Temperature controlled laminar airflow treatment for patients with severe allergic asthma

  • Will Storrar

Student thesis: Doctoral Thesis

Abstract

Background
Severe asthma exacerbations are costly to patients and the NHS and occur frequently in patients
with severe allergic asthma.
Objective
To ascertain whether the use of a temperature-controlled laminar airflow (TLA) device (Airsonett®) over a 12-month period can reduce the frequency of severe exacerbations and improve asthma control and quality of life as compared to a placebo device in adults with severe allergic asthma.

Trial Design
A mixed methods, multi-centre, randomised, double-blind, placebo-controlled, parallel group, trial design.

Participants
Adults (16-75 years) with severe, poorly-controlled, exacerbation-prone, asthma sensitised to a perennial indoor aeroallergen.

Main Outcome Measures
PRIMARY OUTCOME:
Frequency of severe asthma exacerbations occurring within the 12-month follow-up period, defined as worsening of asthma requiring systemic corticosteroids, ≥30mg prednisolone or equivalent daily (or ≥50% increase in dose if maintenance 30mg prednisolone or above) for 3 or more days.
SECONDARY OUTCOMES:
Changes in asthma control, lung function, asthma-specific and global quality of life for participants and device acceptability.

Results
240 participants were randomised. 119 Active Treatment : 121 Placebo. 202 participants (84%) reported use of the device for 9-12 months. Qualitative analyses showed high levels of acceptability. The mean rate of severe exacerbations did not differ between groups (Active: Mean 1.39 (SD 1.57), Placebo: Mean 1.48 (SD 2.03) Risk Ratio 0.92, 95% CI 0.66-1.27, p=0.616). There were no significant differences in secondary outcomes for lung function, except for a reduction in mean daily peak expiratory flow (difference 14.7 L/min, SD 7.35, 95% CI 0.32-29.1 L/min, p=0.045) in the active device, and no differences in asthma control or airway inflammation. There was no difference in generic or disease-specific health-related quality of life overall, although statistically significant higher quality of life at month 6 was observed.

Conclusions
Within the limits of the data, no consistent benefits of the active device were demonstrated.
Date of AwardSep 2018
Original languageEnglish
SupervisorAnoop Chauhan (Supervisor), Rebecca Stores (Supervisor), Karen Pilkington (Supervisor) & Ann Dewey (Supervisor)

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