Original ArticleImpact of obstructive sleep apnea on severe asthma exacerbations
Introduction
Asthma is a common chronic disease of the respiratory system that involves complex interactions among airflow obstruction, airway hyper-responsiveness, and inflammation. It is estimated that about 300 million people of all ages suffer from asthma [1] and, in 2011, more than half of these asthma patients experienced asthma attacks [2]. Severe asthma exacerbations increase the usage of health care resources and families' social and economic burdens. These attacks are associated with reductions in assessed quality of life and are potentially life-threatening [3], [4]. Reducing the risk of exacerbations is a crucial/highly necessary treatment goal within asthma management guidelines. Therefore, identifying the risk factors for exacerbations could lead to appropriate early interventions and greatly benefit patients. While the findings from previous studies have identified that previous asthma exacerbations, the use of bronchodilator therapy, reduced pulmonary function, chronic sinusitis, gastro-esophageal reflux disease, and the need for larger amounts of controller therapy are among the risk factors for asthma exacerbations [5], [6], [7], [8], [9], [10], comorbid conditions have received far less attention.
Findings from studies suggest a bidirectional relationship between obstructive sleep apnea (OSA) and asthma. The findings from epidemiological studies have demonstrated that patients with asthma have a higher prevalence of OSA [11], [12]. A population-based cohort study discovered that the overall incidence of OSA was 2.51 times greater in the cohort of patients with asthma than in the comparison cohort [11]. The findings from a population-based prospective epidemiological study demonstrated that asthma was associated with both new-onset OSA and OSA with habitual sleepiness [12]. Likewise, patients with OSA have been reported to display many of the symptoms associated with asthma. Alharbi et al. reported that patients with OSA had a high prevalence of asthma (35.1%) [13]. The findings from a 14-year prospective study also suggested a pathogenic role for asthma in sleep-disordered breathing [14]. Accumulating evidence suggests that OSA contributes to poor asthma control [10], [15], [16], [17], while continuous positive airway pressure treatment can improve the quality of asthma patients' lives [17].
However, it remains unclear whether OSA affects severe exacerbations in patients with asthma. Understanding the impact of OSA on severe asthma exacerbations is a necessary element in the efforts to reduce the burden of both OSA and asthma. Therefore, we performed a prospective cross-sectional study to investigate the prevalence of OSA among patients with asthma as well as the associations between OSA indices and severe asthma exacerbations.
Section snippets
Ethical approval and informed consent
The study's protocols and the patient consent documents were approved by the ethics committee at Xiangyang Hospital, Hubei University of Medicine and Renmin Hospital, Wuhan University. All of the participants were able and willing to provide informed consent and to complete our study.
Subjects
Subjects aged 18–65 years who had asthma, which was defined as a minimum 12% increase in the post-bronchodilator forced expiratory volume in 1 s (FEV1) and >200 mL of the FEV1, or a positive methacholine challenge
Results
One hundred and forty-six patients with asthma and 157 control individuals completed this study. Table 1 shows the subjects' baseline characteristics. There were no significant differences between the groups in relation to age, sex, the FEV1, the forced vital capacity (FVC), the AHI, the BMI, the mean oxygen saturation level, the minimum oxygen saturation level, and the TSat90.
Forty-three patients were diagnosed with OSA using PSG, comprising 28 patients with asthma and 15 control individuals (
Discussion
The findings from this prospective cross-sectional cohort study showed that the prevalence of OSA was significantly higher among patients with asthma compared with the control subjects. OSA is associated with an increased severity of acute asthma exacerbations among asthma patients, and the patients who had asthma and OSA showed a 14-fold increase in the risk of severe asthma exacerbations compared with the patients who had asthma but did not have OSA. These are novel findings that highlight
Funding sources
The National Natural Science Foundation of China provided financial support in the form of national natural science funding (General Program Numbers 81070065 and 81370181).
Conflict of interest
This was not an industry-supported study, and there are no conflicts of interest to declare.
The ICMJE Uniform Disclosure Form for Potential Conflicts of Interest associated with this article can be viewed by clicking on the following link: http://dx.doi.org/10.1016/j.sleep.2016.06.013.
. ICMJE Form for Disclosure of Potential Conflicts of Interest form.
References (32)
- et al.
Effect of asthma exacerbations on health care costs among asthmatic patients with moderate and severe persistent asthma
J Allergy Clin Immunol
(2012) - et al.
Risk factors and predictive clinical scores for asthma exacerbations in childhood
Chest
(2010) - et al.
Assessing future need for acute care in adult asthmatics: the profile of asthma risk study: a prospective health maintenance organization-based study
Chest
(2007) - et al.
Longitudinal study of risk factors for habitual snoring in a general adult population: the Busselton Health Study
Chest
(2006) - et al.
Association of obstructive sleep apnea risk with asthma control in adults
Chest
(2010) - et al.
Exhaled pentane and nitric oxide levels in patients with obstructive sleep apnea
Chest
(1997) - et al.
Airway inflammation in patients affected by obstructive sleep apnea syndrome
Respir Med
(2004) - et al.
Sleep apnea is associated with bronchial inflammation and continuous positive airway pressure-induced airway hyperresponsiveness
J Allergy Clin Immunol
(2007) - et al.
Body mass index and asthma severity among adults presenting to the emergency department
Chest
(2003) - et al.
The global burden of asthma: executive summary of the GINA dissemination committee report
Allergy
(2004)
Global strategy for asthma management and prevention
Economic burden of asthma: a systematic review
BMC Pulm Med
Factors associated with asthma exacerbations during a long-term clinical trial of controller medications in children
J Allergy Clin Immunol
Global strategy for asthma management and prevention
Development and validation of a novel risk score for asthma exacerbations: the risk score for exacerbations
J Allergy Clin Immunol
Risk factors of frequent exacerbations in difficult-to-treat asthma
Eur Respir J
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2022, Clinics in Chest MedicineCitation Excerpt :Confounders, like obesity, make it difficult to ascertain the relationship between asthma and OSA and likely a bidirectional relationship exists. Regardless, the co-existence of asthma and OSA has been associated with worse clinical outcomes including asthma control and exacerbations, greater FEV1 decline, worse quality of life, and increased health resource utilization, highlighting the importance of diagnosing OSA in patients with asthma.154,158–161 This is especially true as very effective therapies for OSA are available.
Notation: This manuscript has neither been published in whole/in part nor is it being considered for publication elsewhere.