Obstructive sleep apnea syndrome and asthma: the role of continuous positive airway pressure treatment

The frequency of sleep-disordered breathing in preschool children with asthma and its effects on control of asthma

CONCLUSION

The frequency and score of SDB were higher in patients with uncontrolled asthma. Frequency and score of SDB were significantly affected by the severity of asthma. SDB must be evaluated in preschool children with uncontrolled asthma.

CONCLUSION

Sleep-disordered breathing (SDB) is more common in asthmatic patients than in non-asthmatic persons, and SDB affects negatively to control asthma. A limited number of studies are discovered on the effect of SDB in preschool asthmatic children. In this study, we aimed to investigate the prevalence of SDB and its effect on control and severity of asthma in preschool children. A pediatric sleep questionnaire was completed by parents of asthmatic children. Patients who received a score of 0.33 or higher were diagnosed with SDB. Control and severity of asthma was assessed by a pediatric allergy specialist based on the Global Initiative for Asthma (GINA) criteria. The study included 249 patients, with a mean±SD age of 4.37±1.04 (range: 2-5.9) years; 69% were boys; 56.6% children had uncontrolled asthma and 28.7% had SDB. The SDB score was significantly different between controlled and uncontrolled asthma (0.19 vs 0.28; P < 0.001). The frequency of uncontrolled asthma in patients with and without SDB was 74.3% and 49.4%, respectively (P < 0.010). Based on the severity of asthma, the frequency of SDB among patients with mild, moderate, and severe asthma was 23.4%, 35.2%, and 47.4%, respectively (P = 0.010).

Brain response in asthma: the role of "lung-brain" axis mediated by neuroimmune crosstalk

In addition to typical respiratory symptoms, patients with asthma are frequently accompanied by cognitive decline, mood disorders (anxiety and depression), sleep disorders, olfactory disorders, and other brain response manifestations, all of which worsen asthma symptoms, form a vicious cycle, and exacerbate the burden on families and society. Therefore, studying the mechanism of neurological symptoms in patients with asthma is necessary to identify the appropriate preventative and therapeutic measures. In order to provide a comprehensive reference for related research, we compiled the pertinent literature, systematically summarized the latest research progress of asthma and its brain response, and attempted to reveal the possible "lung-brain" crosstalk mechanism and treatment methods at the onset of asthma, which will promote more related research to provide asthmatic patients with neurological symptoms new hope.

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.

Prevalence of and risk factors for obstructive sleep apnea in children with sickle cell: a multicentric cross sectional study

The prevalence of obstructive sleep apnea syndrome (OSAS) is elevated in some high-risk populations. Children with sickle cell disease (SCD) are known to have many comorbidities, including OSAS. The objectives of this study were to assess the prevalence of and risk factors for OSAS among children with SCD in two major tertiary health care facilities in Jeddah, Saudi Arabia. This multicenter cross-sectional study took place in two major tertiary health care facilities-King Abdulaziz University Hospital and King Khalid National Guard Hospital, Jeddah, Saudi Arabia. Children with SCD who were admitted between January 2010 and December 2017 were enrolled. The Pediatric Sleep Questionnaire (PSQ) was used to screen for OSAS. Data were collected from 150 children with SCD aged between 2 and 18 years. Eighty-five percent of the children had sickle cell anemia (SCA) with HbSS, and the rest had sickle beta-thalassemia (HbS/ß-thalassemia). Based on the PSQ, 33 of the 150 (22%) children had OSAS (score ≥ 7). The average score on the PSQ was 3.8/22 (± 3.8). A history of adenotonsillar hypertrophy was found to be a significant risk factor in bivariate and multivariate analyses [aOR 5.5; 95% CI 1.84-16.35 (P < 0.001)]. The odds of having OSAS were ninefold higher in children who had periodic limb movements than in those who did not after adjustment [95% CI 1.75-48.03 (P < 0.001)]. OSAS is a highly prevalent disease among children with SCD. Many factors were associated with OSAS in the bivariate analysis, including nationality, education level, a history of adenotonsillar hypertrophy, and a history of periodic limb movements.

Interrelationship Between Obstructive Sleep Apnea Syndrome and Severe Asthma: From Endo-Phenotype to Clinical Aspects

Sleep-related breathing disorders (SBDs) are characterized by abnormal respiration during sleep. Obstructive sleep apnea (OSA), a common SBD increasingly recognized by physicians, is characterized by recurrent episodes of partial or complete closure of the upper airway resulting in disturbed breathing during sleep. OSA syndrome (OSAS) is associated with decreased patients' quality of life (QoL) and the presence of significant comorbidities, such as daytime sleepiness. Similarly to what seen for OSAS, the prevalence of asthma has been steadily rising in recent years. Interestingly, severe asthma (SA) patients are also affected by poor sleep quality—often attributed to nocturnal worsening of their asthma—and increased daytime sleepiness and snoring compared to the general population. The fact that such symptoms are also found in OSAS, and that these two conditions share common risk factors, such as obesity, rhinitis, and gastroesophageal reflux, has led many to postulate an association between these two conditions. Specifically, it has been proposed a bidirectional correlation between SA and OSAS, with a mutual negative effect in term of disease severity. According to this model, OSAS not only acts as an independent risk factor of asthma exacerbations, but its co-existence can also worsen asthma symptoms, and the same is true for asthma with respect to OSAS. In this comprehensive review, we summarize past and present studies on the interrelationship between OSAS and SA, from endo-phenotype to clinical aspects, highlighting possible implications for clinical practice and future research directions.

Impact of comorbid conditions on asthmatic adults and children

Comorbid conditions (comorbidities) can complicate the diagnosis and management of asthma. In different age groups, comorbid conditions can present varying challenges, including diagnostic confusion due to mimicking asthma symptoms, exacerbation of asthma symptoms, therapy for comorbid conditions affecting asthma or therapy for asthma affecting these conditions. This review aims to summarise some common comorbid conditions with asthma, such as rhinitis, vocal cord dysfunction, gastro-oesophageal reflux, psychiatric disorders, obesity and obstructive sleep apnoea, and discuss their prevalence, symptoms, diagnosis and treatment, highlighting any differences in how they impact children and adults. Overall, there is a lack of data on the impact of treating comorbid conditions on asthma outcomes and further studies are needed to guide age-appropriate asthma management in the presence of these conditions.

Τhe Co-Existence of Obstructive Sleep Apnea and Bronchial Asthma: Revelation of a New Asthma Phenotype?

Bronchial asthma (BA) and obstructive sleep apnea (OSA) are common respiratory obstructive diseases that may coexist. It would be interesting to study the possible influence of that coexistence on both diseases. Until now, reviews focused mainly on epidemiology. The aim of this study was to review the literature in relation to epidemiology, pathophysiology, consequences, screening of patients, and treatment of the coexistence of OSA and BA. We pooled studies from the PubMed database from 1986 to 2019. OSA prevalence in asthmatics was found to be high, ranging from19% to 60% in non-severe BA, reaching up to 95% in severe asthma. Prevalence was correlated with the duration and severity of BA, and increased dosage of steroids taken orally or by inhalation. This high prevalence of the coexistence of OSA and BA diseases could not be a result of just chance. It seems that this coexistence is based on the pathophysiology of the diseases. In most studies, OSA seems to deteriorate asthma outcomes, and mainly exacerbates them. CPAP (continuous positive airway pressure) treatment is likely to improve symptoms, the control of the disease, and the quality of life in asthmatics with OSA. However, almost all studies are observational, involving a small number of patients with a short period of follow up. Although treatment guidelines cannot be released, we could recommend periodic screening of asthmatics for OSA for the optimal treatment of both the diseases.

Exposure to intermittent hypoxia inhibits allergic airway inflammation in a murine model of asthma

PURPOSE

Obesity increases the severity of asthma, and patients with severe asthma are often complicated with obstructive sleep apnea syndrome (OSAS), a concomitant disease of obesity. We investigated whether intermittent hypoxia (IH), which is a physiological feature of OSAS, modifies allergic airway inflammation in a murine model of asthma.

METHODS

Balb/c mice were sensitized by ovalbumin (OVA) intraperitoneally twice (days 1 and 14) and challenged with intranasal OVA three times (days 21, 22, and 23). The mice were exposed to IH either from days 1 to 24 (long exposure) or only from days 21 to 24 (short exposure). The impact of IH exposure to allergic airway inflammation was investigated using these mice models by histologic, morphometric, and molecular techniques. Additionally, the airway responsiveness to acetylcholine was also assessed.

RESULTS

OVA-sensitized and OVA-challenged mice exposed to room air (RA) showed increased total cell and eosinophil numbers in the BALF. The levels of interleukin (IL)-5 and IL-13 in the BALF also increased and goblet cell metaplasia was induced. In contrast, both long and short exposure to IH inhibited the increased total cell and eosinophil numbers. The levels of IL-5 and IL-13 in the BALF also decreased on exposure to IH. Moreover, the goblet cell hyperplasia and airway hyperresponsiveness were significantly reduced in mice exposed to IH compared to those exposed to RA.

CONCLUSIONS

These results suggest that IH may not deteriorate the asthmatic condition in a murine model of asthma.

Obstructive sleep apnea syndrome and autonomic dysfunction

Autonomic nervous system (ANS) has been extensively explored in obstructive sleep apnea (OSA). Autonomic alterations in these patients have been described by means of several methods, evaluating ANS function both directly with microneurography and indirectly through baroreflex sensitivity (BRS, by the sequence method or the cross-spectral approach), heart rate variability analysis (HRV, both in the time and frequency domain) during sleep and wake, or conventional laboratory tests, including cold pressor test, hand grip test or measurement of urinary cathecolamine excretion. Several studies in OSA patients have shown ANS alterations, in particular sympathetic overactivity, both acutely during apnea events and chronically during the daytime, being both also involved in cardiovascular consequences of sleep disordered breathing. The association between OSA and sympathetic dysregulation suggests a dose response relationship between OSA severity and the degree of sympathetic overactivity and this association seems to be reversible as the treatment of OSA is implemented. Additionally ANS is involved in regulating visceral and humoral functions to maintain the body homeostasis and in reaction and adaptation to external and internal stressor stimuli. However, the vast majority of studies have focussed on cardiovascular alterations, which are easier to measure, somewhat neglecting the other functions regulated by ANS. More evidence is therefore needed to better characterize the impact that sleep disorder breathing may have on ANS both in the short and long term.

[The problem of obstructive sleep apnea syndrome in asthmatic patients]

Asthma and obstructive sleep apnea syndrome (OSAS) are one of the most common chronic respiratory diseases. These have common risk factors that include obesity, gastroesophageal reflux disease (GERD) and impaired nasal breathing (allergic rhinitis, sinusitis). At the same time, experimental evidence demonstrates common pathophysiological mechanisms of these diseases, such as involvement in the process of the respiratory tract, a systemic inflammatory response, and implementation of neuromechanical reflexes. Thus, there is an obvious synergism between these conditions, which affects symptoms, response to therapy, and prognosis. The available data allow discussion on whether there is a need to identify and treat OSAS in asthmatic patients. By keeping in mind the high incidence of OSAS in patients with severe asthma, it may be suggested that treatment for OSAS can reduce the number of exacerbations, improve the quality of life, and decline the number of obstinate asthma cases. It is very important for general practitioners to assess risk factors, such as body weight, nasal stuffiness, and GERD, and to utilize screening tools for more efficient use of healthcare resources. Considering the known positive effects of CPAP therapy in short-term studies, future investigations should focus on the impact of CPAP therapy on asthma symptoms in the long-term, as well as on the effects of asthma drugs on the course of OSAS.

Asthma is associated with increased probability of needing CPAP in children with severe obstructive sleep apnea

OBJECTIVE

Initiation of continuous positive airway pressure (CPAP) in children with severe obstructive sleep apnea syndrome (OSAS) is challenging and the distinct features of the subset of children requiring CPAP are poorly defined. Asthma often coexists with OSAS in children. The goal of this study was to explore the influence of asthma in the need for CPAP therapy in children with severe OSAS.

HYPOTHESIS

Asthmatic children with severe OSAS have higher probability of needing CPAP than children with severe OSAS without asthma.

METHODS

Cross-sectional study of clinical presentation, individual risk factors, and initial overnight polysomnogram (PSG) parameters in children with severe OSAS. Severe OSAS was defined as an obstructive apnea hypopnea index ≥10/h. The association between asthma and CPAP initiation was studied individually and adjusted by pertinent covariates.

RESULTS

Four hundred eligible children (mean age 7 years, ±SD 5.3) with severe OSAS were enrolled and 133 individuals (33%) were identified to have asthma. The proportion of children needing CPAP was significantly higher in asthmatics with severe OSAS (29%) compared to those with OSAS alone (14%) (P < 0.01). Multivariate analysis demonstrated that the association between asthma and the need of CPAP in pediatric severe OSAS was independent of demographics, OSAS severity, obesity, and history of adenotonsillectomy (P < 0.01).

CONCLUSION

Asthmatic children with severe OSAS have higher probability of needing CPAP independent of relevant covariables. This study further substantiates the link between OSAS and asthma in children and suggests the diagnosis of asthma may influence the need of CPAP therapy for severe OSAS.

Inherent vs. Induced Loop Gain Abnormalities in Obstructive Sleep Apnea

Unstable ventilatory chemoreflex control, quantified as loop gain, is recognized as one of four key pathophysiological traits that contribute to cause obstructive sleep apnea (OSA). Novel treatments aimed at reducing loop gain are being investigated, with the intention that future OSA treatment may be tailored to the individual's specific cause of apnea. However, few studies have evaluated loop gain in OSA and non-OSA controls and those that have provide little evidence to support an inherent abnormality in either overall chemical loop gain in OSA patients vs. non-OSA controls, or its components (controller and plant gain). However, intermittent hypoxia may induce high controller gain through neuroplastic changes to chemoreflex control, and may also decrease plant gain via oxidative stress induced inflammation and reduced lung function. The inherent difficulties and limitations with loop gain measurements are discussed and areas where further research are required are highlighted, as only by understanding the mechanisms underlying OSA are new therapeutic approaches likely to emerge in OSA.

Does nasal congestion have a role in decreased resistance to regular CPAP usage?

Nasal obstruction is known to cause resistance to continuous positive airway pressure (CPAP) therapy in obstructive sleep apnea syndrome (OSAS). In this paper, short- and long-term nasal congestion in OSAS patients receiving CPAP treatment were evaluated with acoustic rhinometry (AR). A total of 36 patients with moderate-to-severe OSAS, diagnosed with polysomnography were included in the study. Ten healthy subjects without OSAS constituted the control group. Pre-treatment nasal patency were measured with AR in all participants. 26 patients used the recommended CPAP treatment. Ten patients did not accept CPAP treatment. The AR test was repeated for all the subjects after 1 and 3 months except the 3rd month's measurements of the control group. There was no statistically significant difference between the initial minimum cross-sectional area (MCA) measurements of OSAS patients, using or not using CPAP, and the control group (P > 0.05). However, the first month MCA measurements of patients receiving CPAP were found to be significantly decreased compared with the initial values (P < 0.001). There was no significant change in the first and third months MCA values in the control group and patients who did not use CPAP (P > 0.05). No significant difference revealed in the 3rd month MCA measurements of the patients using CPAP compared with the initial values (P > 0.05). In this study, the increased nasal congestion, which is thought to be the cause of CPAP resistance, was objectively demonstrated in OSAS patients using CPAP. In addition, the nasal congestion developing at the first month was shown to disappear over time, supporting the opinion that patient compliance in CPAP treatment is expected to increase after regular device usage.

Síndrome de apnea-hipopnea obstructiva del sueño y enfermedades respiratorias

El síndrome de apnea-hipopnea obstructiva del sueño (SAHOS) es una enfermedad sistémica con afectación de múltiples órganos. El presente artículo trata la relación que existe entre el SAHOS y algunas enfermedades que comprometen el sistema respiratorio como son la enfermedad pulmonar obstructiva crónica, el asma, la tos crónica, el síndrome de hipoventilación alveolar y la fibrosis pulmonar. Por lo general, cada una de estas afectaciones se diagnostica por separado, pero es importante conocer su relación de coexistencia para definir la necesidad de realizar estudios del sueño diagnósticos a los pacientes con enfermedades respiratorias, en especial cuando hay un grado desproporcionado de hipertensión pulmonar al esperado por solo la presencia de la enfermedad respiratoria.

The relationship between allergic status and adenotonsillar regrowth: a retrospective research on children after adenotonsillectomy

Adenotonsillar regrowth in children after adenotonsillectomy (T&A) for obstructive sleep apnea (OSA) is often seen in clinical treatment, however, the relationship between allergic disease and adenotonsillar regrowth remains unclear. In this retrospective study, children were assigned to either the recurrence or control group, and subdivided by age at operation. Among children over 36 months, those in the recurrence group had more allergic disease and higher IgE, IL-4, and IL-5 levels than the same-aged children in control group. The Paediatric Allergic Disease Quality of Life Questionnaire (PADQLQ) scores for nasal symptoms and activity were higher in children older than 36 months in recurrence group. The results of immunohistochemistry and immunofluorescence showed that FoxP3+ cells (Tregs) were less, while GATA3+ cells (Th2 cells) were more in recurrence group for all ages. Allergic status and low levels of FoxP3 were proved as independent risk factors for adenotonsillar regrowth by multivariate logistic regression. These results indicate that allergic disease is a risk factor for adenotonsillar regrowth in children following T&A for OSA, and this risk increases with age. The decreased level of Tregs and subsequent changes in immune function play an important role in the pathogenesis of adenotonsillar regrowth.

Treatment of Obstructive Sleep Apnea. Prospects for Personalized Combined Modality Therapy

Obstructive sleep apnea (OSA) is a common sleep disorder with serious associated morbidities. Although several treatment options are currently available, variable efficacy and adherence result in many patients either not being treated or receiving inadequate treatment long term. Personalized treatment based on relevant patient characteristics may improve adherence to treatment and long-term clinical outcomes. Four key traits of upper airway anatomy and neuromuscular control interact to varying degrees within individuals to cause OSA. These are: (1) the pharyngeal critical closing pressure, (2) the stability of ventilator chemoreflex feedback control (loop gain), (3) the negative intraesophageal pressure that triggers arousal (arousal threshold), and (4) the level of stimulus required to activated upper airway dilator muscles (upper airway recruitment threshold). Simplified diagnostic methods are being developed to assess these pathophysiological traits, potentially allowing prediction of which treatment would best suit each patient. In contrast to current practice of using various treatment modes alone, model predictions and pilot clinical trials show improved outcomes by combining several treatments targeted to each patient's pathophysiology profile. These developments could theoretically improve efficacy and adherence to treatment and in turn reduce the social and economic health burden of OSA and the associated life-threatening morbidities. This article reviews OSA pathophysiology and identifies currently available and investigational treatments that may be combined in the future to optimize therapy based on individual profiles of key patient pathophysiological traits.

Refractory asthma - An old disorder: Novel approaches for effective control

Bronchial asthma is an inflammatory disorder of airways characterized by hyper-responsiveness to a wide range of triggers and is associated with variable airflow obstruction that remits spontaneously or with the treatment. Several phenotype of asthma not responding to the currently acceptable standard therapy of high dose inhaled gluco-corticosteroids along with along acting β2 agonists come under the purview of refractory asthma. This condition is a heterogeneous and complex disease that requires a multi-disciplinary approach to identify accurately various sub-phenotypes to enable improved understanding of the pathogenesis and development of effective management strategies including use of novel methods and targeted therapy.

Long-term CPAP treatment improves asthma control in patients with asthma and obstructive sleep apnoea

PURPOSE

Both asthma and obstructive sleep apnoea cause sleep disturbance, daytime sleepiness and diminished quality of life. Continuous positive airway pressure (CPAP) is efficient in reducing symptoms related to sleep apnoea. Here we report the impact of long-term use of CPAP on asthma symptoms.

METHODS

A survey questionnaire was distributed to all of our obstructive sleep apnoea patients with CPAP therapy in 2013. We used the Finnish version of the Asthma Control Test™ (ACT) and a visual analogue scale (0 = no symptoms, 100 = severe asthma symptoms). Asthma was defined as self-reported physician-diagnosed disease and a special reimbursement for asthma medication by the Social Insurance Institution.

RESULTS

We sent 2577 questionnaires and received 1586 answers (61 %). One hundred ninety-seven patients were asthmatics with a prevalence of asthma among CPAP users of 13 %. We studied 152 patients (58 females) whose CPAP therapy was initiated after starting asthma medication. Their mean (SD) age was 62 (10) years, duration of CPAP 5.7 (4.7) years and their CPAP daily use was 6.3 (2.4) h. Self-reported asthma severity decreased significantly from 48.3 (29.6) to 33.1 (27.4) (p < 0.001), and ACT score increased significantly from 15.35 (5.3) to 19.8 (4.6) (p < 0.001) without a significant change in the body mass index (BMI). The percentage of patients using rescue medication daily reduced from 36 to 8 % with CPAP (P < 0.001).

CONCLUSIONS

We noticed a significant decrease in asthma symptoms with long-term use of CPAP in patients with both asthma and obstructive sleep apnoea.

Overlap syndrome--Asthma and obstructive sleep apnea

INTRODUCTION

Asthma is a chronic inflammatory disease with multiple phenotypes. There is still a major gap in the understanding of its complex causality. Obstructive sleep apnea (OSA) is a common condition that has been implicated as a risk factor for asthma exacerbations.

OBJECTIVES

This study aims to characterize patients with the diagnosis of asthma and suspected OSA; identify the presence of OSA and review, on the current literature, the association between asthma and OSA, as an overlap syndrome.

MATERIALS AND METHODS

The authors present a retrospective study that included patients diagnosed with asthma that underwent sleep study in a 3 year period. Demographic, clinical data, body mass index (BMI), sleep study parameters and treatments were analyzed.

RESULTS

The sample consisted of 47 patients. The majority of population was females (68%) and the mean age was 55.65 ± 13.04 years. The most common nighttime symptom was snoring (93.6%). Regarding BMI, values above the normal limit were observed in 89.36% of the patients. 68% underwent polysomnography and the others cardiorespiratory polygraphy. In 57.4% of the patients, OSA was confirmed with a higher prevalence in males (73.3%) compared to females (50%). The therapeutic approach in 81.8% of these patients was home ventilation therapy.

CONCLUSION

The combination of asthma and OSA has become increasingly more frequent. In the described study, the prevalence of OSA was 57.4%, value that is in fact higher than in general population. After the therapeutic approach, all patients referred improvement of symptoms. It is therefore essential that OSA is investigated in patients with asthma when there is poor control of symptoms, in order to achieve a better control.

Association between asthma and risk of developing obstructive sleep apnea

IMPORTANCE

Obstructive sleep apnea (OSA) is more common among patients with asthma; whether asthma is associated with the development of OSA is unknown.

OBJECTIVE

To examine the prospective relationship of asthma with incident OSA.

DESIGN, SETTING, AND PARTICIPANTS

Population-based prospective epidemiologic study (the Wisconsin Sleep Cohort Study) beginning in 1988. Adult participants were recruited from a random sample of Wisconsin state employees to attend overnight polysomnography studies at 4-year intervals. Asthma and covariate information were assessed during polysomnography studies through March 2013. Eligible participants were identified as free of OSA (apnea-hypopnea index [AHI] of <5 events/h and not treated) by 2 baseline polysomnography studies. There were 1105 4-year follow-up intervals provided by 547 participants (52% women; mean [SD] baseline age, 50 [8] years).

EXPOSURES

Questionnaire-assessed presence and duration of self-reported physician-diagnosed asthma.

MAIN OUTCOMES AND MEASURES

The associations of presence and duration of asthma with 4-year incidences of both OSA (AHI of ≥5 or positive airway pressure treatment) and OSA concomitant with habitual daytime sleepiness were estimated using repeated-measures Poisson regression, adjusting for confounders.

RESULTS

Twenty-two of 81 participants (27% [95% CI, 17%-37%]) with asthma experienced incident OSA over their first observed 4-year follow-up interval compared with 75 of 466 participants (16% [95% CI, 13%-19%]) without asthma. Using all 4-year intervals, participants with asthma experienced 45 cases of incident OSA during 167 4-year intervals (27% [95% CI, 20%-34%]) and participants without asthma experienced 160 cases of incident OSA during 938 4-year intervals (17% [95% CI, 15%-19%]); the corresponding adjusted relative risk (RR) was 1.39 (95% CI, 1.06-1.82), controlling for sex, age, baseline and change in body mass index, and other factors. Asthma was also associated with new-onset OSA with habitual sleepiness (RR, 2.72 [95% CI, 1.26-5.89], P = .045). Asthma duration was related to both incident OSA (RR, 1.07 per 5-year increment in asthma duration [95% CI, 1.02-1.13], P = .01) and incident OSA with habitual sleepiness (RR, 1.18 [95% CI, 1.07-1.31], P = .02).

CONCLUSIONS AND RELEVANCE

Asthma was associated with an increased risk of new-onset OSA. Studies investigating the mechanisms underlying this association and the value of periodic OSA evaluation in patients with asthma are warranted.

Obstructive sleep apnea and asthma

Symptoms of sleep-disordered breathing, especially obstructive sleep apnea syndrome (OSAS), are common in asthma patients and have been associated with asthma severity. It is known that asthma symptoms tend to be more severe at night and that asthma-related deaths are most likely to occur during the night or early morning. Nocturnal symptoms occur in 60-74% of asthma patients and are markers of inadequate control of the disease. Various pathophysiological mechanisms are related to the worsening of asthma symptoms, OSAS being one of the most important factors. In patients with asthma, OSAS should be investigated whenever there is inadequate control of symptoms of nocturnal asthma despite the treatment recommended by guidelines having been administered. There is evidence in the literature that the use of continuous positive airway pressure contributes to asthma control in asthma patients with obstructive sleep apnea and uncontrolled asthma.

Defining severe asthma - an approach to find new therapies

Asthma is a chronic inflammatory disease that has reached epidemic proportions worldwide. It is treatable in the majority of patients, but there is no cure. Moreover, a proportion of patients suffer from severe, difficult-to-control disease with daily symptoms and high morbidity, making it imperative that we continue to improve our understanding of the underlying mechanisms of this disease. Severe asthma is a heterogeneous condition. A systematic approach to identify specific asthma phenotypes, including clinical characteristics and inflammatory processes, is the first step toward individualized, logical therapy. This review focuses on the need to characterize severe asthma phenotypes and on novel, targeted molecular treatment options currently under development.

Nocturnal continuous positive airway pressure in severe non-apneic asthma. A pilot study

INTRODUCTION

It has been demonstrated that brief periods of nocturnal continuous positive airway pressure (nCPAP) reduce airway reactivity in animal models and in patients with asthma. The effects of nCPAP in severe uncontrolled non-apneic asthmatic patients are not well known.

AIM

In this open pilot study, we aimed to assess the effect nCPAP on peak flow (PEF) variability and asthma control in this type of patients.

METHODS

CPAP was applied to 10 patients with severe long-standing asthma without obstructive sleep apnea for seven consecutive nights. CPAP was titrated in auto setting and applied to the patients. Daily PEF, was measured from 2 weeks before the intervention to 2 weeks after the end of nCPAP treatment. PEF amplitude and PEF morning dip (MD) over 24-h periods averaged over 1 week were calculated as indexes of PEF variability. Asthma control test (ACT) and European quality of life (EuroQol) questionnaire were measured at baseline and after 1 month, and at baseline and at the end of CPAP period, respectively.

RESULTS

The PEF amplitude significantly decreased both during CPAP period and in the first week after nCPAP discontinuation as compared with the baseline (19.8 ± 7.5%, 23.9 ± 9.1% and 28.9 ± 11.5%, respectively, always P < 0.05). PEF MD significantly decreased during nCPAP in comparison with the baseline (P < 0.001). The ACT and EuroQol significantly improved after nCPAP in comparison with the basal value.

CONCLUSIONS

In this preliminary report, brief period of nCPAP reduces PEF variability and improves control in severe non-apneic asthma at a short-term evaluation. Further studies with longer-term evaluation and larger number of patients are warranted.

Obstructive sleep apnea and asthma: associations and treatment implications

Obstructive sleep apnea (OSA) and asthma are highly prevalent respiratory disorders and are frequently co-morbid. Risk factors common to the two diseases include obesity, rhinitis, and gastroesophageal reflux (GER). Observational and experimental evidence implicates airways and systemic inflammation, neuromechanical effects of recurrent upper airway collapse, and asthma-controlling medications (corticosteroids) as additional explanatory factors. Therefore, undiagnosed or inadequately treated OSA may adversely affect control of asthma and vice versa. It is important for clinicians to be vigilant and specifically address weight-control, nasal obstruction, and GER in these populations. Utilizing validated screening instruments to affirm high risk of co-morbid OSA or asthma in persistently symptomatic patients will allow clinicians to cost-effectively test and treat appropriate patients, potentially improving outcomes. While non-invasive ventilation in acute asthma improves outcomes, the role of chronic continuous positive airway pressure (CPAP; the first-line treatment for OSA) in improving long-term asthma control is not known. Future research should focus on the impact of optimal CPAP therapy and adherence on asthma symptoms and outcomes.

Nocturnal phenotypical features of obstructive sleep apnea (OSA) in asthmatic children

BACKGROUND

Asthma and obstructive sleep apnea (OSA) often coexists during childhood. To delineate this clinical association, we investigated the phenotypical features of OSA in asthmatic children. Specifically, we hypothesized that asthmatic children have a distinct OSA phenotype that involves a higher prevalence of Rapid-Eye-Movement (REM)-related breathing abnormalities relative to children with OSA alone.

METHODS

We conducted a retrospective cross-sectional analysis of 141 children aged 2-12 years with OSA diagnosed by polysomnography (PSG) in our sleep center. Outcomes included PSG parameters, maximal %SaO2 REM desaturations and prevalence of REM-related OSA. Multivariate linear regression model or logistic regression model was built to study the joint effect of asthma and OSA parameters with control for potential confounders (significance level P < 0.05).

RESULTS

Baseline respiratory parameters, obstructive apnea-hypopnea index (OAHI) severity, and oxygenation during NREM sleep were unaffected by the presence of asthma in children with OSA. In contrast, maximal %SaO2 REM desaturation, REM-OAHI and prevalence of REM-related OSA in children with moderate-severe OSA were significantly increased in asthmatic children with OSA compared to subjects with OSA alone. Multivariate analysis revealed that the association between asthma and REM-related OSA parameters is independent of asthma control, BMI, age, and gender. The presence of REM-related OSA in asthmatics was unaffected by rhinitis or atopic status.

CONCLUSION

These results demonstrate that asthma is associated with REM-related breathing abnormalities in children with moderate-severe OSA. The link between asthma and REM-related OSA is independent of asthma control and obesity. Further research is needed to delineate the REM-sleep biological mechanisms that modulate the phenotypical expression of OSA in asthmatic children.

Obstructive sleep apnea is associated with reduced quality of life in adult patients with asthma

BACKGROUND

Recent data suggest that obstructive sleep apnea (OSA) is an important contributor to severe uncontrolled asthma.

OBJECTIVE

To investigate the clinical characteristics, asthma control, and asthma-related quality of life in adult patients with asthma at a high risk for OSA.

METHODS

A total of 217 patients with asthma who visited our tertiary-care clinic were randomly recruited. They completed the Berlin questionnaire, which screens for OSA risk, a quality-of-life questionnaire for adult Korean patients with asthma (QLQAKA), and underwent an asthma control test (ACT). Fraction of exhaled nitric oxide (FeNO), lung function, blood lipid profiles, and body composition were evaluated.

RESULTS

The mean age was 58.4 ± 15.4, and 91 (41.9%) were male. Eighty-nine subjects (41.0%) were classified as high risk for OSA from the Berlin questionnaire. Patients with a high OSA risk were significantly older, had a higher prevalence of hypertension, higher BMI, non-atopic predisposition, and longer asthma treatment duration in the baseline clinical characteristics. The high OSA risk group had a lower ACT score than the low OSA risk group, but it was not statistically significant (20.9 ± 3.6 vs 21.5 ± 3.3, P = .091). The QLQAKA score was significantly lower in the high OSA risk group compared with the low OSA risk group (64.4 ± 10.9 vs 68.1 ± 11.1, P = .026), especially in the activity-domain (P = .005). The FeNO was not significantly different between the 2 groups.

CONCLUSION

Quality of life is significantly decreased in adult patients with asthma with a high risk of OSA. Special consideration is needed for the care and treatment of patients with asthma who have a high risk of OSA.

The treatment of asthma in obesity

The world is facing an unprecedented epidemic of obesity. This epidemic has led to major changes in the epidemiology of common diseases such as asthma. Obesity is a major risk factor for new-onset asthma. This article will discuss the role of mechanical and metabolic factors, as well as obesity-related comorbidities, in both causing airway disease and also affecting response to therapy in obese asthmatics. Asthma in obese individuals probably includes a spectrum of disease with at least two distinct phenotypes: early-onset allergic disease complicated by obesity and late-onset disease developing in the setting of obesity. Both phenotypes are distinct from asthma in lean individuals. Treatment of asthma in obesity needs to consider altered response to controller therapy, and the fact that mechanical factors, metabolic inflammation and other comorbidities are probably contributing to airway disease. Future studies should focus on the development of therapies specifically tailored towards the treatment of asthma in obesity.

Asthma and obesity: a known association but unknown mechanism

The obese asthma phenotype is an increasingly common encounter in our clinical practice. Epidemiological data indicate that obesity increases the prevalence and incidence of asthma, and evidence that obesity precedes the development of asthma raises the possibility of a causal association. Obese patients with asthma experience more symptoms and increased morbidity compared with non-obese asthma patients. Despite more than a decade of research into this association, the exact mechanisms that underlie the interaction of obesity with asthma remain unclear. It is unlikely that the asthma-obesity association is simply due to comorbidities such as obstructive sleep apnoea or gastroesophageal reflux disease. Although inflammatory pathways are purported to play a role, there is scant direct evidence in humans that systemic inflammation modulates the behaviour of the asthmatic airway or the expression of symptoms in the obese. The role of non-eosinophilic airway inflammation also requires further study. Obesity results in important changes to the mechanical properties of the respiratory system, and these obesity-related factors appear to exert an additive effect to the asthma-related changes seen in the airways. An understanding of the various physiological perturbations that might be contributing to symptoms in obese patients with asthma will allow for a more targeted and rational treatment approach for these patients.

Association of obstructive sleep apnea risk or diagnosis with daytime asthma in adults

OBJECTIVE

Obstructive sleep apnea (OSA) worsens nocturnal asthma, but its potential impact on daytime asthma remains largely unassessed. We investigated whether the sleep disorder is associated with daytime, in addition to nighttime, asthma symptoms.

METHODS

Asthma patients at tertiary-care centers completed the Sleep Apnea scale of the Sleep Disorders Questionnaire (SA-SDQ), and an asthma control questionnaire. SA-SDQ scores ≥36 for males and ≥32 for females defined high OSA risk. Medical records were reviewed for established diagnosis of OSA and continuous positive airway pressure (CPAP) use.

RESULTS

Among 752 asthma patients, high OSA risk was associated similarly with persistent daytime and nighttime asthma symptoms (p < .0001 for each). A diagnosis of OSA was robustly associated with persistent daytime (p < .0001) in addition to nighttime (p = .0008) asthma symptoms. In regression models that included obesity and other known asthma aggravators, high OSA risk retained associations with persistent daytime (odds ratio [OR] = 1.96 [95% confidence interval [CI] = 1.31-2.94]) and nighttime (1.97 [1.32-2.94]) asthma symptoms. Diagnosed OSA retained an association with persistent daytime (2.08 [1.13-3.82]) but not with nighttime (1.48 [0.82-2.69]) asthma symptoms. CPAP use was associated with lower likelihood of persistent daytime symptoms (0.46 [0.23-0.94]).

CONCLUSIONS

Questionnaire-defined OSA risk and historical diagnosis were each associated with persistent daytime asthma symptoms, to an extent that matched or exceeded associations with nighttime asthma symptoms. Unrecognized OSA may be a reason for persistent asthma symptoms during the day as well as the night.

Chronic cough and OSA: a new association?

Chronic cough is defined as cough lasting more than 2 months. Common causes for chronic cough in nonsmokers with normal chest radiographs and pulmonary functions include gastroesophageal reflux disease (GERD), cough-variant asthma (CVA), and upper airway cough syndrome (UACS). Current guidelines recommend diagnosing the etiology of chronic cough based upon the results of therapy for suspected GERD, CVA, and UACS. Despite following current recommendations for diagnosis and treatment, the cause for a significant proportion of chronic cough remains unexplained.Recent reports indicate the resolution of chronic cough following treatment of concomitantly diagnosed obstructive sleep apnea (OSA). Whether this represents a co-occurrence of two commonly prevalent disorders or a pathophysiologic relationship between OSA and cough remains unknown. This review offers insights into a pathophysiologic link between OSA and the commonly purported etiologies for cough, namely, GERD, UACS, and CVA. In addition, evidence for a relationship between airway inflammation that can trigger or perpetuate cough and OSA is discussed. This review explores mechanisms by which nocturnal continuous positive airway therapy resolves cough by improving underlying airway inflammation secondary to OSA and impacts upon GERD, CVA, and UACS.

Current treatment of severe asthma

Severe asthma is considered a heterogeneous disease in which a variety of clinical, physiological and inflammatory markers determine disease severity. Pivotal studies in the last 5 years have led to substantial progress in many areas, ranging from a more accurate definition of truly severe, refractory asthma, to classification of the disease into distinct clinical phenotypes, and introduction of new therapies. This review focuses on three common clinical phenotypes of severe asthma in adults (early onset severe allergic asthma, late onset non-atopic eosinophilic asthma, late onset non-eosinophilic asthma with obesity), and provides an overview of recent developments regarding treatment options that are best suited for each of these phenotypes.

[Sleep and chronic lung diseases: diffuse interstitial lung diseases, bronchial asthma, and COPD]

Chronic lung diseases can be aggravated by various factors and comorbidities, including sleep-disordered breathing. Although changes in the quality of life of patients with chronic lung disease are usually related to daytime variables, the physiological changes in sleep impair the quality of sleep and interfere with the natural history of the disease. Alterations in sleep architecture appear to be a common mechanism in these diseases. During sleep, the upper and lower airways are more interconnected: changes in upper airway resistance during sleep are added to the severe resistive alterations in the lower airways due to asthma and COPD. In addition, there are complex mechanical and ventilatory interactions. The recognition of these interactions allows better assessment of the exacerbations and the progression of chronic lung diseases.

Effects of obstructive sleep apnea and gastroesophageal reflux disease on asthma control in obesity

BACKGROUND

Obesity is a risk factor for asthma. Obese asthmatics often have poor asthma control and respond poorly to therapy. It has been suggested that co-morbidities associated with obesity, such as reflux and obstructive sleep apnea, could be important factors contributing to poor asthma control in obese patients.

OBJECTIVES

The purpose of this study was to determine if (1) reflux and/or (2) symptoms of sleep apnea contribute to poor asthma control in obesity.

METHODS

We studied asthmatic subjects participating in a trial of reflux treatment. Participants underwent baseline evaluation of asthma symptoms and lung function. Overall 304 participants underwent esophageal pH probe testing; 246 participants were evaluated for obstructive sleep apnea symptoms.

RESULTS

Of 402 participants in this trial, 51% were obese. Role of reflux in asthma control. Those with higher body mass index (BMI) reported a higher prevalence of reflux symptoms, but the prevalence of pH probe acid reflux was similar in all groups. Reflux was not associated with measures of asthma control in obese patients. Role of obstructive sleep apnea in asthma control. Symptoms and self-report of obstructive sleep apnea were more common with increasing BMI and associated with worse asthma control as measured by the Juniper Asthma Control questionnaire and Asthma Symptom Utility Index.

CONCLUSIONS

Our data suggest that obstructive sleep apnea, but not gastroesophageal reflux disease, may contribute significantly to poor asthma control in obese patients.

Optimizing maintenance therapy in pediatric asthma

PURPOSE OF REVIEW

There are different phenotypes of asthma, with phenotype-specific differences in medication response observed.

RECENT FINDINGS

Tobacco smoke exposure reduces corticosteroid responsiveness. Treatment for tobacco smoke-triggered asthma must start with treatment of tobacco dependence. Obesity-associated asthma responds to weight loss and treatment of comorbidities. Immunotherapy and omalizumab are specific therapies for atopic asthma, though its use is limited by expense, inconvenience, need for injections, and toxicities. Leukotriene modifier response is more prominent in viral-triggered asthma. Research on intermittent escalation of controller therapy for asthma shows best results when escalation is substantial and early. Inhaled corticosteroid medications in low-to-moderate doses remain the most important maintenance medication for a broad variety of asthma phenotypes, reducing both impairment and risk. When impairment is not fully controlled by an inhaled corticosteroid, combination with a long-acting beta-agonist, leukotriene modifier, or theophylline can be effective. Inhaled corticosteroid use in children does not appear to influence airway caliber or asthma severity after the medication is stopped.

SUMMARY

Optimizing maintenance therapy for asthma is not one size fits all. It is important to assess the asthma phenotype in addition to the symptom pattern, in determining optimal maintenance therapy.

Reversible airway obstruction in children with ataxia telangiectasia

INTRODUCTION

Lung disease is a significant cause of the short life span of ataxia telangiectasia (A-T) patients. Objective lung function measurements are difficult to achieve in A-T.

AIM

To assess lung function by spirometry in relation to the clinical characteristics of A-T patients followed up at the Israeli Ataxia Telangiectasia National Clinic.

PATIENTS AND METHODS

Medical and spirometry data were collected from 27 A-T patients during 2004-2007. Laboratory, nutritional condition, mode of treatment, pulmonary status, and malignancies were assessed. The spirometry values FVC, FEV(1), FEV(0.5), FEF(25-75), PEF and time rise to peak flow were analyzed individually and values were compared to those of healthy age-matched children.

RESULTS

Eleven patients (40.7%) were found to suffer from asthma according to clinical symptoms and response to bronchodilators. We found significant reduction in FEV(1) and FEV(0.5) (z-scores: -0.84 + or - 0.7 SD, -0.7 + or - 0.6 SD; P = 0.0014 and P = 0.003, respectively), in relation to healthy predicted values. FEF(25-75) was significantly lower than that in healthy children in 5 of 11 asthmatic patients. All 27 patients showed higher than healthy FEV(1)/FVC and FEV(0.5)/FVC ratios (z-scores 0.68 + or - 0.99 SD, P < 0.0015, and 2.12 + or - 1.50 SD, P < 0.0015, respectively). The rise time to peak flow was three-fold longer than that of healthy children.

CONCLUSION

Obstructive lung disease is common among A-T patients. Maximal peak flow reduction and prolonged rise time to peak flow may be the first signs of pulmonary involvement in these patients. Early treatment with anti-asthma therapy, bronchodilators, and steroids, may prevent further pulmonary deterioration and improve the prognosis of A-T patients.

Obesity, asthma, and oxidative stress

Obesity is associated with increased systemic and airway oxidative stress, which may result from a combination of adipokine imbalance, comorbidities, and reduced antioxidant defenses. While obesity-mediated increased oxidative stress plays an important role in the pathogenesis of vascular disease and nonalcoholic hepatic steatosis, little is known of how it may affect the lung. Contrary to what has previously been thought, the combination of obesity and asthma, both chronic inflammatory diseases, does not necessarily result in a synergistic effect, leading to even greater oxidative stress. However, most available studies have compared the levels of oxidative stress biomarkers on stable asthma patients, and it is possible that the interaction of oxidative stress between obesity and asthma is not readily detectable under basal conditions. We propose that obesity-mediated oxidative stress, which may affect the lung function of asthmatic subjects by increasing airway inflammation and reducing the effectiveness of inhaled corticosteroids, may become evident during exposure to an aggravating factor or during periods of asthma exacerbation. Understanding whether obesity-mediated oxidative stress has a mechanistic role in the association between obesity and asthma will help in the formation of public health policies and increase our capacity to develop therapeutic interventions that improve the life of obese asthmatic subjects.

Elevated economic burden in obstructive lung disease patients with concomitant sleep apnea syndrome

PURPOSE

The purpose of this study is to examine the incremental economic burden of sleep apnea syndrome (SAS) among individuals with concomitant asthma, chronic obstructive pulmonary disease (COPD), or both (i.e., asthma/COPD).

METHODS

Maryland Medicaid claims data were used to identify beneficiaries with asthma (n = 3,072), COPD (n = 3,455), or both (n = 2,604). We compared patient's baseline characteristics by SAS and stratified the analyses by disease cohort to examine the effect of SAS on medical utilization and cost.

RESULTS

SAS was more prevalent among beneficiaries with asthma/COPD (6.72%) than beneficiaries with COPD alone (2.87%) or asthma alone (2.15%). Asthma/COPD and COPD beneficiaries with SAS had more medical service claims (p < 0.001) and higher medical cost than beneficiaries without SAS: $5,773 and $4,155 in excess costs among asthma/COPD (p = 0.037) and COPD patients (p = 0.035), respectively. Medical utilization and cost did not differ by SAS in asthma patients (p = 0.567).

CONCLUSIONS

SAS may add additional economic burden on beneficiaries who already have COPD or asthma/COPD.