Cardiovascular consequences of obstructive sleep apnea

Validity of Modified STOP-Bang Questionnaire as a Screening Tool for Obstructive Sleep Apnea

OBJECTIVES

The aim of this study was to evaluate the validity of a modified STOP-Bang questionnaire with different body mass index reference as a screening tool for obstructive sleep apnea in Korean population.

METHODS

The medical records of 1417 participants who underwent overnight Level I polysomnography were retrospectively analyzed. Predictive parameters were calculated for each of the 3 groups classified by obstructive sleep apnea severity with a cut-off value of 3 or 4. Responses to modified and traditional questionnaires were comparatively analyzed by receiver-operator characteristic curves and area under the receiver-operator characteristic curves.

RESULTS

The optimal cut-off values of the modified and traditional questionnaires were both 3.5. The area under the receiver-operator characteristic curve of modified STOP-Bang questionnaire for any obstructive sleep apnea group was 0.786 ± 0.018, which was significantly higher than that of the traditional questionnaire. The modified STOP-Bang questionnaire with a cut-off value ≥4 showed significantly higher sensitivity than the traditional one for any obstructive sleep apnea group. The diagnostic accuracy of the modified questionnaire was also significantly higher for the any obstructive sleep apnea group when the cut-off value was 4.

CONCLUSION

The modified STOP-Bang questionnaire, with a cut-off value of 4, can be used as an alternative to the traditional screening tool for the Korean population.

Evaluation of the Continuous Positive Airway Pressure Effect on Neurotrophins' Gene Expression and Protein Levels

Neurotrophins (NT) might be associated with the pathophysiology of obstructive sleep apnea (OSA) due to concurrent intermittent hypoxia and sleep fragmentation. Such a relationship could have implications for the health and overall well-being of patients; however, the literature on this subject is sparse. This study investigated the alterations in the serum protein concentration and the mRNA expression of the brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), neurotrophin-3 (NTF3), and neurotrophin-4 (NTF4) proteins following a single night of continuous positive airway pressure (CPAP) therapy. This study group consisted of 30 patients with OSA. Venous blood was collected twice after a diagnostic polysomnography (PSG) and PSG with CPAP treatment. Gene expression was assessed with a quantitative real-time polymerase chain reaction. An enzyme-linked immunosorbent assay was used to determine the protein concentrations. After CPAP treatment, BDNF, proBDNF, GDNF, and NTF4 protein levels decreased (p = 0.002, p = 0.003, p = 0.047, and p = 0.009, respectively), while NTF3 increased (p = 0.001). Sleep latency was correlated with ΔPSG + CPAP/PSG gene expression for BDNF (R = 0.387, p = 0.038), NTF3 (R = 0.440, p = 0.019), and NTF4 (R = 0.424, p = 0.025). OSA severity parameters were not associated with protein levels or gene expressions. CPAP therapy could have an impact on the posttranscriptional stages of NT synthesis. The expression of different NTs appears to be connected with sleep architecture but not with OSA severity.

PATIENT-REPORTED OUTCOMES WHILE MANAGING OBSTRUCTIVE SLEEP APNEA WITH ORAL APPLIANCES: A SCOPING REVIEW

OBJECTIVE

This scoping review aims to describe dental treatment-related patient-reported outcomes (dPROs) while using oral appliances (OAs) to manage obstructive sleep apnea (OSA) in children and adults.

METHODS

Available literature that assessed dPROs in children and adults with OSA managed through OAs. Any clinical studies were included without restrictions of year or country. The results were analyzed and reported using narrative text and tables accompanying a descriptive summary.

RESULTS

The searches identified 1718 citations, and of these, forty-five studies were finally included. A total of 3498 adults were included in all 42 primary studies included in this review, in which all the studies presented adults as participants. The dPROs assessed were quality of life (QoL), reported side effects after OA usage, patient satisfaction, and experience with treatment, and subjective perception of occlusal changes after treatment.

CONCLUSION

This scoping review suggests that dPROs are mostly investigated as a secondary outcome from major studies exploring the effects of OAs on OSA severity, and often, dPROs are not well discussed or displayed on their report. As no risk of bias or certainty level assessment was completed, findings need to be carefully considered. Although in general terms management with OAs among adults with OSA does not seem to be uncomfortable or causing major problems to their lives, some mild discomfort and endured occlusal disturbances was reported in some studies. QoL seems to improve but consistent agreement was elusive. Data does not include experiences among those that dropped OA use. No data seems to exist about dPROs in children.

Sleep-disordered breathing, sleep apnea, and other obesity-related sleep disorders: An Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) 2022

Background

This Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) provides clinicians an overview of sleep-disordered breathing, (e.g., sleep-related hypopnea, apnea), and other obesity-related sleep disorders.

Methods

The scientific support for this CPS is based upon published citations, clinical perspectives of OMA authors, and peer review by the Obesity Medicine Association leadership.

Results

Obesity contributes to sleep-disordered breathing, with the most prevalent manifestation being obstructive sleep apnea. Obesity is also associated with other sleep disorders such as insomnia, primary snoring, and restless legs syndrome. This CPS outlines the evaluation, diagnosis, and treatment of sleep apnea and other sleep disorders, as well as the clinical implications of altered circadian system.

Conclusions

This Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) on "Sleep-Disordered Breathing, Sleep Apnea, and Other Obesity-Related Sleep Disorders" is one of a series of OMA CPSs designed to assist clinicians in the care of patients with the disease of obesity.

Pharmacotherapy for Obstructive Sleep Apnoea and Coupled Life: A Descriptive Phenomenological Study of a Complex Interaction

BACKGROUND

Obstructive Sleep Apnoea (OSA) is a common chronic sleep-related breathing disorder. Drug therapy is a recent approach to treating OSA, and no data is available regarding its effects on a couple's life. The aim of this study was to investigate the impact on couples' lives of a novel drug treatment for OSA.

METHODS

Participants of a trial on new drug therapy (reboxetine plus oxybutynin) for OSA were interviewed. The study was conducted using a descriptive phenomenological approach by Sundler et al. Results: Ten patients and six of their partners were recruited through a purposive sampling between February and April 2021. The results indicate that drug treatment of OSA had a favourable impact on the couples' lives. Pharmacotherapy improved self-reported sleep quality, as the absence of CPAP allows people to sleep closer to the bed partner and because the patient does not have to sleep in a forced position. Moreover, the couples developed teamwork from the beginning which appeared to be crucial during the trial, especially when some difficulties and adverse events occurred.

CONCLUSIONS

This study presents the presence of a positive closed loop that could be considered a predictor of adherence to drug therapy.

Association Between Smoking Behavior and Obstructive Sleep Apnea: A Systematic Review and Meta-Analysis

INTRODUCTION

To systematically review the association between smoking behavior and obstructive sleep apnea (OSA).

AIMS AND METHODS

PubMed, Medline, the Cochrane Library, EMBASE, and Scopus databases were used to conduct this review. The two researchers independently screened the literatures, conducted the quality assessment, and data extraction according to the inclusion and exclusion criteria. The RevMan 5.3 was used to analysis the apnea hypopnea index (AHI) index, min saturation of oxyhemoglobin (SaO2), Epworth Sleepiness Scale (ESS) score, and oxygen desaturation index (DOI) and publication bias analysis to assess the effect of smoking on OSA patients. Furthermore, we performed subgroup of the severity of OSA, different countries of sample origin (western countries or eastern countries), and pack-years (PYs < 10 or PYs ≥ 20) to analyze the heterogeneity.

RESULTS

Thirteen studies were included in this analysis that conformed to inclusion criteria and exclusion criteria. Totally 3654 smokers and 9796 non-smokers have participated. The meta-analysis of 13 studies demonstrated that AHI levels were significantly higher in smoker group compared with non-smoker, ESS scores were also significantly higher in smoker group compared with non-smoker, min SaO2 levels were obviously lower in smoker group compared with non-smoker, however, DOI levels hadn't significantly different between two groups. The subgroup analysis showed that there was an association between severe OSA, eastern countries, pack-years, and smoking.

CONCLUSIONS

Smoking behavior is a significant association with OSA. Heavy smokers with histories of more than 20 PYs were at a higher risk of OSA. Moreover, patient with severe OSA exhibited a significantly association with smoking compared with patients with mild or moderate OSA.

IMPLICATIONS

The relationship between smoking and OSA was controversial, especially, whether smoking increase or aggravate the risk of OSA. In our review and meta-analysis, we demonstrated that smoking behavior is a significant association with OSA. Heavy smokers with histories of more than 20 PYs were at a higher risk of OSA. Moreover, patient with severe OSA exhibited a significant association with smoking compared with patients with mild or moderate OSA. More prospective long-term follow-up studies about effect of quit smoking on OSA are recommended to establish the further relationship.

Symptoms of Nocturnal Masticatory Muscle Activity among Women of Different Age Groups and Their Association to Obstructive Sleep Apnea-A Cross Sectional Study

Sleep bruxism (SB), snoring, and excessive daytime sleepiness are often associated with obstructive sleep apnea (OSA). OSA, which is characterized by a repetitive collapse of the upper airway during sleep, can cause oxygen desaturation and lead to adverse medical conditions, such as cardiovascular events, hypertension, heart attack, and stroke. In the present study, 112 Arab women aged 20−40 years (Early Adulthood/Adulthood−EarlyA) and 116 Arab women aged 50 and above (Middle Age−MiddleA), were requested to complete questionnaires regarding demographic variables, symptoms of nocturnal masticatory muscle activity (possible SB, headache, and stiffness of the oral and/or neck musculature upon awakening), risk of OSA (STOP-BANG questionnaire), and daytime sleepiness (Epworth sleepiness scale—ESS). Women, who reported snoring, experienced more SB (35.8% vs. 20.6%, chi-square, p < 0.05), more headaches (33.3% vs. 19.3%, p < 0.05), and more muscle stiffness upon awakening (34.3% vs. 16.3%, p < 0.005), than their non-snoring counterparts. Out of the women who snore, 11% showed high risk for OSA, as compared to only 1% among the non-snoring participants (p < 0.000). Symptoms of nocturnal masticatory muscle activity and/or snoring can serve as initial indicators of OSA. Higher awareness of dentists to such symptoms, particularly among their middle-aged female patients, can prevent a development of harmful conditions associated with OSA.

Circulating C-reactive protein levels in patients with suspected obstructive sleep apnea

STUDY OBJECTIVES

To assess determinants of CRP in a cohort of patients referred for investigation of OSA and to determine whether overlap of OSA and COPD (overlap syndrome, OVS) is associated with higher levels of CRP.

METHODS

This was a cross-sectional study that included 2352 patients seen at the West Australian Sleep Disorders Research Institute between 2006 and 2010. All patients had circulating CRP levels, and spirometry performed. OSA was defined apnea-hypopnea index (AHI) ≥ 5 events per hour and COPD defined as FEV1/FVC ratio <0.70 and age > 40 years. Univariate and multivariate regression analysis were used to identify CRP determinants.

RESULTS

Mean age was 51 years (60% male), median (AHI) was 27 events/h, median 3% oxygen desaturation index (ODI3%) was 24 events/h, mean FEV₁ was 88% predicted, and median CRP was 3.0 mg/L. In multivariate analyses: age, body mass index, female sex, neck circumference, AHI, and desaturation markers (nadir and mean oxygen saturation) were independently associated with higher CRP. Spirometric variables were not predictors. There was no significant difference in CRP among OSA patients with or without co-existing COPD.

CONCLUSIONS

Markers of OSA severity (AHI and oxygenation), age, BMI, neck circumference and female sex were independent predictors of circulating CRP levels. OSA overlapping with COPD was not associated with increased CRP compared to either condition alone, suggesting other mechanisms for the increased CVD risk in OVS. Identification of factors that predict CRP will help identify patients at higher risk of CVD and aid risk stratification.

Diagnostic accuracy of screening questionnaires for obstructive sleep apnoea in adults in different clinical cohorts: a systematic review and meta-analysis

PURPOSE

The majority of individuals with clinically significant obstructive sleep apnoea (OSA) are undiagnosed and untreated. A simple screening tool may support risk stratification, identification, and appropriate management of at-risk patients. Therefore, this systematic review and meta-analysis evaluated and compared the accuracy and clinical utility of existing screening questionnaires for identifying OSA in different clinical cohorts.

METHODS

We conducted a systematic review and meta-analysis of observational studies assessing the diagnostic value of OSA screening questionnaires. We identified prospective studies, validated against polysomnography, and published to December 2020 from online databases. To pool the results, we used random effects bivariate binomial meta-analysis.

RESULTS

We included 38 studies across three clinical cohorts in the meta-analysis. In the sleep clinic cohort, the Berlin questionnaire's pooled sensitivity for apnoea-hypopnoea index (AHI) ≥ 5, ≥ 15, and ≥ 30 was 85%, 84%, and 89%, and pooled specificity was 43%, 30%, and 33%, respectively. The STOP questionnaire's pooled sensitivity for AHI ≥ 5, ≥ 15, and ≥ 30 was 90%, 90%, and 95%, and pooled specificity was 31%, 29%, and 21%. The pooled sensitivity of the STOP-Bang questionnaire for AHI ≥ 5, ≥ 15, and ≥ 30 was 92%, 95%, and 96%, and pooled specificity was 35%, 27%, and 28%. In the surgical cohort (AHI ≥ 15), the Berlin and STOP-Bang questionnaires' pooled sensitivity were 76% and 90% and pooled specificity 47% and 27%.

CONCLUSION

Among the identified questionnaires, the STOP-Bang questionnaire had the highest sensitivity to detect OSA but lacked specificity. Subgroup analysis considering other at-risk populations was not possible. Our observations are limited by the low certainty level in available data.

Association between symptoms of sleep apnea and problem behaviors in young adult twins and siblings

BACKGROUND

Sleep apnea is one of the most common sleep disorders and it is related to multiple negative health consequences. Previous studies have shown that sleep apnea is influenced by genetic factors. However, studies have not investigated the genetic and environmental influences of symptoms of sleep apnea in young adults. Furthermore, the underpinnings of the relationship between apnea symptoms and internalizing/externalizing problems are unknown. The objectives of this study were to estimate the magnitude of: (1) genetic and environmental influences on self-reported apnea symptoms; (2) the relationship between self-reported apnea symptoms and internalizing/externalizing traits; (3) genetic and environmental influences on the associations between self-reported apnea symptoms, internalizing behaviors and externalizing behaviors.

METHODS

In a twin/sibling study, univariate and multivariate models were fitted to estimate both individual variance and sources of covariance between symptoms of sleep apnea and internalizing/externalizing behaviors.

RESULTS

Our results show that genetic influences account for 40% of the variance in sleep apnea symptoms. Moreover, there are modest associations between depression, anxiety and externalizing behaviors with apnea symptoms (ranging from r = 0.22-0.29). However, the origins of these associations differ. For example, whereas most of the covariation between symptoms of depression and sleep apnea can be explained by genes (95%), there was a larger role for the environment (53%) in the association between symptoms of anxiety and sleep apnea.

CONCLUSIONS

Genetic factors explain a significant proportion of variance in symptoms of apnea and most of the covariance with depression.

Obstructive sleep apnea and Alzheimer's disease-related cerebrospinal fluid biomarkers in mild cognitive impairment

Previous studies have demonstrated that sleep-breathing disorders, and especially obstructive sleep apnea (OSA), can be observed in patients with a higher risk of progression to Alzheimer's disease (AD). Recent evidence indicates that cerebrospinal fluid (CSF) AD-biomarkers are associated with OSA. In this study, we investigated these associations in a sample of patients with mild cognitive impairment (MCI), a condition that is considered the first clinical phase of AD, when patients showed biomarkers consistent with AD pathology. A total of 57 patients (mean age = 66.19; SD = 7.13) with MCI were included in the study. An overnight polysomnography recording was used to assess objective sleep parameters (i.e. apnea/hypopnea index [AHI], total sleep time, sleep efficiency, sleep latency, arousal index, awakening, stage 1, 2, and slow-wave sleep and rapid eye movement sleep, periodic limb movement index, O2 saturation during sleep, and percentage of time O2 saturation <90%). Phosphorylated-tau (P-tau), total-tau (T-tau), and amyloid-beta 42 (Aβ42) were measured in CSF. Unadjusted correlation analyses showed that a higher AHI (reflecting higher OSA severity) was related to higher P-tau and T-tau (both results remained significant after Bonferroni correction, p = 0.001). Importantly, these associations were observed even after adjusting for potential confounders (i.e. age, sex, body mass index, sleep medication, smoking, hypertension, and heart disease). Although more research is needed to establish a causal link, our findings provide evidence that OSA could be related to the pathophysiological mechanisms involved in neurodegeneration in MCI patients.

Associations of Sleep-disordered Breathing and Insomnia with Incident Hypertension and Diabetes. The Hispanic Community Health Study/Study of Latinos

Rationale: Sleep disorders are associated with hypertension and diabetes, which are primary risk factors for cardiovascular diseases and mortality. It is important to understand these associations in Hispanic/Latino individuals, in whom cardiovascular death is the leading cause of mortality.Objectives: To investigate the prospective associations of sleep-disordered breathing (SDB) and insomnia with incident hypertension and diabetes among U.S. Hispanic/Latino people over 6 years of follow-up and to assess potential sex differences in these associations.Methods: Data from 11,623 Hispanic/Latino participants in the Hispanic Community Health Study/Study of Latinos (visit 1, 2008-2011; visit 2, 2014-2017) were analyzed using survey logistic regression models, adjusting for potential confounders.Measurements and Main Results: SDB (apnea-hypopnea index of 5 or more) and insomnia (Women's Health Initiative Insomnia Rating Scale of 9 or more) were measured at baseline. Incident hypertension (stage 2 or greater) and diabetes were defined according to national guidelines. In the target population, 52.6% were women, with a mean age of 41.1 ± 14.9 years at baseline. SDB was associated with 1.54 higher adjusted odds of incident hypertension (95% confidence interval [CI], 1.18-2.00) and 1.33 higher odds of incident diabetes (95% CI, 1.05-1.67) compared with no SDB. Insomnia was associated with incident hypertension (odds ratio, 1.37; 95% CI, 1.11-1.69) but not with diabetes. The association between insomnia and incident hypertension was stronger among men than among women.Conclusions: SDB was associated with incident hypertension and diabetes. Insomnia was associated with incident hypertension. These findings support the importance of sleep disorders as modifiable targets for disease prevention and reduction.

Circadian influence on inflammatory response during cardiovascular disease

Circadian rhythms follow a 24 h day and night cycle, regulate vital physiological processes, and are especially relevant to cardiovascular growth, renewal, repair, and remodeling. A recent flurry of clinical and experimental studies reveals a profound circadian influence on immune responses in cardiovascular disease. The first section of this review summarizes the importance of circadian rhythms for cardiovascular health and disease. The second section introduces the circadian nature of inflammatory responses. The third section combines these to elucidate a new role for the circadian system, influencing inflammation in heart disease, especially myocardial infarction. Particular focus is on circadian regulation of the NACHT, LRR, and PYD domains-containing protein 3 inflammasome, neutrophils, monocytes/macrophages, and T cells involved in cardiac repair. A role for biological sex is noted. The final section explores circadian influences on inflammation in other major cardiovascular conditions. Circadian regulation of inflammation has profound implications for benefitting the diagnosis, treatment, and prognosis of patients with cardiovascular disease.

Serum matrix metalloproteinase-2 as a predictor of level of hypoxemia and severity of obstructive sleep apnea

PURPOSE

Intermittent hypoxia in obstructive sleep apnea (OSA) resembles ischemia/reperfusion. Oxidative stress during ischemia/reperfusion increases matrix metalloproteinase-2 (MMP-2) activity and leads to adverse cardiovascular consequences in animal models, but there is scarce information about MMP-2 in humans with OSA. The aim of this study was to determine if serum MMP-2 levels of patients with OSA differ from controls and if MMP-2 activity correlates with the severity of OSA and level of hypoxemia.

METHODS

Patients with OSA (n = 124) were recruited from the Sleep Disorders Center (Saskatoon City Hospital, Canada) after in-lab polysomnography (PSG). Controls (n = 26) were subjects referred for PSG who did not have OSA. Severity of OSA was categorized according to American Academy of Sleep Medicine criteria. Level of hypoxemia was expressed as oxygen desaturation index (ODI; 3% desaturation). Gelatin zymography was performed to measure serum MMP-2 activity.

RESULTS

Serum MMP-2 activity was significantly higher in patients with OSA than in controls (p = 0.029). MMP-2 activity in patients with severe OSA was significantly higher than in those with mild/moderate OSA and controls (p = 0.002). Linear regression showed positive associations with MMP-2 activity in serum for AHI (p < 0.001) and ODI (p = 0.003). The associations persisted after adjustment for multiple confounders, including age, sex, BMI, and cardiovascular disease.

CONCLUSIONS

Serum MMP-2 activity was associated with OSA severity, and level of hypoxemia in patients with OSA, suggesting MMP-2 is worth considering as a potential biomarker to be included in future studies on sets of biomarkers for hypoxemic insult in OSA.

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.

Prevalence, Risk Factors, and Impact of Obstructive Sleep Apnea in Adults with Congenital Heart Disease

The objective of our study was to determine the prevalence, risk factors, and the impact of obstructive sleep apnea (OSA) in the adult with congenital heart disease (ACHD). One hundred forty-nine consecutive patients seen in our ACHD program were screened for OSA using the Berlin Questionnaire. Demographic and clinical details on subjects were collected through a chart review. Clinical variables were analyzed to determine risk factors for positive OSA screen, as well as associated outcomes. Seventy-seven (52%) of our cohort were females. The median age of the cohort was 33 years (range = 18-74) and median weight was 79 kg (range = 50-145 kg). Overall, 47 (31%) of our cohort were found to have a positive OSA screen using the Berlin questionnaire. Median age of the patients whom tested positive was 34 years. Compared to patients with a negative screen, patients with a positive OSA screen were more likely to be heavier with a median weight of 99 kg vs 71 kg (p < 0.01) and a larger BMI (31 vs 25 kg/m², p < 0.01). Overall, 55% of patients whom screened positive were obese (defined as a BMI > 30) compared to 15% in the negative group (p < 0.02). Patients with a positive screen were more likely to have other co-morbidities including diabetes (p < 0.04), hypertension (p < 0.05), depression (p < 0.002), and were more likely to have decreased exercise capacity (p < 0.01) and a defibrillator (p < 0.007). Our data demonstrates that OSA is common in the ACHD patient and is associated with increasing weight and BMI. Patients with a positive screen are at increased risk for multiple co morbidities including diabetes, hypertension, and depression. We believe our data supports the use of screening protocols for OSA in the ACHD population in effort to identify early, treat, and potentially prevent late complications.

Increased platelet activation in sleep apnea subjects with intermittent hypoxemia

PURPOSE

Obstructive sleep apnea (OSA) is independently associated with increased risk for stroke and other cardiovascular diseases. Since activated platelets play an important role in cardiovascular disease, the objective of this study was to determine whether platelet reactivity was altered in OSA subjects with intermittent nocturnal hypoxemia.

METHODS

Thirty-one subjects, without hypertension or cardiovascular disease and not taking medication, participated in the study. Subjects were stratified based on OSA-related oxygen desaturation index (ODI) recorded during overnight polysomnography. Platelet reactivity to a broad panel of agonists (collagen, thrombin, protease-activated receptor1 hexapeptide, epinephrine, ADP) was measured by monitoring platelet aggregation and ATP secretion. Expression of platelet activation markers CD154 (CD40L) and CD62P (P-selectin) and platelet-monocyte aggregates (PMA) was quantified by flow cytometry.

RESULTS

Epinephrine-induced platelet aggregation was substantially decreased in OSA subjects with significant intermittent hypoxemia (ODI ≥ 15) compared with subjects with milder hypoxemia levels (ODI < 15) (area under curve, p = 0.01). In addition, OSA subjects with ODI ≥ 15 exhibited decreased thrombin-induced platelet aggregation (p = 0.02) and CD40L platelet surface expression (p = 0.05). Platelet responses to the other agonists, CD62P platelet surface expression, and PMA levels were not significantly different between groups. Reduction in platelet responses to epinephrine and thrombin, and decreased CD40L surface marker expression in significant hypoxemic OSA individuals, is consistent with their platelets being in an activated state.

CONCLUSIONS

Increased platelet activation was present in otherwise healthy subjects with intermittent nocturnal hypoxemia due to underlying OSA. This prothrombotic milieu in the vasculature is likely a key contributing factor toward development of thrombosis and cardiovascular disease.

TRIAL REGISTRATION

NCT00859950.

Association between diet quality and sleep apnea in the Multi-Ethnic Study of Atherosclerosis

Rationale

Although short sleep duration has been linked to unhealthy dietary patterns, little is known about the association of obstructive sleep apnea (OSA), a disorder characterized by sleep fragmentation and diet.

Study Objectives

Investigate associations between diet quality and OSA in the Multi-Ethnic Study of Atherosclerosis and assess whether reductions in slow-wave sleep (stage N3) and rapid eye movement (REM) sleep are potential mediators for these associations.

Methods

A diverse population (N = 1813) completed a food frequency questionnaire and underwent Type 2 in-home polysomnography, which included measurement of N3 and REM sleep and apnea-hypopnea index (AHI). Moderate-to-more severe OSA was defined as having an AHI > 15 events/hr.

Results

Participants were 53.9% female with a mean age of 68.3 (SD 9.1) years. Approximately 33.8% were categorized as having moderate-to-more severe OSA. In adjusted analyses, OSA was associated with lower intakes of whole grains, (β = -0.200, SE = 0.072, p < 0.01), higher intakes of red/processed meat, (β = -0.440, SE = 0.136, p < 0.01), and lower overall diet quality (β = -1.286, SE = 0.535, p = 0.02). Stage N3 sleep partially explained the associations between red/processed meat and overall diet quality score with OSA.

Conclusions

Moderate-to-more severe OSA is associated with a less healthy dietary profile that is partially explained by reduced N3 sleep. These findings suggest the opportunity to target sleep quality in interventions aimed at improving cardio-metabolic risk factors in patients with OSA.

Association of Positive Airway Pressure Use With Acute Care Utilization and Costs

STUDY OBJECTIVES

The current value-based medical climate has led to scrutiny of all medical costs. Given the relationship between obstructive sleep apnea (OSA) and many significant comorbid medical conditions, treating patients with OSA via positive airway pressure (PAP) therapy might reduce health care expenditures. Our goal was to determine the relationship between PAP use and acute care utilization and costs.

METHODS

This was a retrospective cohort study of adult patients who initiated PAP therapy after a diagnosis of moderate-severe OSA at a large integrated health system during 2014-2016.

RESULTS

The study consisted of 1,098 patients, of which 60% were on PAP > 4 h/night for ≥ 70% of the nights. The average h/night were 5.3 (standard deviation 2.4). Increasing PAP usage was associated with reduced inpatient (rate ratio [RR] 0.92, 95% confidence interval [CI] 0.86-0.98) and overall acute care visits (RR 0.96, 95% CI 0.92-0.99). The linear relationships were supported by the threshold effects identified in the categorical adherence measures. No linear association was identified with emergency department visits and inpatient stays. However, lower number of emergency department visits (RR 0.78, 95% CI 0.62-0.98) and inpatient stays (RR 0.56, 95% CI 0.35-0.91) were observed among adherent (> 4 h/night for ≥ 70% of the nights) patients.

CONCLUSIONS

PAP usage was linearly associated with reduced number of inpatient and overall acute care visits, and lower likelihood of having positive costs from these visits. PAP usage was also associated with less emergency department visits and inpatient stays when comparing adherent patients to less adherent patients.

CITATION

Kirsch DB, Yang H, Maslow AL, Stolzenbach M, McCall A. Association of positive airway pressure use with acute care utilization and costs. J Clin Sleep Med. 2019;15(9):1243-1250.

Matrix metalloproteinases as possible biomarkers of obstructive sleep apnea severity - A systematic review

Obstructive sleep apnea is an underdiagnosed sleep-related breathing disorder affecting millions of people. Recurrent episodes of apnea/hypopnea result in intermittent hypoxia leading to oxidative stress. Obstructive sleep apnea is considered an independent risk factor for cardiovascular disease but the exact pathophysiology of adverse cardiovascular outcomes of obstructive sleep apnea has not been fully elucidated. Matrix metalloproteinases (MMPs) have been associated with both oxidative stress and cardiovascular diseases. Hypoxic conditions were shown to influence MMP expression, secretion and activity. Moreover, matrix metalloproteinases contribute to ischemia/reperfusion injury. Therefore, action of matrix metalloproteinases can provide a possible molecular mechanism linking obstructive sleep apnea with oxidative stress and cardiovascular disease. The aim of this paper was to review the current evidence of association between matrix metalloproteinases and obstructive sleep apnea with focus on hypoxemia and severity of obstructive sleep apnea.

Impact Of Spinal Cord Injury On Sleep: Current Perspectives

Sleep disorders are commonly encountered in people living with spinal cord injury (SCI). Primary sleep disorders such as sleep-disordered breathing (SDB), sleep-related movement disorders, circadian rhythm sleep-wake disorders, and insomnia disorder are common conditions after SCI but remain under-recognized, underdiagnosed and therefore remain untreated for a majority of patients. Sleep disturbances in people living with SCI are associated with significant impairments of daytime function and quality of life. Previous reviews have described findings related mainly to SDB but have not examined the relationship between other sleep disorders and SCI. This narrative review examines various sleep abnormalities and related functional and physical impairments in people living with SCI. It discusses new evidence pertaining to management, highlights existing limitations in the literature and recommends future directions for research.

Untreated Obstructive Sleep Apnea Is Associated With Myocardial Injury Independent of Blood Pressure Control in Hypertension

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) and hypertension are independent risk factors of cardiovascular morbidities. This study aims to investigate the relationship between OSA, blood pressure (BP) control, and myocardial injury in patients with difficult-to-control hypertension.

METHODS

Patients with hypertension who required three or more medications were prospectively recruited at a tertiary referral center. In-laboratory polysomnography, followed by blood tests for fasting glucose, glycated hemoglobin, lipids, high-sensitivity troponin I (hsTnI), B-type natriuretic peptide (BNP), C-reactive protein, and advanced oxidation protein products were performed. After polysomnography, 24-hour ambulatory BP monitoring was arranged.

RESULTS

A total of 98 participants were analyzed, with mean age 51 ± 9 years and body mass index 30 ± 5 kg/m². Previously undiagnosed severe OSA (apneahypopnea index [AHI] ≥ 30 events/h) was present in 51 patients (52%). hsTnI was negatively correlated with nocturnal dip in systolic BP (r = -.205, P = .048). After controlling for confounders, including BP control, AHI and oxygen desaturation index (ODI) were positively correlated with hsTnI (r = .282, P = .009 and r = .279, P = .010, respectively) and C-reactive protein (r = .302, P = .005 and r = .285, P = .008, respectively), but not with BNP or advanced oxidation protein products. Age, ODI, and loss of nocturnal systolic BP dip were significant determinants of hsTnI level (β = .225, P = .022; β = .293, P = .003; and β = -.215, P = .029; R² = .151). Age, female sex, 24-hour mean diastolic BP, and metabolic syndrome, but not indices of apnea severity, were predictors of BNP level.

CONCLUSIONS

Unrecognized severe OSA was common in patients with difficult-to-control hypertension, and OSA severity was associated with myocardial injury, independent of BP control with medications.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov, Title: A Cross-sectional Study of the Occurrence and Effect of Obstructive Sleep Apnea in Subjects With Resistant Hypertension, Identifier: NCT00843583, URL: https://clinicaltrials.gov/ct2/show/NCT00843583.

Oximetry use in obstructive sleep apnea

INTRODUCTION

Overnight oximetry has been proposed as an accessible, simple, and reliable technique for obstructive sleep apnea syndrome (OSAS) diagnosis. From visual inspection to advanced signal processing, several studies have demonstrated the usefulness of oximetry as a screening tool. However, there is still controversy regarding the general application of oximetry as a single screening methodology for OSAS. Areas covered: Currently, high-resolution portable devices combined with pattern recognition-based applications are able to achieve high performance in the detection of this disease. In this review, recent studies involving automated analysis of oximetry by means of advanced signal processing and machine learning algorithms are analyzed. Advantages and limitations are highlighted and novel research lines aimed at improving the screening ability of oximetry are proposed. Expert commentary: Oximetry is a cost-effective tool for OSAS screening in patients showing high pretest probability for the disease. Nevertheless, exhaustive analyses are still needed to further assess unattended oximetry monitoring as a single diagnostic test for sleep apnea, particularly in the pediatric population and in populations with significant comorbidities. In the following years, communication technologies and big data analyses will overcome current limitations of simplified sleep testing approaches, changing the detection and management of OSAS.

Circulating lipopolysaccharide-binding protein and carotid intima-media thickness in obstructive sleep apnea

Circulating lipopolysaccharide-binding protein (LBP), a metabolic endotoxemia marker, was identified as an independent predictor of atherosclerosis. Although increases in carotid intima-media thickness (CIMT) were repeatedly reported in obstructive sleep apnea (OSA), neither the role of OSA in metabolic endotoxemia nor of LBP in early atherosclerosis were explored in patients with OSA. At a tertiary university hospital we investigated the relationships between OSA, LBP and CIMT in 117 men who underwent full polysomnography and CIMT assessment by B-mode ultrasound. Circulating LBP concentrations and average CIMT increased from patients without OSA to those with mild-moderate and severe OSA (from 32.1+/-10.3 to 32.3+/-10.9 to 38.1+/-10.3 microg.ml(-1), p=0.015; from 0.52+/-0.09 to 0.58+/-0.06 to 0.62+/-0.10 mm, p=0.004, respectively). Oxygen desaturation index (ODI) was a predictor of serum LBP levels independent of age, waist-to-hip ratio (WHR), smoking, hypertension, HDL cholesterol, triglycerides and fasting glucose [p (ANOVA)=0.002, r(2)=0.154], with no independent effect of the ODI*WHR interaction term on LBP. Furthermore, serum LBP predicted CIMT independently of known risk factors of atherosclerosis including obesity (p<0.001, r(2)=0.321). Our results suggest that OSA severity contributes to metabolic endotoxemia in patients with OSA independently of obesity, and that LBP might represent a contributing factor promoting early atherosclerosis in such patients.

Electrical stimulation for the treatment of obstructive sleep apnoea: a review of the evidence

INTRODUCTION

Obstructive sleep apnoea is an increasingly prevalent clinical condition with significant impact on individuals and public health. Continuous positive airway pressure therapy is the standard treatment, but adherence is limited and alternative treatments are needed. In this context, non-invasive and invasive methods for the electrical stimulation of upper airway dilator muscles have been demonstrated to be effective in selected patients. Areas covered: This review will cover investigations on the clinical effects, safety, and tolerability of non-invasive and invasive electrical stimulation of the upper airway for the management of obstructive sleep apnoea. Following a search of the relevant literature published on PubMed this review is focused mainly on data obtained from randomized clinical trials and clinical studies. Expert commentary: The available evidence provides a rationale to consider upper airway electrical stimulation as treatment for selected patients with obstructive sleep apnoea, who have poor adherence or experience difficulties with continuous positive airway pressure therapy. Non-invasive stimulation using transcutaneous electrodes and implantable hypoglossal nerve stimulator technologies may provide an alternative to continuous positive airway pressure for the treatment of obstructive sleep apnoea via restoration of neuromuscular tone and improved upper airway patency.

Genistein Protects Genioglossus Myoblast Against Hypoxia-induced Injury through PI3K-Akt and ERK MAPK Pathways

Obstructive sleep apnea and hypopnea syndrome (OSAHS) is a clinical syndrome characterized by recurrent episodes of obstruction of the upper airway during sleep that leads to a hypoxic condition. Genioglossus, an important pharyngeal muscle, plays an important role in maintaining an open upper airway for effective breathing. Our previous study found that genistein (a kind of phytoestrogen) protects genioglossus muscle from hypoxia-induced oxidative injury. However, the underlying mechanism is still unknown. In the present study, we examined the effects of hypoxia on genioglossus myoblast proliferation, viability and apoptosis, and the protective effect of genistein and its relationship with the PI3K/Akt and ERK MAPK pathways. Cell viability and Bcl-2 were reduced under hypoxic condition, while ROS generation, caspase-3, MDA, and DNA damage were increased following a hypoxia exposure. However, the effects of hypoxia were partially reversed by genistein in an Akt- and ERK- (but not estrogen receptor) dependent manner. In conclusion, genistein protects genioglossus myoblasts against hypoxia-induced oxidative injury and apoptosis independent of estrogen receptor. The PI3K-Akt and ERK1/2 MAPK signaling pathways are involved in the antioxidant and anti-apoptosis effect of genistein on genioglossus myoblasts.