Asthma Respiratory Asthma
Conditions
Interventions
The active TLA device (Airsonett®) significantly reduces nocturnal allergen exposure by filtering ambient air through a high efficiency particulate air filter, slightly cooling (5-8ºC) and 'showering'
Sponsors
Queen Alexandra Hospital (UK)
Eligibility
Sex/Gender
All
Inclusion criteria
Inclusion criteria: Current inclusion criteria as of 24/07/2015: 1. Adults (aged 16-75 years inclusive) 2. A clinical diagnosis of asthma for =6 months supported by evidence of any one of the following: 2.1. Airflow variability with a mean diurnal peak expiratory flow (PEF) variability >15% during the baseline 2-week period or a variability in FEV1 of >20% across clinic visits within the preceding 12 months, with concomitant evidence of airflow obstruction (FEV1/FVC ratio 1 at Screening Visit 1 and Randomisation Visit 2. 5. Atopic status: 5.1. Sensitisation to =1 perennial indoor aeroallergen[2] (including House Dust Mite, domestic pet or fungi) to which they are likely to be exposed during the study, demonstrated by a positive skin prick test (wheal diameter =3mm more than negative control) or specific IgE =0.35 IU/L). 6. Exacerbation free and taking stable maintenance asthma medications (not including short-acting bronchodilator or other reliever therapies) for at least 2-weeks prior to Screening Visit 1 7. Exacerbation free and taking stable maintenance asthma medications (not including short-acting bronchodilator or other reliever therapies) in the period between Screening Visit 1 and Randomisation Visit 2.(the Screening Period). Participants suffering a severe exacerbation during the Screening Period can be rescreened 2 weeks after returning to their maintenance asthma medications (See 11.3.2) 8. Able to use the TLA device during sleep on at least five nights per week (excluding holidays) 9. Able to understand and give written informed consent prior to participation in the trial and able to comply with the trial requirements Previous inclusion criteria: 1. Adults (aged 18-75 years inclusive) 2. A clinical diagnosis of asthma for =6 months prior to trial entry supported by evidence of either: 2.1. Airflow variabili
Exclusion criteria
Exclusion criteria: 1. Current smokers or ex-smokers abstinent for <6 months 2. Ex-smokers with =15 pack year smoking history 3. Partner who is a current smoker and smokes within the bedroom where the TLA device is installed 4. TLA device cannot be safely installed within the bedroom, intending to move out of study area within the trial period or unable to use the TLA device for at least 8 hours on at least 5 nights per week 5. Documented poor treatment adherence 6. Occupational asthma with continued exposure to known sensitising agents in the workplace 7. Previous bronchial thermoplasty within 12 months 8. Maintenance treatment with Omalizumab (anti-IgE) within 3 months 9. Using long-term oxygen, Continuous Positive Airway Pressure (CPAP) or Non-Invasive Ventilation (NIV) routinely overnight as this will impair the effect of the TLA device 10. Uncontrolled symptomatic gastro-oesophageal reflux that may act as a persistent asthma trigger 11. Presence of clinically significant lung disease other than asthma, including smoking-related chronic obstructive pulmonary disease (COPD), bronchiectasis associated with recurrent bacterial infection, allergic bronchopulmonary aspergillosis (mycosis), pulmonary fibrosis, sleep apnoea, pulmonary hypertension, or lung cancer 12. Patients with clinically significant co-morbidity (including cardiovascular, endocrine, metabolic, gastro-intestinal, hepatic, neurological, renal, haematological and malignant conditions) that remains uncontrolled with standard treatment 13. Patients currently taking part in other interventional clinical trials
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| The primary efficacy end point in this study, the rate of clinically significant exacerbations over the 12-month period, will be modelled as a Poisson random variable. A Poisson regression model with an adjustment for over-dispersion will be used to compare the rate of asthma exacerbations between the two groups with log of time used as an offset variable. Further analysis will adjust for the baseline characteristics including the ACQ score, age, BMI and sex. Intention to treat (ITT) analysis will be performed on the primary outcome on all participants who will be randomised. The study results will be reported in accordance with the CONSORT (Consolidated Standards of Reporting Trials) 2010 statements. Stata (or equivalent stats package) will be used for all the analyses. All the tests will be done at a 5% two-sided significance level. | — |
Secondary
| Measure | Time frame |
|---|---|
| Kaplan-Meier curves and log-rank test will be used to compare the time to first asthma exacerbation between the two groups. In addition, Cox proportional hazards models will be used to evaluate the effect of the TLA device on the time to first asthma exacerbation, adjusting for the same covariates as in the primary analysis. Since the analysis of only time to first exacerbation leaves out much of the data, analysis incorporating multiple time-to-event (recurrent exacerbations) methods will also be carried out. Andersen-Gill (1982) extension of the Cox proportional regression will be used to analyze recurrent exacerbations. Using this model, the problem reduces to the analysis of time to first exacerbation, time to second exacerbation, and so on. Poisson regression will be used to compare the incidence of severe exacerbations, and incidence of moderate exacerbations between the two groups over the 12-month period. The proportion of participants experiencing severe, moderate, or any exacerbations over the 12-month period will be compared using a continuity-corrected Chi-squared test. The duration of severe and moderate exacerbations, the total number of days with an exacerbation over the 12-month period, and the number of health care utilisations will be compared between the two groups using a two-sample independent t-test. We will utilise longitudinal analysis methods for the continuous secondary endpoints, which involve repeated measures at baseline, 3, 6, 9, and 12 months follow-ups (measures of airflow obstruction, composite asthma control scores, symptom measures, and health-related quality of life measures). Mixed effect models will be used to determine whether there is an effect of the TLA device over time in these measures. Changes from baseline to 12 months in markers of allergy will be analysed using ANCOVA (analysis of covariance) models, with the corresponding baseline measurement used as a covariate and treatment group as a factor. | — |
Countries
United Kingdom
Outcome results
None listed