Nocturnal temperature-controlled laminar airflow device for adults with severe allergic asthma: the LASER RCT

Clinical Medicine and Climate Change

The health care system contributes substantially to global greenhouse gas emissions, a driver of climate change. At the same time, climate change has caused disruptions in health care delivery. In this article, the authors describe both how the health care industry contributes to climate change and how climate change affects patient care. The authors also provide clinical recommendations for health care practitioners to counsel patients on health effects of climate change and underscore the need for developing the workforce needed to respond to unique health care delivery challenges resulting from climate-related factors.

Temperature-controlled Laminar Airflow (TLA) in symptomatic severe asthma – a post hoc analysis of severe exacerbations, quality of life and health economics

Purpose

Uncontrolled severe asthma constitutes a major economic burden to society. Add-ons to standard inhaled treatments include inexpensive oral corticosteroids and expensive biologics. Nocturnal treatment with Temperature-controlled Laminar Airflow (TLA; Airsonett®) could be an effective, safe and cheaper alternative. The potential of TLA in reducing severe asthma exacerbations was addressed in a recent randomised placebo-controlled trial (RCT) in patients with severe asthma (Global Initiative for Asthma (GINA) step 4/5), but the results were inconclusive. We re-analysed the RCT with severe exacerbations stratified by the level of baseline asthma symptoms and Quality of Life.

Methods

More uncontrolled patients, defined by Asthma Control Questionnaire 7 (ACQ7) > 3, EuroQoL 5-Dimension Questionnaire Visual Analogue Scale (EQ5D-VAS) ≤ 65 and Asthma Quality of Life Questionnaire (AQLQ) ≤ 4 were selected for re-analysis. The rates of severe asthma exacerbations, changes in QoL and health-economics were analysed and compared between TLA and placebo.

Results

The study population included 226 patients (113 TLA / 113 placebo.) The rates of severe asthma exacerbations were reduced by 33, 31 and 25% (p = 0.083, 0.073, 0.180) for TLA compared to placebo, dependent on selected control measures (ACQ7, EQ5D-VAS, AQLQ, respectively). For patients with less control defined by AQLQ≤4, the difference in mean AQLQ0-12M between TLA and placebo was 0.31, 0.33, 0.26 (p = 0.085, 0.034, 0.150), dependent on selected covariate (AQLQ, EQ5D-VAS, ACQ7, respectively). For patients with poor control defined by ACQ7 > 3, the difference in EQ5D-5 L utility scores between TLA and placebo was significant at 9 and 12 months with a cost-effective ICER. The results from the original study did not demonstrate these differences.

Conclusion

This post hoc analysis demonstrated an effect of TLA over placebo on severe exacerbations, asthma control and health economics in a subgroup of patients with more symptomatic severe allergic asthma. The results are consistent with the present recommendations for TLA. However, these differences were not demonstrated in the full study. Several explanations for the different outcomes have been outlined, which should be addressed in future studies.

Funding

NIHR Health Technology Assessment Programme and Portsmouth Hospitals NHS Trust.

Current practice in the measurement and interpretation of intervention adherence in randomised controlled trials: A systematic review

BACKGROUND

Ideally all participants in a randomised controlled trial (RCT) should fully receive their allocated intervention; however, this rarely occurs in practice. Intervention adherence affects Type II error so influences the interpretation of trial results and subsequent implementation. We aimed to describe current practice in the definition, measurement, and reporting of intervention adherence in non-pharmacological RCTs, and how this data is incorporated into a trial's interpretation and conclusions.

METHODS

We conducted a systematic review of phase III RCTs published between January 2018 and June 2020 in the National Institute for Health Research Journals Library for the Health Technology Assessment, Programme Grants for Applied Research, and Public Health Research funding streams.

RESULTS

Of 237 reports published, 76 met the eligibility criteria and were included. Most RCTs (n = 68, 89.5%) reported adherence, though use of terminology varied widely; nearly three quarters of these (n = 49, 72.1%) conducted a sensitivity analysis. Adherence measures varied between intervention types: behavioural change (n = 10, 43.5%), psychological therapy (n = 5, 83.3%) and physiotherapy/rehabilitation (n = 8, 66.7%) interventions predominately measured adherence based on session attendance. Whereas medical device and surgical interventions (n = 17, 73.9%) primarily record the number of participants receiving the allocated intervention, a third (n = 33, 67.3%) of studies reported a difference in findings between primary and sensitivity analyses.

CONCLUSIONS

Although most trials report elements of adherence, terminology was inconsistent, and there was no systematic approach to its measurement, analyses, interpretation, or reporting. Given the importance of adherence within clinical trials, there is a pressing need for a standardised approach or framework.

The Efficacy of the Dyson Air Purifier in Improving Asthma Control: Protocol for a Single-Center, Investigator-Led, Randomized, Double-Blind, Placebo-Controlled Trial

BACKGROUND

Indoor air quality has been shown to influence asthma control and outcomes. Air purifiers and high-efficiency particulate air filtration devices can improve indoor air quality by reducing the indoor levels of air pollution and allergens. However, the influence of this improved indoor air quality on asthma control remains unclear; hence, randomized controlled trials are needed to further elucidate this phenomenon.

OBJECTIVE

This study aims to investigate the effect of reducing the levels of allergens and pollutants in the bedroom and living room through the use of Dyson air purifiers (Dyson Pure Cool) on asthma control.

METHODS

This is an 18-month long, investigator-led, randomized, double-blinded, placebo-controlled, single-center trial. Subjects will be randomized in a 1:1 ratio to active or placebo Dyson filters. The primary outcome is the change in the scores of Asthma Control Questionnaire 6 and Asthma-specific Quality of Life Questionnaire from baseline. Secondary outcomes include changes in lung function (forced expiratory volume in one second, forced expiratory volume in one second/forced vital capacity ratio, and midexpiratory flows), peak expiratory flow measurements, airway hyperresponsiveness (assessed by methacholine bronchial challenge), fractional exhaled nitric oxide, and indoor air pollutant levels. The sample size will be 50 subjects, and all subjects will have a confirmed diagnosis of mild persistent to moderate persistent asthma along with an Asthma Control Questionnaire 6 score of >1.5.

RESULTS

This study was approved by the West Midlands Research Ethics Committee (18/WM/0277). The study results will be published in peer-reviewed scientific journals; presented at relevant scientific conferences; and shared in plain English with participants in our newsletters, in our clinics, and via the David Hide Asthma and Allergy Research Centre website. Our trial began in September 2019 and is expected to end in August 2021.

CONCLUSIONS

This is a double-blinded, placebo-controlled, randomized, investigator-led study to investigate the efficacy of a novel air purifier in improving asthma control in adults. The trial period of 18 months will facilitate the collection of robust data and will therefore generate clear signals. However, this extended trial duration may lead to patient withdrawal. Furthermore, this trial is conducted at a single center and in a location with a homogenous cohort of people, which may affect translatability. Nonetheless, it is hoped that the findings of this trial may help further inform clinicians regarding the utility of this novel device as an adjunct in asthma care.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04729530; https://clinicaltrials.gov/ct2/show/NCT04729530.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/28624.

Effect of nocturnal Temperature-controlled Laminar Airflow on the reduction of severe exacerbations in patients with severe allergic asthma: a meta-analysis

Background: Allergen avoidance is important in allergic asthma management. Nocturnal treatment with Temperature-controlled Laminar Airflow (TLA) has been shown to provide a significant reduction in the exposure to allergens in the breathing zone, leading to a long-term reduction in airway inflammation and improvement in Quality of life (QoL). Allergic asthma patients symptomatic on Global Initiative for Asthma (GINA) step 4/5 were found to benefit the most as measured by Asthma Quality of Life Questionnaire (AQLQ). However, the effect of TLA on severe asthma exacerbations is uncertain and therefore a meta-analysis was performed.

Methods: Patients with severe allergic asthma (GINA 4/5) were extracted from two 1-year randomised, double-blind, placebo-controlled trials conducted with TLA. A meta-analysis of the effect on severe exacerbations was performed by negative binomial regression in a sequential manner, defined by baseline markers of asthma control (symptoms and QoL scores).

Results: The pooled dataset included 364patients. Patients with more symptoms at baseline (ACT<18 or ACQ7>3; N=179), had a significant mean 41% reduction in severe exacerbations (RR=0.59 (0.38-0.90); p=0.015) in favour of TLA. Higher ACQ7 cut-points of 3.5-4.5 resulted in significant reductions of 48-59%.More uncontrolled patients based on AQLQ total and symptom domains ≤3.0 at baseline also showed a significant reduction in severe exacerbations for TLA vs. placebo ((47% (p=0.037) and 53% (p=0.011), respectively). The meta-analysis also confirmed a significant difference in AQLQ-responders ((Minimal Clinically Important Difference)≥0.5; 74% vs. 43%, p=0.04).

Conclusion: This meta-analysis of individual patient data shows a beneficial effect on severe exacerbations and quality of life for TLA over placebo in more symptomatic patients with severe allergic asthma. These outcomes support the national management recommendations for patients with symptomatic severe allergic asthma. The actual effect of TLA on severe exacerbations should be confirmed in a prospective study with larger numbers of patients.

Air Pollution and Asthma: Mechanisms of Harm and Considerations for Clinical Interventions

There is global concern regarding the harmful impact of polluted air on the respiratory health of patients with asthma. Multiple epidemiologic studies have shown ongoing associations between high levels of air pollution and poor early life lung growth, development of allergic sensitization, development of asthma, airway inflammation, acutely impaired lung function, respiratory tract infections, and asthma exacerbations. However, studies have often yielded inconsistent findings, and not all studies have found significant associations; this may be related to both variations in statistical, measurement, and modeling methodologies between studies as well as differences in the concentrations and composition of air pollution globally. Overall, this variation in findings suggests we still do not fully understand the effects of ambient pollution on the lungs and on the evolution and exacerbation of airway diseases. There is clearly a need to augment epidemiologic studies with experimental studies to clarify the underlying mechanistic basis for the adverse responses reported and to identify the key gaseous and particle-related components within the complex air pollution mixture driving these outcomes. Some progress toward these aims has been made. This article reviews studies providing an improved understanding of causal pathways linking air pollution to asthma development and exacerbation. The article also considers potential strategies to reduce asthma morbidity and mortality through regulation and behavioral/pharmacologic interventions, including a consideration of pollutant avoidance strategies and antioxidant and/or vitamin D supplementation.