Phenotype and Risk Burden of Sleep Apnea: A Population-Based Cohort Study

Effect of continuous positive pressure ventilation on left ventricular diastolic function E/A ratio in patients with obstructive sleep apnea: a meta-analysis

PURPOSE

Many studies have shown that obstructive sleep apnea (OSA) is related to reduced left ventricular diastolic function. Continuous positive airway pressure (CPAP) is generally recognized as the preferred therapy for OSA. Yet, the effect of CPAP on left ventricular diastolic function in patients with OSA is inconclusive. In order to assess the influence of CPAP on left ventricular diastolic function in patients with OSA, we performed this meta-analysis of clinical experiments.

METHODS

PubMed, Web of Science, OVID, Embase, and Cochrane Library from the establishment of the database to July 6, 2022, were searched for clinical trial data. Inclusion criteria for this meta-analysis were: (1) Patients in the experimental group were diagnosed with OSA by polysomnography; (2) CPAP treatment course ≥ 4 weeks; (3) baseline and follow-up data of the diastolic function parameter E/A ratio were reported in the literature. Exclusion criteria were: (1) Central sleep apnea (CSA); (2) comorbid organic heart diseases such as coronary heart disease; (3) age < 18 years old; (4) conference abstracts or duplicate publications.

RESULTS

After exclusions, 7 studies (2 RCTs and 5 prospective studies) with 473 subjects (225 in the treatment group and 248 in the matched control group) were included in the meta-analysis. Subgroup analysis indicated that after CPAP therapy, the left ventricular (LV) E/A ratio was significantly increased in patients with OSA (weighted mean difference (WMD) = 0.22, 95% CI =  - 0.06-0.38; P = 0.007). Sensitivity analyses showed that the combined results were not influenced by single studies. Publication bias was not significant (Egger's test, P = 0.813).

CONCLUSIONS

The results of this meta-analysis suggest that CPAP may improve the E/A ratio in patients with OSA patients. However, the small number of studies (n = 7) decreases confidence in the findings. Thus, carefully designed randomized controlled trials are needed to confirm the findings.

Adherence to CPAP therapy in Down syndrome: the population-based DISCOVERY study

STUDY OBJECTIVES

Persons with Down syndrome (DS) have an increased risk of obstructive sleep apnea (OSA) needing continuous positive airway pressure (CPAP), but data on the therapy and outcomes in this population are scarce. We aimed to compare patient characteristics and outcomes of CPAP treatment for patients with OSA with and without DS.

METHODS

This was a population-based, longitudinal study on patients initiating CPAP therapy between July 2010 and March 2018 in Sweden and a population-based sex- and age-matched control group (control:case ratio 5:1), with linked data from the Swedish National Patient Registry and the Prescribed Drug Registry (DISCOVERY study cohort).

RESULTS

Patients with DS (n = 64) had a higher apnea-hypopnea index (51.7 ± 30.3 vs 36.8 ± 29.1 events/h, P < .001), Epworth Sleepiness Scale score (13.7 ± 5.9 vs 11.0 ± 4.9, P = .001), rate of previous surgery of tonsils and/or adenoids (21.9% vs 8.2%, P = .001), and more thyroid replacement hormone therapy (45.3% vs 7.8%, P < .001), but lower use of cardiovascular drugs (7.8% vs 22.3%, P = .003) compared with controls. At follow-up after 1.3 ± 0.9 years, there were no differences in nocturnal CPAP usage time (5.6 ± 2.4 vs 5.5 ± 2.0 hours, P = .77), CPAP adherence ≥ 4 hours/night (62% vs 65%, P = .93), or improvement in Epworth Sleepiness Scale score (-5.4 ± 6.8 vs -5.0 ± 2.0, P = .84) between DS and non-DS patients.

CONCLUSIONS

OSA severity was substantially higher in patients with DS despite an increased rate of tonsil surgery. Treatment outcomes in terms of adherence and improved daytime sleepiness were comparable between groups, underlining the importance of both OSA diagnosis and treatment in patients with DS.

CITATION

Svensson M, Ekström M, Sundh J, Ljunggren M, Grote L, Palm A. Adherence to CPAP therapy in Down syndrome: the population-based DISCOVERY study. J Clin Sleep Med. 2023;19(3):453-458.

Genetic insights into the risk of snoring on stroke and ischemic stroke: A single-variable and multivariable Mendelian randomization

Background

Multiple risk factors of stroke have been identified in previous studies; however, the causal role of snoring in the onset of stroke is less investigated. To clarify the causal association of snoring on stroke and its subtypes, this study is performed.

Methods

The single nucleotide polymorphisms in relation to snoring were retrieved from the UK biobank cohort with 408,317 participants. The data for stroke and its subtypes of European ancestry (67,162 cases and 453,702 controls) were obtained from the MEGASTROKE consortium. In single-variable Mendelian randomization (SVMR) and multivariable MR (MVMR) analyses, inverse variance weighting was used as the primary estimate, complemented with sensitivity analyses more robust to pleiotropy.

Results

Genetically predicted snoring increased the risk of stroke (odds ratio [OR] = 2.69, 95% confidence interval [CI] = 1.19-6.08, P = 0.016) and ischemic stroke (IS) (OR = 2.82, 95% CI = 1.23-6.44, P = 0.013), but not large artery stroke (LAS) (OR = 3.02, 95% CI = 0.31-29.44, P = 0.339), cardioembolic stroke (CES) (OR = 1.51, 95% CI = 0.58-3.92, P = 0.395). We provide novel genetic evidence that snoring increases the risk of stroke and IS, but not LAS, CES, and SVS.

Conclusion

Our findings provide novel genetic evidence that snoring increases the risk of stroke and IS, but not LAS, CES, and SVS.

Obstructive sleep apnea is associated with depressed myocardial mechanoenergetics

PURPOSE

To evaluate the association between the myocardial mechanoenergetic efficiency index (MEEi) and the Apnea-Hypopnea Index (AHI) in the initial phase of obstructive sleep apnea (OSA) diagnosis.

METHODS

In this cohort study, we included a total of 382 eligible participants without cardiovascular disease in a tertiary outpatient clinic between January 2013 and January 2015. We recorded demographic, clinical, polysomnographic and echocardiographic variables of the patients. In addition, myocardial mechanoenergetic efficiency (MEE) and MEEi were calculated by an echocardiography-derived validated measurement.

RESULTS

The mean (±SD) age of the participants was 48.47 ± 12.13, and male/female ratio was 287/95. Comparing with non-OSA, MEEi was significantly lower in OSA patients at all stages (0.35 ± 0.08 vs. 0.42 ± 0.05; p < .001). MEEi was negatively correlated with hypertension (r = -0.518, p < .001), body mass index (r = -0.382, p < .001), AHI (r = -0.656, p < .001), total apne (r = -0.525, p < .001), hypopnea (r = -0.415, p < .001), systolic pulmonary pressure (r = -0.318, p < .001), relative wall thickness (RWT; r = -0.415, p < .001), and positive correlated with left ventricular ejection fraction (r = 0.586, p < .001). According to multiple linear regression analysis AHI (β = -0.625, p < .001), total apnea (β = -0.402, p = .001), hypopnea (β = -0.395, p = .001), LV ejection fraction (β = 0.478, p < .001) and RWT (β = -0.279, p < .001) have an independent relationship with MEEi.

CONCLUSIONS

MEEi was lower in OSA patients. A reduced MEEi may reflect a disturbance in energy use of the myocardium. Consequently, our results may provide insight into the mechanisms leading to structural cardiac diseases in OSA patients.

Sex differences in the association between arterial hypertension, blood pressure, and sleep apnea in the general population

STUDY OBJECTIVES

To assess sex-related differences in the relationship between hypertension (HT), blood pressure (BP), and sleep apnea in the general population.

METHODS

We performed home polygraphy in a cohort of 1809 men and women in the general population. Office BP was measured. Presence of HT (drug-treated, physician-diagnosed, or high BP during study visit) was also recorded. HT rate and BP were assessed over a range of 7 sleep apnea severity categories based on the respiratory event index (REI).

RESULTS

The age-adjusted HT prevalence rate increased with higher REI in both sexes. After additional adjustment for obesity the association remained significant in women but not in men. In participants not treated with antihypertensive medications, age-adjusted BP increased with REI. Remarkably, the association was already significant within the normal range (REI < 5 events/h). The REI threshold for higher BP was situated at a distinctly lower cutoff point in women compared to men. After additional adjustment for obesity, the associations remained significant for diastolic but not systolic BP.

CONCLUSIONS

Significant increases in the age-adjusted BP and HT rate in the general population were present at lower REI cutoffs in women compared to men. Even a very low number of respiratory events was associated with higher BP and HT prevalence. Adjustment for obesity attenuated these associations, especially in men. Sex differences in BP susceptibility across the sleep apnea spectrum may be present.

The Impact of Obstructive Sleep Apnea on the Sleep of Critically Ill Patients

Obstructive sleep apnea is becoming increasingly prevalent in society and thus critical care practitioners need to be prepared to care for these patients in the intensive care unit. Preparation begins with equipping the critical care nurse with the knowledge necessary to provide interventions which can enhance patient outcomes and mitigate complications.

Time-dependence and comparison of regional and overall anthropometric features between Asian and Caucasian populations with obstructive sleep apnea: a cumulative meta-analysis

Background

Anthropometric measurements are simple and reachable tools for self-evaluating and screening patients with a high risk of obstructive sleep apnea (OSA). However, the accumulated relationship of obesity on the anthropometric characteristics of OSA is not well understood. The aim of the study was to show the time-dependent trend of OSA patients and compare overall and regional anthropometric between two ethnicities.

Methods

A cumulative meta-analysis was performed to assess obesity metrics in patients with and without OSA between Asians and Caucasians. We searched PubMed, Web of Science, Embase, and Scopus up to Jun 2020. Included studies used body mass index (BMI), neck circumference (NC), waist circumference (WC) and waist-to-hip ratio (WHR) as measures of anthropometric features in the adult OSA population and controls, utilized in-lab polysomnography or home sleep testing with apnea-hypopnea index (AHI) or respiratory disturbance index (RDI) classification, reported ethnicity/race, and were published in English. Any studies lacking one of these criteria or sufficient data were excluded.

Results

Forty studies with a total of 19,142 subjects were investigated. Comparison of changes between patients with and without OSA showed that OSA patients had a higher BMI [mean difference (MD) 3.12, 95% confidence interval (CI): 2.51–3.73], NC (MD 3.10, 95% CI: 2.70–3.51), WC (MD 9.84, 95% CI: 8.42–11.26) and waist-hip ratio (MD 0.04, 95% CI: 0.03–0.05) than the control subjects. The accumulated time-dependent increase in population with OSA was significantly apparent with all anthropometric features. BMI increased from 2000 (MD 0.50) to 2012 (MD 3.08–3.48) and remained stable afterwards (MD 2.70–3.17), NC increased from 2000 (MD 0.40) to 2013 (MD 3.09) and remained stable afterwards too (MD 3.06–3.21). WC increased from 2000 (MD 2.00) to 2012 (MD 9.37–10.03) and also remained stable afterwards (MD 8.99–9.84). WHR was stable from 2000 to 2004 with an MD of 0.01 and then stable from 2007 onwards with an increased MD of 0.03–0.04. Compared with Caucasian patients, Asian patients had lower obesity relevant variates.

Conclusions

BMI, NC, WC and WHR are associated with OSA in both ethnic groups. Anthropometry for overall and regional obesity could facilitate differentiation of patients with OSA from individuals without OSA by ethnicity.

Targeting subclinical organ damage in obstructive sleep apnea: a narrative review

Subclinical abnormalities in cardiac and vascular structure reflect the adverse effects triggered by a variety of risk factors on the cardiovascular (CV) system thereby representing an intermediate step in the cardiovascular continuum; such alterations are recognized as reliable markers of increased cardiovascular risk in different clinical settings including obstructive sleep apnea (OSA). The mechanisms underlying subclinical organ damage (OD) in the OSA setting are multifactorial. Hypoxemia and hypercapnia, induced by repeated collapses of upper airways, have been suggested to trigger a cascade of events such as activation of the sympathetic tone, renin-angiotensin-aldosterone system leading to endothelial dysfunction, vasoconstriction, myocardial and vascular remodeling, and hypertension. Furthermore, coexisting non-haemodynamic alterations such as increased oxidative stress, release of inflammatory substances, enhanced lipolysis and insulin resistance have been reported to play a role in the pathogenesis of both cardiac and extra-cardiac OD. In this article we reviewed available evidence on the association between OSA and subclinical cardiac (i.e., left and right ventricular hypertrophy, left atrial dilatation) and extra-cardiac organ damage (i.e., carotid atherosclerosis, arterial stiffness, microvascular retinal changes, and microalbuminuria). This association is apparently stronger for cardiac and carotid subclinical damage than for other markers (i.e., arterial stiffness and retinal changes) and mostly evident in the setting of severe OSA.

The effect of intermittent hypoxia and fecal microbiota of OSAS on genes associated with colorectal cancer

Purpose

Colorectal cancer (CRC) is one of the common causes of cancer death worldwide. Obstructive sleep apnea syndrome (OSAS), sharing many risk factors in common with CRC, is prevalent among CRC patients. OSAS may promote the CRC development independently but the mechanism is still unknown. Intermittent hypoxia (IH) is one of the characteristics of OSAS, and hypoxia may influence the genes associated with CRC. Intestinal microbiota plays important role in CRC carcinogenesis, and OSAS patients have been shown to have intestinal microbiota dysbiosis. We hypothesized that IH and intestinal microbiota dysbiosis may be involved for CRC in patients with OSAS.

Methods

We established precancerous cell models of CRC with Immorto-Min colonic epithelial (IMCE) cells. First, the cells were exposed to IH in a special chamber for 4 h, 8 h, and 12 h. Feces from 6 patients with OSAS and 6 healthy controls were collected and made into sterile fecal fluid for incubation with IMCE cells for 12 h. The cells were then exposed to IH for 4 h, 8 h, and 12 h. After IH exposure, the expressions of genes and inflammation cytokines associated with CRC, such as β-catenin, STAT3, HIF-1α, IL-6, TNF-α, c-myc, and cyclinD1, were tested.

Results

IH activated the expression of HIF-1α and STAT3 both in mRNA and protein level (HIF-1α: P = 0.015 for mRNA level, P = 0.027 for protein level; STAT3: P = 0.023 for mRNA level, P = 0.023 for protein level), and promoted p-STAT3 shifting to the nucleus (P = 0.023). The mRNA of β-catenin (P = 0.022) and cyclinD1 (P = 0.023) was elevated, but there was no change for the β-catenin protein in the nucleus. Gut microbiota of OSAS patients promoted the expression of STAT3 (protein level: 0 h: P = 0.037; 4 h: P = 0.046; 8 h: P = 0.049; 12 h: P = 0.037), promoted p-STAT3 (4 h: P = 0.049; 8 h: P = 0.046; 12 h: P = 0.046) shifting to the nucleus, and also elevated the expression of IL-6 and TNF-α in mRNA level at 4 h (IL-6: P = 0.037, TNF-α: P = 0.037) and 8 h (IL-6: P = 0.037, TNF-α: P = 0.037). The protein of β-catenin in the nucleus was not affected by IH and gut microbiota from OSAS.

Conclusions

Our study demonstrated that IH and gut microbiota of patients with OSAS activated HIF-1α expression and STAT3 pathway in IMCE cells, with no influence on β-catenin pathway, which suggested that IH, STAT3 pathway, chronic inflammation, and intestinal microbiota dysbiosis may be involved in CRC carcinogenesis correlated with OSAS These findings must be interpreted cautiously and further research is necessary to clarify the causative steps in CRC development.

Rapid Geriatric Assessment Using Mobile App in Primary Care: Prevalence of Geriatric Syndromes and Review of Its Feasibility

With the aging population and consequent increase in associated prevalence of frailty, dementia, and multimorbidity, primary care physicians will be overwhelmed with the complexity of the psychosocial and clinical presentation. Geriatric syndromes including frailty, sarcopenia, cognitive impairment, and anorexia of aging (AA) either in isolation or in combination are associated with an increased risk of adverse outcomes and if recognized early, and appropriately managed, will lead to decreased disability. Primary care practices are often located in residential settings and are in an ideal position to incorporate preventive screening and geriatric assessment with personalized management. However, primary care physicians lack the time, multidisciplinary resources, or skills to conduct geriatric assessment, and the limited number of geriatricians worldwide further complicates the matter. There is no one effective strategy to implement geriatric assessment in primary care which is rapid, cost-effective, and do not require geriatricians. Rapid Geriatric Assessment (RGA) takes <5 min to complete. It screens for frailty, sarcopenia, AA, and cognition with assisted management pathway without the need of a geriatrician. We developed RGA iPad application for screening with assisted management in two primary care practices and explored the feasibility and overall prevalence of frailty, sarcopenia, and AA. The assessment was conducted by trained nurses and coordinators. Among 2,589 older patients ≥65 years old, the prevalence of frailty was 5.9%, pre-frail 31.2%, and robust 62.9%. Fatigue was present in 17.8%, and among them, the prevalence of undiagnosed depression as assessed by the Patient Health Questionnaire (PHQ)-9 was 76.4% and 13.5% of total. The prevalence of sarcopenia was 15.4%, and 13.9% experienced at least one fall in the past year. AA was prevalent in 10.9%. The time taken to do the assessment with defined algorithm was on average 5 min or less per patient, and 96% managed to complete the assessment prior to seeing their doctor in the same session. The RGA app is a rapid and feasible tool to be used by any healthcare professional in primary care for identification of geriatric syndrome with assisted management.

Sleep Disordered Breathing, a Novel, Modifiable Risk Factor for Hypertensive Disorders of Pregnancy

PURPOSE OF REVIEW

Pathophysiology of hypertensive disorders of pregnancy (HDP), especially preeclampsia, has not been fully elucidated. Most trials aimed at the prevention of preeclampsia have failed to show significant benefit and investigation of novel, modifiable risk factors is sorely needed. Sleep disordered breathing (SDB), a group of disorders for which treatments are available, meets these criteria. SDB impacts about a third of all pregnancies and is associated with hypertension in the general non-pregnant population.

RECENT FINDINGS

Recent studies have shown a high prevalence of SDB, especially in complicated pregnancies. Several studies have shown that pregnant women with SDB have a higher risk for developing HDP, and these two disorders are associated with similar maternal long-term cardiovascular outcomes. Based on limited animal models of gestational intermittent hypoxia and human studies, SDB and HDP share similar risk factors and some pathophysiological mechanisms. However, there is paucity of studies addressing causality of this association and identifying therapeutic targets for intervention. Maternal SDB represents a novel and modifiable risk factor of HDP. Further studies are needed in order to establish the exact mechanisms underlying this association and to identify specific areas for clinical interventions.

Insights into the aetiology of snoring from observational and genetic investigations in the UK Biobank

Although snoring is common in the general population, its aetiology has been largely understudied. Here we report a genetic study on snoring (n ~ 408,000; snorers ~ 152,000) using data from the UK Biobank. We identify 42 genome-wide significant loci, with an SNP-based heritability estimate of ~10% on the liability scale. Genetic correlations with body mass index, alcohol intake, smoking, schizophrenia, anorexia nervosa and neuroticism are observed. Gene-based associations identify 173 genes, including DLEU7, MSRB3 and POC5, highlighting genes expressed in the brain, cerebellum, lungs, blood and oesophagus. We use polygenic scores (PGS) to predict recent snoring and probable obstructive sleep apnoea (OSA) in an independent Australian sample (n ~ 8000). Mendelian randomization analyses suggest a potential causal relationship between high BMI and snoring. Altogether, our results uncover insights into the aetiology of snoring as a complex sleep-related trait and its role in health and disease beyond it being a cardinal symptom of OSA.

Snoring is common in the population and tends to be more prevalent in older and/or male individuals. Here, the authors perform GWAS for habitual snoring, identify 41 genomic loci and explore potential causal relationships with anthropometric and cardiometabolic disease traits.

Obstructive sleep apnea and cardiac mechanics: how strain could help us?

Obstructive sleep apnea (OSA) syndrome is the most common sleep-breathing disorder, which is associated with increase cardiovascular morbidity and mortality. OSA increases risk of resistant arterial hypertension, coronary artery disease, heart failure, pulmonary hypertension, and stroke. Studies showed the significant relationship between OSA and cardiac remodeling. The majority of investigations were focused on the left ventricle and its hypertrophy and function. Fewer studies investigated right ventricular structure and function revealing deteriorated diastolic and systolic function. Data regarding left and right ventricular mechanics in OSA patients are scarce and controversial. The results of the studies that were focused on the influence of continuous positive airway pressure and weight reduction on cardiac remodeling revealed favorable effect on left and right ventricular structure and function. Recently published analyses confirmed positive effect of treatment on cardiac mechanics. Deterioration of left and right ventricular mechanics occurs before functional and structural cardiac impairments in the cascade of cardiac remodeling and therefore the assessment of left and right ventricular strain may represent a cornerstone in detection of subtle cardiac changes that develop significantly before other, often irreversible, alterations. Considering the fact that left and right ventricular strains have important predictive value in wide range of cardiovascular diseases, one should consider the evaluation of left and right ventricular strains in the routine echocardiographic assessment at all stages of disease-from diagnosis, during follow-up and evaluation of therapeutic effects. The main aim of this review is to provide the current overview of cardiac mechanics in OSA patients before and after (during) therapy, as well as mechanisms that could be responsible for cardiac changes.

Sleep disordered breathing in Marfan syndrome: Value of standard screening questionnaires

Background

A high prevalence of sleep disordered breathing (SDB) has been reported in persons with Marfan syndrome (MFS), a single gene disorder of connective tissue resulting in premature death from aortic rupture. The burden of SDB and accompanying hemodynamic stress could warrant broad screening in this population. Our goal was to assess the utility of traditional SDB screening tools in our sample of persons with MFS.

Methods

Participants were recruited during an annual Marfan Foundation meeting and Marfan status confirmed using the Ghent criteria. Screening questionnaires were administered and SDB assessed by home sleep testing. We assessed accuracy of screening tools using receiver‐operating characteristic curve analyses.

Results

The prevalence of moderate‐severe SDB was 32% in our sample of 31 MFS participants. The Stop‐Bang questionnaire had the highest positive predictive value (PPV) of 60% and the highest negative predictive value (NPV) of 100% using the high‐ and moderate‐risk cut‐offs, respectively, and the Berlin questionnaire had a PPV of 50% and an NPV of 92.3% at the high‐risk cut‐off. When those with mild SDB were included, the Stop‐Bang and the Sleep Apnea Clinical Score (SACS) questionnaires demonstrated useful screening accuracies with PPVs of 94.7% and 92.9%, and NPVs of 63.6% and 47.1%, respectively, at the moderate‐risk cut‐offs.

Conclusion

A survey of SDB in a sample of persons with MFS reveals not only a high burden of SDB but also that conventional screening instruments have utility if adapted appropriately. Future studies should validate the utility of these screening tools given concerns that SDB may contribute to progression of aortic pathology in MFS.