Short-acting β-agonist use as a marker of current asthma control

Asthma and COPD: A Focus on β-Agonists - Past, Present and Future

Asthma has been recognised as a respiratory disorder for millennia and the focus of targeted drug development for the last 120 years. Asthma is one of the most common chronic non-communicable diseases worldwide. Chronic obstructive pulmonary disease (COPD), a leading cause of morbidity and mortality worldwide, is caused by exposure to tobacco smoke and other noxious particles and exerts a substantial economic and social burden. This chapter reviews the development of the treatments of asthma and COPD particularly focussing on the β-agonists, from the isolation of adrenaline, through the development of generations of short- and long-acting β-agonists. It reviews asthma death epidemics, considers the intrinsic efficacy of clinical compounds, and charts the improvement in selectivity and duration of action that has led to our current medications. Important β2-agonist compounds no longer used are considered, including some with additional properties, and how the different pharmacological properties of current β2-agonists underpin their different places in treatment guidelines. Finally, it concludes with a look forward to future developments that could improve the β-agonists still further, including extending their availability to areas of the world with less readily accessible healthcare.

The Changing Asthma Management Landscape and Need for Appropriate SABA Prescription

Short-acting β2 agonists (SABAs) have been a mainstay of asthma treatment since the 1950s, and have been mainly recommended as-needed for symptom relief alongside daily inhaled corticosteroid (ICS)-based maintenance treatment for the past 30 years. However, patient adherence to regular ICS-based anti-inflammatory maintenance therapy is frequently poor, leading to SABA overuse for symptom relief and associated poor outcomes. At present, there is a lack of consensus between treatment guidelines on how SABA should be used, and as-needed ICS-formoterol is suggested by some as an alternative reliever therapy. Here, we examine the pharmacology and current use of inhaled SABAs, identify that regular dosing of ICS can encourage appropriate SABA use, and appraise the evidence used to support the changing reliever treatment recommendations. We conclude that SABA continues to play an important role in the asthma management landscape, and give our views on how it should be used in patients with mild-moderate asthma, to complement regular ICS-based maintenance treatment.

Asthma

Asthma is one of the most common chronic non-communicable diseases worldwide and is characterised by variable airflow obstruction, causing dyspnoea and wheezing. Highly effective therapies are available; asthma morbidity and mortality have vastly improved in the past 15 years, and most patients can attain good asthma control. However, undertreatment is still common, and improving patient and health-care provider understanding of when and how to adjust treatment is crucial. Asthma management consists of a cycle of assessment of asthma control and risk factors and adjustment of medications accordingly. With the introduction of biological therapies, management of severe asthma has entered the precision medicine era-a shift that is driving clinical ambitions towards disease remission. Patients with severe asthma often have co-existing conditions contributing to their symptoms, mandating a multidimensional management approach. In this Seminar, we provide a clinically focused overview of asthma; epidemiology, pathophysiology, diagnosis, and management in children and adults.

Over-prescription of short-acting beta agonists in the treatment of asthma

BACKGROUND

Despite a clear guideline for asthma medication, excessive use of short-acting β2-agonists (SABAs) is common in clinical practice. Previous research has shown that excessive use of SABAs is associated with poor asthma control.

OBJECTIVE

This study examines current use of asthma medication in primary care and whether excessive use of SABAs is associated with exacerbations.

METHODS

The study design was a retrospective analysis using information from electronical medical records from patients aged 18 and older of five Julius Health Centers located in Utrecht, the Netherlands, in the period of 1 July 2018 through 1 July 2019. Excessive SABA use was defined as ≥400 inhalations per year. An exacerbation was defined as an acute worsening of asthma symptoms with the need for systemic corticosteroids.

RESULTS

A total of 1161 patients were included in the study. Of the patients using SABAs (n = 766), 193 (25%) overused SABAs. Among the patients with inappropriate SABA use (n = 193), 19% had an exacerbation compared with 7% of the appropriate SABA users. For patients using asthma medication the odds of having an exacerbation were 2.9 times higher if they used an inappropriate number of SABAs than if SABAs were used appropriately (odds ratio, 2.897; 95% confidence interval, 1.87-4.48).

CONCLUSIONS

This study shows that overuse of SABAs is still common and that it is associated with asthma exacerbations. It highlights that clinicians need to be aware of inappropriate SABA use as it is a sign of and can even contribute to poor asthma control.

Prevalence of overuse of short-acting beta-2 agonists (SABA) and associated factors among patients with asthma in Germany

BACKGROUND

Overuse of short-acting beta-2 agonists (SABA), which do not treat the underlying inflammation of asthma, is linked to poor clinical outcomes such as increased exacerbation risk. This study, as part of the SABINA program, estimated the prevalence of SABA overuse and associated variables in outpatients in Germany.

METHODS

This retrospective study used anonymized electronic healthcare data from the Disease Analyzer database (IQVIA). A total of 15,640 patients aged ≥ 12 years with asthma who received ≥ 1 SABA prescription(s) between July 2017 and June 2018 in 924 general physician and 22 pneumologist (PN) practices were included. SABA overuse was defined as ≥ 3 prescribed inhalers (~ 200 puffs each) during the study period. The associations between SABA overuse and physician specialty, Global Initiative for Asthma (GINA) steps (based on asthma medications), age, sex, and inhaled corticosteroid (ICS)/long-acting beta agonist (LABA) use were estimated using multivariable regression for patients with probable moderate (GINA step 2) and probable severe (GINA steps 3-5) asthma.

RESULTS

Annually, 36% of all patients (GINA steps 1-5) in general and 38% in PN practices received ≥ 3 SABA inhalers. The risk of SABA overuse was 14% higher in patients treated by a general practitioner vs. a PN; 34% and 85% higher in GINA steps 4 and 5, respectively, vs. GINA step 3; and 40% higher in male vs. female patients.

CONCLUSIONS

SABA overuse is prevalent among patients with asthma across all GINA steps in Germany, which may indicate suboptimal asthma control. Further studies are needed to investigate the reasons behind SABA overuse.

[Description of the use of inhaled rescue medication in an asthmatic population treated in the Primary Care clinics. UMI-ASMA Study]

OBJECTIVE

To describe the quantitative use of inhaled rescue medication in an asthmatic population treated in the Primary Care clinics, and secondly to determine its possible relationship as regards other variables associated with control.

MATERIAL AND METHODS

An observational, descriptive study was conducted on a randomised sample of all the asthmatic patients with more than one year of onset, and coming from 17 Primary Care catchment areas. 1 year observation period. The data collected included sociodemographic variables and characteristics of the asthma, such as the use of short-acting beta-agonists (SABA) and level of control as regards its frequency of use, the use of inhaled control medication (ICM), number of hospital exacerbations, smoking habits, and availability of an action plan. The data were obtained from the clinical history and the computerised prescription modules.

RESULTS

A total of 442 asthmatic patients were included (59.5% female), with a mean age of 45.4 years. The total number of SABA containers prescribed in one year per patient was between 0 and 25 containers, with a mean of 4.26 (SD=4.1). Only 46.6% showed a regular use of an ICM. The number of SABA containers prescribed to patients with an intermittent use of an ICM was significantly higher than those patients that used it regularly (P=.001). There was an association between the number of exacerbations and the number of SABA containers prescribed (Spearman correlation coefficient=0.474, P<.001), as such that the higher the number of containers prescribed there was also a higher number of hospitalised asthmatic exacerbations.

CONCLUSIONS

A considerable number of asthmatics in the sample had elevated prescriptions for SABA inhalers and within the defined quantitative ranges of at least a partially or poor-controlled asthma. There is a positive relationship between the overuse of SABA and the intermittent use of the ICM, the same as with hospital exacerbations, smoking, and the lack of a written action plan..

Asthma-Related Health Outcomes Associated with Short-Acting β2-Agonist Inhaler Use: An Observational UK Study as Part of the SABINA Global Program

INTRODUCTION

Patients with asthma typically increase short-acting β₂-agonists (SABA) use with worsening symptoms. Excessive SABA use may lead to a higher risk of adverse outcomes. We evaluated, in a large population cohort, an association between SABA inhaler use and asthma exacerbations and healthcare utilization.

METHODS

As part of the SABINA (SABA use IN Asthma) global program, we conducted a retrospective longitudinal observational study (SABINA I) using UK primary care electronic healthcare records (Clinical Practice Research Datalink; 2007-2017) from asthma patients aged ≥ 12 years. SABA inhaler use was classified as 'high use', ≥ 3 canisters/year versus 'low use', 0-2 canisters/year. Taking into consideration all their asthma prescriptions, patients were categorized into a treatment step according to 2016 British Thoracic Society (BTS) asthma management guidelines. Multivariable regression assessed the association of SABA inhaler use by BTS treatment steps (grouped as BTS steps 1/2 and 3-5), separately, and with outcomes of exacerbations or asthma-related healthcare utilization (primary care and hospital outpatient consultations); only patients with linked hospital data were included in this analysis.

RESULTS

Of the 574,913 patients included, 218,365 (38%) had high SABA inhaler use. Overall, 336,412 patients had linked hospital data. High SABA inhaler use was significantly associated with an increased risk of exacerbations [adjusted hazard ratio, 95% confidence interval (CI): BTS steps 1/2 = 1.20, 1.16-1.24; BTS steps 3-5 = 1.24, 1.20-1.28], asthma-related primary care consultations [adjusted incidence rate ratio (IRR), 95% CI: BTS steps 1/2 = 1.24, 1.23-1.26; BTS steps 3-5 = 1.13, 1.11-1.15], and asthma-related hospital outpatient consultations (adjusted IRR, 95% CI: BTS steps 1/2 = 1.19, 1.12-1.27; BTS steps 3-5 = 1.19, 1.13-1.26).

CONCLUSION

High SABA inhaler use was frequent across BTS steps and was associated with a significant increase in exacerbations and asthma-related healthcare utilization.

Detecting asthma exacerbations using daily home monitoring and machine learning

OBJECTIVE

Acute exacerbations contribute significantly to the morbidity of asthma. Recent studies have shown that early detection and treatment of asthma exacerbations leads to improved outcomes. We aimed to develop a machine learning algorithm to detect severe asthma exacerbations using easily available daily monitoring data.

METHODS

We analyzed daily peak expiratory flow and symptom scores recorded by participants in the SAKURA study (NCT00839800), an international multicentre randomized controlled trial comparing budesonide/formoterol as maintenance and reliever therapy versus budesonide/formoterol maintenance plus terbutaline as reliever, in adults with persistent asthma. The dataset consisted of 728,535 records of daily monitoring data in 2010 patients, with 576 severe exacerbation events. Data post-processing techniques included normalization, standardization, calculation of differences or slopes over time and the use of smoothing filters. Principal components analysis was used to reduce the large number of derived variables to a smaller number of linearly independent components. Logistic regression, decision tree, naïve Bayes, and perceptron algorithms were evaluated. Model accuracy was assessed using stratified cross-validation. The primary outcome was the detection of exacerbations on the same day or up to three days in the future.

RESULTS

The best model used logistic regression with input variables derived from post-processed data using principal components analysis. This had an area under the receiver operating characteristic curve of 0.85, with a sensitivity of 90% and specificity of 83% for severe asthma exacerbations.

CONCLUSION

Asthma exacerbations may be detected using machine learning algorithms applied to daily self-monitoring of peak expiratory flow and asthma symptoms.

Usage Patterns of Short-Acting β2-Agonists and Inhaled Corticosteroids in Asthma: A Targeted Literature Review

Despite the availability of effective asthma treatments, some patients are poorly controlled because of overreliance on short-acting β₂-agonists (SABAs) and underuse of inhaled corticosteroids (ICSs). To identify patient characteristics and outcomes associated with SABA overreliance and ICS underuse, we conducted a targeted literature review of the quantitative evidence on asthma medication use. Articles evaluating SABA and/or ICS use in patients with asthma (aged ≥12 years), published between January 2012 and March 2018, were identified using MEDLINE and EMBASE. We observed that studies classified SABA usage as "overuse," "high use," "excess use," "extreme overuse," "suboptimal use," and "inappropriate use." Multiple thresholds were used to define overuse of SABA (≥3 to ≥12 canisters/y). SABA overreliance was prevalent, with approximately 20% of adults using 3 or more canisters per year (≥12 inhalations/wk). Similarly, inappropriate ICS use, classified as "suboptimal," "high use," "underuse," and "unlicensed use," was defined by varying thresholds. Specific patient populations, such as older adults, smokers, and patients with low income, were more susceptible to SABA overreliance and ICS underuse. Overreliance on SABAs was associated with increased risk of severe exacerbations, asthma-related hospitalizations, emergency department visits, and asthma-related costs. These findings emphasize the prevalence and related burden of SABA overreliance at the potential expense of appropriate ICS use.

Evaluation and management of the critically ill adult asthmatic in the emergency department setting

INTRODUCTION

Asthma is a common reason for presentation to the Emergency Department and is associated with significant morbidity and mortality. While patients may have a relatively benign course, there is a subset of patients who present in a critical state and require emergent management.

OBJECTIVE

This narrative review provides evidence-based recommendations for the assessment and management of patients with severe asthma.

DISCUSSION

It is important to consider a broad differential diagnosis for the cause and potential mimics of asthma exacerbation. Once the diagnosis is determined, the majority of the assessment is based upon the clinical examination. First line therapies for severe exacerbations include inhaled short-acting beta agonists, inhaled anticholinergics, intravenous steroids, and magnesium. Additional therapies for refractory cases include parenteral epinephrine or terbutaline, helium‑oxygen mixture, and consideration of ketamine. Intravenous fluids should be administered, as many of these patients are dehydrated and at risk for hypotension if they receive positive pressure ventilatory support. Noninvasive positive pressure ventilation may prevent the need for endotracheal intubation. If mechanical ventilation is required, it is important to avoid breath stacking by setting a low respiratory rate and allowing permissive hypercapnia. Patients with severe asthma exacerbations will require intensive care unit admission.

CONCLUSIONS

This review provides evidence-based recommendations for the assessment and management of severe asthma with a focus on the emergency clinician.

Assessing asthma control: comparison of electronic-recorded short-acting beta-agonist rescue use and self-reported use utilizing the asthma control test

Background: Question 4 (Q4) of the Asthma Control Test (ACT) asks patients to report their SABA use over the prior 4 weeks, a criterion for evaluating the impairment domain of asthma control. Biases in recall may lead to a misclassification of asthma control and has implications for asthma control determination and management strategies.Objective: To correlate objective electronic-recorded short-acting beta-agonist (SABA) use with self-reported use via Q4 of the ACT.Methods: Patients ≥18 years of age with a self-reported diagnosis of asthma were enrolled in a digital health electronic medication monitoring (EMM) platform, which recorded the date and time of SABA actuations and prompted the completion of the ACT. The correlations between ACT Q4 responses and EMM-recorded SABA use were evaluated using Spearman's rank correlation coefficients.Results: 1,062 patients (mean age: 35.4 years, mean ACT: 16.3) were included in analyses. Higher Q4 scores, indicating lower SABA use, were moderately and negatively correlated with EMM-recorded SABA use (ρ = -0.59 [95% CI: -0.63, -0.54]). Thirty-five percent of patients underreported SABA use when comparing Q4 to EMM-recorded SABA use.Conclusions: While ACT Q4 and EMM-recorded use were moderately correlated, underreported SABA use on the ACT highlights the need for objective measures of SABA use in asthma control assessments. The use of EMM-recorded SABA data has the potential for clinicians to more accurately determine asthma control, guide changes to controller therapy, and estimate imminent exacerbation risk.

Insights into frequent asthma exacerbations from a primary care perspective and the implications of UK National Review of Asthma Deaths recommendations

The United Kingdom National Review of Asthma Deaths (NRAD) recommends that patients who require ≥3 courses of oral corticosteroids (OCS) for exacerbations in the past year or those on British Thoracic Society (BTS) Step 4/5 treatment must be referred to a specialist asthma service. The aim of the study was to identify the proportion of asthma patients in primary care that fulfil NRAD criteria for specialist referral and factors associated with frequent exacerbations. A total of 2639 adult asthma patients from 10 primary care practices in Glasgow, UK were retrospectively studied between 2014 and 2015. Frequent exacerbators and short-acting β2-agonist (SABA) over-users were identified if they received ≥2 confirmed OCS courses for asthma and ≥13 SABA inhalers in the past year, respectively. Community dispensing data were used to assess treatment adherence defined as taking ≥75% of prescribed inhaled corticosteroid (ICS) dose. The study population included 185 (7%) frequent exacerbators, 137 (5%) SABA over-users, and 319 (12%) patients on BTS Step 4/5 treatment. Among frequent exacerbators, 41% required BTS Step 4/5 treatment, 46% had suboptimal ICS adherence, 42% had not attended an asthma review in the past year and 42% had no previous input from a specialist asthma service. Older age, female gender, BTS Step 4/5, SABA over-use and co-existing COPD diagnosis increased the risk of frequent exacerbations independently. Fourteen per 100 asthma patients would fulfil the NRAD criteria for specialist referral. Better collaboration between primary and secondary care asthma services is needed to improve chronic asthma care.

Validation of a metered dose inhaler electronic monitoring device: implications for asthma clinical trial use

Background

The SmartTouch Ventolin monitor (Adherium, Auckland, New Zealand) is an electronic monitor for use with a Ventolin metered dose inhaler, which records the date and time of inhaler actuations. This technology has the potential to allow in-depth analysis of patterns of inhaler use in clinical trial settings. The aim of this study was to determine the accuracy of the SmartTouch Ventolin monitor in recording Ventolin actuations.

Methods

20 SmartTouch Ventolin monitors were attached to Ventolin metered dose inhalers. Bench testing was performed over a 10-week period, to reflect the potential time frame between visits in a clinical trial. Inhaler actuations were recorded in a paper diary, which was compared with data uploaded from the monitors.

Results

2560 actuations were performed during the 10-week study period. Monitor sensitivity for diary-recorded actuations was 99.9% with a lower 97.5% confidence bound of 99.7%. The positive predictive value for diary-recorded actuations was 100% with a 97.5% lower confidence bound of 99.9%.

Conclusions

The SmartTouch Ventolin monitor is highly accurate in recording and retaining electronic data. It can be recommended for use in clinical trial settings in which training and quality control systems are incorporated into study protocols to ensure accurate data acquisition.

The Digital Asthma Patient: The History and Future of Inhaler Based Health Monitoring Devices

The wave of digital health is continuously growing and promises to transform healthcare and optimize the patients' experience. Asthma is in the center of these digital developments, as it is a chronic disease that requires the continuous attention of both health care professionals and patients themselves. The accurate and timely assessment of the state of asthma is the fundamental basis of digital health approaches and is also the most significant factor toward the preventive and efficient management of the disease. Furthermore, the necessity of inhaled medication offers a basic platform upon which modern technologies can be integrated, namely the inhaler device itself. Inhaler-based monitoring devices were introduced in the beginning of the 1980s and have been evolving but mainly for the assessment of medication adherence. As technology progresses and novel sensing components are becoming available, the enhancement of inhalers with a wider range of monitoring capabilities holds the promise to further support and optimize asthma self-management. The current article aims to take a step for the mapping of this territory and start the discussion among healthcare professionals and engineers for the identification and the development of technologies that can offer personalized asthma self-management with clinical significance. In this direction, a technical review of inhaler based monitoring devices is presented, together with an overview of their use in clinical research. The aggregated results are then summarized and discussed for the identification of key drivers that can lead the future of inhalers.

Three-month validation of a turbuhaler electronic monitoring device: implications for asthma clinical trial use

BACKGROUND

Electronic monitoring of inhaled asthma therapy is suggested as the 'gold standard' for measuring patterns of medication use in clinical trials. The SmartTurbo (Adherium (NZ) Ltd, Auckland, New Zealand) is an electronic monitor for use with a turbuhaler device (AstraZeneca, UK). The aim of this study was to determine the accuracy of the SmartTurbo in recording Symbicort actuations over a 12-week period of use.

METHODS

Twenty SmartTurbo monitors were attached to the base of 20 Symbicort turbuhalers. Bench testing in a research facility was undertaken on days 0, 5, 6, 7, 8, 9, 14, 21, 28, 56 and 84. Patterns of 'low-use' (2 sets of 2 actuations on the same day) and 'high-use' (2 sets of 8 actuations on the same day) were performed. The date and time of actuations were recorded in a paper diary and compared with data uploaded from the SmartTurbo monitors.

RESULTS

2800 actuations were performed. Monitor sensitivity was 99.9% with a lower 97.5% confidence bound of 99.6%. The positive predictive value was 99.9% with a 97.5% lower confidence bound of 99.7%. Accuracy was not affected by whether the pattern of inhaler use was low or high, or whether there was a delay in uploading the actuation data.

CONCLUSIONS

The SmartTurbo monitor is highly accurate in recording and retaining electronic data in this 12-week bench study. It can be recommended for use in clinical trial settings, in which quality control systems are incorporated into study protocols to ensure accurate data acquisition.