Increased risk for cardiovascular disease in patients with obstructive sleep apnoea syndrome-chronic obstructive pulmonary disease (overlap syndrome)

Predictive value of red cell distribution width for overlap syndrome in obstructive sleep apnea

Purpose

Obstructive sleep apnea syndrome (OSAS) and chronic obstructive pulmonary disease (COPD) are prevalent disorders, and the concurrence so-called overlap syndrome (OVS) is not rare either. Early recognition of OVS is essential because this group is more prone to cardiovascular morbidities and requires effective multidisciplinary follow-up. This study aimed to evaluate RDW in patients with severe OSAS and investigate whether it can predict OVS.

Patients and methods

96 patients were retrospectively analyzed, of whom 66 were found to have severe OSAS alone and 30 OVS during diagnostic workups. Demographic, polysomnographic, and laboratory results, including RDW, were compared between groups. Multivariate logistic regression was used to determine independent associates of OVS.

Results

Gender and body mass index (BMI) were similar, however, the mean age and RDW were higher in the OVS group (p:0.008, p:0.002). The increase in RDW remained significant after adjustment for age, BMI, and cardiovascular risk factors. An RDW value of >13.65% was shown to have a 78.3% sensitivity and 60% specificity for predicting OVS in severe OSAS (p:0.004).

Conclusion

The results suggest that RDW can be a reliable indicator for diagnosing OVS in OSAS. It can help in identifying the subset of patients who would benefit from proper consultations and multidisciplinary follow-up, leading to appropriate treatment of each disease component and effective monitoring to prevent adverse cardiovascular outcomes.

Prevalence and Characteristics of Patients with Obstructive Sleep Apnea and Chronic Obstructive Pulmonary Disease: Overlap Syndrome

Overlap syndrome (OVS) is a distinct clinical entity that seems to result in potential cardiovascular consequences. We aimed to estimate the prevalence and risk factors for OVS in OSA patients and analyze clinical and PSG characteristics associated with OVS. In this cross-sectional study, 2616 patients evaluated for OSA underwent type-1 polysomnography (PSG). They were grouped as pure OSA (AHI > 15/h) and OVS patients. Demographics, PSG data, pulmonary function tests and arterial blood gases (ABGs) were compared between groups after adjustments for confounders. OSA was diagnosed in 2108 out of 2616 patients. Of those, 398 (19%) had OVS. Independent predictors of OVS were older age [OR: 5.386 (4.153-6.987)], current/former smoking [OR: 11.577 (7.232-18.532)], BMI [OR: 2.901 (2.082-4.044)] and ABG measurements [PaCO2 ≥ 45 OR: 4.648 (3.078-7.019), PO2 [OR: 0.934 (0.920-0.949)], HCO3- [OR: 1.196 (1.133-1.263), all p < 0.001]. OVS was also associated with prevalent hypertension [OR: 1.345 (1.030-1.758), p = 0.03] and cardiovascular disease [OR: 1.617 (1.229-2.126), p < 0.001], depressive symptoms [OR: 1.741 (1.230-2.465), p = 0.002] and nocturia [OR: 1.944 (1.378-2.742), p < 0.001], as well as with indices of OSA severity. Disturbances in sleep architecture were more prominent in OVS expressed by lower %N3 and REM% and higher arousal index. Our data suggest that OVS is prevalent among OSA patients, with distinct clinical and PSG characteristics. These characteristics could be utilized as predictive factors for early identification and further evaluation of these patients towards desirable patient-reported outcomes.

Is COPD the Determinant Factor for Myocardial Injury and Cardiac Wall Stress in OSA Patients?

Background and Objectives: Evidence shows that COPD-OSA overlap syndrome (OS) is more frequently accompanied by cardiovascular disease (CVD) in comparison to either disease alone. The aim of the study was to explore whether patients with OS have a higher burden of subclinical myocardial injury and wall stress compared with OSA patients. Materials and Methods: Consecutive patients, without established CVD, underwent polysomnography and pulmonary function testing, due to suspected sleep-disordered breathing. An equal number of patients with OS (n = 53, with an apnea hypopnea index (AHI) > 5/h and FEV1/FVC < 0.7) and patients with OSA (n = 53, AHI > 5/h and FEV1/FVC > 0.7) were included in the study. The detection of asymptomatic myocardial injury and wall stress was performed via the assessment of serum high-sensitivity cardiac troponin T (hs-cTnT) and N-terminal pro-B-type natriuretic peptide (NT-proBNP), respectively. Results: OS patients were older (p < 0.001) and had worse hypoxemic parameters, namely average oxyhemoglobin saturation (SpO2) (p = 0.002) and time spent with SpO2 < 90% (p = 0.003) during sleep as well as daytime pO2 (p < 0.001), than patients with OSA. No difference was observed between groups in terms of Epworth Sleepiness Scale (p = 0.432) and AHI (p = 0.587). Both levels of hs-cTnT (14.2 (9.1-20.2) vs. 6.5 (5.6-8.7) pg/mL, p < 0.001) and NT-proBNP (93.1 (37.9-182.5) vs. 19.2 (8.3-35.4) pg/mL, p < 0.001) were increased in OS compared to OSA patients. Upon multivariate linear regression analysis, levels of NT-proBNP and hs-cTnT correlated with age and average SpO2 during sleep. Conclusions: Our study demonstrated higher levels of hs-cTnT and NT-proBNP in OS patients, indicating an increased probability of subclinical myocardial injury and wall stress, compared with OSA individuals.

Effect of the Implementation of a Structured Diet Management Plan on the Severity of Obstructive Sleep Apnea: A Systematic Review

PURPOSE OF REVIEW

The prevalence of obstructive sleep apnea (OSA) is increasing worldwide, in line with the increase in obesity prevalence. Taken into consideration the low compliance rates to continuous positive airway pressure (CPAP) treatment, and since obesity is a risk factor for OSA, these patients should receive additional counseling for weight loss through a diet plan. The aim of this review is to examine the role of a structured diet management plan on OSA severity, nocturnal oxygen indices, and subjective sleep parameters.

RECENT FINDINGS

Τhis systematic review of the literature resulted in four studies and demonstrated that severity of OSA, assessed by the apnea-hypopnea index, is reduced by a dietary management plan when delivered through an educational program. Moreover, nocturnal oxygenation is improved, as well as subjective sleep parameters, when initiating a diet on top of CPAP use. In summary, the present systematic review reports on the beneficial effects of a structured diet management plan in patients with OSA. Although CPAP remains the gold standard of OSA treatment, a specific dietary plan should be sought when managing patients with OSA. Nevertheless, still the evidence is low, and further research on this field is needed to reduce the burden of OSA.

The Overlap Syndrome of Obstructive Sleep Apnea and Chronic Obstructive Pulmonary Disease: A Systematic Review

Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) are common diseases that strongly impact the quality and length of life. Their coexistence is determined by overlap syndrome (OS). This systematic review aims to define the significance of these comorbidities according to the current state of knowledge. For this systematic review, we searched PubMed, Scopus, and Cochrane for studies published between 2018 and 26 October 2022, to find original, observational, human studies published in English, where the diagnosis of COPD was according to the Global Initiative for Obstructive Lung Disease guidelines and the diagnosis of OSA was based on polysomnography. The quality of studies was assessed using the Newcastle-Ottawa quality assessment tool for cohort and case-control studies, as well as its modification for cross-sectional studies. Of the 1548 records identified, 38 were eligible and included in this systematic review. The included studies covered a total population of 27,064 participants. This paper summarizes the most important, up-to-date information regarding OS, including the prevalence, meaning of age/gender/body mass index, polysomnography findings, pulmonary function, comorbidities, predicting OSA among COPD patients, and treatment of this syndrome.

Vitamin D Levels in Patients with Overlap Syndrome, Is It Associated with Disease Severity?

Background: The coexistence of chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) has been defined as overlap syndrome (OVS). Recently, a link between OSA, COPD and Vitamin D (Vit D) serum concentration was reported, however, evidence regarding Vit D status in patients with OVS is scarce. The aim of the present study was to evaluate Vit D serum levels and to explore the association of those levels with anthropometric, pulmonary function and sleep parameters in patients with OVS. Methods: Vit D serum levels were measured in patients diagnosed with OVS, as confirmed by overnight polysomnography and pulmonary function testing. Results: A total of 90 patients (79 males and 11 females) were included in the analysis. The patients were divided into three groups matched for age, gender, and BMI: the control group that included 30 patients (27 males and 3 females), the OSA group that included 30 patients (26 males and 4 females), and the OVS group that included 30 patients (26 males and 4 females). Patients with OVS exhibited decreased serum 25(OH)D levels compared with OSA patients and controls (14.5 vs. 18.6 vs. 21.6 ng/mL, p < 0.001). In the OVS group, multiple linear regression analysis identified AHI and FEV1, as predictors of serum 25(OH)D levels (p = 0.041 and p = 0.038, respectively). Conclusions: Lower Vit D levels have been observed in patients with OVS compared with OSA patients and non-apneic controls, indicating an increased risk of hypovitaminosis D in this population which might be associated with disease severity.

Comparison of invasive intubation and noninvasive mechanical ventilation in patients with chronic obstructive pulmonary disease and obstructive sleep apnoea syndrome

Objective

The concurrence of chronic obstructive pulmonary disease (COPD) and obstructive sleep apnoea syndrome (OSAS) is defined as overlap syndrome (OS), but investigations into predictors of OS in patients with COPD remain limited. Here, potential markers of OS in patients with COPD were investigated, and results of intubation were compared between patients with COPD only or OS.

Methods

This retrospective study included patients with COPD who were divided according to OS diagnosis: COPD only (COPD group) or OS (OS group).

Results

Among 206 patients with COPD, 120 were diagnosed with OS. Mean body mass index (BMI) was significantly higher in the OS versus COPD group (28.95 ± 2.96 versus 23.84 ± 4.06, respectively). Receiver operating characteristic curve analyses revealed that BMI was associated with OS (area under the curve, 0.835). The rate of invasive intubation within 48 h was lower in the OS versus COPD group (9.2% versus 20.9%, respectively), and the duration of noninvasive ventilation was longer in the OS versus COPD group.

Conclusions

BMI may be a predictor of OS in patients with COPD. The duration of noninvasive ventilation was longer in patients with OS than in patients with COPD alone.

Risk for Cardiovascular Disease and One-Year Mortality in Patients With Chronic Obstructive Pulmonary Disease and Obstructive Sleep Apnea Syndrome Overlap Syndrome

Background: Patients with chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSAS) overlap syndrome (OS) are thought to be at increased risk for cardiovascular diseases.

Objective: To evaluate the burden of cardiovascular diseases and long-term outcomes in patients with OS.

Methods: This was a retrospective cohort study. The prevalence of cardiovascular diseases and 1-year mortality were compared among patients diagnosed with OS (OS group), COPD alone (COPD group) and OSAS alone (OSAS group), and Cox proportional hazards models were used to assess independent risk factors for all-cause mortality.

Results: Overall, patients with OS were at higher risk for pulmonary hypertension (PH), heart failure and all-cause mortality than patients with COPD or OSAS (all p < 0.05). In multivariate Cox regression analysis, the Charlson comorbidity index (CCI) score [adjusted hazard ratio (aHR): 1.273 (1.050–1.543); p = 0.014], hypertension [aHR: 2.006 (1.005–4.004); p = 0.048], pulmonary thromboembolism (PTE) [aHR: 4.774 (1.335–17.079); p = 0.016] and heart failure [aHR: 3.067 (1.521–6.185); p = 0.002] were found to be independent risk factors for 1-year all-cause mortality.

Conclusion: Patients with OS had an increased risk for cardiovascular diseases and 1-year mortality. More efforts are needed to identify the causal relationship between OS and cardiovascular diseases, promoting risk stratification and the management of these patients.

Burden of Comorbidities in Patients with OSAS and COPD-OSAS Overlap Syndrome

Background and Objectives: Obstructive sleep apnea syndrome (OSAS) and chronic obstructive pulmonary disease (COPD) are usually associated with multi-morbidity. The aim of this study was to retrospectively investigate the prevalence of comorbidities in a cohort of patients with OSAS and COPD-OSAS overlap syndrome (OS) patients and to explore differences between these two groups. Materials and Methods: Included were consecutive OS patients and OSAS patients who had been referred to our sleep laboratory, and were matched in terms of sex, age, BMI, and smoking history. Presence of comorbidities was recorded based on their medical history and after clinical and laboratory examination. Results: The two groups, OS patients (n = 163, AHI > 5/h and FEV₁/FVC < 0.7) and OSAS patients (n = 163, AHI > 5/h, and FEV₁/FVC > 0.7), did not differ in terms of apnea hypopnea index (p = 0.346), and oxygen desaturation index (p = 0.668). Compared to OSAS patients, OS patients had lower average SpO₂ (p = 0.008) and higher sleep time with oxygen saturation <90% (p = 0.002) during sleep, and lower PaO₂ (p < 0.001) and higher PaCO₂ (p = 0.04) in wakefulness. Arterial hypertension was the most prevalent comorbidity for both OS and OSAS, followed by dyslipidemia, cardiovascular disease (CVD) and diabetes. OS was characterized by a higher prevalence of total comorbidities (median (IQR):2 (1–3) vs. 2 (1–2), p = 0.033), which was due to the higher prevalence of CVD (p = 0.016) than OSAS. No differences were observed in other comorbidities. Conclusions: In OS patients, nocturnal hypoxia and impaired gas exchange in wakefulness are more overt, while a higher burden of CVD is observed among them in comparison to sex-, age- and BMI-matched OSAS patients.

The association between shift work and possible obstructive sleep apnea: a systematic review and meta-analysis

BACKGROUND

Shift work is a workschedule, since industrial era and some employees work in shift. It causes a desynchronization of the biological clock with consequences on sleep amount and quality, such as insomnia and easy fatigue. Obstructive sleep apnea (OSA) is one of the sleep problems that are getting more and more attention, but studies on the association between shift work and OSA were rare. Herein, we aimed to conduct a systematic review and meta-analysis to investigate the association between shift work and possible OSA.

METHODS

This study was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We queried PubMed, Embase, and Web of Science databases using a related set of keywords. The inclusion criteria were as follows: (1) participants were adult employees hired by a company or organization; (2) exposure was shift work; and (3) outcome was possible OSA according to examination or assessment.

RESULTS

We included six studies in the systematic review and five studies were selected for further meta-analysis. A random-effects model showed an association of shift work with a small, non-significant increase in possible OSA cases (pooled prevalence relative risk = 1.05; 95% CI 0.85-1.30; p = 0.65). This association occurred in both healthcare and non-healthcare workers group.

CONCLUSION

The association between shift work and possible OSA remains inconclusive and could be small if not negligible. Future studies should assess the association between specific work schedules and specific OSA definitions.

TRIAL REGISTRATION NUMBER

PROSPERO ID: CRD42020156837.

Obstructive Sleep Apnea in Patients with Chronic Obstructive Pulmonary Disease: Facts and Perspectives

The co-occurrence of obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD) in the same patient, named the overlap syndrome (OS), was first described in 1985. Although the American Thoracic Society underlined the limited knowledge of OS, stated research priorities for this condition, and recommended a "screening" strategy to identify OSA in COPD patients with chronic stable hypercapnia, research studies on OS remain scarce. This review aims to summarize the current knowledge and perspectives related to OSA in COPD patients. OS prevalence is 1.0-3.6% in the general population, 3-66% in COPD patients, and 7-55% in OSA patients. OS patients may have worse sleep quality than those with OSA or COPD alone. Scoring hypopneas may be difficult in COPD patients; desaturation episodes may have origins in these patients, namely upper airway obstruction, hypoventilation during paradoxical sleep, ventilation/perfusion mismatches, and obesity. The apnea-hypopnea index is similar in OSA and OS patients. Desaturations may be greater and more prolonged in OS patients than in patients with COPD or OSA alone. Low body mass index, hyperinflation, and less collapsible airways reduce the risk of OSA in COPD patients. OSA is a risk factor for pulmonary hypertension in COPD patients. Whether OS increases mortality and morbidity risks compared to COPD or OSA alone remains to be confirmed. No guidelines currently recommend specific approaches to the treatment of OSA in patients with COPD.

Cardiovascular Complications of Sleep Disorders: A Better Night's Sleep for a Healthier Heart / From Bench to Bedside

Sleep is essential to and an integral part of life and when lacking or disrupted, a multitude of mental and physical pathologies ensue, including cardiovascular (CV) disease, which increases health care costs. Several prospective studies and meta-analyses show that insomnia, short (<7h) or long (>9h) sleep and other sleep disorders are associated with an increased risk of hypertension, metabolic syndrome, myocardial infarction, heart failure, arrhythmias, CV disease risk and/or mortality. The mechanisms by which insomnia and other sleep disorders lead to increased CV risk may encompass inflammatory, immunological, neuro-autonomic, endocrinological, genetic and microbiome perturbations. Guidelines are emerging that recommend a target of >7 h of sleep for all adults >18 years for optimal CV health. Treatment of sleep disorders includes cognitive-behavioral therapy considered the mainstay of non-pharmacologic management of chronic insomnia, and drug treatment with benzodiazepine receptor agonists binding to gamma aminobutyric acid type A (benzodiazepine and non-benzodiazepine agents) and some antidepressants. However, observational studies and meta-analyses indicate an increased mortality risk of anxiolytics and hypnotics, although bias may be involved due to confounding and high heterogeneity in these studies. Nevertheless, it seems that the risk incurred by the non-benzodiazepine hypnotic agents (Z drugs) may be relatively less than the risk of anxiolytics, with evidence indicating that at least one of these agents, zolpidem, may even confer a lower risk of mortality in adjusted models. All these issues are herein reviewed.

The Association Between Serum/Plasma Leptin Levels and Obstructive Sleep Apnea Syndrome: A Meta-Analysis and Meta-Regression

BACKGROUND

Obstructive sleep apnea syndrome (OSAS) is associated with various adipokines. Leptin, a common adipokine, has attracted considerable attention of many researchers in recent years. So far, there has been little agreement on whether blood leptin levels differ in patients with OSAS. Thus, this meta-analysis examined the relationship between serum/plasma leptin levels and the occurrence of OSAS.

METHOD

WanFang, Embase, CNKI, Medline, SinoMed, Web of Science, and PubMed were searched for articles before March 30, 2021, with no language limitations. STATA version 11.0 and R software version 3.6.1 were used to analyze the obtained data. The weighted mean difference and correlation coefficients were used as the main effect sizes with a random-effects model and a fixed-effects model, respectively. Trial sequential analysis was conducted using dedicated software.

RESULT

Screening of 34 publications identified 45 studies that met the inclusion criteria of this meta-analysis and meta-regression. Our results suggested that plasma/serum leptin levels were remarkably higher in individuals with OSAS than in healthy individuals. Subgroup analyses were performed based on OSAS severity, ethnicity, age, body mass index, assay type, and sample source. The serum and plasma leptin levels were increased in nearly all OSAS subgroups compared to those in the corresponding control groups. Meta-regression analysis indicated that age, BMI, severity, assay approaches, study design, PSG type and ethnicity did not have independent effect on leptin levels. Furthermore, a positive relationship between the serum/plasma leptin level and apnea-hypopnea index (AHI) was found in the meta-analysis. The results of the trial sequential analysis suggested that the enrolled studies surpassed the required information size, confirming that our study findings were reliable.

CONCLUSION

Our study results demonstrate that OSAS patients have higher leptin levels in serum/plasma compared to controls, and the serum/plasma leptin level is positively correlated with AHI, especially in adults.

Metabolic Syndrome and Abnormal Peri-Organ or Intra-Organ Fat (APIFat) Deposition in Chronic Obstructive Pulmonary Disease: An Overview

Chronic obstructive pulmonary disease (COPD) is a common disorder with an increasing prevalence, characterised by persistent respiratory symptoms and airflow limitation. Systemic inflammation is involved in the pathogenesis of COPD and can also predispose to metabolic disorders (e.g., metabolic syndrome (MetS) and non-alcoholic fatty liver disease (NAFLD)). Such comorbidities can negatively affect COPD outcomes, cardiovascular risk, and quality of life. Apart from NAFLD, abnormal peri-organ or intra-organ fat (APIFat) could be considered as markers for cardiometabolic diseases and even for COPD. The present narrative review considers the associations of COPD with MetS, NAFLD, and other APIFat, including epicardial, perirenal, peripancreatic, and intramuscular adipose tissue. Further research is needed to define these relationships and identify any potential clinical implications.

Metabolic Syndrome in Patients with Coexistent Obstructive Sleep Apnea Syndrome and Chronic Obstructive Pulmonary Disease (Overlap Syndrome)

Background: Evidence suggests that metabolic syndrome (MetS) is highly prevalent in patients with obstructive sleep apnea syndrome (OSAS) and chronic obstructive pulmonary disease (COPD). However, data on the prevalence of MetS in patients having both OSAS and COPD, or overlap syndrome (OS), are scarce. The aim of this study was to evaluate the prevalence and identify predictors of MetS in patients with OS. Methods: MetS was evaluated in consecutive patients who were diagnosed with OS by polysomnography and pulmonary function testing. Results: A total of 163 subjects (138 males and 25 females) were included. MetS was present in 38% of OS patients. Patients were divided into group A (OS without MetS group: 101 patients) and group B (OS with MetS group: 62 patients). Groups were similar in terms of pulmonary function and sleep parameters. In group B, abdominal obesity was the most prevalent component of MetS (100%), followed by hypertension (82.3%), hypertriglyceridemia (72.6%), and hyperglycemia (51.6%). Age (P = 0.009) and body mass index (P = 0.029) were independent predictors of MetS in patients with OS. Conclusions: An increased prevalence of MetS was observed in a group of patients with OS. Early identification and treatment of MetS may play a significant role in prevention of complications related to OS.