Does Continuous Positive Airway Pressure (CPAP) treatment of obstructive sleep apnoea (OSA) improve asthma-related clinical outcomes in patients with co-existing conditions?- A systematic review

The CORE syndrome: an overlap of severe asthma, obstructive sleep apnea, rhinosinusitis, and esophageal reflux

PURPOSE

Asthma, obstructive sleep apnea (OSA), rhinosinusitis, and esophageal reflux are conditions that may overlap, forming a syndrome known as CORE. Whenever clinical remission of severe asthma (SA) is not achieved, it is essential to investigate the presence of comorbidities, in particular the presence of OSA that may lead to the diagnosis of CORE syndrome.

METHODS

The study was conducted on naive patients with SA and concomitant rhinosinusitis and esophageal reflux, referred to our institute since 2018. Patients who did not experience clinical remission were investigated for OSA through a home sleep apnea test. Subsequently, for those diagnosed with OSA, continuous positive airway pressure (CPAP) was proposed and was re-evaluated after 12 months.

RESULTS

Six patients with CORE syndrome were enrolled. The mean apnea-hypopnea index (AHI) was 33.25 ± 20.13 events/h, oxygen desaturation index (ODI) was 28.95 ± 19.95 events/h, and time in bed with SaO2 < 90% (T90) was 26.40 ± 27.22% for which continuous positive airway pressure (CPAP) treatment was proposed but only 3 out of 6 patients accepted. After 12 months, all CPAP-treated patients manifested a significant reduction in daytime sleepiness (ESS score was 6.33 ± 3.8), an improvement in ACT score (+ 8 (+ 32%), + 9 (+ 36%), and + 14 (+ 56%) points), a discontinuation of oral corticosteroids (OCS), an absence of exacerbations, and an improvement of lung function leading to clinical remission of asthma.

CONCLUSION

Whenever facing SA patients, non-responders to therapy, it is important to suspect the presence of CORE syndrome; in particular, the detection and subsequent treatment of OSA would seem to improve the outcome of such patients.

State of the art: Alternative overlap syndrome-asthma and obstructive sleep apnea

In the general population, Bronchial Asthma (BA) and Obstructive Sleep Apnea (OSA) are among the most prevalent chronic respiratory disorders. Significant epidemiologic connections and complex pathogenetic pathways link these disorders via complex interactions at genetic, epigenetic, and environmental levels. The coexistence of BA and OSA in an individual likely represents a distinct syndrome, that is, a collection of clinical manifestations attributable to several mechanisms and pathobiological signatures. To avoid terminological confusion, this association has been named alternative overlap syndrome (vs overlap syndrome represented by the chronic obstructive pulmonary disease-OSA association). This comprehensive review summarizes the complex, often bidirectional links between the constituents of the alternative overlap syndrome. Cross-sectional, population, or clinic-based studies are unlikely to elucidate causality or directionality in these relationships. Even longitudinal epidemiological evaluations in BA cohorts developing over time OSA, or OSA cohorts developing BA during follow-up cannot exclude time factors or causal influence of other known or unknown mediators. As such, a lot of pathophysiological interactions described here have suggestive evidence, biological plausibility, potential or actual directionality. By showcasing existing evidence and current knowledge gaps, the hope is that deliberate, focused, and collaborative efforts in the near-future will be geared toward opportunities to shine light on the unknowns and accelerate discovery in this field of health, clinical care, education, research, and scholarly endeavors.

Obstructive Sleep Apnea Effects on Chronic Airway Disease Exacerbations-Missed Opportunities for Improving Outcomes in Chronic Obstructive Pulmonary Disease and Asthma

In patients with chronic obstructive pulmonary disease (COPD) and asthma, exacerbations determine the natural history of both diseases. Patients with both respiratory diseases who suffer from obstructive sleep apnea (OSA) as a comorbidity (overlap syndromes) have a higher risk of exacerbations and hospitalization. In cases of OSA/COPD and OSA/asthma, continuous positive airway pressure treatment is indicated. Adequate adherence to therapy appears to reduce exacerbations and their severity, especially in OSA/COPD overlap. However, there is a lack of randomized trials that definitively demonstrate this evidence.

Dyspnea and Quality of Life Improvements with Management of Comorbid Obstructive Sleep Apnea in Chronic Lung Disease

Obstructive sleep apnea (OSA) has emerged as a significant and prevalent comorbidity associated with chronic lung diseases, including chronic obstructive pulmonary disease, asthma, and interstitial lung diseases. These overlap syndromes are associated with worse patient-reported outcomes (sleep quality, quality of life measures, mental health) than each condition independently. Observational studies suggest that patients with overlap syndrome who are adherent to positive airway pressure therapy report improved quality of life, sleep quality, depression, and daytime symptoms. Screening for and management of OSA in patients with overlap syndrome should emphasize the interconnected nature of these 2 conditions and the positive impact that OSA management can have on patients' well-being and overall health.

Contribution of Obstructive Sleep Apnea to Asthmatic Airway Inflammation and Impact of Its Treatment on the Course of Asthma

Asthma and obstructive sleep apnea (OSA) are very common respiratory disorders in the general population. Beyond their high prevalence, shared risk factors, and genetic linkages, bidirectional relationships between asthma and OSA exist, each disorder affecting the other's presence and severity. The author reviews here some of the salient links between constituents of the alternative overlap syndrome, that is, OSA comorbid with asthma, with an emphasis on the effects of OSA or its treatment on inflammation in asthma. In the directional relationship from OSA toward asthma, beyond direct influences, multiple factors and comorbidities seem to contribute.

The Effect of Simulated Obstructive Apneas on Mechanical Characteristics of Lower Airways in Individuals with Asthma

Increased negative intrathoracic pressure that occurs during pharyngeal obstruction can increase thoracic fluid volume that may contribute to lower airway narrowing in individuals with obstructive sleep apnea (OSA) and asthma. Our previous study showed that fluid accumulation in the thorax induced by simulated OSA can increase total respiratory resistance. However, the effect of fluid shift on lower airway narrowing has not been investigated. To examine the effect of fluid accumulation in the thorax on the resistance of the lower airway. Non-asthma participants and individuals with (un)controlled asthma were recruited and underwent a single-day experiment. A catheter with six pressure sensors was inserted through the nose to continuously measure pressure at different sites of the airway, while a pneumotachograph was attached to a mouthpiece to record airflow. To simulate obstructive apneas, participants performed 25 Mueller maneuvers (MMs) while lying supine. Using the recordings of pressure sensor and airflow, total respiratory (RT), lower respiratory components (RL), and upper airway (RUA) resistances were calculated before and after MMs. Generalized estimation equation method was used to find the predictors of RL among variables including age, sex, body mass index, and the effect of MMs and asthma. Eighteen participants were included. Performing MMs significantly increased RT (2.23 ± 2.08 cmH2O/L/s, p = 0.003) and RL (1.52 ± 2.00 cmH2O/L/s, p = 0.023) in participants with asthma, while only RL was increased in non-asthma group (1.96 ± 1.73 cmH2O/L/s, p = 0.039). We found the model with age, and the effect of MMs and asthma severity generated the highest correlation (R2 = 0.69, p < 0.001). We provide evidence that fluid accumulation in the thorax caused by excessive intrathoracic pressure increases RL in both non-asthma and asthma groups. The changes in RL were related to age, having asthma and the effect of simulated OSA. This can explain the interrelationship between OSA and asthma.

Asthma and obstructive sleep apnea: Unveiling correlations and treatable traits for comprehensive care

Asthma and obstructive sleep apnea (OSA) are common respiratory disorders. They share characteristics such as airway obstruction, poor sleep quality, and low quality of life. They are often present as comorbidities, along with obesity, gastroesophageal reflux disease (GERD), and allergic rhinitis (AR), which impacts the disease's control. In recent years, there has been discussion about the association between these conditions and their pathophysiological and clinical consequences, resulting in worse health outcomes, increased healthcare resource consumption, prolonged hospital stays, and increased morbidity and mortality. Some studies demonstrate that treatment with continuous positive airway pressure (CPAP) can have a beneficial effect on both pathologies. This review summarizes the existing evidence of the association between asthma and OSA at their pathophysiological, epidemiological, clinical, and therapeutic levels. It intends to raise awareness among healthcare professionals about these conditions and the need for further research.

Revisiting Asthma Obstructive Sleep Apnea Overlap: Current Knowledge and Future Needs

Asthma and obstructive sleep apnea are highly prevalent conditions with a high cost burden. In addition to shared risk factors, existing data suggest a bidirectional relationship between asthma and OSA, where each condition can impact the other. Patients with asthma often complain of sleep fragmentation, nocturnal asthma symptoms, daytime sleepiness, and snoring. The prevalence of OSA increases with asthma severity, as evidenced by multiple large studies. Asthma may lower the threshold for arousal in OSA, resulting in the hypopnea with arousal phenotype. Epidemiologic studies in adults have shown that OSA is associated with worse asthma severity, increased frequency of exacerbation, and poor quality of life. The current literature assessing the relationship among OSA, asthma, and CPAP therapy is heavily dependent on observational studies. There is a need for randomized controlled trials to minimize the interference of confounding shared risk factors.

Management of comorbidities in difficult and severe asthma

Difficult-to-treat and severe asthma are challenging clinical entities. In the face of suboptimal asthma control, the temptation for clinicians is to reflexively escalate asthma-directed therapy, including increasing exposure to corticosteroids and commencement of costly but potent biologic therapies. However, asthma control is objectively and subjectively assessed based on measurable parameters (such as exacerbations or variability in pulmonary physiology), symptoms and patient histories. Crucially, these features can be confounded by common untreated comorbidities, affecting clinicians' assessment of asthma treatment efficacy.

Positive airway pressure treatment affects respiratory symptoms and gastro-oesophageal reflux: the Icelandic Sleep Apnea Cohort Study

Aim

To study the effect of positive airway pressure (PAP) treatment on nocturnal gastro-oesophageal reflux (nGOR) and respiratory symptoms among clinical obstructive sleep apnoea (OSA) patients.

Methods

822 patients newly diagnosed with OSA referred for PAP treatment were recruited. 732 patients had a 2-year follow-up visit with continuous PAP compliance data (366 full PAP users, 366 partial/non-PAP users). They answered questionnaires, including reporting of nGOR, sleep and respiratory symptoms and general health. Patients with nGOR symptoms once a week or more were defined as "with nGOR". Those without nGOR symptoms and nGOR medication were defined as "no nGOR". Others were defined as "possible nGOR".

Results

At 2-year follow-up, PAP treatment among full users resulted in decreased nGOR (adjusted OR 0.58, 95% CI 0.40-0.86) and wheezing (adjusted OR 0.56, 95% CI 0.35-0.88) compared with partial/non-PAP users. Decreased nGOR, among both full and partial/non-users of PAP treatment, was associated with a decrease in productive morning cough (adjusted OR 4.70, 95% CI 2.22-9.99) and a decrease in chronic bronchitis (adjusted OR 3.86, 95% CI 1.74-8.58), but not decreased wheezing (adjusted OR 0.90, 95% CI 0.39-2.08). A mediation analysis found that PAP treatment directly led to a decrease in wheezing, not mediated through nGOR. Conversely, PAP treatment decreased productive cough mediated through a decrease in nGOR.

Conclusion

In an unselected group of OSA patients, PAP treatment for 2 years was associated with a decrease in nGOR and respiratory symptoms. The PAP treatment itself was associated with less wheezing. A decrease in nGOR through PAP treatment was associated with a decrease in productive cough.

Prevalence and impact of exercise-induced laryngeal obstruction in asthma: a study protocol for a cross-sectional and longitudinal study

INTRODUCTION

Exercise-induced laryngeal obstruction (EILO) and exercise-induced asthma can cause troublesome respiratory symptoms that can be difficult to distinguish between. Further, there is now a growing appreciation that the two conditions may coexist, complicating the interpretation of symptoms. The primary aim of this study is to investigate the prevalence of EILO in patients with asthma. Secondary aims include evaluation of EILO treatment effects and investigation of comorbid conditions other than EILO in patients with asthma.

METHODS AND ANALYSIS

The study will be conducted at Haukeland University Hospital and Voss Hospital in Western Norway, and enrol 80-120 patients with asthma and a control group of 40 patients without asthma. Recruitment started in November 2020, and data sampling will continue until March 2024. Laryngeal function will be assessed at baseline and at a 1-year follow-up, using continuous laryngoscopy during high-intensity exercise (CLE). Immediately after the EILO diagnosis is verified, patients will be treated with standardised breathing advice guided by visual biofeedback from the laryngoscope video screen. The primary outcome will be the prevalence of EILO in patients with asthma and control participants. Secondary outcomes include changes in CLE scores, asthma-related quality of life, asthma control and number of the asthma exacerbations, as assessed between baseline and the 1-year follow-up.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the Regional Committee for Medical and Health Research Ethics, Western Norway, (ID number 97615). All participants will provide signed informed consent before enrolment. The results will be presented in international journals and conferences.

TRIAL REGISTRATION NUMBER

NCT04593394.

Association between Previous CPAP and Comorbidities at Diagnosis of Obesity-Hypoventilation Syndrome Associated with Obstructive Sleep Apnea: A Comparative Retrospective Observational Study

Obesity-hypoventilation syndrome (OHS) is associated with many comorbidities. The aim of this study was to evaluate the association between previous continuous positive airway pressure (CPAP) and the prevalence of comorbidities in OHS associated with obstructive sleep apnea (OSA). We performed a retrospective, single-center study at the University Hospital of Martinique, the referral hospital for the island of Martinique. A total of 97 patients with OHS associated with severe OSA on non-invasive ventilation (NIV) were included; 54 patients (56%) had previous treatment of OSA with a positive airway pressure (PAP) device before shifting to NIV (PAP group) and 43 (44%) had no previous treatment of OSA with a PAP device before initiating NIV PAP (no PAP group). Sociodemographic characteristics were similar between groups; there were 40 women (74%) in the PAP group versus 34 (79%) in the no PAP group, mean age at OHS diagnosis was 66 ± 15 versus 67 ± 16 years, respectively, and the mean age at inclusion 72 ± 14 versus 71 ± 15 years, respectively. The average number of comorbidities was 4 ± 1 in the PAP group versus 4 ± 2 in the no PAP group; the mean Charlson index was 5 ± 2 in both groups. The mean BMI was 42 ± 8 kg/m2 in both groups. The mean follow-up duration was 5.8 ± 4.4 years in the PAP group versus 4.7 ± 3.5 years in the no PAP group. Chronic heart failure was less common in patients who had a previous PAP 30% versus 53% (p = 0.02). It is also noted that these patients were diagnosed less often in the context of acute respiratory failure in patients with previous PAP: 56% versus 93% (p < 0.0001). In contrast, asthma patients were more frequent in patients with previous treatment of OSA with a PAP device at the time of OHS diagnosis but not significantly: 37% versus 19% (p = 0.07). Early treatment of severe OSA with a PAP device prior to diagnosis of OHS seems to be associated with a reduced prevalence of cardiac diseases, notably chronic heart failure, in patients diagnosed with OHS associated with severe OSA.

Improvement in severe asthma patients receiving biologics and factors associated with persistent insufficient control: a real-life national study

BACKGROUND

Biological therapies have revolutionized the treatment of severe asthma with type 2 inflammation. Although such treatments are very effective in reducing exacerbation and the dose of oral steroids, little is known about the persistence of symptoms in severe asthma patients treated with biologics.

PURPOSE

We aim to describe asthma control and healthcare consumption of severe asthma patients treated with biologics.

DESIGN

The Second Souffle study is a real-life prospective observational study endorsed by the Clinical Research Initiative in Severe Asthma: a Lever for Innovation & Science Network.

METHODS

Adults with a confirmed diagnosis of severe asthma for at least 12 months' duration were enrolled in the study. A self-administered questionnaire including the Asthma Control Questionnaire (ACQ), Asthma Quality of Life Questionnaire (AQLQ) and a compliance evaluation test was given to the patients. Healthcare consumption within 12 months prior to enrolment was documented. In patients receiving biologics, doctors indicated whether the patients were biologic responders or non-responders.

RESULTS

The characteristics of 431 patients with severe asthma were analysed. Among them, 409 patients (94.9%) presented asthma with type 2 inflammation (T2 high) profile, and 297 (72.6%) patients with a T2 high phenotype were treated with a biologic. Physicians estimated that 88.2% of patients receiving biologics were responders. However, asthma control was only achieved in 25.3% of those patients (ACQ > 0.75). A high proportion of patients (77.8%) identified as responders to biologics were not controlled according to the ACQ score. About 50% of patients continue to use oral corticosteroids either daily (25.2%) or more than three times a year for at least three consecutive days (25.6%). Gastro-oesophageal Reflux Disease (GERD) and Obstructive Sleep Apnoea syndrome (OSA) were identified as independent factors associated with uncontrolled asthma.

CONCLUSION

Although a high proportion of severe asthma patients respond to biologics, only 25.3% have controlled asthma. GERD and OSA are independent factors of uncontrolled asthma.

Differences in L-arginine metabolism and asthma morbidity among asthma patients with and without obstructive sleep apnea

BACKGROUND

Imbalance in L-arginine and nitric oxide (NO) metabolism has been implicated in the pathophysiology of asthma and obstructive sleep apnea (OSA), and both diseases impact the other's morbidity. We sought to determine whether L-arginine/NO metabolism differs between adults with asthma with or without comorbid OSA, and its association with asthma morbidity.

METHODS

This is a cross-sectional study of 322 adults with asthma recruited in Denver, CO and New York City, NY. Data were collected on OSA status, spirometry, and metrics of asthma control and morbidity. L-Arginine metabolites were quantified in patient serum. Bivariate analyses and multiple regression were performed to determine differences between L-arginine metabolism, OSA and association with asthma morbidity.

RESULTS

Among the 322 participants, 92 (28.5%) had OSA. The cohort was 81.6% female, 23.4% identified as Black and 30.6% as Latino. Patients with asthma and OSA had significantly higher serum concentrations of NO synthase inhibitor asymmetric dimethylarginine (ADMA) (p-value = 0.019), lower L-arginine to ornithine ratios (p-value = 0.003), and increased ornithine (p-value = 0.001) and proline levels (p-value < 0.001) compared to those without OSA. In adjusted models, OSA was associated with worse asthma control, adjusted mean difference in asthma control questionnaire of 0.36 (95% confidence interval [CI]: 0.06 to 0.65), and asthma quality of life questionnaire, adjusted mean difference: - 0.53 (95% CI: - 0.85 to - 0.21), after adjusting for relevant covariates including body mass index and L-arginine metabolites.

CONCLUSIONS

Adults with asthma and OSA had increased ADMA, an inhibitor of nitric oxide synthase, and greater metabolism of L-arginine via the arginase pathway compared to those with asthma alone, indicating a possible shared pathophysiological mechanism of these diseases.

Overlaps between obstructive sleep apnoea and other respiratory diseases, including COPD, asthma and interstitial lung disease

In the past, there was limited research relating to the role of sleep in respiratory diseases. Physicians treating these patients tended to focus mainly on the daily disabling symptoms, overlooking the possible significant role of coexisting sleep disorders such as obstructive sleep apnoea (OSA). Nowadays, OSA has been recognised as an important, highly prevalent comorbidity for respiratory diseases such as COPD, asthma and interstitial lung diseases (ILDs). Overlap syndrome refers to the coexistence of chronic respiratory disease and OSA in the same patient. Although, in the past, overlap syndromes have been poorly studied, recent data underline that they result in increased morbidity and mortality compared with either underlying disorder alone. OSA and respiratory disease may be of different severity, and this, along with the existence of various clinical phenotypes, points to the necessity of an individualised therapeutic plan. Early recognition and OSA management could offer key benefits, such as improved sleep, quality of life and disease outcomes.

Educational aims

Describe pathophysiological aspects of OSA in chronic respiratory diseases such as COPD, asthma and ILDs.Understand the bidirectional clinical importance when OSA coexists in chronic respiratory diseases.Review current knowledge of treatment strategies towards an individualised therapeutic plan resulting in patient-centric outcomes.

Brazilian Thoracic Association Consensus on Sleep-disordered Breathing

Sleep is essential for the proper functioning of all individuals. Sleep-disordered breathing can occur at any age and is a common reason for medical visits. The objective of this consensus is to update knowledge about the main causes of sleep-disordered breathing in adult and pediatric populations, with an emphasis on obstructive sleep apnea. Obstructive sleep apnea is an extremely prevalent but often underdiagnosed disease. It is often accompanied by comorbidities, notably cardiovascular, metabolic, and neurocognitive disorders, which have a significant impact on quality of life and mortality rates. Therefore, to create this consensus, the Sleep-Disordered Breathing Department of the Brazilian Thoracic Association brought together 14 experts with recognized, proven experience in sleep-disordered breathing.

OSA and Chronic Respiratory Disease: Mechanisms and Epidemiology

Obstructive sleep apnea (OSA) is a highly prevalent disorder that has profound implications on the outcomes of patients with chronic lung disease. The hallmark of OSA is a collapse of the oropharynx resulting in a transient reduction in airflow, large intrathoracic pressure swings, and intermittent hypoxia and hypercapnia. The subsequent cytokine-mediated inflammatory cascade, coupled with tractional lung injury, damages the lungs and may worsen several conditions, including chronic obstructive pulmonary disease, asthma, interstitial lung disease, and pulmonary hypertension. Further complicating this is the sleep fragmentation and deterioration of sleep quality that occurs because of OSA, which can compound the fatigue and physical exhaustion often experienced by patients due to their chronic lung disease. For patients with many pulmonary disorders, the available evidence suggests that the prompt recognition and treatment of sleep-disordered breathing improves their quality of life and may also alter the course of their illness. However, more robust studies are needed to truly understand this relationship and the impacts of confounding comorbidities such as obesity and gastroesophageal reflux disease. Clinicians taking care of patients with chronic pulmonary disease should screen and treat patients for OSA, given the complex bidirectional relationship OSA has with chronic lung disease.

The Role of Comorbidities in Difficult-to-Control Asthma in Adults and Children

Assessment of asthma comorbidities, conditions that adversely affect the pathobiology of asthma or impair its response to therapies, is a fundamental step in the evaluation and management of patients with difficult-to-treat asthma. Identifying and effectively treating asthma comorbidities, such as obesity, obstructive sleep apnea, and chronic sinusitis with nasal polyps, may improve asthma control and reduce exacerbations. In addition, identifying comorbid T2 inflammatory conditions may help guide optimal selection of biologic therapies. Here, we describe common comorbid conditions found in adult and pediatric difficult-to-control asthma, discuss evidence for the association with asthma morbidity and treatment benefit, and provide information on how and when to assess comorbidities.

Asthma and obstructive sleep apnoea in adults and children - an up-to-date review

Obstructive sleep apnoea (OSA) and asthma are two common respiratory disorders in children and adults. Apart from common risk factors, such as obesity, gastroesophageal reflux disease and allergic rhinitis, emerging evidence suggest that the two diseases may complicate the clinical course of each other. On one hand, OSA modifies asthmatic airway inflammation and is associated with poor asthma control. On the other hand, asthma and its medications increase the collapsibility of the upper airways contributing to the development and worsening of OSA. The overnight respiratory symptoms of OSA and asthma are often similar, and an inpatient polysomnography is often necessary for a proper diagnosis, especially in children. Continuous positive pressure, the gold standard treatment for OSA can improve asthma control in patients suffering from both diseases. However, there is limited evidence how anti-asthma medications act in the same patients. Nevertheless, adenotonsillectomy seems to be effective in children with concomitant asthma and OSA. This review summarises the evidence for the bidirectional link between asthma and OSA, focuses on diagnostic and therapeutic challenges and highlights the need for further research.

Association of Obstructive Apnea with Thoracic Fluid Shift and Small Airways Narrowing in Asthma During Sleep

RATIONALE

Obstructive sleep apnea (OSA) is highly prevalent among patients with asthma, suggesting a pathophysiological link between the two, but a mechanism for this has not been identified.

HYPOTHESIS

Among patients with asthma, those with OSA will have greater overnight increases in thoracic fluid volume and small airways narrowing than those without OSA.

METHODS

We enrolled 19 participants with asthma: 9 with OSA (apnea-hypopnea index (AHI) ≥10) and 10 without OSA (AHI <10). All participants underwent overnight polysomnography. Before and after sleep, thoracic fluid volume was measured by bioelectrical impedance and small airways narrowing was primarily assessed by respiratory system reactance at 5Hz using oscillometry.

RESULTS

Patients with asthma and OSA (OSA group) had a greater overnight increase in thoracic fluid volume by 120.5 mL than patients without OSA (non-OSA group) (164.4 ± 44.0 vs 43.9 ± 47.3 mL, p=0.006). Compared to the non-OSA group, the OSA group had greater overnight decrease in reactance at 5Hz (-1.08 ± 0.75 vs 0.21 ± 0.27 cmH₂O/L/s, p=0.02), and overnight increase in reactance area (14.81 ± 11.09 vs -1.20 ± 2.46 cmH₂O/L, p=0.04), frequency dependence of resistance (1.02 ± 0.68 vs 0.05 ± 0.18 cmH₂O/L/s, p=0.04), and resonance frequency (2.80 ± 4.14 vs -1.42 ± 2.13 cmH₂O/L/s, p=0.04).

CONCLUSION

Patients with asthma and co-existing OSA had greater overnight accumulation of fluid in the thorax in association with greater small airways narrowing than those without OSA. This suggests OSA could contribute to worsening of asthma at night by increasing fluid accumulation in the thorax.

Obstructive sleep apnea in patients with severe asthma: Prevalence and association between severity and asthma control

INTRODUCTION:

Asthma and obstructive sleep apnea (OSA) are common respiratory disorders that can coexist and cause sleep disturbances. The strength of this association and the impact of OSA on asthma severity and control remain unclear. The study aims to estimate the prevalence of OSA in patients with severe asthma in Oman and to examine whether the severity of OSA contributed to the level of asthma control.

METHODS:

Adult patients with confirmed diagnosis of severe asthma who attended the respiratory clinic in a tertiary hospital in Oman over a period of 19 months were enrolled in the study. Eligible participants were screened by asthma control test (ACT) and Berlin questionnaire (BQ). Patients with high risk for OSA were subjected further to level 3 sleep study. The prevalence of OSA in patients with severe asthma and the associations between the severity of OSA and asthma control were calculated.

RESULTS:

We identified 312 adult asthma patients on Global Initiative for Asthma step 4 or 5 management out of 550 who were screened. The mean age of the study population was 56.59 ± 12.40 years and the mean body mass index (BMI) 40.30 ± 12.24 kg/m². The prevalence of OSA in asthma patients with severe asthma was found to be 32.4%. Out of the 138 well-controlled asthma patients (ACT ≥20), 35 had high risk of OSA based on BQ, and 32 were confirmed to have OSA (23%). Of the 174 uncontrolled patients, 80 patients had high risk of OSA and 69 patients were confirmed to have OSA (39.65%). Severe OSA was seen in 63.8% and 9.4% in uncontrolled and controlled asthma patients, respectively (P = 0.002). The median respiratory event index in the uncontrolled group was 43, and it was significantly higher than 12.5 in the controlled group (P < 0.001).

CONCLUSIONS:

The prevalence of OSA was high (32.37%) in patients with severe asthma. Uncontrolled severe asthma was significantly associated with severe OSA.

Chronic Intermittent Hypoxia Reduces the Effects of Glucosteroid in Asthma via Activating the p38 MAPK Signaling Pathway

Aims

Obstructive sleep apnea (OSA) is a risk factor for steroid-resistant (SR) asthma. However, the underlying mechanism is not well defined. This study aimed to investigate how chronic intermittent hypoxia (CIH), the main pathophysiology of OSA, influenced the effects of glucocorticoids (GCs) on asthma.

Main Methods

The effects of dexamethasone (Dex) were determined using the ovalbumin (OVA)-challenged mouse model of asthma and transforming growth factor (TGF)-β treated airway smooth muscle cells (ASMCs), with or without CIH. The p38 MAPK signaling pathway activity was then detected in the mouse (n = 6) and ASMCs models (n = 6), which were both treated with the p38 MAPK inhibitor SB239063.

Key Findings

Under CIH, mouse pulmonary resistance value, inflammatory cells in bronchoalveolar lavage fluid (BALF), and inflammation scores increased in OVA-challenged combined with CIH exposure mice compared with OVA-challenged mice (p < 0.05). These indicators were similarly raised in the OVA + CIH + Dex group compared with the OVA + Dex group (P < 0.05). CIH exposure enhanced the activation of the p38 MAPK pathway, oxidative stress injury, and the expression of NF-κB both in lung tissue and ASMCs, which were reversed by treatment with Dex and SB239063. In the in vitro study, treatment with Dex and SB239063 decreased ASMCs proliferation induced by TGF-β combined with CIH and suppressed activation of the p38 MAPK pathway, oxidative stress injury, and NF-κB nuclear transcription (p < 0.05).

Significance

These results indicated that CIH decreased GC sensitivity by activating the p38 MAPK signaling pathway.

Asthma and Three Colinear Comorbidities: Obesity, OSA, and GERD

Asthma is a complex disease with heterogeneous phenotypes and endotypes that are incompletely understood. Obesity, obstructive sleep apnea, and gastroesophageal reflux disease co-occur in patients with asthma at higher rates than in those without asthma. Although these diseases share risk factors, there are some data suggesting that these comorbidities have shared inflammatory pathways, drive the development of asthma, or worsen asthma control. This review discusses the epidemiology, pathophysiology, management recommendations, and key knowledge gaps of these common comorbidities.

Continuous Positive Airway Pressure (CPAP) in Non-Apneic Asthma: A Clinical Review of Current Evidence

The use of continuous positive airway pressure (CPAP) in asthma has been a point of debate over the past several years. Various studies, including those on animals and humans have attempted to understand the role and pathophysiology of CPAP in patients with either well controlled or poorly controlled asthma. The aim of this manuscript is to review the currently available literature on the physiologic and clinical effects of CPAP in animal models of asthma and on humans with stable asthma.

Association between lung function decline and obstructive sleep apnoea: the ALEC study

Purpose

To study changes in lung function among individuals with a risk of obstructive sleep apnoea (OSA), and if asthma affected this relationship.

Methods

We used data from the European Community Respiratory Health Survey II and III, a multicentre general population study. Participants answered questionnaires and performed spirometry at baseline and 10-year follow-up (n = 4,329 attended both visits). Subjects with high risk for OSA were identified from the multivariable apnoea prediction (MAP) index, calculated from BMI, age, gender, and OSA symptoms at follow-up. Asthma was defined as having doctor’s diagnosed asthma at follow-up. Primary outcomes were changes in forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) from baseline to follow-up.

Results

Among 5108 participants at follow-up, 991 (19%) had a high risk of OSA based on the MAP index. Participants with high OSA risk more often had wheeze, cough, chest tightness, and breathlessness at follow-up than those with low OSA risk. Lung function declined more rapidly in subjects with high OSA risk (low vs high OSA risk [mean ± SD]: FEV1 = − 41.3 ± 24.3 ml/year vs − 50.8 ± 30.1 ml/year; FVC = − 30.5 ± 31.2 ml/year vs − 45.2 ± 36.3 ml/year). Lung function decline was primarily associated with higher BMI and OSA symptoms. OSA symptoms had a stronger association with lung function decline among asthmatics, compared to non-asthmatics.

Conclusion

In the general population, a high probability of obstructive sleep apnoea was related to faster lung function decline in the previous decade. This was driven by a higher BMI and more OSA symptoms among these subjects. The association between OSA symptoms and lung function decline was stronger among asthmatics.

Electronic supplementary material

The online version of this article (10.1007/s11325-020-02086-1) contains supplementary material, which is available to authorized users.

Role of serum periostin in severe obstructive sleep apnea with albuminuria: an observational study

BACKGROUND

Periostin is a matricellular protein and is a useful marker in respiratory diseases. However, the roles of periostin in patients with obstructive sleep apnea (OSA) remain unclear. Several in vitro studies have suggested that mechanical stress, hypoxia, impaired metabolism, and kidney injury, which often accompany OSA, may upregulate the expression of periostin. Meanwhile, serum periostin level has been negatively associated with body mass index (BMI) in the general population. In this study, we hypothesized that a high level of serum periostin despite being overweight/obese may discriminate severe OSA or OSA with comorbidities from mild OSA with obesity alone. We aimed to clarify the roles of periostin in patients with OSA to assist in elucidating the heterogeneity of OSA with comorbidities.

METHODS

Among patients diagnosed as OSA, we examined the associations between serum periostin levels and clinical indices, including the severity of OSA, BMI, and comorbidities, using a multifaceted approach. The serum periostin levels and clinical indices were assessed after 3 months of continuous positive airway pressure (CPAP) treatment.

RESULTS

In 96 patients with OSA, serum periostin level was negatively correlated with BMI, albeit marginally, and tended to be higher in severe OSA than in others when adjusted for BMI. Cluster analysis identified four clusters, including two severe OSA clusters, one of which was characterized by high serum periostin levels and the presence of comorbidities, including albuminuria. In a comparative analysis of severe OSA cases (n = 53), the level of serum-free fatty acids and the frequency of albuminuria were higher in patients with high serum periostin level of ≥87 ng/mL, which was the highest quintile among all participants, than in those with low serum periostin levels (< 87 ng/mL, n = 41). In patients with severe OSA and high serum periostin levels, the levels of serum periostin and urinary albumin significantly decreased after 3 months of CPAP treatment.

CONCLUSIONS

Elevated serum periostin in patients with OSA despite being overweight/obese may be an indicator of severe OSA with comorbidities, particularly albuminuria.

Comorbidities associated with severe asthma

Background:

Severe asthma can be a challenging disease to manage by the provider and by the patient, supported by evidence of increased health-care utilization by this population. Patients with severe asthma should be screened for comorbidities because these often contribute to poorly controlled asthma. The impact of comorbidities, however, are not completely understood.

Objective:

To review common comorbidities and their impact on severe asthma.

Methods:

A review of relevant clinical research studies that examined comorbidities in severe or difficult-to-treat asthma.

Results:

A number of comorbid diseases, including rhinitis, rhinosinusitis, gastroesophageal reflux, and obstructive sleep apnea, are associated with severe or difficult-to-treat asthma. If present and untreated, these conditions may adversely affect asthma control, quality of life, and/or lung function, despite adequate treatment with step-up asthma controller therapy.

Conclusion:

Treatable comorbidities are associated with severe and difficult-to-control asthma. Failure to recognize these comorbidities may divert appropriate care and increase disease burden. Assessment and management of these risk factors may contribute to improved asthma outcome; however, more investigation is needed to understand the relationship of comorbidities and asthma due to inconsistency in the findings.

Obstructive sleep apnea and comorbidities: a dangerous liaison

Obstructive sleep apnea (OSA) is a highly prevalent disease, and is traditionally associated with increased cardiovascular risk. The role of comorbidities in OSA patients has emerged recently, and new conditions significantly associated with OSA are increasingly reported. A high comorbidity burden worsens prognosis, but some data suggest that CPAP might be protective especially in patients with comorbidities. Aim of this narrative review is to provide an update on recent studies, with special attention to cardiovascular and cerebrovascular comorbidities, the metabolic syndrome and type 2 diabetes, asthma, COPD and cancer. Better phenotypic characterization of OSA patients, including comorbidities, will help to provide better individualized care. The unsatisfactory adherence to CPAP in patients without daytime sleepiness should prompt clinicians to examine the overall risk profile of each patient in order to identify subjects at high risk for worse prognosis and provide the optimal treatment not only for OSA, but also for comorbidities.