Sleep apnea and risk of deep vein thrombosis: a non-randomized, pair-matched cohort study

The Association between Obstructive Sleep Apnea and Venous Thromboembolism: A Bidirectional Two-Sample Mendelian Randomization Study

BACKGROUND

 Despite previous observational studies linking obstructive sleep apnea (OSA) to venous thromboembolism (VTE), these findings remain controversial. This study aimed to explore the association between OSA and VTE, including pulmonary embolism (PE) and deep vein thrombosis (DVT), at a genetic level using a bidirectional two-sample Mendelian randomization (MR) analysis.

METHODS

 Utilizing summary-level data from large-scale genome-wide association studies in European individuals, we designed a bidirectional two-sample MR analysis to comprehensively assess the genetic association between OSA and VTE. The inverse variance weighted was used as the primary method for MR analysis. In addition, MR-Egger, weighted median, and MR pleiotropy residual sum and outlier (MR-PRESSO) were used for complementary analyses. Furthermore, a series of sensitivity analyses were performed to ensure the validity and robustness of the results.

RESULTS

 The initial and validation MR analyses indicated that genetically predicted OSA had no effects on the risk of VTE (including PE and DVT). Likewise, the reverse MR analysis did not find substantial support for a significant association between VTE (including PE and DVT) and OSA. Supplementary MR methods and sensitivity analyses provided additional confirmation of the reliability of the MR results.

CONCLUSION

 Our bidirectional two-sample MR analysis did not find genetic evidence supporting a significant association between OSA and VTE in either direction.

Venous valve hypoxia as a possible mechanism of deep vein thrombosis: a scoping review

INTRODUCTION

The pathogenesis of deep vein thrombosis (DVT) has been explained by an interplay between a changed blood composition, vein wall alteration, and blood flow abnormalities. A comprehensive investigation of these components of DVT pathogenesis has substantially promoted our understanding of thrombogenesis in the venous system. Meanwhile, the process of DVT initiation remains obscure. This systematic review aims to collect, analyze, and synthesize the published evidence to propose hypoxia as a possible trigger of DVT.

EVIDENCE ACQUISITION

An exhaustive literature search was conducted across multiple electronic databased including PubMed, EMBASE, Scopus, and Web of Science to identify studies pertinent to the research hypothesis. The search was aimed at exploring the connection between hypoxia, reoxygenation, and the initiation of deep vein thrombosis (DVT). The following key words were used: "deep vein thrombosis," "venous thrombosis," "venous thromboembolism," "hypoxia," "reoxygenation," "venous valve," and "venous endothelium." Reviews, case reports, editorials, and letters were excluded.

EVIDENCE SYNTHESIS

Based on the systematic search outcome, 156 original papers relevant to the issue were selected for detailed review. These studies encompassed a range of experimental and observational clinical research, focusing on various aspects of DVT, including the anatomical, physiological, and cellular bases of the disease. A number of studies suggested limitations in the traditional understanding of Virchow's triad as an acceptable explanation for DVT initiation. Emerging evidence points to more complex interactions and additional factors that may be critical in the early stages of thrombogenesis. The role of venous valves has been recognized but remains underappreciated, with several studies indicating that these sites may act as primary loci for thrombus formation. A collection of studies describes the effects of hypoxia on venous endothelial cells at the cellular and molecular levels. Hypoxia influences several pathways that regulate endothelial cell permeability, inflammatory response, and procoagulation activity, underpinning the endothelial dysfunction noted in DVT.

CONCLUSIONS

Hypoxia of the venous valve may serve as an independent hypothesis to outline the DVT triggering process. Further research projects in this field may discover new molecular pathways responsible for the disease and suggest new therapeutic targets.

Obstructive Sleep Apnea as a Risk Factor for Venous Thromboembolism: A Systematic Review

Obstructive sleep apnea (OSA), is a prevalent condition characterized by repeated episodes of pharyngeal airway obstruction resulting in hypopnea and apnea episodes during sleep leading to nightly awakenings. OSA is a major contributor to the healthcare burden worldwide due to its high cardiovascular morbidity and mortality. There is growing evidence to support a pathophysiological link between OSA and venous thromboembolism (VTE). The pro-inflammatory state along with intermittent hypoxia that is invoked in OSA is associated with blood hypercoagulability, venous stasis, and endothelial dysfunction leading to deep vein thrombosis (DVT) and pulmonary embolism (PE). In this systematic review, we aim to analyze and assess the available literature on OSA and VTE (or DVT/PE) to determine whether OSA is an independent risk factor for VTE.

THE ASSOCIATION BETWEEN CENTRAL SEROUS CHORIORETINOPATHY AND SLEEP APNEA: A Nationwide Population-Based Study

PURPOSE

To identify the association between sleep apnea (SA) and central serous chorioretinopathy (CSC).

METHODS

In this nationwide population-based study using the Taiwan National Health Insurance Database, we enrolled adult patients with a diagnosis of SA and matched each patient to 30 age- and gender-matched control subjects without any SA diagnosis. Using Poisson regression analyses, the incidence rate of CSC was compared between SA patients and control subjects.

RESULTS

A total of 10,753 SA patients and 322,590 control subjects were identified. After adjusting for age, gender, residency, income level, and comorbidities, the incidence rate of CSC was significantly higher in SA patients than in the control subjects (adjusted incident rate ratio for probable SA: 1.2 [95% CI: 1.1-1.4], P < 0.0001). Analyses of the propensity score-matched subpopulations also confirmed our findings. Risk factors for CSC in SA patients included male gender, age ≤50 years, higher income, presence of heart disease, absence of chronic pulmonary disease, and presence of liver disease. In SA patients, those who had received continuous positive airway pressure titration had a significantly lower incidence rate of CSC than the others.

CONCLUSION

Our study revealed a significantly higher incidence rate of CSC in SA patients compared with the control subjects.

Association of obstructive sleep apnea with all-cause readmissions after hospitalization for asthma exacerbation in adults aged 18-54 years: a population-based study, 2010-2013

OBJECTIVE

To investigate associations between obstructive sleep apnea (OSA) and readmission risk after hospitalization for asthma exacerbation.

METHODS

We conducted a retrospective, population-based cohort study using State Inpatient Databases from seven U.S. states (Arkansas, California, Florida, Iowa, Nebraska, New York, and Utah) from 2010 to 2013. We identified all adults (aged 18-54 years) hospitalized for asthma exacerbation. The outcome measure was all-cause readmissions within one year after hospitalization for asthma exacerbation. To determine associations between OSA and readmission risk, we constructed negative binomial regression models estimating the incidence rate ratio (IRR) for readmissions and Cox proportional hazards models estimating hazard rate (HR) for the time-to-first readmission.

RESULTS

Among 65,731 patients hospitalized for asthma exacerbation, 6,549 (10.0%) had OSA. Overall, OSA was associated with significantly higher incident rate of all cause readmission (1.36 vs. 0.85 readmissions per person-year; unadjusted IRR 1.60; 95%CI 1.54-1.66). Additionally, OSA was associated with higher incident rates of readmissions for five major diseases-asthma (IRR 1.21; 95%CI 1.15-1.27), COPD (IRR 2.03; 95%CI 1.88-2.19), respiratory failure (IRR 3.04; 95%CI 2.76-3.34), pneumonia (IRR 1.67; 95%CI 1.49-1.88), and congestive heart failure (IRR 3.78; 95%CI 3.36-4.24), compared to non-OSA. The Cox model demonstrated that patients with OSA had significantly higher rates for all-cause readmission compared to those without OSA (HR 1.56; 95% CI 1.50-1.62). These associations remained significant after adjustment for confounders.

CONCLUSIONS

The observed association of OSA with a higher risk of readmissions after hospitalization for asthma exacerbation underscores the importance of identifying coexistent OSA in this population and optimizing both OSA and asthma management.

Predictors of venous thromboembolism in patients with COVID-19 in an underserved urban population: A single tertiary center experience

Introduction

Venous thromboembolism (VTE) is reported in up to 27% of patients with COVID‐19 due to SARS‐CoV‐2 infection. Dysregulated systemic inflammation and various patient traits are presumed to underlie this anomaly. Optimal VTE prophylaxis in COVID‐19 patients has not been established due to a lack of validated models for predicting VTE in this population. Our study aims to address this deficiency by identifying demographic and clinical characteristics of COVID‐19 patients associated with increased VTE risk.

Methods

This study is a retrospective analysis of all adult patients (final sample, n = 355) hospitalized with confirmed COVID‐19 at Einstein Medical Center Philadelphia between March 1 and April 24, 2020. Demographic and clinical patient data were collected and factors associated with VTE were identified and analyzed using t‐tests, multivariable logistic regression, and receiver operating characteristic (ROC) curves.

Results

Thirty patients (8.5%) developed VTE. Patients with VTE had significantly higher D‐dimer levels on admission (P = 0.045) and peak D‐dimer levels (P < 0.0001), in addition to higher rates of vasopressor requirements (P = 0.038), intubation (P = 0.003), and death (P = 0.023). Age (OR 1.042), obstructive sleep apnea (OR 5.107), and need for intubation (OR 3.796) were associated with significantly increased odds of VTE. Peak D‐dimer level was a good predictor of VTE (AUC 0.806, P < 0.0001) and a D‐dimer cutoff of >6640 ng/mL had high (>70%) sensitivity and specificity for VTE.

Conclusion

Peak D‐dimer level may be the most reliable clinical marker in COVID‐19 patients for predicting VTE and future prospective studies should attempt to further validate this.

Obstructive sleep apnea and influenza infection: a nationwide population-based cohort study

OBJECTIVES

Influenza infection could trigger acute myocardial infarction. Obstructive sleep apnea (OSA) increases risk for myocardial infarction. Evidence evaluating the risk of influenza in patients with OSA is limited. We aimed to investigate the association between OSA and influenza using a nationwide population-based data set.

METHODS

A total of 5483 individuals with OSA were enrolled from January, 2000, to December, 2012, and compared with a control group of 21,932 individuals who had never been diagnosed with OSA (at a 1:4 ratio propensity score matched by age, sex, index years, and comorbidities) in the context of subsequent influenza infection. Cox proportional hazard regression analysis was conducted to analyze the association between OSA and influenza incidence. We conducted sensitivity analyses to examine our finding.

RESULTS

During the 1.81 (±2.12) years of the follow-up period, the incidence rate of influenza infection was higher in the OSA group compared with the non-OSA group (36.40 and 30.09 per 100 person-years). After adjusting for age, sex, comorbidities, outpatients visits, the risk of influenza infection among patients with OSA was significantly higher (hazard ratio = 1.18; 95% confidence interval = 1.14-1.23; P < 0.001). Sensitivity analyses showed consistent positive association. Males with OSA had increased risk of influenza infection compared with males without OSA (adjusted HR, 1.21; 95% CI, 1.16-1.27; P value for interaction = 0.03).

CONCLUSIONS

This study found a significantly higher risk of influenza infection in patients with OSA, and sex acted as an effect modifier between OSA and risk of influenza infection.

Increased risk of major depressive disorder in sleep apnea patients in Taiwan

The association between sleep apnea (SA) and depression had been reported in a few previous studies. However, whether SA increases the risk of major depressive disorder (MDD) has not been studied comprehensively in a large-scale study. We performed this population-based cohort study to assess the association between SA and MDD. We identified adult patients having SA from the Taiwan National Health Insurance Research Database and excluded those having MDD before SA diagnosis. Thirty control subjects were randomly selected to match to each SA patient by age and sex. Totally, 10,259 SA patients were matched to 102,590 control subjects. The incidence rate and cumulative incidence of MDD were significantly higher in SA patients than in the control subjects (both p < 0.0001). Multivariable Cox regression analysis showed that SA remained an independent risk factor for incident MDD after adjusting for age, sex, residency, income level, and comorbidities (hazard ratio = 2.9 [95% CI 2.8–3.1], p < 0.0001). In summary, SA patients have an increased risk to develop MDD. Physicians caring for SA patients must pay attention to their psychosocial health status.

Assessment of the frequency of deep venous thromboembolism in obstructive sleep apnea syndrome

The present study aimed to investigate the frequency of deep venous thrombosis (DVT) among patients with obstructive sleep apnea syndrome (OSAS). Patients who referred the preliminary diagnosis of OSAS were included in this study. D-dimer levels of all patients were measured, and D-dimer (+) patients were evaluated by Doppler USG of the lower-extremity. Mean age of the patient group was 52 ± 12 years and 31.8% (76/239) were women. The rate of D-dimer positivity among severe-OSAS cases (15/85) was significantly higher compared to the rest (13/154) (17.6% and 8.4%, respectively; p = 0.034). The risk of D-dimer positivity was elevated by 2.3 folds in severe-OSAS cases (OR: 2,324, 95% confidence interval: 1.048-5.152). Among 28 D-dimer (+) cases, 4 (14.2%) had DVT as demonstrated by USI of the lower-extremity. All four cases with DVT had severe OSAS. D-dimer was positive in 17.6% (15/85) of all severe OSAS cases. DVT was diagnosed in 4.7% (4/85) of severe-OSAS cases. DVT frequency was 26.6% (4/15) in D-dimer (+) severe-OSAS. Findings of this study indicate that severe-OSAS can be a significant risk factor for DVT. Additionally, data obtained in this study underline the benefits of questioning severe-OSAS patients with respect to DVT symptoms, investigating D-dimer levels and evaluating D-dimer (+) severe-OSAS cases for DVT prophylaxis.

Real-world evidence on the use of benzodiazepine receptor agonists and the risk of venous thromboembolism

BACKGROUND

Venous thromboembolism (VTE) is a life-threatening disease, and some studies reported that benzodiazepine receptor agonist (BZRA) use could increase the risk of VTE, but this association lacks population-based evidence.

OBJECTIVES

To investigate the association between BZRA use and the risk of VTE.

PATIENTS/METHODS

A nested case-control study analyzing Taiwan's claims database was conducted of patients with at least one new BZRA prescription on record from January 1, 2002, to December 31, 2012. We included new users who did not have any BZRA prescriptions in the preceding 2 years and identified cases with VTE and disease risk score matched control subjects. We used a logistic regression model to investigate the association between BZRA exposure and the risk of VTE. The exposure duration, dose, and classes of BZRAs were comprehensively evaluated.

RESULTS

We identified 2800 VTE cases and 2800 matched controls. Current BZRA prescription (≤90 days) was associated with VTE occurrence (adjusted odds ratio [aOR]: 1.83; 95% confidence interval [CI], 1.62-2.06). The point estimates of benzodiazepine hypnotics (aOR: 2.00; 95% CI, 1.45-2.76) had a marginally higher risk of VTE than nonbenzodiazepine hypnotics (aOR: 1.39; 95% CI, 1.07-1.81). The VTE risk was increased with combination BZRA use, number of BZRA used, and a higher dose of BZRA. On examination of individual BZRA, the risk of VTE was higher with flunitrazepam use (aOR: 2.99; 95% CI, 1.43-6.28) than other BZRAs.

CONCLUSIONS

This study presents that current BZRA use may increase the risk of VTE. Also, benzodiazepine hypnotics, especially flunitrazepam, have a higher risk of VTE.

The Association between Temporomandibular Disorder and Sleep Apnea-A Nationwide Population-Based Cohort Study

An increased incidence of temporomandibular disorders (TMD) among patients with sleep apnea (SA) has been reported. However, the association between TMD and SA has not been demonstrated in a large-scale study. This population-based cohort study with the Taiwan National Health Insurance (NHI) Research Database aimed to understand the association between SA and TMD. We identified adult patients with suspected SA (identified with diagnostic codes) and excluded those diagnosed with TMD prior to SA. Patients with SA diagnosis after polysomnography were also identified as probable SA patients. The index dates were the dates of their initial SA diagnosis. Ten control subjects were matched, by age and sex, to each SA patient, and were assigned the same index dates as the SA patients. In total, 10,408 suspected SA patients (including 4105 probable SA patients) matched to 104,080 control subjects (including 41,050 subjects matched to the probable SA patients) in this study. The TMD incidence rate was significantly higher in the SA patients than in the control subjects (2.8 vs. 1.0 per thousand-patient-year in probable SA patients vs. the corresponding control subjects, with an adjusted incidence rate ratio [95% confidence interval] = 2.5 [2.3–2.7], p < 0.0001). SA patients significantly showed a higher cumulative incidence of TMD than the corresponding control subjects (p < 0.0001). Multivariable Cox regression analysis revealed SA as an independent risk factor for the development of TMD (adjusted hazard ratio = 2.5 [1.7–3.7], p < 0.0001). In summary, this study confirmed an increased TMD incidence in the SA patients. While treating TMD patients, dentists should pay careful attention to the potential underlying SA.

Acute pulmonary embolism in patients with obstructive sleep apnea: frequency, hospital outcomes, and recurrence

STUDY OBJECTIVES

The objectives of this study were to assess the effect of obstructive sleep apnea (OSA) on the risk of acute pulmonary embolism (PE), hospital outcomes including mortality, and PE recurrence.

METHODS

We retrospectively enrolled adult patients, admitted to Mayo Clinic Hospital in Rochester, Minnesota, within a 5-year period (2009-2013). We compared frequency of PE, hospital mortality, and secondary outcomes in patients with OSA versus patients without OSA. We assessed risk of PE recurrence in relation to compliance with OSA therapy.

RESULTS

Of 25,038 patients, 3,184 (13%) had OSA and 283 (1.1%) experienced PE. Frequency of PE in patients with and without OSA was 2.4% versus 0.9% (odds ratio [OR], 2.51; 95% confidence interval [CI], 1.9-3.3; P < .001). OSA was independently associated with increased risk of PE after adjusting for demographics and comorbidities (OR, 1.44; 95% CI, 1.07-1.9; P = .017). Adjusted hospital mortality was increased in patients with PE (OR, 2.88; 95% CI, 1.7-4.9; P < .001) but not in patients with OSA (OR, 0.98; 95% CI, 0.7-1.4, P = .92). OSA was not a significant determining factor for mortality in patients who experienced a PE (OR, 0.56; 95% CI, 0.1.1-2.78; P = .47), adjusting for demographics, PE severity, and Charlson comorbidity index. Adjusted risk of PE recurrence was greater in patients with OSA compared with patients without OSA (OR, 2.21; 95% CI, 1.05-4.68; P < .04). The patients compliant with OSA therapy had a lower rate of PE recurrence (16% vs 32%; P = not significant).

CONCLUSIONS

Although OSA significantly increases risk of acute PE occurrence and recurrences, related hospital mortality was not greater in patients with OSA compared with those without OSA. OSA therapy might have a modifying effect on PE recurrence.

The Goals of Treating Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) syndrome is a destructive and insidious entity mostly underdiagnosed and undertreated. It affects not only individuals but the society as a whole. The costs to the populations can be measured not only in morbidity and mortality but also in the financial wellbeing of a society. Financial burden of this disease is staggering. The social fabric of society is also greatly impacted. Physiologic effects of OSA are far reaching. It has been shown that early intervention with treatment of OSA can often prevent and/or reverse many of the negative outcomes associated with this condition.

Obstructive sleep apnea and venous thromboembolism: Overview of an emerging relationship

Obstructive sleep apnea (OSA) is a risk factor for cardiovascular syndromes. Venous thromboembolism (VTE) is a chronic disease, and pulmonary embolism (PE) is the major expression of VTE and the third most frequent cardiovascular disease. An increasing and emerging number of cross-sectional and longitudinal studies have linked OSA to VTE, and have postulated different putative pathways to explain how OSA might increase the risk of PE. We aim to provide a critical overview of the existing evidence about the complex relationship between these two conditions, with some factors and confounding variables still to be clarified. A global interpretation of the studies shows OSA is highly prevalent in VTE patients. This association represents a major public health burden, given the high prevalence and the mortality rates of both disorders. Although still not proven, OSA may induce a persistent hypercoagulable state that may contribute to increase VTE rate and its recurrence. Coagulant activity, platelet function and fibrinolytic system may improve after continuous positive airway pressure (CPAP) in OSA. However, there is a still a lack of randomized controlled trials to evaluate the potential of CPAP and/or extend oral anticoagulation to reduce PE incidence, recurrence and mortality by PE in patients with OSA.

Obstructive sleep apnoea and venous thromboembolism: pathophysiological links and clinical implications

Obstructive sleep apnoea (OSA) and pulmonary embolism (PE) remain major health issues worldwide. Data from pathophysiological studies suggest that both intermittent hypoxia and sleep fragmentation are associated with increased blood coagulability, endothelial dysfunction and venous stasis. There is growing evidence that OSA is potentially prevalent in and a risk factor for PE. Conversely, patients with acute PE have two to four times greater risk of moderate-to-severe OSA. The role of continuous positive airway pressure (CPAP) treatment in improving clinically meaningful outcomes in PE patients remains unclear, although some authors have suggested that CPAP could improve the hypercoagulability state and normalise circadian alterations in some of the coagulation molecules, as observed in patients with OSA. Emerging research highlights the complex interdependent relationships between OSA and PE, emphasising the need for rigorous, well-powered trials that address the impact of OSA and its treatment on the prevention and management of PE. Undoubtedly, these will require closer collaboration between the sleep medicine and clinical/venous thromboembolism communities.

Obstructive Sleep Apnea in Elective Spine Surgery: National Prevalence and Inpatient Outcomes

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

Epidemiologic studies suggest that the prevalence of moderate to severe obstructive sleep apnea (OSA) is increasing. OSA has been linked to increased rates of postoperative complications following surgery. Large studies, however, regarding surgical outcomes in this patient population, particularly in the spine literature, are limited. Consequently, the purpose of this study was to assess the prevalence of and postoperative risks conferred by OSA in the elective spine population.

METHODS

Using data from the National Inpatient Sample from 2008 to 2012, an estimated 56 372 (5.1%) patients with OSA undergoing elective cervical and thoracolumbar spine surgery were selected and compared to 1 052 837 patients without OSA undergoing the same procedures. Our primary outcome measures included postoperative complication rates, inpatient mortality, length of stay, and total hospital charges.

RESULTS

Patients with OSA were, on average 2.6 years older than those without OSA (P < .001) and had a higher comorbidity burden. The prevalence of OSA increased between 2008 and 2012 from 3.5% to 6.8%; P < .001. OSA was associated with a 3-fold increase in major complications (P < .001) and was confirmed as an independent risk factor for major complications based on multivariate analysis (odds ratio [OR] = 2.82; 95% CI = 2.59-2.79; P < .001). Rates of deep venous thrombosis were doubled in patients with OSA. OSA was determined to be an independent predictor of pulmonary complications (OR = 2.69; 95% CI = 2.59-2.79; P < .001). OSA did not increase the risk of postoperative mortality.

CONCLUSIONS

Patients with OSA often have multiple concomitant comorbidities and consequently are at increased risk of experiencing a more difficult postoperative course following elective spine surgery. Specifically, increased risks of pulmonary complications and deep venous thrombosis should be anticipated.

Sleep apnea and risk of vertigo: A nationwide population-based cohort study

OBJECTIVE

To investigate the risk of vertigo in patients with sleep apnea.

STUDY DESIGN

Retrospective cohort study.

METHODS

This study used data from the National Health Insurance Research Database of Taiwan, a population-based database. A total of 5,025 patients who were newly diagnosed with sleep apnea between January 1, 1997, and December 31, 2012, were identified from the Longitudinal Health Insurance Database 2000, a nationally representative database of 1 million randomly selected patients. Moreover, 20,100 patients without sleep apnea were matched at a 1:4 ratio by age, sex, socioeconomic status, and urbanization level. Patients were followed up until death or the end of the study period (December 31, 2013). The primary outcome was the occurrence of vertigo.

RESULTS

Patients with sleep apnea had a significantly higher cumulative incidence of vertigo than those without sleep apnea (P < 0.001). The adjusted Cox proportional hazard model showed that sleep apnea was significantly associated with a higher incidence of vertigo (hazard ratio, 1.71; 95% confidence interval [CI], 1.48-1.97; P < 0.001). Sensitivity and subgroup analyses were performed to adjust for confounders, including head trauma, diabetes mellitus, hypertension, stroke, and obesity. Sleep apnea was demonstrated to be an independent risk factor for vertigo.

CONCLUSION

This is the first nationwide population-based cohort study to investigate the association between sleep apnea and vertigo. The findings strongly support that sleep apnea is an independent risk factor for vertigo. Based on the study results, physicians should be aware of potential vertigo occurrence following sleep apnea.

LEVEL OF EVIDENCE

4. Laryngoscope, 128:763-768, 2017.

Repercusiones cardiovasculares del síndrome de apnea-hipopnea obstructiva del sueño (SAHOS)

En la población de sujetos con síndrome de apnea-hipopnea obstructiva del sueño se describen entidades clínicas cardiovasculares asociadas con esta entidad y que afectan su curso y pronóstico. Dentro de estas se encuentran hipertensión arterial, arritmias, enfermedad coronaria, insuficiencia cardíaca, hipertensión pulmonar y tromboembolismo venoso. Del mismo modo, se describen los mecanismos fisiopatológicos de estas asociaciones, su prevalencia e impacto. Dado que afectan el curso de la enfermedad y, por tanto, la severidad de la misma, estas entidades juegan un papel muy importante en la toma de decisiones al momento de ofrecer el mejor manejo en cada caso, el cual debe ser abordado de forma multidisciplinaria.

Comorbidities and risk of mortality in patients with sleep apnea

BACKGROUND

A variety of disorders, most notably cardiovascular diseases, was linked to sleep apnea (SA), but their impact on mortality of SA patients had not been systematically investigated. We aimed to develop a composite index based on the comorbidity burden to predict mortality risk.

METHODS

Using Taiwan National Health Insurance Research Database, 9853 adult SA patients were enrolled and their comorbidity profile at baseline was recorded. The subjects were followed from 1995 till death or the end of 2011. A Cox regression model was used for multivariable adjustment to identify independent predictors for mortality.

RESULTS

During an average follow-up period of 5.3 ± 3.1 years, 311 (3.2%) subjects died. SA patients with any comorbidity had a higher risk for death compared to those without comorbidity (HR: 11.01, 95% CI 4.00-30.33, p < 0.001). Age and 10 comorbidities related to increased overall mortality were identified, from which the CoSA (Comorbidities of Sleep Apnea) index was devised. The corresponding hazard ratios for patients with CoSA index scores of 0, 1-3, 4-6, and >6 were 1 (reference), 3.29 (95% CI, 2.04-5.28, p < 0.001), 13.56 (95% CI, 8.63-21.33, p < 0.001), and 38.47 (95% CI, 24.92-59.38, p < 0.001), respectively.

CONCLUSIONS

Based on the comorbidity burden, we developed an easy-to-use tool to evaluate mortality risk in SA. Key messages: Sleep apnea (SA) is linked to a variety of disorders, particularly cardiovascular diseases. SA patients with any comorbidity may experience a higher risk of death in comparison to those without comorbidity. Comorbidities related to increased mortality are identified and converted into a simple risk indicator, the CoSA (Comorbidities of Sleep Apnea) index scores, which may help to stratify risk of death in daily practice.

Altered clot microstructure detected in obstructive sleep apnoea hypopnoea syndrome

Abnormal clot microstructure plays a pivotal role in the pathophysiology of thromboembolic diseases. Assessing the viscoelastic properties of clot microstructure using novel parameters, Time to Gel Point (T_GP), Fractal Dimension (d_f) and clot elasticity (G׳_GP) could explain the increased cardiovascular and thromboembolic events in patients with Obstructive Sleep Apnoea Hypopnea Syndrome (OSAHS). We wanted to compare T_GP, d_f, and G׳_GP and their diurnal variation in OSAHS and symptomatic comparators. thirty six patients attending a sleep disturbed breathing clinic with symptoms of OSAHS were recruited. T_GP, d_f and G׳_GP were measured alongside standard coagulation screening, thrombin generation assays, and platelet aggregometry at 16:00 h and immediately after an in-patient sleep study at 07:30 h. OSAHS group had significantly lower afternoon d_f than comparators (1.705±0.033 vs. 1.731±0.031, p<0.05). d_f showed diurnal variation and only in the OSAHS group, being significantly lower in the afternoon than morning (p<0.05). Diurnal changes in d_f correlated with 4% DR, even after controlling for BMI (r=0.37, p=0.02). The lower d_f in the afternoon in OSAHS suggests a partial compensatory change that may make up for other pro-clotting abnormalities/hypertension during the night. The change to the thrombotic tendency in the afternoon is biggest in severe OSAHS. d_f Shows promise as a new microstructural indicator for abnormal haemostasis in OSAHS.

High D-dimer levels after stopping anticoagulants in pulmonary embolism with sleep apnoea

Obstructive sleep apnoea is a risk factor for pulmonary embolism. Elevated D-dimer levels and other biomarkers are associated with recurrent pulmonary embolism. The objectives were to compare the frequency of elevated D-dimer levels (>500 ng·mL−1) and further coagulation biomarkers after oral anticoagulation withdrawal in pulmonary embolism patients, with and without obstructive sleep apnoea, including two control groups without pulmonary embolism.

We performed home respiratory polygraphy. We also measured basic biochemical profile and haemogram, and coagulation biomarkers (D-dimer, prothrombin fragment 1+2, thrombin-antithrombin complex, plasminogen activator inhibitor 1, and soluble P-selectin).

64 (74.4%) of the pulmonary embolism cases and 41 (46.11%) of the controls without pulmonary embolism had obstructive sleep apnoea. Plasmatic D-dimer was higher in PE patients with OSA than in those without obstructive sleep apnoea. D-dimer levels were significantly correlated with apnoea–hypopnoea index, and nocturnal hypoxia. There were more patients with high D-dimer after stopping anticoagulants in those with pulmonary embolism and obstructive sleep apnoea compared with PE without obstructive sleep apnoea (35.4% versus 19.0%, p=0.003). Apnoea–hypopnoea index was independently associated with high D-dimer.

Pulmonary embolism patients with obstructive sleep apnoea had higher rates of elevated D-dimer levels after anticoagulation discontinuation for pulmonary embolism than in patients without obstructive sleep apnoea and, therefore, higher procoagulant state that might increase the risk of pulmonary embolism recurrence.

Sleep, death, and the heart

Obstructive and central sleep apnea have been associated with increased risk of adverse cardiovascular events and mortality. Sympathetic dysregulation occurring as a result of the respiratory disturbance is thought to play a role in this increased risk. Sleep apnea increases the risk of arrhythmias, myocardial ischemia/infarction, stroke, and heart failure, all of which may increase mortality risk. A higher incidence of nocturnal arrhythmias, cardiac ischemia, and sudden death has been noted in subjects with sleep-disordered breathing (SDB). In this review, the association between SDB and each of these conditions is discussed, as well as the potential mechanisms underlying these risks and the effects of treatment of SDB. Particular emphasis is placed on the relationship between SDB and nocturnal atrial and ventricular arrhythmias, myocardial ischemia/infarction and sudden death.

Erectile Dysfunction in Patients with Sleep Apnea--A Nationwide Population-Based Study

Increased incidence of erectile dysfunction (ED) has been reported among patients with sleep apnea (SA). However, this association has not been confirmed in a large-scale study. We therefore performed a population-based cohort study using Taiwan National Health Insurance (NHI) database to investigate the association of SA and ED. From the database of one million representative subjects randomly sampled from individuals enrolled in the NHI system in 2010, we identified adult patients having SA and excluded those having a diagnosis of ED prior to SA. From these suspected SA patients, those having SA diagnosis after polysomnography were defined as probable SA patients. The dates of their first SA diagnosis were defined as their index dates. Each SA patient was matched to 30 randomly-selected, age-matched control subjects without any SA diagnosis. The control subjects were assigned index dates as their corresponding SA patients, and were ensured having no ED diagnosis prior to their index dates. Totally, 4,835 male patients with suspected SA (including 1,946 probable SA patients) were matched to 145,050 control subjects (including 58,380 subjects matched to probable SA patients). The incidence rate of ED was significantly higher in probable SA patients as compared with the corresponding control subjects (5.7 vs. 2.3 per 1000 patient-year; adjusted incidence rate ratio = 2.0 [95% CI: 1.8-2.2], p<0.0001). The cumulative incidence was also significantly higher in the probable SA patients (p<0.0001). In multivariable Cox regression analysis, probable SA remained a significant risk factor for the development of ED after adjusting for age, residency, income level and comorbidities (hazard ratio = 2.0 [95%CI: 1.5-2.7], p<0.0001). In line with previous studies, this population-based large-scale study confirmed an increased ED incidence in SA patients in Chinese population. Physicians need to pay attention to the possible underlying SA while treating ED patients.

Sleep apnea and venous thromboembolism. A systematic review

Recent evidence suggests that obstructive sleep apnea is a significant and independent risk factor for a number of cardiovascular disorders. Since the association between obstructive sleep apnea and cardiovascular disease is mediated by endothelial dysfunction, hypercoagulability and platelet abnormalities, we sought to investigate whether sleep apnea may also be considered a risk factor for venous thromboembolism (VTE). We carried out an electronic search in Medline and Scopus using the keywords "apnea" OR "apnoea" AND "venous thromboembolism" OR "deep vein thrombosis" OR "pulmonary embolism" in "Title/Abstract/Keywords", with no language or date restriction. Fifteen studies (8 case-control, 4 retrospective observational, 2 prospective case-control and 1 prospective observational) were finally selected for this systematic review. In all studies except one (14/15; 93 %), obstructive sleep apnea was found to be an independent risk factor for VTE, either deep-vein thrombosis (DVT) or pulmonary embolism (PE). In the two prospective case-control studies the risk of DVT or PE was found to be two- to three-fold higher in patients with obstructive sleep apnea than in those without. In conclusion, the current epidemiological evidence supports the hypothesis that obstructive sleep apnea may be an independent risk factor for VTE.

OSA and pulmonary hypertension: time for a new look

OSA is a common yet underdiagnosed disorder encountered in everyday practice. The disease is a unique physiologic stressor that contributes to the development or progression of many other disorders, particularly cardiovascular conditions. The pulmonary circulation is specifically affected by the intermittent hypoxic apneas associated with OSA. The general consensus has been that OSA is associated with pulmonary hypertension (PH), but only in a minority of OSA patients and generally of a mild degree. Consequently, there has been no sense of urgency to screen for either condition when evaluating the other. In this review, we explore available evidence describing the interaction between OSA and PH and seek to better understand underlying pathophysiology. We describe certain groups of patients who have a particular preponderance of OSA and PH. Failure to recognize the mutual additive effects of these disorders can lead to suboptimal patient outcomes. Among patients with PH and OSA, CPAP, the mainstay treatment for OSA, may ameliorate pulmonary pressure elevations, but has not been studied adequately. Conversely, among patients with OSA, PH significantly limits functional capacity and potentially shortens survival; yet, there is no routine screening for PH in patients with OSA. We think it is time to study the interaction between OSA and PH more carefully to identify high-risk subgroups. These would be screened for the presence of combined disorders, facilitating earlier institution of therapy and improving outcomes.

Metformin use in patients with type 2 diabetes mellitus is associated with reduced risk of deep vein thrombosis: a non-randomized, pair-matched cohort study

Background

Metformin, an insulin-sensitizer, may correct several physiologic abnormalities owing to insulin resistance in patients with type 2 diabetes mellitus (DM). The effects of metformin on venous thrombosis in patient with type 2 DM have not been reported. Our study strived to explore the relationship of metformin therapy and the subsequent development of deep vein thrombosis (DVT) using a nationwide, population-based database.

Methods

From 1997 to 2003, we identified a study cohort consisting of patients with type 2 DM using metformin 7154 cases in the National Health Insurance Research Database. A control cohort without metformin, matched for age, sex, comorbidities, and medications was selected for comparison.

Results

Of the 14945 patients (7167 patients with metformin vs. 7778 control), 60 (0.40%) patients developed DVT during a mean follow-up period of 3.74 years, including 16 (0.21%) from the cohort with metformin and 44 (0.56%) from the control group. Subjects with metformin experienced a 0.427 fold (95% confidence interval 0.240-0.758; P = 0.004) changes of risk reduction in development of DVT, which was independent of age, sex and co-morbidities. Kaplan-Meier analysis also revealed metformin therapy is associated with lower occurrence of DVT (log-rank test, P = 0.001).

Conclusions

Metformin may have protective effect in patients with type 2 DM for DVT.

Incidence and risk of atrial fibrillation in sleep-disordered breathing without coexistent systemic disease

BACKGROUND

Although the link between sleep-disordered breathing (SDB) and atrial fibrillation (AF) has been reported, a population-based longitudinal cohort study was lacking. The goal of the present study was to investigate the AF risk carried by SDB, using the National Health Insurance Research Database in Taiwan. METHODS AND RESULTS: From 2000 to 2001, a total of 579,521 patients who had no history of cardiac arrhythmias or significant comorbidities were identified. Among them, 4,082 subjects with the diagnosis of SDB were selected as the study group, and the remaining 575,439 subjects constituted the control group. The study endpoint was the occurrence of new-onset AF. During a follow-up of 9.2±2.0 years, there were 4,023 patients (0.7%) experiencing new-onset AF. The occurrence rate of AF was higher in patients with SDB compared to those without it (1.3% vs. 0.7%, P<0.001). The AF incidences were 1.38 and 0.76 per 1,000 person-years for patients with and without SDB, respectively. After anadjustment for age and sex, SDB was a significant risk factor of AF with a hazard ratio of 1.536. The AF risk increased with increasing clinical severity of SDB, represented by the requirement of continuous positive airway pressure use.

CONCLUSIONS

SDB itself, without the coexistence of other systemic diseases, was a risk factor of AF.

High dosage of hypnotics predicts subsequent sleep-related breathing disorders and is associated with worse outcomes for depression

OBJECTIVES

The rates of sleep related breathing disorders (SRBD) and treatment outcomes of depression were compared among insomnia patients who had stratified levels of hypnotic use during a 10-year follow-up (2001-2010).

DESIGN

A nationwide population-based cohort study.

SETTING

A nationally representative cohort of 1,000,000 enrollees.

PARTICIPANTS

Data were collected from patients with major depressive disorder (MDD) and comorbid insomnia during January 2001 to December 2003 (study cohort N = 3,235). The mean dosage of hypnotics at baseline in the study cohort was calculated, and this information was used to categorize the cohort into three equal-sized groups based on levels of hypnotic dosage.

MAIN OUTCOME MEASURES

Patient response to antidepressants during a period that extended from 1 year before to 1 year after the study (short-term outcome) and patient psychiatric and non-psychiatric visits and hospitalizations during follow-up (long-term outcome) were analyzed.

RESULTS

High-dosage patients presented the highest rates of subsequent SRBD diagnosis (3.9%), compared to medium-dosage patients (2.2%) and low-dosage patients (2.0%) (P = 0.011). Significantly more patients in the high-dosage group were difficult to treat with antidepressants compared to the other 2 groups (8.7% vs. 4.1% vs. 3.0%, P < 0.001), and their long-term depression outcome was worse for most parameters. Logistic regression showed that high-dosage hypnotics predicted the development of SRBD later (OR 1.678 [CI, 1.051 to 2.680], P = 0.030).

CONCLUSIONS

There is a reliable association between a history of high dosages of hypnotics, subsequent diagnosis of sleep related breathing disorder, and worse depression outcomes.

Sleep apnea and risk of pneumonia: a nationwide population-based study

BACKGROUND

Evidence evaluating the risk of pneumonia in patients with obstructive sleep apnea is limited and mostly focuses on patients who receive continuous positive airway pressure (CPAP) therapy or on pediatric patients. We aimed to explore the risk of incident pneumonia among adults with sleep apnea, either with or without the need of CPAP therapy.

METHODS

From Jan. 1, 2000, we identified adult patients with sleep apnea from the Taiwan National Health Insurance Research Database. A control cohort without sleep apnea, matched for age, sex and comorbidities, was selected for comparison. The 2 cohorts were followed until Dec. 31, 2010, and observed for occurrence of pneumonia.

RESULTS

Of the 34,100 patients (6816 study patients and 27,284 matched controls), 2757 (8.09%) had pneumonia during a mean follow-up period of 4.50 years, including 638 (9.36%) study patients and 2119 (7.77%) controls. Kaplan-Meier analysis showed a higher incidence of pneumonia among patients with sleep apnea (log rank test, p < 0.001). After multivariate adjustment, patients with sleep apnea experienced a 1.20-fold (95% confidence interval 1.10-1.31) increase in incident pneumonia. The risk was even higher among patients who received CPAP therapy.

INTERPRETATION

Sleep apnea appeared to confer a higher risk for future pneumonia, possibly in a severity-dependent manner.

Sleep apnoea patients have higher mortality when confronting sepsis

BACKGROUND

Sleep is essential for the maintenance of an intact immune function. Patients with sleep apnoea experience frequent sleep interruption due to apnoea-related arousals, possibly adversely impacting their immunity and affecting their outcomes when confronting sepsis. This case-control study aimed to compare the outcomes of sepsis patients with and without sleep apnoea.

METHODS

From 2000 to 2009, 168 sleep apnoea patients who were first admitted for sepsis were identified from the Taiwan National Health Insurance Research Database. Also, 672 sepsis patients without sleep apnoea, who were matched by age, gender and Charlson's comorbidity index scores, served as controls. Hospital outcomes of the two groups were compared. Binary logistic regression was employed for multivariate analysis.

RESULTS

The mortality rates of sepsis patients with and without sleep apnoea were 60.1% and 47.9%, respectively (P = 0. 005). After multivariate adjustment, sleep apnoea (OR: 1.805, 95% CI: 1.227-2.656, P = 0.003), presence of shock (OR: 3.600, 95% CI: 2.144-6.046, P < 0.001) and number of organs with dysfunction (OR: 1.591, 95% CI: 1.087-2.329, P = 0.017) were found to be independently associated with mortality. Sleep apnoea patients who needed continuous positive airway pressure treatment had an even higher risk of mortality.

CONCLUSIONS

Sepsis patients with sleep apnoea may have poorer hospital outcomes than those without sleep apnoea.

Obstructive sleep apnea screening and postoperative mortality in a large surgical cohort

OBJECTIVE

A recent investigation at Barnes-Jewish Hospital located in St. Louis, Missouri, found that an estimated 22% of adults presenting for inpatient surgery screened as high risk for obstructive sleep apnea (OSA). Surgical patients with OSA have multiple comorbidities and are at increased risk for perioperative complications. Our objective was to determine if a prior diagnosis of OSA or a positive screen for OSA was associated with increased risk for 30-day and one-year mortality.

METHODS

B-J APNEAS (Barnes-Jewish Apnea Prevalence in Every Admission Study) was a prospective cohort study. Unselected adult surgical patients at Barnes Jewish Hospital were prospectively enrolled between February 2006 and April 2010. All patients completed preoperative OSA screening and those who were at risk for OSA according to a combination of the Berlin and Flemons screening tools received targeted postoperative interventions. STOP (loud Snoring, daytime Tiredness, Observed apneas, and high blood Pressure) and STOP-BANG (STOP, plus body mass index [BMI], age, neck circumference, and gender) scores also were obtained.

RESULTS

Overall, the sample included 14,962 patients, of whom 1939 (12.9%) reported a history of OSA. All four screening tools identified a high prevalence of undiagnosed patients at risk for OSA (9.5%-41.6%), but agreement among screens was not strong with κ statistic ranging from 0.225 to 0.611. There was no significant difference in 30-day postoperative mortality between patients with possible OSA (based on their history or on a positive OSA screen with any of the four instruments) and the rest of the surgical population. Significant differences in one-year mortality were noted between the low-risk and high-risk groups as identified by the Flemons' (4.96% vs 6.91%; p<0.0001), STOP (5.28% vs 7.57%; p<0.0001) and STOP-BANG (4.13% vs 7.45%; p<0.0001) screens. After adjusting for risk factors, none of the OSA screening tools independently predicted mortality rate up to one year postoperatively.

CONCLUSION

Neither a prior diagnosis of OSA nor a positive screen for OSA risk was associated with increased 30-day or one-year postoperative mortality. Differences in 1 year postoperative mortality were noted with three of the screening tools. The results of our study highlight uncertainties and research priorities for the medical community.