Applying UK real-world primary care data to predict asthma attacks in 3776 well-characterised children: a retrospective cohort study

Derivation of asthma severity from electronic prescription records using British thoracic society treatment steps

Background:

Asthma severity is typically assessed through a retrospective assessment of the treatment required to control symptoms and to prevent exacerbations. The joint British Thoracic Society and Scottish Intercollegiate Guidelines Network (BTS/SIGN) guidelines encourage a stepwise approach to pharmacotherapy, and as such, current treatment step can be considered as a severity categorisation proxy. Briefly, the steps for adults can be summarised as: no controller therapy (Step 0), low-strength Inhaled Corticosteroids (ICS; Step 1), ICS plus Long-Acting Beta-2 Agonist (LABA; Step 2), medium-dose ICS + LABA (Step 3), and finally either an increase in strength or additional therapies (Step 4). This study aimed to investigate how BTS/SIGN Steps can be estimated from across a large cohort using electronic prescription records, and to describe the incidence of each BTS/SIGN Step in a general population.

Methods:

There were 41,433,707 prescriptions, for 671,304 individuals, in the Asthma Learning Health System Scottish cohort, between 1/2009 and 3/2017. Days on which an individual had a prescription for at least one asthma controller (preventer) medication were labelled prescription events. A rule-based algorithm was developed for extracting the strength and volume of medication instructed to be taken daily from free-text data fields. Asthma treatment regimens were categorised by the combination of medications prescribed in the 120 days preceding any prescription event and categorised into BTS/SIGN treatment steps.

Results:

Almost 4.5 million ALHS prescriptions were for asthma controllers. 26% of prescription events had no inhaled corticosteroid prescriptions in the preceding 120 days (Step 0), 16% were assigned to BTS/SIGN Step 1, 7% to Step 2, 21% to Step 3, and 30% to Step 4. The median days spent on a treatment step before a step-down in treatment was 297 days, whereas a step-up only took a median of 134 days.

Conclusion

We developed a reproducible methodology enabling researchers to estimate BTS/SIGN asthma treatment steps in population health studies, providing valuable insights into population and patient-specific trajectories, towards improving the management of asthma.

Preventing unscheduled hospitalisations from asthma: a retrospective cohort study using routine primary and secondary care data in the UK (The PUSH-Asthma Study)-protocol paper

INTRODUCTION

Asthma is the most common chronic respiratory disease in children and adults. Asthma results in significant disease-related morbidity, healthcare costs and, in some cases, death. Despite efforts through implementation of national guidelines to improve asthma care, the UK has one of the highest asthma-related morbidity and mortality rates in the western world. New approaches are necessary to prevent asthma attacks in children and adults. The objectives of this study are to assess the association between demographic and clinical factors and asthma-related hospital admissions in children and adults, describe the epidemiology of asthma phenotypes among hospital attenders, and externally validate existing asthma risk prediction models.

METHODS AND ANALYSIS

This is a retrospective cohort study of children and adults with asthma. Data will be extracted from the Clinical Practice Research Datalink (CPRD) Aurum database, which holds anonymised primary care data for over 13 million actively registered patients and covers approximately 19% of the UK population. The primary outcome will be asthma-related hospital admissions. The secondary outcomes will be prescriptions of short courses of oral corticosteroids (as a surrogate measure for asthma exacerbations), a composite outcome measure including hospital admissions and prescriptions of short courses of oral corticosteroids and delivery of asthma care management following hospital discharge. The primary analysis will use a Poisson regression model to assess the association between demographic and clinical risk factors and the primary and secondary outcomes. Latent class analysis will be used to identify distinct subgroups, which will further our knowledge on potential phenotypes of asthma among patients at high risk of asthma-related hospital admissions. A Concordance statistic (C-statistic) and logistic regression model will also be used to externally validate existing risk prediction models for asthma-related hospitalisations to allow for the optimal model to be identified and evaluated provide evidence for potential use of the optimal performing risk prediction model in primary care.

ETHICS AND DISSEMINATION

This study was approved by the CPRD Independent Scientific Advisory Committee (reference number: 21_000512). Findings from this study will be published in a peer-reviewed journal and disseminated at national and international conferences.

An assessment of asthma exacerbations in pediatric patients using a long-acting B2-agonist plus inhaled corticosteroid versus an inhaled corticosteroid alone

Background

An asthma exacerbation is an anticipated sudden worsening of the disease severity, which usually does not respond to conservative therapy. The management of asthma depends on the severity of the disease symptoms, which includes an inhaled corticosteroid (ICS) and a bronchodilator. This study aimed to assess the efficacy of combining a long-acting B2-agonist (LABA) with ICS, compared to ICS alone, to reduce the incidence of asthma exacerbations in pediatric patients, diagnosed with severe persistent asthma.

Methods

A retrospective analysis of the medical records was conducted for 586 children, admitted to the Emergency Department (ED) at King Abdullah Specialized Children Hospital in Riyadh, Saudi Arabia, for the management of severe persistent asthma symptoms, from January 2016 to September 2019.

Results

The majority (n = 480, 81.9%) of the patients received fluticasone (Flovent)® as the standard of care ICS treatment for controlling asthma, and a small proportion (n = 106, 18.1%) were treated with a combination of LABA and ICS. A significant increase in the frequency of recurrent asthma exacerbation episodes occurred in the group receiving ICS alone (98.5%), compared to 67.0% in the combination group (p < 0.0001). Moderate to severe exacerbations were significantly higher in the ICS group compared to the combination group (95.6% versus 84.5%, respectively, p = 0.0005).

Conclusions

The current results confirm the substantial efficacy of the LABA/ICS combination therapy in reducing the incidence and severity of asthma exacerbations in pediatric patients, compared to ICS alone.

Blood eosinophil count as predictor of asthma exacerbation. A meta-analysis

BACKGROUND

Evidence about the association of high blood eosinophil count with asthma exacerbation is inconsistent and unclear. The objective of this meta-analysis was to determine whether elevated blood eosinophil count predicts asthma exacerbation.

METHODS

We searched MEDLINE, EMBASE, and additional databases, without any language restriction. We also checked the reference lists of the included studies and of relevant systematic reviews. The main outcome was the occurrence of asthma exacerbation. We calculated global pooled odds ratios (ORs) and their 95% confidence intervals (CIs) and performed predefined subgroup analyses. We appraised the quality of the studies using Newcastle-Ottawa Scale, examined the heterogeneity between studies, assessed publication bias, and carried out sensitivity analyses.

RESULTS

Among 1567 retrieved publications, 23 observational studies comprising 155,772 participants met the inclusion criteria. High blood eosinophil count was associated with higher odds of asthma exacerbation [OR: 1.31 (95% CI: 1.16, 1.49)], specifically with asthma-related outpatient visits [OR: 1.46 (95% CI: 1.25, 1.70)] and emergency department visits [OR: 1.63 (95% CI: 1.29, 2.07)]. A significant association was observed starting from an eosinophils' cutoff value of 200 cells/μl. The association was observed for cohort studies [OR: 1.30 (95%CI: 1.13, 1.49)], North American studies [OR: 1.43 (95%CI: 1.31, 1.57)], Asian populations [OR: 1.67 (95%CI: 1.34, 2.08)], children [OR: 1.38 (95%CI: 1.22, 1.56)], and studies that adjusted for inhaled corticosteroids therapy [OR: 1.42 (95%CI: 1.28, 1.56)].

CONCLUSIONS

Blood eosinophil counts ≥ 200 cells/µL are associated with asthma exacerbation. Blood eosinophil count is a modifiable factor that could be addressed in asthma management strategies.

Using routinely collected primary care records to identify and investigate severe asthma: a scoping review

Shielding during the coronavirus pandemic has highlighted the potential of routinely collected primary care records to identify patients with 'high-risk' conditions, including severe asthma. We aimed to determine how previous studies have used primary care records to identify and investigate severe asthma and whether linkage to other data sources is required to fully investigate this 'high-risk' disease variant. A scoping review was conducted based on the Arksey and O'Malley framework. Twelve studies met all criteria for inclusion. We identified variation in how studies defined the background asthma cohort, asthma severity, control and clinical outcomes. Certain asthma outcomes could only be investigated through linkage to secondary care records. The ability of primary care records to represent the entire known asthma population is unique. However, a number of challenges need to be overcome if their full potential to accurately identify and investigate severe asthma is to be realised.

Observational studies assessing the pharmacological treatment of obstructive lung disease: strengths, challenges and considerations for study design

Randomised controlled trials (RCTs) are the gold standard for evaluating treatment efficacy in patients with obstructive lung disease. However, due to strict inclusion criteria and the conditions required for ascertaining statistical significance, the patients included typically represent as little as 5% of the general obstructive lung disease population. Thus, studies in broader patient populations are becoming increasingly important. These can be randomised effectiveness trials or observational studies providing data on real-world treatment effectiveness and safety data that complement efficacy RCTs. In this review we describe the features associated with the diagnosis of asthma and chronic obstructive pulmonary disease (COPD) in the real-world clinical practice setting. We also discuss how RCTs and observational studies have reported opposing outcomes with several treatments and inhaler devices due to differences in study design and the variations in patients recruited by different study types. Whilst observational studies are not without weaknesses, we outline recently developed tools for defining markers of quality of observational studies. We also examine how observational studies are capable of providing valuable insights into disease mechanisms and management and how they are a vital component of research into obstructive lung disease. As we move into an era of personalised medicine, recent observational studies, such as the NOVEL observational longiTudinal studY (NOVELTY), have the capacity to provide a greater understanding of the value of a personalised healthcare approach in patients in clinical practice by focussing on standardised outcome measures of patient-reported outcomes, physician assessments, airway physiology, and blood and airway biomarkers across both primary and specialist care.

A worldwide charter for all children with asthma

Childhood asthma is a huge global health burden. The spectrum of disease, diagnosis, and management vary depending on where children live in the world and how their community can care for them. Global improvement in diagnosis and management has been unsatisfactory, despite ever more evidence-based guidelines. Guidelines alone are insufficient and need supplementing by government support, changes in policy, access to diagnosis and effective therapy for all children, with research to improve implementation. We propose a worldwide charter for all children with asthma, a roadmap to better education and training which can be adapted for local use. It includes access to effective basic asthma medications. It is not about new expensive medications and biologics as much can be achieved without these. If implemented carefully, the overall cost of care is likely to fall and the global future health and life chance of children with asthma will greatly improve. The key to success will be community involvement together with the local and national development of asthma champions. We call on governments, institutions, and healthcare services to support its implementation.

Burden of asthma exacerbations and health care utilization in pediatric patients with asthma in the US and England

Background

Data on asthma burden in pediatric patients are limited; this real‐world study investigated exacerbation frequency and health care resource utilization (HCRU) in pediatric asthma patients from the US and England.

Methods

Data from pediatric patients (aged 6‐17 years) in the Optum claims database (US) or Clinical Practice Research Datalink with linkage to Hospital Episode Statistics (England) were analyzed. Patients were categorized into four hierarchical groups: treated asthma (patients with ≥1 baseline asthma medication), severe asthma (plus Global Initiative for Asthma Step 4/5), severe refractory asthma ([SRA] plus ≥2 baseline severe asthma exacerbations), and eosinophilic SRA (SRA plus blood eosinophil count ≥150 cells/µL). Exacerbation frequency and HCRU during the 12 months postindex were described.

Results

Of 151 549 treated asthma patients in the US, 18 086 had severe asthma, 2099 SRA, and 109 eosinophilic SRA. There were 32 893 treated asthma patients in England, of whom 2711 had severe asthma, 265 SRA, and 8 eosinophilic SRA. In the 12 months postindex, ≥1 exacerbation occurred in 12.4% and 10.8% of patients with severe asthma, and 32.6% and 42.6% with SRA in the US and England, respectively. The proportions of patients with ≥1 asthma hospitalization in the 30 days after the first asthma exacerbation were 2.7% and 4.4% (treated), 3.5% and 8.2% (severe asthma), and 6.0% and 16.8% (SRA) in the US and England, respectively.

Conclusion

This study provides insights into current asthma management practices in the US and England and indicates that some patients with severe disease have an unmet need for effective management.

Treatment patterns among non-active users of maintenance asthma medication in the United Kingdom: a retrospective cohort study in the Clinical Practice Research Datalink

Objective: To describe patient characteristics, treatment patterns and healthcare utilization (HCU) of non-active users of maintenance asthma medications in the United Kingdom.Methods: Retrospective, cohort analysis of patients with asthma, aged ≥ 6 years who were non-active users of maintenance therapy (no prescription for inhaled corticosteroids (ICS), combined ICS/long-acting beta agonists (ICS/LABA) or 'other' bronchodilatory therapies in last 12 months) were identified in the Clinical Practice Research Datalink (2012-2015) and followed-up for 2 years after a new prescription for an asthma maintenance medication (index date). Patient characteristics, most common maintenance treatment sequences and HCU were described.Results: 55,293 patients were identified (ICS: 46,297, ICS/LABA: 8,367; Other: 629). Mean age was 37 years and 56% were female. During follow-up, the most common treatment sequences across groups implied intermittent use, comprising periods of maintenance therapy interspersed with maintenance-free periods. During year 1 and year 2 of follow-up, the proportion of patients prescribed OCS was 19% and 13%, prescribed ≥ 4 short-acting bronchodilators (SABD) was 24% and 19%, having ≥ 3 asthma-related primary care consultations/year was 59% and 36% and experiencing ≥ 1 exacerbation/year was 15% and 11%, respectively.Conclusions: In previously non-active users of asthma maintenance medication subsequently commenced on maintenance therapy, intermittent use was common during the 2-year follow-up despite the potential need for regular use as evidenced by patient HCU and SABD usage patterns. This highlights the need for regular patient assessment and education on medication adherence to ensure appropriateness of prescribing to maintain asthma control.

Reliability and validity of the Chinese version of the Test for Respiratory and Asthma Control in Kids (TRACK) in preschool children with asthma: a prospective validation study

OBJECTIVE

The limited existing asthma control questionnaires that are available for children 5 years of age or younger in China mostly assess only the impairment domain of asthma control. Here, the English version of the Test for Respiratory and Asthma Control in Kids (TRACK) was translated into Chinese and validated for its application in asthma control in preschool children.

DESIGN

Prospective validation study.

SETTING AND PARTICIPANTS

A total of 321 Chinese preschool children suffering from asthma completed the study from December 2017 to February 2018.

METHOD

The TRACK translation into Chinese employed the translation and back translation technique. The caregivers of the preschool children with asthma symptoms completed TRACK during two clinical visits over 4-6 weeks. Moreover, the physicians completed a Global Initiative for Asthma (GINA)-based asthma control survey at both visits. The utility of TRACK for assessing the change in asthma control status and its reliability and discriminant validity were evaluated.

RESULTS

The Chinese version of TRACK showed internal consistency reliability values of 0.63 and 0.71 at each visit, respectively (Cronbach's α). The test-retest reliability was 0.62 for individuals whose GINA-based assessment results were the same at both visits (n=206). The TRACK scores for the children in the various asthma control categories were significantly different (p<0.001). Children recommended for increased treatment by the physicians had lower TRACK scores than those recommended for no change in treatment or decreased treatment (p<0.001).

CONCLUSION

The study verifies the validity and reliability of the Chinese version of TRACK. Changes in the TRACK scores effectively reflected the level of asthma control in preschool children and guided further treatment strategies.

TRIAL REGISTRATION NUMBER

NCT02649803.

Predicting asthma attacks in primary care: protocol for developing a machine learning-based prediction model

INTRODUCTION

Asthma is a long-term condition with rapid onset worsening of symptoms ('attacks') which can be unpredictable and may prove fatal. Models predicting asthma attacks require high sensitivity to minimise mortality risk, and high specificity to avoid unnecessary prescribing of preventative medications that carry an associated risk of adverse events. We aim to create a risk score to predict asthma attacks in primary care using a statistical learning approach trained on routinely collected electronic health record data.

METHODS AND ANALYSIS

We will employ machine-learning classifiers (naïve Bayes, support vector machines, and random forests) to create an asthma attack risk prediction model, using the Asthma Learning Health System (ALHS) study patient registry comprising 500 000 individuals across 75 Scottish general practices, with linked longitudinal primary care prescribing records, primary care Read codes, accident and emergency records, hospital admissions and deaths. Models will be compared on a partition of the dataset reserved for validation, and the final model will be tested in both an unseen partition of the derivation dataset and an external dataset from the Seasonal Influenza Vaccination Effectiveness II (SIVE II) study.

ETHICS AND DISSEMINATION

Permissions for the ALHS project were obtained from the South East Scotland Research Ethics Committee 02 [16/SS/0130] and the Public Benefit and Privacy Panel for Health and Social Care (1516-0489). Permissions for the SIVE II project were obtained from the Privacy Advisory Committee (National Services NHS Scotland) [68/14] and the National Research Ethics Committee West Midlands-Edgbaston [15/WM/0035]. The subsequent research paper will be submitted for publication to a peer-reviewed journal and code scripts used for all components of the data cleaning, compiling, and analysis will be made available in the open source GitHub website (https://github.com/hollytibble).

Asthma Across Age: Insights From Primary Care

Asthma is a heterogeneous disease comprising of multiple phenotypes and affects patients from childhood up to old age. In this review, we summarize the current knowledge on the similarities and differences in asthma across different age-groups, with emphasis on the perspective from primary care. Despite the similar disease presentation, phenotyping studies showed that there are differences in the distribution of phenotypes of asthma presenting in childhood compared to that in adulthood. Whereas, asthma with early age of onset tends to be of the atopic phenotype, the disease shifts toward the non-atopic phenotypes at later ages. Studies within primary care patients aiming to elucidate risk factors for future asthma exacerbation have shown pediatric and elderly patients to be at higher risk for future asthma attacks compared to other adult patients. Regardless, both pediatric and adult studies demonstrated previous asthma episodes and severity, along with high blood eosinophil to predict subsequent asthma attacks. Differences in childhood and adult asthma are not limited to the underlying phenotypes but also extends to the challenges in the diagnosis, treatment, and management of the disease. Diagnosis of asthma is complicated by age-specific differential diagnoses such as infectious wheezing and nasal obstruction in children, and aging-related problems such as heart disease and obesity in the elderly. There are also age-related issues leading to decreased disease control such as non-adherence, tobacco use, difficulty in using inhalers and corticosteroid-related side effects which hinder asthma control at different patient age-groups. Several clinical guidelines are available to guide the diagnosis and drug prescription of asthma in pediatric patients. However, there are conflicting recommendations for the diagnostic tools and treatment for pediatric patients, posing additional challenges for primary care physicians in working with multiple guidelines. While tools such as spirometry and peak flow variability are often available in primary care, their usage in preschool patients is not consistently recommended. FeNO measurement may be a valuable non-invasive tool which can be adopted by primary physicians to assist asthma diagnosis in preschool-age patients.