Patients with venous thromboembolism appear to have higher prevalence of obstructive sleep apnea than the general population

Pooled prevalences of obstructive sleep apnea and heart failure: a systematic review and meta-analysis

Obstructive sleep apnea (OSA) is a disease with intermittent hypoxemia during sleep. It has been shown that OSA is related to several cardiovascular diseases including heart failure. Both OSA and heart failure have a close association bidirectionally. This study aimed to estimate the pooled prevalence of OSA in patients with heart failure as well as pooled prevalence of heart failure in patients with OSA. This was a systematic review with a meta-analysis. The inclusion criteria were observational or epidemiological studies conducted in adult patients with heart failure to evaluate the prevalence of OSA and patients with OSA to evaluate the prevalence of heart failure. The outcomes of this study were prevalence of OSA in patients with heart failure and prevalence of heart failure in patients with OSA. Four databases were used for systematic searching including PubMed, Science Direct, Scopus, and CINAHL Plus. Manual searches for related studies were also conducted. Proportion meta-analyses using a random-effects model were conducted to identify pooled proportion (prevalence) of heart failure in patients with OSA and vice versa. Among 3,941 articles from the four databases met the study criteria. Thirty-three studies showed the prevalence of OSA in patients with heart failure, while thirteen studies presented the prevalence of heart failure in patients with OSA. The prevalence of OSA in patients with heart failure was 38.4% (95% CI 31.9 to 45.2; I2 of 96.1%). Using a diagnostic criterion of OSA of more than 10 events/hr had the highest prevalence of OSA in patients with heart failure at 53.4% (95% CI 42.0 to 64.5). The highest prevalence of OSA in patients with heart failure was 60.1% (95% CI 51.4 to 68.3) in a report from India. The pooled prevalence of heart failure in patients with OSA was 12.8% (95% CI 8.1 to 19.5; I2 of 94.6%). The prevalence in Romania was highest at 22.6% (95% CI 20.4 to 24.9). The pooled prevalence of OSA in patients with heart failure was higher than the pooled prevalence of heart failure in patients with OSA. The pooled prevalence rates of these associations varied among the diagnostic criteria of OSA and countries.

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.

Co-existence of OSA and respiratory diseases and the influence of gender

INTRODUCTION

Sleep-disordered breathing (SDB), especially obstructive sleep apnea (OSA), is commonly associated with respiratory diseases, such as COPD, asthma and interstitial lung disease.

AREAS COVERED

This narrative review aims to comprehensively synthesize the existing information on SDB in respiratory diseases, investigate the role of gender in this association, and highlight the importance of OSA management in improving sleep, quality of life, and disease prognosis in these specific patient populations.

EXPERT OPINION

Research indicates a synergistic link between OSA and chronic respiratory diseases, which leads to greater morbidity and mortality compared to each disorder alone. Given the lack of an optimal OSA screening tool for these patients, a comprehensive patient approach and overnight diagnostic sleep study are imperative. Despite the limited evidence available, it seems that gender has an impact on the prevalence, severity, and susceptibility of this coexistence. Recognizing the role of gender in the coexistence of OSA and other respiratory diseases can enhance everyday medical practice and enable clinicians to adopt a more personalized approach toward optimal screening and diagnosis of these patients.

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.

Association between obstructive sleep apnea and venous thromboembolism recurrence: results from a French cohort

Background

Growing evidence suggests the relationship between obstructive sleep apnea (OSA) and venous thromboembolism (VTE). Few studies focused on VTE recurrence risk associated with OSA after anticoagulation cessation.

Methods

In a prospective cohort study, patients with documented VTE, were followed for an indefinite length of time and VTE recurrence were documented and adjudicated. The primary outcome was recurrent VTE after anticoagulation discontinuation. Secondary outcomes included all-cause mortality and the clinical presentation of VTE. Univariable and multivariable analyses were performed to identify risk factors for recurrence and mortality.

Results

Among the 2109 patients with documented VTE included, 74 patients had moderate to severe OSA diagnosis confirmed by home sleep test or polysomnography. During a median follow-up of 4.8 (interquartile range 2.5–8.0) years recurrent VTE occurred in 252 patients (9 with OSA and 243 without OSA). The recurrence risk in the univariable and multivariable analysis was not increased in patients with OSA, regardless of the time of diagnosis (before or after index VTE or pooled). VTE phenotype was significantly more often PE with or without associated deep vein thrombosis in the first event and recurrence for OSA patients compared to non-OSA patients. The risk of death was not increased in the OSA population compared to non-OSA patients in multivariable analysis.

Conclusions

In patients with OSA and VTE, the risk of all-cause mortality and VTE recurrence after anticoagulation discontinuation was not increased compared to non-OSA patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12959-021-00358-8.

Obstructive sleep apnea and stroke: The mechanisms, the randomized trials, and the road ahead

When considered separately from cardiovascular disease, stroke is the third leading cause of death in the U.S. and is the leading cause of long-term disability in adults. New approaches that can be offered to the majority of ischemic stroke patients, can be continued throughout post-stroke care, can limit stroke severity, and can complement or even enhance rehabilitation, would transform ischemic stroke recovery. The treatment of obstructive sleep apnea (OSA) in patients with acute ischemic stroke may represent one such approach. This manuscript reviews the epidemiologic studies of the bidirectional association between OSA and stroke, and the mechanisms and molecular signatures of OSA leading to transient ischemic attack and stroke as well as the randomized controlled trials and observational cohort studies examining continuous positive airway treatment efficacy on the impact of stroke outcomes. Finally, the insights these studies provide on future research are also discussed.

Sex-differences in the effect of obstructive sleep apnea on patients hospitalized with pulmonary embolism and on in-hospital mortality

We determined sex differences in the prevalence of obstructive sleep apnea (OSA) among patients hospitalized with pulmonary embolism (PE) in Spain (2016–2018). We also compared outcomes according to the presence of OSA, and identified variables associated with in-hospital-mortality (IHM) after PE using the Spanish National Hospital Discharge Database. We identified 46,794 hospital admissions for PE; of these, 5.47% had OSA. OSA was more prevalent among men than women (7.57% vs. 3.65%, p < 0.001), as in the general population. Propensity score matching did not reveal differences in concomitant conditions or procedures between patients with and without OSA, except for the use of non-invasive ventilation, which was more frequent in patients with OSA. IHM was similar in patients with and without OSA (3.58% vs. 4.31% for men and 4.39% vs. 4.93% for women; p > 0.05). Older age, cancer, atrial fibrillation, non-septic shock, and need for mechanical ventilation increased IHM in men and women with OSA hospitalized with PE. The logistic regression model showed no sex differences in IHM among patients with OSA.

Prognostic Impact of Obstructive Sleep Apnea in Patients Presenting with Acute Symptomatic Pulmonary Embolism

BACKGROUND

 In patients with pulmonary embolism (PE), there is a lack of comprehensive data on the prevalence and prognostic significance of pre-existing obstructive sleep apnea (OSA).

METHODS

 In this study of patients with PE from the Registro Informatizado de la Enfermedad TromboEmbólica (RIETE) registry, we assessed the prevalence of OSA, and the association between pre-existing OSA and the outcomes of all-cause mortality, PE-related mortality, recurrences, and major bleeding over 30 days after initiation of PE treatment. Additionally, we also examined rates of outcomes within 90 days and 1 year following the diagnosis of PE.

RESULTS

 Of 4,153 patients diagnosed with PE, 241 (5.8%; 95% confidence interval [CI]: 5.1-6.6%) had pre-existing OSA. Overall, 166 (4.0%; 95% CI: 3.4-4.6%) died during the first 30 days of follow-up. In multivariable analysis, the OSA syndrome was not a significant predictor of death from any cause (odds ratio [OR]: 1.5; 95% CI: 0.8-2.9; p = 0.19). However, patients with pre-existing OSA had an increased PE-specific mortality (adjusted OR: 3.0; 95% CI: 1.3-6.8; p = 0.01) compared with those without OSA. OSA was not significantly associated with 30-day recurrent venous thromboembolism (adjusted OR: 0.6; 95% CI: 0.1-4.7; p = 0.65) or major bleeds (adjusted OR: 1.0; 95% CI: 0.4-2.2; p = 1.0). Findings were similar at 90-day and 1-year follow-ups.

CONCLUSION

 In patients presenting with PE, pre-existing OSA is relatively infrequent. Patients with OSA were at increased risk of PE-related mortality when compared with those without OSA.

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.

The role of obstructive sleep apnea on the prognosis of pulmonary embolism: a systemic review and meta-analysis

PURPOSE

The relationship between obstructive sleep apnea (OSA) and pulmonary embolism (PE) has been reported by some studies but the underlying mechanism remains unclear. We aimed to systematically assess the role of OSA on the disease prognosis of PE.

METHODS

We searched for studies on the relationship of OSA and the prognosis of PE published up to February 2020 among PubMed, Web of Science, EMBASE, and Cochrane Library databases. Two independent reviewers conducted the process of study search and screening, quality assessment, and data extraction. Meta-analysis was carried out using RevMan 5.3.

RESULTS

A total of 9 articles were included, and the funnel plots suggested no evidence of publication bias among studies. The results showed that compared to PE patients without OSA, the PE patients with moderate-severe OSA were more likely to be high-risk type (OR = 1.96, 95% CI [1.14, 3.34]) and with higher index of disease severity (sPESI: OR = 2.29, 95% CI [1.50, 3.47]; PAOI%: MD = 13.52, 95% CI [7.2, 19.83]). The prevalence of recurrent PE was higher in PE patients with OSA than those without OSA (RR = 3.87, 95% CI [1.65, 9.07]). However, there was no significant difference in right ventricle to left ventricle short-axis diameter (MD = 0.08, 95% CI [- 0.06, 0.21]), length of hospital stay (MD = 1.03, 95% CI [- 1.11, 3.17]), or prevalence of deep vein thrombosis (OR = 0.87, 95% CI [0.48, 1.57]). Sensitivity and subgroup analysis showed that the pooled outcomes were stable.

CONCLUSION

OSA, especially moderate-severe OSA, was a risk factor for high-risk PE and recurrent PE. However, the current evidence showed that the length of hospital stay is not influenced by OSA.

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 apnea is associated with pulmonary artery thrombus load, disease severity, and survival in acute pulmonary embolism

INTRODUCTION

Obstructive sleep apnea (OSA) may have prothrombotic effects.

OBJECTIVE

To investigate the effect of OSA on disease severity, pulmonary artery thrombus load, and prognosis in patients with acute pulmonary embolism (PE).

METHODS

In 101 PE patients, disease severity was determined by the simplified PE severity index (sPESI) score, pulmonary artery thrombus load was quantified by the pulmonary artery obstruction index (PAOI), and sleep-disordered breathing was evaluated by nocturnal polygraphy.

RESULTS

Obstructive sleep apnea patients with an apnea-hypopnea index (AHI) ≥ 15/h cohort were significantly older (p < 0.001) and had significantly lower oxygen saturations (p = 0.008) when acute PE was diagnosed. The sPESI scores (p < 0.001), the PAOI (p = 0.005) and the N-terminal pro-brain-type natriuretic peptide (NT-proBNP) values (p = 0.009), were significantly higher in the AHI ≥ 15/h subgroup. In a multivariate regression analysis, the AHI remains a significant predictor for sPESI scores ≥ 1 (p = 0.003), increased NT-proBNP levels (p = 0.047), and elevated PAOI (p = 0.032). During the median follow-up time of 53 (interquartile range 38-70) months, all-cause and cardiovascular-related mortality was significantly higher in the AHI ≥ 15/h cohort (p = 0.004 and p = 0.015, respectively).

CONCLUSIONS

Obstructive sleep apnea is associated with pulmonary artery thrombus load, disease severity, and survival in acute PE possibly due to its prothrombotic effects.

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.

Impact of obstructive sleep apnea on cardiovascular outcomes in patients with acute symptomatic pulmonary embolism: Rationale and methodology for the POPE study

In normotensive patients with acute symptomatic pulmonary embolism (PE), the effect of undiagnosed obstructive sleep apnea (OSA) on cardiovascular (CV) outcomes lacks clarity. The Prognostic Significance of Obstructive Sleep Apnea in Patients With Acute Symptomatic Pulmonary Embolism (POPE) study is a multicenter, observational study designed to prospectively assess the prognostic significance of concomitant OSA in hemodynamically stable outpatients with acute symptomatic PE. Adult patients with acute stable PE are eligible. Recruited patients undergo an overnight sleep study using a level III portable diagnostic device within 7 days (and preferably within 48 hours) of diagnosis of PE. The sleep tracings are analyzed by a certified sleep technologist and audited by a sleep physician, both of whom are blinded to other study data. The patients are divided into 2 groups based on apnea-hypopnea index (AHI): OSA (AHI ≥15) and non-OSA (AHI <15) groups. The study uses a composite of PE-related death, CV death, clinical deterioration requiring an escalation of treatment, or nonfatal CV events (recurrent venous thromboembolism, acute myocardial infarction, or stroke) within 30 days after the diagnosis of PE as the primary outcome. The projected sample size of 225 patients will provide 80% power to test the hypothesis that OSA will increase the primary outcome from 7% in the non-OSA group to 20% in the OSA group, with α ≤0.05. The trial results will be important to understand the burden and CV effects of OSA in PE patients.

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.

Relationship between obstructive sleep apnea and 30-day mortality among patients with pulmonary embolism

Background:

Pulmonary embolism (PE) is the most life-threatening form of venous thrombosis which causes the majority of mortalities in this category. Obstructive sleep apnea (OSA) has been indicated as one of the risk factors for thromboembolism because of hemostatic alterations. The present study was designed to seek for the relationship between OSA and 30-day mortality of patients with PE.

Materials and Methods:

This prospective cohort study was conducted among 137 consecutive patients referred to hospital with symptoms of PE and preliminary stable hemodynamic. Confirmation of PE was made by multislice computed tomography pulmonary angiography and in the case of contraindication; V/Q lung scan and Doppler sonography were done. A STOP-Bang Questionnaire was used to determine patients with high- and low-risk of OSA. Patients were followed up for 1-month, and their survivals were recorded.

Results:

This study showed that there was no relationship between OSA and 30-day mortality (P = 0.389). Chronic kidney disease (P = 0.004), hypertension (P = 0.003), main thrombus (P = 0.004), and segmental thrombus (P = 0.022) were associated with 30-day mortality. In the logistic regression analysis, history of chronic kidney disease was diagnosed as a risk factor for 30-day mortality among the PE patients (P = 0.029, odds ratio = 4.93).

Conclusion:

Results of this study showed 30-day mortality was not affected by OSA directly. In fact, it was affected by complications of OSA such as hypertension and thrombus. Also, positive history of chronic kidney disease increased the risk of 30-day mortality.

Mean platelet volume is associated with disease severity in patients with obstructive sleep apnea syndrome

OBJECTIVE

Obstructive sleep apnea syndrome is associated with cardiovascular diseases and thromboembolic events. The mean platelet volume (MPV) is a predictor of cardiovascular thromboembolic events. The aim of the present study is to investigate the association between the MPV and disease severity in patients with obstructive sleep apnea syndrome.

METHODS

We prospectively included 194 obstructive sleep apnea syndrome patients without cardiovascular disease (mean age 56.5±12.5 years) who were undergoing sleep tests. An overnight full laboratory polisomnography examination was conducted on each patient. The patients were divided into 3 groups according to the apnea-hypopnea index (AHI): (1) AHIlow group: 5≤AHI<15, (2) AHImid group: 1530.

RESULTS

The highest MPV values were found in the AHIhigh group compared with other groups (p<0.05 for all). Multiple linear regression analysis indicated that the MPV was associated with the AHI (β=0.500, p<0.001) and the high sensitivity C-reactive protein (hs-CRP) level (β=0.194, p=0.010).

CONCLUSION

The MPV is independently associated with both disease severity and inflammation in patients with obstructive sleep apnea syndrome.

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.

Intracranial hypertension associated with obstructive sleep apnea: a discussion of potential etiologic factors

Obstructive sleep apnea has been shown to increase intracranial pressure, and to be a secondary cause of intracranial hypertension. There are a few theories that attempt to explain this relationship, however there is little data, and even less recognition among physicians that this actually occurs. This paper discusses multiple pieces of data, from anatomical correlates to biochemical information involving neuro-excitotoxicity, as well as hematologic factors and issues surrounding brain edema and blood-brain barrier dysfunction. A complex paradigm for how obstructive sleep apnea may lead to increased intracranial pressure is thus proposed. In addition, suggestions are made for how obstructive sleep apnea must as a result be managed differently in the setting of idiopathic intracranial hypertension.

Association between obstructive sleep apnea and deep vein thrombosis / pulmonary embolism: a population-based retrospective cohort study

BACKGROUND

Obstructive sleep apnea (OSA) is a major contributor to cardiovascular disease, and may cause severe morbidity and mortality. Recent studies have indicated that OSA patients exhibited elevated platelet activity, fibrinogen levels, and platelet aggregation.

OBJECTIVES

We investigated the risk of deep vein thrombosis (DVT) and pulmonary embolism (PE) in patients diagnosed with OSA compared with age- and sex-matched unaffected people.

PATIENTS/METHODS

This longitudinal, nationwide, population-based cohort study was conducted using data from Taiwan National Health Insurance Research Database (NHIRD) recorded between January 2000 and December 2011. The study consisted of 3511 patients with OSA and 35110 matched comparison individuals. A Cox proportional hazard regression was used to compute the risk of DVT and PE in patients with OSA compared with those without OSA.

RESULTS

The DVT and PE risks were 3.50- and 3.97-fold higher (95% CI=1.83-6.69 and 1.85-8.51) respectively, in the OSA cohort than in the reference cohort after we adjusted for age, sex, and comorbidities.

CONCLUSION

This nationwide population-based cohort study indicates that patients with OSA exhibit a higher risk of subsequent DVT and PE.

Coagulability in obstructive sleep apnea

BACKGROUND

Obstructive sleep apnea (OSA) is a common disorder that affects both quality of life and cardiovascular health. The causal link between OSA and cardiovascular morbidity⁄mortality remains elusive. One possible explanation is that repeated episodes of nocturnal hypoxia lead to a hypercoagulable state that predisposes patients to thrombotic events. There is evidence supporting a wide array of hematological changes that affect hemostasis (eg, increased hematocrit, blood viscosity, platelet activation, clotting factors and decreased fibrinolytic activity).

OBJECTIVE

To provide a comprehensive review of the current evidence associating OSA with increased coagulability, and to highlight areas for future research.

METHODS

Keyword searches in Ovid Medline were used to identify relevant articles; all references in the articles were searched for relevant titles. The Web of Science was used to identify articles citing the relevant articles found using the Ovid Medline search. All original peer-reviewed articles, meta-analyses and systematic reviews regarding the pertinent topics between 1990 and present were selected for review.

RESULTS

Hematocrit, blood viscosity, certain clotting factors, tissue factor, platelet activity and whole blood coagulability are increased in patients with OSA, while fibrinolysis is impaired.

CONCLUSION

There is considerable evidence that OSA is associated with a procoagulant state. Several factors are involved in the procoagulant state associated with OSA. There is a need for adequately powered clinical studies involving well-matched control groups to address potential confounding variables, and to accurately delineate the individual factors involved in the procoagulant state associated with OSA and their response to treatment.