The impact of obstructive sleep apnea and PAP therapy on all-cause and cardiovascular mortality based on age and gender - a literature review

The Effects of Obstructive Sleep Apnea on the Cardiovascular System: A Comprehensive Review

Obstructive sleep apnea (OSA) is an increasingly relevant cause of cardiovascular morbidity worldwide. Although the association between OSA and the cardiovascular system is well-known, the extent of its effects is still a topic of interest, including pathophysiologic mechanisms, cardiovascular sequelae, and OSA therapies and their effects. Commonly described mechanisms of cardiovascular etiologies revolve around sympathetic activation, inflammation, and intermittent hypoxia resulting from OSA. Ultimately, these effects lead to manifestations in the cardiovascular system, such as arrhythmias, hypertension, and heart failure, among others. The resulting sequelae of OSA may also have differential effects based on gender and age; several studies suggest female gender to have more susceptibility to cardiovascular mortality, as well as an increase in age. Furthermore, several therapies for OSA, both established and emerging, show a reduction in cardiovascular morbidity and may even reduce cardiovascular burden. Namely, the establishment of CPAP has led to improvement in hypertension and cardiac function in patients with heart failure and even reduced the progression of early stages of atherosclerosis. Effective management of OSA decreases abnormal neural sympathetic activity, which results in better rhythm control and blood pressure control, both in waking and sleep cycles. With newer therapies for OSA, its effects on the cardiovascular system may be significantly reduced or even reversed after long-term management. The vast extent of OSA on the cardiovascular system, as well as current and future therapeutic strategies, will be described in detail in this review.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Multi-Omics Analysis of Circulating Exosomes in Adherent Long-Term Treated OSA Patients

Obstructive sleep apnea (OSA) is a highly prevalent chronic disease affecting nearly a billion people globally and increasing the risk of multi-organ morbidity and overall mortality. However, the mechanisms underlying such adverse outcomes remain incompletely delineated. Extracellular vesicles (exosomes) are secreted by most cells, are involved in both proximal and long-distance intercellular communication, and contribute toward homeostasis under physiological conditions. A multi-omics integrative assessment of plasma-derived exosomes from adult OSA patients prior to and after 1-year adherent CPAP treatment is lacking. We conducted multi-omic integrative assessments of plasma-derived exosomes from adult OSA patients prior to and following 1-year adherent CPAP treatment to identify potential specific disease candidates. Fasting morning plasma exosomes isolated from 12 adult patients with polysomnographically-diagnosed OSA were analyzed before and after 12 months of adherent CPAP therapy (mean ≥ 6 h/night) (OSAT). Exosomes were characterized by flow cytometry, transmission electron microscopy, and nanoparticle tracking analysis. Endothelial cell barrier integrity, wound healing, and tube formation were also performed. Multi-omics analysis for exosome cargos was integrated. Exosomes derived from OSAT improved endothelial permeability and dysfunction as well as significant improvement in tube formation compared with OSA. Multi-omic approaches for OSA circulating exosomes included lipidomic, proteomic, and small RNA (miRNAs) assessments. We found 30 differentially expressed proteins (DEPs), 72 lipids (DELs), and 13 miRNAs (DEMs). We found that the cholesterol metabolism (has04979) pathway is associated with lipid classes in OSA patients. Among the 12 subjects of OSA and OSAT, seven subjects had complete comprehensive exosome cargo information including lipids, proteins, and miRNAs. Multi-omic approaches identify potential signature biomarkers in plasma exosomes that are responsive to adherent OSA treatment. These differentially expressed molecules may also play a mechanistic role in OSA-induced morbidities and their reversibility. Our data suggest that a multi-omic integrative approach might be useful in understanding how exosomes function, their origin, and their potential clinical relevance, all of which merit future exploration in the context of relevant phenotypic variance. Developing an integrated molecular classification should lead to improved diagnostic classification, risk stratification, and patient management of OSA by assigning molecular disease-specific therapies.

Case report: An OSAS patient with comorbid RLS/PLMS - a closer look at the causes of PAP intolerance

Since 2017, hypoglossal nerve stimulation has been included in the S3-guidelines on restorative sleep/sleep disorders as an alternative treatment for patients with obstructive sleep related breathing disorders who cannot tolerate conventional PAP-therapy. Under certain conditions, some of these patients have the option to have a tongue pacemaker implanted during a surgical procedure to regain a restful night's sleep. However, in some cases it does not solve the problem. In this case report, we present a patient who continued to have restless sleep despite implantation of a hypoglossus nerve stimulator. We provide a closer look at the underlying causes of PAP intolerance and emphasize the importance of a combined pneumological and neurological approach to sleep medicine in sleep-specific therapy evaluation.

Uvulopalatopharyngoplasty with and without modified thyrohyoid suspension for obstructive sleep apnea treatment: a randomized clinical trial

PURPOSE

This study aims to compare the efficacy of Uvulopalatopharyngoplasty + Tongue Base Radiofrequency (TB-RF) and Uvulopalatopharyngoplasty + modified thyrohyoid suspension techniques + TB-RF which aimed to suspend base of tongue muscles anteriorly toward thyroid cartilage.

METHODS

This randomized controlled trial study was conducted on 48 cases of confirmed OSA between Jan, 2019 and Aug, 2022. We divided patients into two groups. One group underwent Uvulopalatopharyngoplasty + modified thyrohyoid suspension + TB-RF technique, and another one underwent Uvulopalatopharyngoplasty + TB-RF. Then, Apnea-Hypopnea Index (AHI), mean and lowest O2 saturation, Drug-Induced Sleep Endoscopy (DISE), Epworth Sleepiness Scale (ESS), Digit Symbol Substitution Test (DSST), Stanford Subjective Snoring Scale (SSSS), and T90 indexes were evaluated before and after each surgery.

RESULTS

The mean ± SD age was 39.4 ± 11.17 years. Of the 48 patients, 79.1% (n = 33) were male and 20.9% (n = 15) were female. AHI and SSSS in the Uvulopalatopharyngoplasty + modified thyrohyoid suspension group were significantly better than Uvulopalatopharyngoplasty group (P-value; 0.010). Though, there was no significant difference in terms of mean saturation, lowest desaturation, ESS, DSST, and T90 scores. The success rate in the Uvulopalatopharyngoplasty + modified thyrohyoid suspension and Uvulopalatopharyngoplasty groups, according to the Sher criteria: a minimum of 50% reduction with a final AHI less than 20, were 75% (18/24) and 41.7% (10/24), respectively. It was significantly higher in the Uvulopalatopharyngoplasty + modified thyrohyoid suspension group (P-value: 0.021).

CONCLUSION

The addition of modified thyrohyoid suspension technique to Uvulopalatopharyngoplasty have better surgical outcomes and more success rate than Uvulopalatopharyngoplasty in OSA patients.

TRIAL REGISTRATION

IRCT: IRCT20190602043791N2. https://en.irct.ir/trial/53365 .

Clinical phenotype of obstructive sleep apnea in older adults: a hospital-based retrospective study in China

BACKGROUND

The prevalence of obstructive sleep apnea (OSA) in older people (aged over 65 years) is high. However, OSA in older populations has not received sufficient attention. This study examined the clinical phenotypic characteristics of older patients with newly diagnosed OSA.

METHODS

A total of 110 older patients (≥ 65 years) and 220 younger patients (< 65 years), matched by gender, body mass index (BMI), and apnea-hypopnea index (AHI), were enrolled in this retrospective study. Clinical manifestations, comorbidities, and polysomnographic results were compared between the two groups, and correlations between age ≥ 65 years and OSA comorbidities were explored.

RESULTS

Nocturia was more common in older patients with OSA, as with lower sleep efficiency, longer wake after sleep onset, increased stage N1 sleep, and decreased stage N3 sleep and average SpO2. The proportions of older OSA patients who had comorbid hypertension, coronary artery disease (CAD), chronic obstructive pulmonary disease, and ischemic stroke were significantly higher than those of younger patients. The incidence of tonsillar enlargement and pharyngeal narrowing was lower in older patients. Age ≥ 65 years was an independent risk factor for patients with OSA to have hypertension (OR: 1.89, 95% CI: 1.11-3.21), CAD (OR: 4.83, 95% CI: 2.29-10.21), and ischemic stroke (OR: 2.92, 95% CI: 1.02 to 8.38).

CONCLUSIONS

The presence of OSA in older adults was associated with significant abnormalities of sleep architecture, aggravated nocturnal hypoxia and increased risks of hypertension, CAD, and stroke, which can be distinguished as a unique clinical phenotype.

Adherence to CPAP Treatment: Can Mindfulness Play a Role?

Obstructive sleep apnea (OSA) is considered a chronic disease that requires long-term multidisciplinary management for effective treatment. Continuous Positive Airway Pressure (CPAP) is still considered the gold standard of therapy. However, CPAP effectiveness is limited due to poor patients' adherence, as almost 50% of patients discontinue treatment after a year. Several interventions have been used in order to increase CPAP adherence. Mindfulness-based therapies have been applied in other sleep disorders such as insomnia but little evidence exists for their application on OSA patients. This review aims to focus on the current data on whether mindfulness interventions may be used in order to increase CPAP adherence and improve the sleep quality of OSA patients. Even though controlled trials of mindfulness and CPAP compliance remain to be performed, this review supports the hypothesis that mindfulness may be used as an adjunct method in order to increase CPAP adherence in OSA patients.

Factors affecting obstructive sleep apnea patients' use of upper airway stimulation treatment

STUDY OBJECTIVES

Upper airway stimulation (UAS) is an alternative treatment for obstructive sleep apnea that must be activated nightly. Although the implanted device offsets the mask- or pressure-related side effects often associated with continuous positive airway pressure therapy, some UAS recipients do not use the therapy consistently. This study qualitatively explored factors associated with UAS usage in obstructive sleep apnea patients.

METHODS

Semistructured interviews were conducted with 24 obstructive sleep apnea patients who received UAS treatment. Twelve patients were categorized as high users with mean usage of ≥ 4 hours/night and 12 were categorized as low users with < 4 hours/night or nonuse. Interviews explored patients' experiences regarding barriers and facilitators to UAS use and their advice for new UAS recipients. Demographic and clinical data including the Insomnia Severity Index and Generalized Anxiety Disorder Scale were collected.

RESULTS

Compared to high users, low users had higher levels of insomnia (mean Insomnia Severity Index: 3.6 vs 15.2, respectively) and anxiety (mean Generalized Anxiety Disorder Scale: 3.4 vs 6.9). High users reported more positive experiences with UAS treatment, such as improvements in symptoms and convenience of treatment, as facilitators of use. Low users tended to focus on the negative aspects of treatment, particularly stimulation-related discomfort and associated sleep disturbance.

CONCLUSIONS

Insomnia with or without anxiety contributes to differing patient-reported experiences in high vs low user groups, with increased insomnia symptoms among low users. Improved understanding of the specific barrier and facilitators of UAS adherence may drive better long-term use and more personalized management strategies, including concomitant insomnia treatment.

CLINICAL TRIALS REGISTRATION

Registry: ClinicalTrials.gov; Name: Stimulation Therapy for Apnea: Reporting Thoughts (START); URL: https://clinicaltrials.gov/ct2/show/NCT04768543; Identifier: NCT04768543.

CITATION

Luyster FS, Ni Q, Lee K, et al. Factors affecting obstructive sleep apnea patients' use of upper airway stimulation treatment. J Clin Sleep Med. 2022;18(9):2207-2215.

Effects of Surgical Treatment for Obstructive Sleep Apnea on Renal and Survival Outcomes in Patients with Chronic Kidney Disease: A Taiwanese Nationwide Cohort Study

The association between surgical treatment for obstructive sleep apnea (OSA) in chronic kidney disease (CKD) patients and end-stage renal disease (ESRD) and survival outcomes is not established, and this study aimed to evaluate this association. A retrospective cohort analysis was conducted from 2001 to 2015, including 32,220 eligible CKD patients with incident OSA. By 1:3 propensity score matching, 1078 CKD patients with incident OSA who received surgery (treated cohort) and 3234 untreated cohort who never received surgery were analyzed. The risk of ESRD in the competing mortality was significantly lower in the treated cohort than in the untreated cohort, with an adjusted hazard ratio (aHR) of 0.38 (95% confidence interval (CI0, 0.15−0.97; p = 0.043). In addition, the adjusted HRs of overall, cardiovascular, and non-cardiovascular mortality in the treated and untreated cohorts were 2.54 (95% CI, 1.79−3.59; p < 0.0001), 1.46 (95% CI, 0.29−7.22; p = 0.64), and 2.62 (95% CI, 1.83−3.75; p < 0.0001), respectively. Furthermore, the risks of overall and non-cardiovascular mortality for the treated cohort primarily occurred during a 3-month follow-up. In conclusion, surgical treatment for incident OSA in CKD patients was associated with decreased ESRD risk, but with increased non-cardiovascular mortality risk, especially within 3 months after surgical treatment.

Brazilian Thoracic Association Consensus on Sleep-disordered Breathing

Sleep is essential for the proper functioning of all individuals. Sleep-disordered breathing can occur at any age and is a common reason for medical visits. The objective of this consensus is to update knowledge about the main causes of sleep-disordered breathing in adult and pediatric populations, with an emphasis on obstructive sleep apnea. Obstructive sleep apnea is an extremely prevalent but often underdiagnosed disease. It is often accompanied by comorbidities, notably cardiovascular, metabolic, and neurocognitive disorders, which have a significant impact on quality of life and mortality rates. Therefore, to create this consensus, the Sleep-Disordered Breathing Department of the Brazilian Thoracic Association brought together 14 experts with recognized, proven experience in sleep-disordered breathing.

OSA and cardiorespiratory fitness: a review

The effects of untreated obstructive sleep apnea (OSA) on cardiopulmonary function remain unclear. Cardiorespiratory fitness (CRF), commonly reflected by VO₂ max measured during cardiopulmonary exercise testing, has gained popularity in evaluating numerous cardiopulmonary conditions and may provide a novel means of identifying OSA patients with the most clinically significant disease. This emerging testing modality provides simultaneous assessment of respiratory and cardiovascular function with results helping uncover evidence of evolving pathology in either organ system. In this review, we highlight the current state of the literature in regard to OSA and CRF with a specific focus on changes in cardiovascular function that have been previously noted. While OSA does not appear to limit respiratory function during exercise, studies seem to suggest an abnormal cardiovascular exercise response in this population including decreased cardiac output, a blunted heart rate response (ie, chronotropic incompetence), and exaggerated blood pressure response. Surprisingly, despite these observed changes in the cardiovascular response to exercise, results involving VO₂ max in OSA remain inconclusive. This is reflected by VO₂ max studies involving middle-aged OSA patients showing both normal and reduced CRF. As prior studies have not extensively characterized oxygen desaturation burden, we propose that reductions in VO₂ max may exist in OSA patients with only the most significant disease (as reflected by nocturnal hypoxia). Further characterizing this relationship remains important as some research suggests that positive airway pressure therapy or aerobic exercise may improve CRF in patients with OSA. In conclusion, while it likely that severe OSA, via an abnormal cardiovascular response to exercise, is associated with decreased CRF, further study is clearly warranted to include determining if OSA with decreased CRF is associated with increased morbidity or mortality.

CITATION

Powell TA, Mysliwiec V, Brock MS, Morris MJ. OSA and cardiorespiratory fitness: a review. J Clin Sleep Med. 2022;18(1):279-288.

Sleep Apnea-Specific Hypoxic Burden, Symptom Subtypes, and Risk of Cardiovascular Events and All-Cause Mortality

Rationale: Data from population-based cohorts suggest that symptom subtypes and obstructive sleep apnea (OSA)-specific hypoxic burden (HB) could help to better identify patients with OSA at high cardiovascular (CV) risk. Objectives: We aimed to evaluate whether those new markers are associated with the risk of major adverse CV events (MACE) in clinical setting. Methods: Data from the Pays de la Loire cohort were linked to health administrative data to identify the occurrence of MACE (a composite outcome including all-cause mortality, acute myocardial infarction, stroke, and unplanned coronary revascularization) in patients with newly diagnosed OSA and no overt CV disease. Latent class analysis was used to identify subtypes based on eight clinically relevant variables. HB was defined as the total area under the respiratory event-related desaturation curve. Cox proportional hazards models were used to evaluate the association of symptom subtypes and HB with MACE. Measurements and Main Results: Four symptom subtypes were identified (minimally symptomatic [22.0%], disturbed sleep [17.5%], excessively sleepy [49.8%], and moderately sleepy [10.6%]). After a median follow-up of 78 months (interquartile range, 52-109), 592 (11.05%) of 5,358 patients experienced MACE. In a fully adjusted model, HB and overall nocturnal hypoxemia assessed by sleep time with oxygen saturation <90% were the only predictors of MACE (hazard ratio, 1.21; 95% confidence interval, 1.07-1.38; and hazard ratio, 1.34; 95% confidence interval, 1.16-1.55, respectively). The association appeared stronger toward younger patients and women. Conclusion: In clinical setting, patients with OSA who demonstrate elevated OSA-specific HB are at higher risk of a CV event and all-cause mortality. Symptom subtypes were not associated with MACE after adjustment for confounders.

Chronic lung diseases and sleep

Sleep is vitally important part of our life. Its quality and quantity influence all physiological processes in our organism. The relationship between the lung diseases and sleep is bidirectional - the lack of quality sleep worsens the compensation and the course of the diseases and in the same time chronic lung diseases are negatively affecting sleep quality. The coexistence of the sleep disordered breathing and lung disorders is another important issue to discuss. In case of chronic obstructive pulmonary disease the overlap with sleep disordered breathing is characterized by higher prevalence of hypercapnia and overall worse prognosis. Moreover, there is a growing body of evidence about possible links of sleep disordered breathing to lung fibrosis and tumors. The complex healthcare in patients with respiratory diseases should not omit sleep examination.

H3K23/H3K36 hypoacetylation and HDAC1 up-regulation are associated with adverse consequences in obstructive sleep apnea patients

The aim of this study is to determine the roles of global histone acetylation (Ac)/methylation (me), their modifying enzymes, and gene-specific histone enrichment in obstructive sleep apnea (OSA). Global histone modifications, and their modifying enzyme expressions were assessed in peripheral blood mononuclear cells from 56 patients with OSA and 16 matched subjects with primary snoring (PS). HIF-1α gene promoter-specific H3K36Ac enrichment was assessed in another cohort (28 OSA, 8 PS). Both global histone H3K23Ac and H3K36Ac expressions were decreased in OSA patients versus PS subjects. H3K23Ac expressions were further decreased in OSA patients with prevalent hypertension. HDAC1 expressions were higher in OSA patients, especially in those with excessive daytime sleepiness, and reduced after more than 6 months of continuous positive airway pressure treatment. H3K79me3 expression was increased in those with high C-reactive protein levels. Decreased KDM6B protein expressions were noted in those with a high hypoxic load, and associated with a higher risk for incident cardiovascular events or hypertension. HIF-1α gene promoter-specific H3K36Ac enrichment was decreased in OSA patients versus PS subjects. In vitro intermittent hypoxia with re-oxygenation stimuli resulted in HDAC1 over-expression and HIF-1α gene promoter-specific H3K36Ac under-expression, while HDAC1 inhibitor, SAHA, reversed oxidative stress through inhibiting NOX1. In conclusions, H3K23/H3K36 hypoacetylation is associated with the development of hypertension and disease severity in sleep-disordered breathing patients, probably through up-regulation of HDAC1, while H3K79 hypermethylation is associated with higher risk of cardiovascular diseases, probably through down-regulation of KDM6B.

Improving CPAP Adherence in Adults With Obstructive Sleep Apnea Syndrome: A Scoping Review of Motivational Interventions

Objective: This scoping review aims to provide an accessible summary of available evidence on the efficacy of motivational interventions to increase adherence to Continuous Positive Airway Pressure (CPAP) among patients with Obstructive Sleep Apnea Syndrome (OSAS) and of their specific aspects and strategies by assessing adherence measures. Methods: A literature search was performed in PubMed, Scopus, Medline, PsycINFO, and Web of Science databases using the concepts of "obstructive sleep apnea syndrome," "continuous positive airway pressure," "motivational intervention," and "adherence." Rigorous inclusion criteria and screening by at least two reviewers were applied. Data were extracted to address the review aims and were presented as a narrative synthesis. Results: Search for databases produced 11 randomized controlled trials, all including naïve CPAP users. Findings showed that motivational interventions were more effective than usual care and educational programs in increasing adherence to CPAP, despite results were not always maintained over time across studies. Discussion: To our knowledge, this is the first scoping review of the literature aimed to explore the characteristics and impact of motivational interventions to promote adherence to CPAP in patients with OSAS. More research providing a detailed description of motivational strategies, and testing of their association with positive treatment outcomes via both direct and indirect measures are needed to increase awareness on active mechanisms of change.

The protective role of SOD1 overexpression in central mediation of bradycardia following chronic intermittent hypoxia in mice

Obstructive sleep apnea (OSA) is a highly prevalent sleep disorder that is associated with many cardiovascular complications. Similar to OSA, chronic intermittent hypoxia (CIH) (a model for OSA) leads to oxidative stress and impairs baroreflex control of the heart rate (HR) in rodents. The baroreflex arc includes the aortic depressor nerve (ADN), vagal efferent, and central neurons. In this study, we used mice as a model to examine the effects of CIH on baroreflex sensitivity, aortic baroreceptor afferents, and central and vagal efferent components of the baroreflex circuitry. Furthermore, we tested whether human Cu/Zn Superoxide Dismutase (SOD1) overexpression in transgenic mice offers protection against CIH-induced deficit of the baroreflex arc. Wild-type C57BL/6J and SOD1 mice were exposed to room air (RA) or CIH and were then anesthetized, ventilated, and catheterized for measurement of mean arterial pressure (MAP) and HR. Compared with wild-type RA control, CIH impaired baroreflex sensitivity but increased maximum baroreceptor gain and bradycardic response to vagal efferent stimulation. Additionally, CIH reduced the bradycardic response to ADN stimulation, indicating a diminished central regulation of bradycardia. Interestingly, SOD1 overexpression prevented CIH-induced attenuation of HR responses to ADN stimulation and preserved HR responses to vagal efferent stimulation in transgenic mice. We suggest that CIH decreased central mediation of the baroreflex and SOD1 overexpression may prevent the CIH-induced central deficit.

Evaluation of Obstructive Sleep Apnea in Female Patients in Primary Care: Time for Improvement?

Obstructive sleep apnea (OSA) has historically been regarded as a male disease. However, there are a number of significant gender-related differences in the symptoms, diagnosis, and consequences of OSA, which seems to be more severe in male than in female patients, although this sex difference decreases with increasing age. Female patients with OSA tend to present nonspecific symptoms, such as insomnia, depressive symptoms, fatigue, morning headache, and nightmares, often resulting in underdiagnosis and undertreatment compared to male patients. Understanding these differences in women is essential for early identification and referral of patients for diagnosis and treatment of OSA.

The Association Between Obstructive Sleep Apnea Defined by 3 Percent Oxygen Desaturation or Arousal Definition and Self-Reported Cardiovascular Disease in the Sleep Heart Health Study

Background

Studies have established that OSA defined using a hypopnea definition requiring a ≥4% oxygen desaturation (AHI4%) is associated with cardiovascular (CVD) or coronary heart (CHD) disease. This study determined whether OSA defined using a hypopnea definition characterized by a ≥3% oxygen desaturation or an arousal (AHI3%A) is associated with CVD/CHD.

Methods

Data were analyzed from 6307 Sleep Heart Health Study participants who had polysomnography. Self-reported CVD included angina, heart attack, heart failure, stroke, previous coronary bypass surgery or angioplasty. Self-reported CHD included the aforementioned conditions but not stroke or heart failure. The association between OSA and CVD/CHD was examined using logistic regression models with stepwise inclusion of demographic, anthropometric, social/behavioral and co-morbid medical conditions. A parsimonious model in which diabetes and hypertension were excluded because of their potential to be on the causal pathway between OSA and CVD/CHD also was constructed.

Results

For CVD, the odds ratios and 95% confidence intervals for AHI3%A ≥30/hour were 1.39 (1.03-1.87) and 1.45 (1.09-1.94) in the fully adjusted and parsimonious models. Results for CHD were 1.29 (0.96-1.74) and 1.36 (0.99-1.85). In participants without OSA according to more stringent AHI4% criteria but with OSA using the AHI3%A definition, similar findings were observed.

Conclusion

OSA defined using an AHI3%A is associated with both CVD and CHD. Use of a more restrictive AHI4% definition will misidentify a large number of individuals with OSA who have CVD or CHD. These individuals may be denied access to therapy, potentially worsening their underlying CVD or CHD.

Obesity and cardiovascular disease in women

As the prevalence of obesity continues to grow worldwide, the health and financial burden of obesity-related comorbidities grows too. Cardiovascular disease (CVD) is clearly associated with increased adiposity. Importantly, women are at higher risk of CVD when obese and insulin resistant, in particular at higher risk of developing heart failure with preserved ejection fraction and ischemic heart disease. Increased aldosterone and mineralocorticoid receptor activation, aberrant estrogenic signaling and elevated levels of androgens are among some of the proposed mechanisms explaining the heightened CVD risk. In addition to traditional cardiovascular risk factors, understanding nontraditional risk factors specific to women, like excess weight gain during pregnancy, preeclampsia, gestational diabetes, and menopause are central to designing personalized interventions aimed to curb the epidemic of CVD. In the present review, we examine the available evidence supporting a differential cardiovascular impact of increased adiposity in women compared with men and the proposed pathophysiological mechanisms behind these differences. We also discuss women-specific cardiovascular risk factors associated with obesity and insulin resistance.

Variability and Misclassification of Sleep Apnea Severity Based on Multi-Night Testing

BACKGROUND

Portable monitoring is a convenient means for diagnosing sleep apnea. However, data on whether one night of monitoring is sufficiently precise for the diagnosis of sleep apnea are limited.

RESEARCH QUESTION

The current study sought to determine the variability and misclassification in disease severity over three consecutive nights in a large sample of patients referred for sleep apnea.

METHODS

A sample of 10,340 adults referred for sleep apnea testing was assessed. A self-applied type III monitor was used for three consecutive nights. The apnea-hypopnea index (AHI) was determined for each night, and a reference AHI was computed by using data from all 3 nights. Pairwise correlations and the proportion misclassified regarding disease severity were computed for each of the three AHI values against the reference AHI.

RESULTS

Strong correlations were observed between the AHI from each of the 3 nights (r = 0.87-0.89). However, substantial within-patient variability in the AHI and significant misclassification in sleep apnea severity were observed based on any 1 night of monitoring. Approximately 93% of the patients with a normal study on the first night and 87% of those with severe sleep apnea on the first night were correctly classified compared with the reference derived from all three nights. However, approximately 20% of the patients with mild and moderate sleep apnea on the first night were misdiagnosed either as not having sleep apnea or as having mild disease, respectively.

CONCLUSIONS

In patients with mild to moderate sleep apnea, one night of portable testing can lead to misclassification of disease severity given the substantial night-to-night variability in the AHI.