better sleep quality.

Prevalence of Obstructive Sleep Apnea Among Saudi Pilots

PURPOSE

To evaluate the presence of obstructive sleep apnea (OSA), using home sleep testing in pilots and first officers in Saudi-based airlines. This will allow for proper diagnosis and management of OSA in that group which can help in minimizing any possible aviation accidents related to sleep disturbances secondary to OSA.

MATERIALS AND METHODS

This is a cross-sectional study conducted through Saudi-based aviation among pilots and first officers who were in service, active, and flying short- to medium-haul flights. Forty-one participants met the inclusion criteria. However, 39 out of 41 completed the study questionnaires (Berlin questionnaire, Epworth sleepiness scale, Pittsburgh sleep quality index (PSQI), Fatigue severity scale (FSS), Visual analog fatigue scale (VAFS), and Patient health questionnaire (PHQ9), along with home sleep testing.

RESULTS

Sixty-nine percent of the study population had OSA by home sleep testing. Majority of which had mild OSA (64%) and 5% had moderate and severe OSA (2.5% each). Results of different questionnaires showed one-third of the participants had insomnia, 33.3% of the participants had severe fatigue, excessive daytime sleepiness was found in 23.1% of the participants, and 10.3% had moderate depression, while 25.6% were classified as having mild depression symptoms.

CONCLUSION

Sleep apnea is prevalent among the studied Saudi-based airline pilots and first officers. Screening for workers of this high-risk occupation needs to be considered. Fatigue, depression, and insomnia can be secondary consequences of sleep apnea and should be assessed and treated early.

Brain-derived neurotrophic factor in relation to central obesity in children with sleep disordered breathing

INTRODUCTION

Sleep disordered breathing (SDB) represents common comorbidities of childhood obesity leading to interrupted sleep and sleep deprivation. Sleep deprivation alters secretion of brain-derived neurotrophic factor (BDNF), which is an appetite regulator. However, little is known about the relation between BDNF and central obesity in children with SDB. The aim of the study was to evaluate BDNF level and anthropometric indices in relation to SDB in children with obesity.

MATERIAL AND METHODS

A prospective case-control study was conducted on 30 children with obesity (BMI > 95^th percentile) and 30 healthy lean children (BMI 5^th-85^th percentile). Polysomnographic, anthropometric data and BDNF serum level were obtained from all included children. Serum level of BDNF and anthropometric indices of obesity were assessed in relation to SDB in children with obesity. Regression analysis was done to determine predictors for SDB in children with obesity.

RESULTS

In comparison to healthy controls, anthropometric indices of central obesity were significantly higher while BDNF was significantly lower in obese children, especially those with SDB. Respiratory disturbance index has a significant positive correlation with anthropometric indices of central obesity and a significant negative correlation with BDNF level. Central obesity and decreased BDNF were associated with 2-fold increased risk for SDB. Waist circumference/height ratio and neck circumference/height ratio have 89.5%, 75% sensitivity and 81.23%, 84.62% specificity at a cutoff point > 0.62, > 0.24 respectively for prediction of SDB in children with obesity.

CONCLUSIONS

Central obesity and decreased BDNF represent independent predictors for SDB in children with obesity. Anthropometric indices adjusted to height are a simple screening tool for SDB in obese children.

[Efficacy of weight management combined with uvulopalatopharyngoplasty for obesityrelated obstructive sleep apnea-hypopnea syndrome]

OBJECTIVE

To evaluate the clinical efficacy of weight management combined with pharyngoplasty for treatment of obesity-related obstructive sleep apnea-hypopnea syndrome (OSAHS).

METHODS

Sixty obese patients with OSAHS were randomly assigned into the combined treatment group and control group (n=30) and received treatment with uvulopalatopharyngoplasty (UPPP) combined with cognitive-behavioral-psychological intervention for family weight management and uvulopalatopharyngoplasty with conventional management. At 3 and 6 months of the treatment, the patients were examined for changes in body mass index (BMI), neck circumference, waist circumference, Epworth Sleepiness Scale (ESS) scores, apnea-hypopnea index (AHI), the lowest oxygen saturation (LSaO2) and the percentage of time with oxygen saturation below 90% (CT90).

RESULTS

After 6 months of treatment, the patients receiving the combined treatment showed significant reductions of BMI, neck circumference and waist circumference as compared with the measurements before treatment and with those in the control group (P < 0.01); these parameters showed no significant changes in the control group (P > 0.05). In the combined treatment group, the ESS score, CT90, AHI, and LSaO2 at 6 months were all superior to those in the control group (P < 0.01) and differed significantly cross different time points during the treatment, and their improvements were the most obvious after 6 months (P < 0.01). After 6 months of treatment, the combined treatment group had a similar cure rate with the control group (6.6% vs 7.1%; χ2=1.66, P > 0.05) but a significantly higher good response (defined as an AHI < 20 h-1 and an AHI reduction by ≥50%) rate (60% vs 35.7%; χ2=8.71, P < 0.01) and a higher overall response (a AHI reduction ≥50%) rate (83.3% vs 53.6%; χ2=10.62, P < 0.01).

CONCLUSIONS

Weight management combined with uvulopalatopharyngoplasty can produce a good clinical efficacy for treatment of OSAHS with obesity, and the patients should have strengthened continuous family weight management while receiving surgical treatment.

Impact of BMI on Complications of Gastric Endoscopic Submucosal Dissection

BACKGROUND

Gastric endoscopic submucosal dissection (ESD) has a high rate of complications. However, it is unclear whether BMI affects ESD complications. We aimed to investigate the impact of BMI on ESD complications.

METHODS

A total of 7,263 patients who underwent gastric ESD were classified into 3 groups according to the Asia-Pacific classification of BMI: normal (BMI <23 kg/m2, n = 2,466), overweight (BMI 23-24.9 kg/m2, n = 2,117), and obese (BMI ≥25 kg/m2, n = 2,680). Adjusted logistic regression analyses were conducted to assess the association between BMI and ESD complications.

RESULTS

Compared to the normal group, a lower incidence of perforation and a higher incidence of pneumonia and leukocytosis were found in the overweight and obese groups, and intra-ESD desaturation and hypertension were more frequent in the obese group. After adjustment for confounders, the risk of perforation significantly decreased in the overweight (odds ratio [OR] = 0.24, 95% confidence interval [CI]: 0.17-0.33) and obese (OR = 0.12, 95% CI: 0.08-0.18) groups compared to that in the normal group. Meanwhile, the risk of pneumonia significantly increased in the overweight (OR = 11.04, 95% CI: 6.31-19.31) and obese (OR = 10.71, 95% CI: 6.14-18.66) groups compared to the normal group. During sedation, the obese group had a significantly increased risk of desaturation (OR = 2.81, 95% CI: 1.18-6.69) and hypertension (OR = 1.35, 95% CI: 1.11-1.63) compared to the normal group.

CONCLUSIONS

High BMI was significantly associated with ESD complications. More caution is needed in cases of obese patients undergoing ESD.

Sleep-disordered breathing in patients with stroke-induced dysphagia

This study examined the nature and characteristics of sleep-disordered breathing, including obstructive sleep apnea and central sleep apnea, in patients with post-stroke dysphagia, to determine the demographic, anthropometric and clinical variables that were associated with sleep-disordered breathing. Thirty-nine patients diagnosed with acute stroke (28 males and 11 females with a mean age of 72.3 ± 10.0 years) underwent overnight polysomnography (within 3.9 ± 1.6 days after admission). Sleep-disordered breathing was described by the apnea-hypopnea index and its obstructive and central components by the obstructive apnea-hypopnea index and central apnea-hypopnea index, respectively. Severity of dysphagia was assessed using the Mann Assessment of Swallowing Ability score. Severity of stroke and functional dependence were assessed by the National Institute of Health Stroke Scale and the modified Barthel index, respectively. Most of the cohort (87%) had moderate-to-severe dysphagia (Mann Assessment of Swallowing Ability of 143.2 ± 19.9). Sleep-disordered breathing (apnea-hypopnea index ≥ 5 events/hr) was present in 38 participants (97%) with a mean apnea-hypopnea index of 37.5 ± 24.4 events/hr. Sleep-disordered breathing was predominantly obstructive in nature, with a mean obstructive apnea-hypopnea index and central apnea-hypopnea index of 19.6 ± 15.7 and 11.4 ± 17.6 events/hr, respectively. Multivariate linear regression analyses showed that the apnea-hypopnea index was associated with sex (p = .0001), body mass index (p = .029) and the modified Barthel index (p = .006); the obstructive apnea-hypopnea index was associated with the Mann Assessment of Swallowing Ability (p = .006), sex (p = .004) and body mass index (p = .015) and had a nonlinear relationship with the modified Barthel index (p = .019); and the central apnea-hypopnea index was associated with sex (p = .027) and the modified Barthel index (p = .019). The present study showed that dysphagia severity was associated with obstructive sleep apnea severity and this association was independent of sex, modified Barthel index and body mass index. However, stroke-induced dysphagia was not associated with central sleep apnea or overall sleep-disordered breathing.

Polysomnographic phenotyping of obstructive sleep apnea and its implications in mortality in Korea

Conventionally, apnea–hypopnea index (AHI) is used to define and categorize the severity of obstructive sleep apnea. However, routine polysomnography (PSG) includes multiple parameters for assessing the severity of obstructive sleep apnea. The goal of this study is to identify and categorize obstructive sleep apnea phenotypes using unsupervised learning methods from routine PSG data. We identified four clusters from 4,603 patients by using 29 PSG variable and arranged according to their mean AHI. Cluster 1, spontaneous arousal (mean AHI = 8.52/h); cluster 2, poor sleep and periodic limb movements (mean AHI = 12.16/h); cluster 3, hypopnea (mean AHI = 38.60/h); and cluster 4, hypoxia (mean AHI = 69.66/h). Conventional obstructive sleep apnea classification based on apnea–hypopnea index severity showed no significant difference in cardiovascular or cerebrovascular mortality (Log rank P = 0.331), while 4 clusters showed an overall significant difference (Log rank P = 0.009). The risk of cardiovascular or cerebrovascular mortality was significantly increased in cluster 2 (hazard ratio = 6.460, 95% confidence interval 1.734–24.073) and cluster 4 (hazard ratio = 4.844, 95% confidence interval 1.300–18.047) compared to cluster 1, which demonstrated the lowest mortality. After adjustment for age, sex, body mass index, and underlying medical condition, only cluster 4 showed significantly increased risk of mortality compared to cluster 1 (hazard ratio = 7.580, 95% confidence interval 2.104–34.620). Phenotyping based on numerous PSG parameters gives additional information on patients’ risk evaluation. Physicians should be aware of PSG features for further understanding the pathophysiology and personalized treatment.

Association Between Nocturnal Hypoxemia and Cancer Incidence in Patients Investigated for OSA: Data From a Large Multicenter French Cohort

BACKGROUND

Previous studies have yielded inconsistent findings regarding the association between OSA and cancer in humans.

RESEARCH QUESTION

Is there an association between indexes of sleep-disordered breathing severity and cancer incidence in patients investigated for suspected OSA?

STUDY DESIGN AND METHODS

Data from a large multicenter cohort of cancer-free patients investigated for OSA were linked to health administrative data to identify new-onset cancer. Kaplan-Meier survival analysis and Cox proportional hazards models were used to evaluate the association of cancer incidence with OSA severity and nocturnal hypoxemia.

RESULTS

After a median follow-up period of 5.8 years (interquartile range, 3.8-7.8), 718 of 8,748 patients (8.2%) had received a diagnosis of cancer. On unadjusted Kaplan-Meier survival analyses, cancer incidence was associated with increasing severity of OSA (log-rank test, P < .0005) and nocturnal hypoxemia (log-rank test, P < .0001 for both oxygen desaturation index and percent night time with oxygen saturation < 90% [T90]). After adjustment for anthropomorphic data, smoking and alcohol consumption, comorbid cardiac, metabolic, and respiratory diseases, marital status, type of sleep study, and study site, only T90 was associated with cancer incidence (adjusted hazard ratio, 1.33; 95% CI, 1.05-1.68 for T90 ≥ 13% vs < 0.01%; P = .02). On stratified analyses, the association between T90 and cancer appeared stronger in older patients with obesity and no adequate OSA therapy. Among the most frequent cancer sites, nocturnal hypoxemia was associated with lung and breast malignancies.

INTERPRETATION

Nocturnal hypoxemia was associated with all-cancer incidence in patients investigated for OSA. Whether OSA therapy might reduce the risk of cancer needs further evaluation.

Obstructive sleep apnea and the risk of gout: a population-based case-control study

Background

Patients with obstructive sleep apnea (OSA) might be at risk of gout because of pathophysiological mechanisms that can lead to hyperuricemia and eventually gout or because of shared risk factors between both diseases. The objective of the present study was to investigate the risk of gout in patients with OSA.

Methods

A population-based case-control study using the UK Clinical Practice Research Datalink GOLD including all patients aged 40 years and older with a first diagnosis of gout between 1987 and 2014. Gout cases were matched by year of birth, sex, and practice to non-gout controls. Conditional logistic regression estimated the risk of gout with an earlier diagnosis of OSA. Analyses were adjusted for lifestyle factors, comorbidities, and recent drug use.

Results

One hundred eleven thousand five hundred nine cases were matched with 210,241 controls. Patients with OSA were at increased risk of gout (OR 1.86; 95%CI (1.71–2.02). However, this association disappeared (OR 1.05; 95% CI 0.96–1.16) after adjustment for smoking status, body mass index (BMI), alcohol use, a history of heart failure, diabetes mellitus, renal function, and recent use of diuretics and other medications. Among females with OSA and patients with OSA associated with heart failure, renal impairment, or higher BMI, the risk of gout was however still increased when compared to the total control population.

Conclusion

This study showed that the observed association between OSA and gout disappeared after adjustment.

Sea level nocturnal minimal oxygen saturation can accurately detect the presence of obstructive sleep apnea in a population with high pretest probability

PURPOSE

To evaluate whether a predictive model based on nocturnal minimal oxygen saturation (SpO₂) alone can accurately detect the presence of obstructive sleep apnea (OSA) in a population with suspected OSA.

METHODS

A total of 4297 participants with suspected OSA were enrolled in this study, and laboratory-based polysomnography (PSG) tests were performed at sea level in all subjects. Nocturnal minimal SpO₂ was obtained automatically as part of the PSG test. Stratified sampling was used to divide the participants' data into the training set (75%) and the test set (25%). An OSA detection model based on minimal SpO₂ alone was created using the training set data and its performance was evaluated using the independent test set data ("hold-out" evaluation). Gender-specific models, and models based on minimal SpO₂ in combination with other predictive factors (age, body mass index, waist-to-hip ratio, snoring grade, Epworth Sleepiness Scale score, and comorbidities), were also created and compared in terms of OSA detection performance.

RESULTS

The prevalence of OSA was 85.6% in our study population. The models including multiple predictors, and the gender-specific models, failed to outperform the model based solely on minimal SpO₂, which showed good predictive performance (C statistic, 0.922) having an overall accuracy rate of 0.86, sensitivity of 0.87, specificity of 0.84, positive predictive value of 0.97, and positive likelihood ratio of 5.34. In addition, the model based on minimal SpO₂ alone could also accurately predict the presence of moderate-to-severe OSA and severe OSA, with C statistics of 0.914 and 0.900, respectively.

CONCLUSIONS

A predictive model based on nocturnal minimal SpO₂ alone may be an alternative option to detect the presence of OSA in a high-risk population when standard diagnostic tests are unavailable.

Phenotypic Subtypes of OSA: A Challenge and Opportunity for Precision Medicine

Current strategies for the management of OSA reflect a one-size-fits-all approach. Diagnosis and severity of OSA are based on the apnea-hypopnea index and treatment initiated with CPAP, followed by trials of alternatives (eg, oral appliances) if CPAP "fails." This approach does not consider the heterogeneity of individuals with OSA, reflected by varying risk factors, pathophysiological causes, clinical manifestations, and consequences. Recently, studies using analytic approaches such as cluster analysis have taken advantage of this heterogeneity to identify OSA phenotypes, or subtypes of patients with unique characteristics, that may enable more personalized approaches to prognostication and treatment. Examples include symptom-based subtypes such as "excessively sleepy" and "disturbed sleep" with differing impact of CPAP on symptoms and health-related quality of life. Polysomnographic subtypes, distinguished by respiratory event association with hypoxemia, arousals, or both, exhibit varying risks of cardiovascular disease and response to therapy. This review summarizes the findings from recent cluster analysis studies in sleep apnea and synthesizes common themes to describe the potential role (and limitations) of phenotypic subtypes in precision medicine for OSA. It also highlights future directions, including linking of phenotypes to clinically relevant outcomes, rigorous and transparent assessment of phenotype reproducibility, and need for tools that categorize patients into subtypes, to prospectively validate phenotype-based prognostication and treatment approaches. Finally, we highlight the critical need to include women and more racially/ethnically diverse populations in this area of research if we are to leverage the heterogeneity of OSA to improve patient lives.

Obstructive sleep apnea in obese minipigs

Objective:

Obesity has reached epidemic proportions and is a strong risk factor for obstructive sleep apnea (OSA). However, the underlying mechanisms are poorly understood and current treatment strategies for OSA and obesity have critical limitations. Thus, establishment of an obesity-related large animal model with spontaneous OSA is imperative.

Materials and methods:

Natural and sedated sleep were monitored and characterized in 4 obese (body mass index - BMI>48) and 3 non-obese (BMI<40) minipigs. These minipigs were instrumented with the BioRadio system under sedation for the wireless recording of respiratory airflow, snoring, abdominal and chest respiratory movements, electroencephalogram, electrooclulogram, electromyogram, and oxygen saturation. After instrumentation, the minipigs were placed in a dark room with a remote night-vision camera for monitoring all behaviors. Wakefulness and different sleep stages were classified, and episodes of apneas and/or hypopneas were identified during natural and/or sedated sleep.

Results:

No hypopnea episodes were observed in two of the non-obese minipigs, but one non-obese minipig had 5 hypopnea events. Heavy snoring and 27-58 apnea and/or hypopnea episodes were identified in all 4 obese minipigs. Most of these episodes occurred in the rapid eye movement stage during natural sleep and/or sedated sleep in Yucatan minipigs.

Conclusions:

Obese minipigs can experience naturally occurring OSA, thus are an ideal large animal model for obese-related OSA studies.

Sleep-disordered breathing and poststroke outcomes

OBJECTIVE

To examine the association between sleep-disordered breathing and stroke outcomes, and determine the contribution of sleep-disordered breathing to outcome disparities in Mexican Americans.

METHODS

Ischemic stroke patients (n = 995), identified from the population-based Brain Attack Surveillance in Corpus Christi Project (2010-2015), were offered participation in a sleep-disordered breathing study including a home sleep apnea test (ApneaLink Plus). Sleep-disordered breathing (respiratory event index ≥10) was determined soon after stroke. Neurologic, functional, cognitive, and quality of life outcomes were assessed at 90 days poststroke. Regression models were used to assess associations between sleep-disordered breathing and outcomes, adjusted for sociodemographics, prestroke function and cognition, health-risk behaviors, stroke severity, and vascular risk factors.

RESULTS

Median age was 67 years (interquartile range [IQR] = 59-78); 62.1% were Mexican American. Median respiratory event index was 14 (IQR = 6-25); 62.8% had sleep-disordered breathing. Sleep-disordered breathing was associated with worse functional outcome (mean difference in activities of daily living/instrumental activities of daily living score = 0.15, 95% confidence interval [CI] = 0.01-0.28) and cognitive outcome (mean difference in modified Mini-Mental State Examination = -2.66, 95% CI = -4.85 to -0.47) but not neurologic or quality of life outcomes. Sleep-disordered breathing accounted for 9 to 10% of ethnic differences in functional and cognitive outcome and was associated with cognitive outcome more strongly for Mexican Americans (β = -3.97, 95% CI = -6.63 to -1.31) than non-Hispanic whites (β = -0.40, 95% CI = -4.18 to 3.39, p-interaction = 0.15).

INTERPRETATION

Sleep-disordered breathing is associated with worse functional and cognitive function at 90 days poststroke. These outcomes are reasonable endpoints for future trials of sleep-disordered breathing treatment in stroke. If effective, sleep-disordered breathing treatment may somewhat lessen ethnic stroke outcome disparities. ANN NEUROL 2019;86:241-250.

Associations Between the Apnea-Hypopnea Index During REM and NREM Sleep and Cognitive Functioning in a Cohort of Middle-Aged Adults

STUDY OBJECTIVES

Prior research has linked obstructive sleep apnea (OSA) to varied cognitive deficits. Additionally, OSA in rapid eye movement (REM) versus non-rapid eye movement (NREM) sleep has been shown to be a stronger predictor of outcomes such as hypertension. The present study aimed to investigate whether OSA-as characterized by the apnea-hypopnea index (AHI)-during REM and NREM sleep is associated with performance on a range of cognitive tasks. We also investigated whether the presence/absence of the apolipoprotein E4 allele (APOE4) modifies the associations between AHI during REM and NREM sleep and cognitive performance.

METHODS

A cross-sectional sample of 1,250 observations from 755 community-dwelling adults (mean [standard deviation] age, 62.3 [8.2] years) participating in the Wisconsin Sleep Cohort study was carried out by means of overnight polysomnography, paper-and-pencil cognitive tasks, and genetic data. Linear mixed effects models with repeated measures estimated associations of AHI during REM and NREM sleep with cognitive outcomes, stratified by APOE4 status (carrier versus noncarrier).

RESULTS

No significant associations were found between REM AHI and cognitive outcomes for either APOE4 carriers and non-carriers. Higher NREM AHI was associated with worse memory retention among APOE4 carriers; among noncarriers of APOE4, higher NREM AHI was associated with worse performance on a test of psychomotor speed, but better performance on two tests of executive function.

CONCLUSIONS

Sleep state-specific (REM, NREM) OSA may be differentially associated with varying dimensions of cognitive deficits in middle-aged to older adults, and such associations are likely to be modified by genetic factors, include APOE polymorphisms.

Central sleep apnea: misunderstood and mistreated!

Central sleep apnea is prevalent in patients with heart failure, healthy individuals at high altitudes, and chronic opiate users and in the initiation of "mixed" (that is, central plus obstructive apneas). This brief review focuses on (a) the causes of repetitive, cyclical central apneas as mediated primarily through enhanced sensitivities in the respiratory control system and (b) treatment of central sleep apnea through modification of key components of neurochemical control as opposed to the current universal use of positive airway pressure.