The risk of cardiovascular and cerebrovascular disease in overlap syndrome: a meta-analysis

Chronic Obstructive Pulmonary Disease and Obstructive Sleep Apnea Overlap Syndrome: An Update on the Epidemiology, Pathophysiology, and Management

This review provides an up-to-date summary of the prevalence, pathophysiology, diagnosis, and treatment of the chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) overlap syndrome (OVS). The presence of OVS is high in patients with COPD and in patients with OSA and is associated with profound nocturnal oxygen desaturation and systemic inflammation. There is a high prevalence of cardiovascular disease among patients with OVS and this likely contributes to increased mortality. Observational studies suggest that positive airway pressure therapy improves survival and reduces COPD exacerbations; however, randomized controlled trials will be required to confirm these findings.

Chronic obstructive pulmonary disease and obstructive sleep apnea overlap: who to treat and how?

INTRODUCTION

The co-existence of chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA), or the overlap syndrome, is common and associated with a distinct pattern of nocturnal hypoxemia and worse clinical outcomes than either disease alone. Consequently, identifying who and how to treat these patients is essential.

AREAS COVERED

Treatment is recommended in all patients with OSA and symptoms or systemic hypertension, but determining symptoms attributable to OSA can be challenging in patients with COPD. Treatment should be considered in asymptomatic patients with moderate to severe OSA and COPD with pulmonary hypertension and comorbid cardiovascular and cerebrovascular disease, especially if marked hypoxic burden. CPAP is effective, but in patients with the overlap syndrome and daytime hypercapnia, high-intensity noninvasive ventilation aiming to lower PaCO2 may have additional benefits. Additionally, in those with severe resting daytime hypoxemia, supplemental oxygen improves survival and should be added to positive airway pressure. The role of alternative non-positive airway pressure therapies in the overlap syndrome needs further study.

EXPERT OPINION

Both COPD and OSA are heterogeneous disorders with a wide range of disease severity and further research is needed to better characterize and prognosticate patients with the overlap syndrome to personalize treatment.

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.

Outcomes of coronary artery bypass grafting (CABG) in patients with OSA-COPD overlap syndrome versus COPD alone: an analysis of US Nationwide Inpatient Sample

BACKGROUND

Obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD) are associated with unfavorable outcomes following coronary artery bypass grafting (CABG). The purpose of this study was to compare in-hospital outcomes of patients with COPD alone versus OSA-COPD overlap after CABG.

METHODS

Data of adults ≥ 18 years old with COPD who received elective CABG between 2005 and 2018 were extracted from the US Nationwide Inpatient Sample (NIS). Patients were divided into two groups: with OSA-COPD overlap and COPD alone. Propensity score matching (PSM) was employed to balance the between-group characteristics. Logistic and linear regression analyses determined the associations between study variables and inpatient outcomes.

RESULTS

After PSM, data of 2,439 patients with OSA-COPD overlap and 9,756 with COPD alone were analyzed. After adjustment, OSA-COPD overlap was associated with a significantly increased risk of overall postoperative complications (adjusted odd ratio [aOR] = 1.12, 95% confidence interval [CI]: 95% CI: 1.01-1.24), respiratory failure/prolonged mechanical ventilation (aOR = 1.27, 95%CI: 1.14-1.41), and non-routine discharge (aOR = 1.16, 95%CI: 1.03-1.29), and AKI (aOR = 1.14, 95% CI: 1.00-1.29). Patients with OSA-COPD overlap had a lower risk of in-hospital mortality (adjusted odd ratio [aOR] = 0.53, 95% CI: 0.35-0.81) than those with COPD only. Pneumonia or postoperative atrial fibrillation (AF) risks were not significantly different between the 2 groups. Stratified analyses revealed that, compared to COPD alone, OSA-COPD overlap was associated with increased respiratory failure/prolonged mechanical ventilation risks among patients ≥ 60 years, and both obese and non-obese subgroups. In addition, OSA-COPD overlap was associated with increased risk of AKI among the older and obese subgroups.

CONCLUSION

In US adults who undergo CABG, compared to COPD alone, those with OSA-COPD are at higher risks of non-routine discharge, AKI, and respiratory failure/prolonged mechanical ventilation, but a lower in-hospital mortality. No increased risk of AF was noted.

Evaluation of a 3-Item Health Index in Predicting Mortality Risk: A 12-Year Follow-Up Study

This study was carried out using a large cohort (N = 4265; 416 deceased) of older, community-dwelling adults from The Irish Longitudinal Study on Ageing (TILDA). The study compared the performance of a new 3-item health index (HI) with two existing measures, the 32-item frailty index (FI) and the frailty phenotype (FP), in predicting mortality risk. The HI was based on the objective measurement of resting-state systolic blood pressure sample entropy, sustained attention reaction time performance, and usual gait speed. Mortality data from a 12-year follow up period were analyzed using Cox proportional regression. All data processing was performed using MATLAB and statistical analysis using STATA 15.1. The HI showed good discriminatory power (AUC = 0.68) for all-cause mortality, similar to FI (AUC = 0.68) and superior to FP (AUC = 0.60). The HI classified participants into Low-Risk (84%), Medium-Risk (15%), and High-Risk (1%) groups, with the High-Risk group showing a significant hazard ratio (HR) of 5.91 in the unadjusted model and 2.06 in the fully adjusted model. The HI also exhibited superior predictive performance for cardiovascular and respiratory deaths (AUC = 0.74), compared with FI (AUC = 0.70) and FP (AUC = 0.64). The HI High-Risk group had the highest HR (15.10 in the unadjusted and 5.61 in the fully adjusted models) for cardiovascular and respiratory mortality. The HI remained a significant predictor of mortality even after comprehensively adjusting for confounding variables. These findings demonstrate the effectiveness of the 3-item HI in predicting 12-year mortality risk across different causes of death. The HI performed similarly to FI and FP for all-cause mortality but outperformed them in predicting cardiovascular and respiratory deaths. Its ability to classify individuals into risk groups offers a practical approach for clinicians and researchers. Additionally, the development of a user-friendly MATLAB App facilitates its implementation in clinical settings. Subject to external validation in clinical research settings, the HI can be more useful than existing frailty measures in the prediction of cardio-respiratory risk.

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.

Risk factors of cardiovascular and cerebrovascular diseases in young and middle-aged adults: A meta-analysis

BACKGROUND

The risk factors for cardiovascular and cerebrovascular diseases in young and middle-aged people have not yet been determined. We conducted a meta-analysis to find the risk factors for cardiovascular and cerebrovascular diseases, in order to provide guidance for the prevention of diseases in the young and middle-aged population.

METHODS

We searched PubMed, Embase, Cochrane Library from the establishment of the database to Mar 2022. We included case-control or cohort studies reporting risk factors for cardiovascular and cerebrovascular disease in young and middle-aged adults. We excluded repeated publication, research without full text, incomplete information or inability to conduct data extraction and animal experiments, reviews and systematic reviews. STATA 15.1 was used to analyze the data.

RESULTS

The pooled results indicated that increased systolic blood pressure was significantly associated with increased risk of any stroke, ischemic stroke and hemorrhagic stroke. Body Mass Index (BMI), current smoking, hypertension, and diabetes were significantly associated with increased risk of any stroke and ischemic stroke. Atrial fibrillation was only significantly associated with increased risk of any stroke. Increased total cholesterol was significantly associated with an increased risk of ischemic stroke, whereas increased triglycerides were significantly associated with a decreased risk of ischemic stroke. In addition, increased hypertension was also significantly associated with an increased risk of acute coronary syndrome.

CONCLUSION

Our pooled results show that BMI, current smoking, atrial fibrillation, hypertension, systolic blood pressure, and total cholesterol can be used as risk factors for cardiovascular and cerebrovascular diseases in young people, while triglycerides can be used as protective factors for cardiovascular and cerebrovascular diseases in young and middle-aged adults.

Is obstructive sleep apnea associated with increased arterial stiffness in patients with COPD?

PURPOSE

To evaluate arterial stiffness, a predictor of vascular damage was assessed by means of pulse wave velocity (PWV) in patients with chronic obstructive pulmonary disease (COPD) and comorbid obstructive sleep apnea (OSA), namely overlap syndrome (OS).

METHODS

Consecutive stable patients with COPD were evaluated for OSA by means of overnight polysomnography in the laboratory. A clinical assessment was performed according to a strict protocol, including two COPD questionnaires: the COPD assessment test and the modified Medical Research Council scale. COPD severity was graded according to the guidelines of the Global Initiative for Chronic Obstructive Lung Disease. Arterial stiffness was assessed by means of PWV, using a standard technique.

RESULTS

Of 102 patients with COPD, 51 had associated OSA. The OS group had more men than the COPD group (73% vs. 47%, respectively; p < 0.01). Both groups had similar ages (66.2 ± 9.2 years vs. 69.6 ± 10.7, p = 0.09) and airflow limitation (p = 0.37). Hypertension was found in 22% of COPD patients, as opposed to 17% patients in the OS group (p = 0.29). High PWV values were present in 42% of the patients. Patients with COPD and OS had the same PWV values (9.8 vs. 10.5 m/s, p = 0.34). There were no differences in central blood pressure, peripheral blood pressure, and augmentation index between the two groups (p > 0.05).

CONCLUSION

High PWV values were frequently observed in patients with COPD. However, there was no difference in PWV between patients with OS and those with COPD alone.

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.

Machine learning for nocturnal diagnosis of chronic obstructive pulmonary disease using digital oximetry biomarkers

Objective.Chronic obstructive pulmonary disease (COPD) is a highly prevalent chronic condition. COPD is a major cause of morbidity, mortality and healthcare costs globally. Spirometry is the gold standard test for a definitive diagnosis and severity grading of COPD. However, a large proportion of individuals with COPD are undiagnosed and untreated. Given the high prevalence of COPD and its clinical importance, it is critical to develop new algorithms to identify undiagnosed COPD. This is particularly true in specific disease groups in which the presence of concomitant COPD increases overall morbidity/mortality such as those with sleep-disordered breathing. To our knowledge, no research has looked at the feasibility of automated COPD diagnosis using a data-driven analysis of the nocturnal continuous oximetry time series. We hypothesize that patients with COPD will exert certain patterns and/or dynamics of their overnight oximetry time series that are unique to this condition and that may be captured using a data-driven approach.Approach.We introduce a novel approach to nocturnal COPD diagnosis using 44 oximetry digital biomarkers and five demographic features and assess its performance in a population sample at risk of sleep-disordered breathing. A total ofn=350 unique patients' polysomnography (PSG) recordings were used. A random forest (RF) classifier was trained using these features and evaluated using nested cross-validation.Main results.The RF classifier obtainedF1 = 0.86 ± 0.02 and AUROC = 0.93 ± 0.02 on the test sets. A total of 8 COPD individuals out of 70 were misclassified. No severe cases (GOLD 3-4) were misdiagnosed. Including additional non-oximetry derived PSG biomarkers resulted in minimal performance increase.Significance.We demonstrated for the first time, the feasibility of COPD diagnosis from nocturnal oximetry time series for a population sample at risk of sleep-disordered breathing. We also highlighted what set of digital oximetry biomarkers best reflect how COPD manifests overnight. The results motivate that overnight single channel oximetry can be a valuable modality for COPD diagnosis, in a population sample at risk of sleep-disordered breathing. Further data is needed to validate this approach on other population samples.

Sleep disordered breathing and chronic obstructive pulmonary disease: a narrative review on classification, pathophysiology and clinical outcomes

Chronic obstructive pulmonary disease (COPD) causes load-capacity-drive imbalance in both wakefulness and sleep, principally driven by expiratory flow limitation and hyperinflation. Sleep imposes additional burdens to the respiratory muscle pump, driven by changes in respiratory muscle tone, neural respiratory drive and consequences of the supine position. COPD patients are therefore at higher risk of decompensation during sleep, which may manifest as altered sleep architecture, isolated nocturnal desaturation, sleep hypoventilation and restless legs. Each form of sleep disordered breathing in COPD is associated with adverse clinical and patient-reported outcomes, including increased risk of exacerbations, hospitalisation, cardiovascular events, reduced survival and poorer quality of life. COPD-obstructive sleep apnoea (OSA) overlap syndrome represents a distinct clinical diagnosis, in which clinical outcomes are significantly worse than in either disease alone, including increased mortality, risk of cardiovascular events, hospitalisation and exacerbation frequency. Sleep disordered breathing is under-recognised by COPD patients and their clinicians, however early diagnosis and management is crucial to reduce the risk of adverse clinical outcomes. In this narrative review, we describe the pathophysiology of COPD and physiological changes that occur during sleep, manifestations and diagnosis of sleep disordered breathing in COPD and associated clinical outcomes.

Comorbid Conditions in Chronic Obstructive Pulmonary Disease: Potential Therapeutic Targets for Unmet Needs

The management of chronic obstructive pulmonary disease (COPD) has improved significantly due to advances in therapeutic agents, but it has also become apparent that there are issues that remain difficult to solve with the current treatment algorithm. COPD patients face a number of unmet needs concerning symptoms, exacerbations, and physical inactivity. There are various risk factors and triggers for these unmet needs, which can be roughly divided into two categories. One is the usual clinical characteristics for COPD patients, and the other is specific clinical characteristics in patients with comorbid conditions, such as asthma, cardiovascular disease, and bronchiectasis. These comorbidities, which are also associated with the diversity of COPD, can cause unmet needs resistance to usual care. However, treatable conditions that are not recognized as therapeutic targets may be latent in patients with COPD. We again realized that treatable traits should be assessed and treated as early as possible. In this article, we categorize potential therapeutic targets from the viewpoint of pulmonary and systemic comorbid conditions, and address recent data concerning the pathophysiological link with COPD and the impact of intervention on comorbid conditions in order to obtain evidence that could enable us to provide personalized COPD management.