The Efficacy of Continuous Positive Airway Pressure in Achieving Asthma Control in Patients With Severe Asthma and Obstructive Sleep Apnea

Asthma is a common heterogeneous chronic disorder of the airways, characterized by variables, usually reversible and recurring symptoms related to one or more of airflow obstruction, bronchial hyper-responsiveness, and underlying inflammation. the prevalence of Asthma has been increasing in the last decades, affecting over 2 million Saudis. Multiple factors had been reported in the literature that contribute to poor asthma control. Uncontrolled asthma is affecting the quality of life and is a well-known cause of mortalities. Approximately 5-10% of asthmatics have severe or difficult to treat asthma that remains problematic despite optimal treatment. It is well known that using asthma medications alone in severe asthma patients without managing the associated comorbid disease such as cardiac disease, allergic rhinitis, obesity and obstructive sleep apnea (OSA) will apprehend our goal in asthma treatment. Therefore, Current asthma guideline recommend investigating the presence of OSA in the cases of severe or uncontrolled asthma.

Obstructive sleep apnea (OSA) is a disease that characterized by frequent narrowing or collapsed of upper airways during sleep. OSA diagnoses is underestimated in the asthma population although it is considered as one of the significant comorbid disease in such populations. Overlap syndrome between Asthma and OSA has been increasing in prevalence lately, as per a recent Meta-analysis up to 50% of adults with Asthma had OSA contributing to their poor control. Yigla etal did polysomnography in a small group of patients with difficult to treat asthma who have been on long term steroid and the prevalence of OSA in this population was reported to be as high as 95%.(5) Wang et al reported that patients with asthma has a high prevalence of OSA (19.2%) compared with the control individuals (9.6%) and that OSA is associated with severe asthma exacerbation.

The mechanism of interaction between OSA and asthma is complex. Moreover, the two diseases have common comorbid conditions such as GERD and obesity which negatively impact asthma control. Using continuous positive airway pressure (CPAP) is considered to be the gold standard in the management of OSA, improving the symptoms and enhancing the quality of life. Several cohort studies of CPAP in patients with both asthma and OSA showed significant effect in achieving asthma control by improving symptoms and lung function as well as reducing the use of rescue medication. Three months of CPAP in patients with moderate to severe persistent asthma reduced serum inflammatory markers, including CRP, TNF, and IL-6. Furthermore, more recently Serrano-Pariente et al reported that asthma control, quality of life, and lung function improved after starting CPAP in asthmatics with moderate to severe OSA . However, a recent systemic review showed that CPAP therapy in asthma patient with concurrent OSA has a positive effect on quality of life and this effect is more pronounced with severe OSA in uncontrolled asthma patients.

Polysomnography (SOMNO medics plus; SOMNO medics, Randersacker, Germany) consists of continuous recordings from surface leads for electroencephalography (EEG), electrooculography, electromyography (submental and bilateral anterior tibialis muscles), electrocardiography, nasal pressure, nasal and oral airflow (thermocouple), chest and abdominal impedance belts for respiratory muscle efforts, pulse oximetry for oxygen saturation and pulse rate, a tracheal microphone for snoring and body position sensors for sleep position. PSG records are scored manually according to the American Academy of Sleep Medicine (AASM) 2012 scoring.

Abnormal obstructive breathing events during monitored sleep are described according to the latest recommendation of the AASM as a decrease in airflow by 90% or more from baseline for at least 10 seconds (apnea) and a discernible reduction in airflow of at least 30% of the pre-event baseline using nasal pressure associated with a reduction in oxygen saturation of at least 3% and/or followed by an EEG arousal (hypopnea), despite persistent chest and abdominal muscle efforts to overcome the obstruction. EEG arousal is defined according to the recommendation of the AASM. The average number of these apnea and hypopnea events per hour of sleep (i.e., the AHI) is then calculated.

Subjects with an AHI of ≥15 are categorized as having OSA, whereas those with excessive daytime sleepiness (EDS) and an AHI of ≥5 are categorized as having OSAS. Clinically diagnosed OSA (COSAS) is defined per the latest AASM recommendations (2014), i.e., A- an AHI of ≥15 determined by PSG or B- an AHI of ≥5 but <15 events, in addition to one of the following: 1) daytime sleepiness, non-restorative sleep, fatigue or insomnia symptoms; 2) incidences of waking up with gasping or choking sensations; 3) reported snoring, breathing interruptions or both during sleep; or 4) a known history of hypertension, mood or cognitive dysfunction, coronary artery disease, stroke, congestive heart failure, atrial fibrillation or diabetes mellitus. Three registered polysomnographic technologists (RPSGTs) were assigned to manually score data from these PSG studies.

For each patient with OSA, titration of CPAP pressure will be performed by conventional polysomnography or using auto-CPAP equipment using a validated protocol . The CPAP device should have an hour meter recording systems, so that machine-on time hours could be checked at each clinical visit.

Rationale The investigators aim in this study to examine the effect of CPAP treatment in severe asthma patient with concurrent moderate and severe OSA.

Study Location The study will be conducted in two tertiary hospitals in Jeddah, Saudi Arabia: King Abdulaziz Medical City and King Abdulaziz University Hospital. The patients' medical records will be reviewed to determine patients with severe asthma..