Continuous Positive Airway Pressure Use in Asthma With Moderate to Severe Obstructive Sleep Apnea Patients (OSA)
Obstructive sleep apnea syndrome (OSAS) and asthma are both common disorders in Hong Kong, with prevalence of at least 4% among the middle-aged male Hong Kong (HK) Chinese populations and 7.2% in young adults respectively. OSAS is characterized by repetitive episodes of upper airway obstruction, causing intermittent hypoxia, sleep fragmentation, disabling daytime sleepiness, impaired cognitive function and poor health status. Continuous positive airway pressure (CPAP) is the first line of therapy for sleep apnea. CPAP provides a pneumatic stent for the upper airway, eliminating the airway collapse during inspiration.
Asthma is a chronic inflammatory disorder of airways, characterized by airway hyperresponsiveness that leads to recurrent episodes of wheezing, breathless, chest tightness, and coughing, particularly at night or in the early morning. Nocturnal asthma is not a different condition from asthma and is defined as a variable worsening of asthma at night, in which the mechanisms are not completely understood.
The prevalence of OSAS in asthmatic patients has not yet been studied, but several studies have reported an increased prevalence of OSAS symptoms in asthmatic patients. OSAS and asthma share some common risk factors, which include obesity, gastroesophageal reflux and rhinitis. CPAP treatment has been shown in prospective clinical studies to have a positive impact on asthma outcome in patients with concomitant OSAS, for example, improvement of asthma related quality of life in subjects with stable mild-to-moderate asthma, but there was no change in the airway responsiveness or forced expiratory volume in one second. Although important, these studies included small numbers of participants used nonrandomized designs. This study is to assess the impact of CPAP treatment on asthma control among patients with nocturnal symptoms and moderate OSAS.
|Study Design:||Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Single Blind (Investigator)
Primary Purpose: Treatment
|Official Title:||Effect of Nasal Continuous Positive Airway Pressure in Uncontrolled Nocturnal Asthmatic Patients With Moderate Obstructive Sleep Apnea Syndrome|
- Asthma control test score [ Time Frame: 3 months ] [ Designated as safety issue: No ]All patients with moderate OSAS will be assessed by an easy assessment tool for asthma control, known as the Asthma Control Test (ACT). It is a validated questionnaire in which various studies have proved its correlation with the clinical asthma control. The ACT consisted of five items; for each item, five options are provided pertaining to asthma control during the past 4 weeks. Each item is scored according to a 5-point scale, and the item scores are totalled for assessing asthma control, with higher total scores indicating better asthma control.
- Spirometry [ Time Frame: 3 months ] [ Designated as safety issue: No ]Spirometry is a physiological test that measures how an individual inhales or exhales volumes of air as a function of time. The most important aspects of spirometry are the forced vital capacity (FVC), which is the volume delivered during an expiration made as forcefully and completely as possible starting from full inspiration, and the forced expiratory volume in one second(FEV1), which is the volume delivered in the first second of an FVC manoeuvre. The value of FEV1 and FVC will be monitored in baseline and 3 months.
- Epworth Sleepiness Score (ESS) [ Time Frame: 3 months ] [ Designated as safety issue: No ]The Epworth Sleepiness Scale (ESS) is a questionnaire for assessing daytime sleepiness. It was first described in 1991 as a simple, self-administered questionnaire. The questionnaire is based on eight common situations in life. Subjects are asked to rate on a scale of 0-3 about how likely they would fall asleep or doze off in these circumstances. This gives a total score of 0 to 24 in each subject.
- SF 36 questionnaire [ Time Frame: 3 months ] [ Designated as safety issue: No ]The Short Form Health Survey (SF-36) is a survey of patient health. It is commonly used in health economics as a variable in the quality-adjusted life year calculation to determine the cost-effectiveness of a health treatment. It consists of eight scaled scores, which are the weighted sums of the questions in their section. The eight sections are: vitality, physical functioning, bodily pain, general health perceptions, physical role functioning, emotional role functioning, social role functioning and mental health.
- Bronchial challenge test [ Time Frame: 3 months ] [ Designated as safety issue: No ]A bronchial challenge test is one method of assessing airway responsiveness in which patient breathes in nebulised methacholine and then will be assessed by measuring the Forced Expiratory Volume in one second (FEV1).
|Study Start Date:||January 2011|
|Estimated Study Completion Date:||December 2013|
|Estimated Primary Completion Date:||December 2012 (Final data collection date for primary outcome measure)|
|Active Comparator: CPAP group||
Procedure: CPAP group
Patients will be given a CPAP education program by our respiratory nurse supplemented by education brochure and a video. Attended overnight CPAP titration will be performed with the auto-titrating device. The CPAP level for each patient in the therapeutic CPAP arm is set at the minimum pressure needed to abolish snoring, obstructive respiratory events and airflow limitation for 95% of the night as determined by the overnight CPAP titration study. Patients in the CPAP therapy will be provided careful mask-fitting, chin strap to prevent mouth leak, regular review by our nurses, a basic CPAP device with intrinsic time clock to monitor CPAP usage and standard stroke rehabilitation programme. Patients on conservative treatment will only be offered standard treatment for asthma
Other Name: CPAP intervention group
|Placebo Comparator: non CPAP group||
Procedure: non CPAP group
Patients who are randomised to non CPAP group will receive general health advice and no CPAP therapy will be arranged for them during the study period.
Other Name: No CPAP given
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|Contact: Susanna SS Ng, MBChB||852 2632 email@example.com|
|China, Hong Kong|
|Prince of Wales Hospital||Recruiting|
|Hong Kong, Hong Kong, China|
|Contact: S S Ng, MBChB 852 2632 2211 firstname.lastname@example.org|
|Principal Investigator:||Susanna SS Ng, MBChB||Chinese Univesrity of Hong Kong|