Predictors of symptoms are different from predictors of severe exacerbations from asthma in children

Prediction of Asthma Exacerbations in Children

Asthma exacerbations are common in asthmatic children, even among those with good disease control. Asthma attacks result in the children and their parents missing school and work days; limit the patient's social and physical activities; and lead to emergency department visits, hospital admissions, or even fatal events. Thus, the prompt identification of asthmatic children at risk for exacerbation is crucial, as it may allow for proactive measures that could prevent these episodes. Children prone to asthma exacerbation are a heterogeneous group; various demographic factors such as younger age, ethnic group, low family income, clinical parameters (history of an exacerbation in the past 12 months, poor asthma control, poor adherence to treatment, comorbidities), Th2 inflammation, and environmental exposures (pollutants, stress, viral and bacterial pathogens) determine the risk of a future exacerbation and should be carefully considered. This paper aims to review the existing evidence regarding the predictors of asthma exacerbations in children and offer practical monitoring guidance for promptly recognizing patients at risk.

Predictors of asthma control differ from predictors of asthma attacks in children: The Swiss Paediatric Airway Cohort

BACKGROUND

It is unclear if predictors of asthma attacks are the same as those of asthma symptom control in children.

OBJECTIVE

We evaluated predictors for these two outcomes in a clinical cohort study.

METHODS

The Swiss Paediatric Airway Cohort (SPAC) is a multicentre prospective clinical cohort of children referred to paediatric pulmonologists. This analysis included 516 children (5-16 years old) diagnosed with asthma. At baseline, we collected sociodemographic information, symptoms, personal and family history and environmental exposures from a parental baseline questionnaire, and treatment and test results from hospital records. Outcomes were assessed 1 year later by parental questionnaire: asthma control in the last 4 weeks as defined by GINA guidelines, and asthma attacks defined as any unscheduled visit for asthma in the past year. We used logistic regression to identify and compare predictors for suboptimal asthma control and asthma attacks.

RESULTS

At follow-up, 114/516 children (22%), reported suboptimal asthma control, and 114 (22%) an incident asthma attack. Only 37 (7%) reported both. Suboptimal asthma control was associated with poor symptom control at baseline (e.g. ≥1 night wheeze/week OR: 3.2; 95% CI: 1.7-6), wheeze triggered by allergens (2.2; 1.4-3.3), colds (2.3; 1.4-3.6) and exercise (3.2; 2-5), a more intense treatment at baseline (2.4; 1.3-4.4 for Step 3 vs. 1), history of preschool (2.6; 1.5-4.4) and persistent wheeze (2; 1.4-3.2), and exposure to tobacco smoke (1.7; 1-2.6). Incident asthma attacks were associated with previous episodes of severe wheeze (2; 1.2-3.3) and asthma attacks (2.8; 1.6-5 for emergency care visits), younger age (0.8; 0.8-0.9 per 1 year) and non-Swiss origin (0.3; 0.2-0.5 for Swiss origin). Lung function, exhaled nitric oxide (FeNO) and allergic sensitization at baseline were not associated with control or attacks.

CONCLUSION

Children at risk of long-term suboptimal asthma control differ from those at risk of attacks. Prediction tools and preventive efforts should differentiate these two asthma outcomes.

Effectiveness of a Vendor Predictive Model for the Risk of Pediatric Asthma Exacerbation: A Difference-in-Differences Analysis

BACKGROUND

Asthma is a common cause of morbidity and mortality in children. Predictive models may help providers tailor asthma therapies to an individual's exacerbation risk. The effectiveness of asthma risk scores on provider behavior and pediatric asthma outcomes remains unknown.

OBJECTIVE

Determine the impact of an electronic health record (EHR) vendor-released model on outcomes for children with asthma.

METHODS

The Epic Systems Risk of Pediatric Asthma Exacerbation model was implemented on February 24, 2021, for volunteer pediatric allergy and pulmonology providers as a noninterruptive risk score visible in the patient schedule view. Asthma hospitalizations, emergency department (ED) visits, or oral steroid courses within 90 days of the index visit were compared from February 24, 2019, to February 23, 2022, using a difference-in-differences design with a control group of visits to providers in the same departments. Volunteer providers were interviewed to identify barriers and facilitators to model use.

RESULTS

In the intervention group, asthma hospitalizations within 90 days decreased from 1.4% (54/3,842) to 0.7% (14/2,165) after implementation with no significant change in the control group (0.9% [171/19,865] preimplementation to 1.0% [105/10,743] post). ED visits in the intervention group decreased from 5.8% (222/3,842) to 5.5% (118/2,164) but increased from 5.5% (1,099/19,865) to 6.8% (727/10,743) in the control group. The adjusted difference-in-differences estimators for hospitalization, ED visit, and oral steroid outcomes were -0.9% (95% confidence interval [CI]: -1.6 to -0.3), -2.4% (-3.9 to -0.8), and -1.9% (-4.3 to 0.5). In qualitative analysis, providers understood the purpose of the model and felt it was useful to flag high exacerbation risk. Trust in the model was calibrated against providers' own clinical judgement.

CONCLUSION

This EHR vendor model implementation was associated with a significant decrease in asthma hospitalization and ED visits within 90 days of pediatric allergy and pulmonology clinic visits, but not oral steroid courses.

A systematic review of questionnaires measuring asthma control in children in a primary care population

Several questionnaires are used to measure asthma control in children. The most appropriate tool for use in primary care is not defined. In this systematic review, we evaluated questionnaires used to measure asthma control in children in primary care and determined their usefulness in asthma management. Searches were performed in the MEDLINE, Embase, Web of Science, Google Scholar and Cochrane databases with end date 24 June 2022. The study population comprised children aged 5-18 years with asthma. Three reviewers independently screened studies and extracted data. The methodological quality of the studies was assessed, using the COSMIN criteria for the measurement properties of health status questionnaires. Studies conducted in primary care were included if a minimum of two questionnaires were compared. Studies in secondary or tertiary care and studies of quality-of-life questionnaires were excluded. Heterogeneity precluded meta-analysis. Five publications were included: four observational studies and one sub-study of a randomized controlled trial. A total of 806 children were included (aged 5-18 years). We evaluated the Asthma Control Test (ACT), childhood Asthma Control Test (c-ACT), Asthma APGAR system, NAEPP criteria and Royal College of Physicians' '3 questions' (RCP3Q). These questionnaires assess different symptoms and domains. The quality of most of the studies was rated 'intermediate' or 'poor'. The majority of the evaluated questionnaires do not show substantial agreement with one another, which makes a comparison challenging. Based on the current review, we suggest that the Asthma APGAR system seems promising as a questionnaire for determining asthma control in children in primary care.

Independent risk factors of asthma exacerbations: 3-year follow-up in a single-center prospective cohort study

Background

Because minimizing future risk is the goal of asthma chronic asthma management, it is particularly important to identify risk factors. We conducted this 3-year single-center prospective cohort study to determine the independent risk factors of asthma exacerbations (AEs).

Methods

We performed this prospective, longitudinal, observational study with a 3-year follow-up on 257 patients aged 18-81 years with at least a 1-year history of asthma. Follow-up visits are conducted through regular annual phone calls, and the primary endpoints were AE.

Results

The uncontrolled group was more likely to develop AE than the well-controlled group [odds ratio (OR): 6.34, 95% confidence interval (CI): 1.14-35.21, P<0.05]. Patients with low Asthma Quality of Life Questionnaire (AQLQ) scores were more likely to develop AE than these with high AQLQ scores (OR: 0.59, 95% CI: 0.35-0.99, P<0.05). AQLQ and Asthma Control Questionnaires (ACQ) were both strong independent risk factors within 3 years of enrollment; the cut-off values (COV) of the AQLQ and the ACQ (uncontrolled) that better evaluated the risk with the AE were ≤5.4 and >1, respectively. The AQLQ scores had a sensitivity of 79.07% and a specificity of 59.09% [area under curve (AUC): 0.70, P<0.0001], and the ACQ (uncontrolled) had a sensitivity of 81.4% and a specificity of 52.29% (AUC 0.68, P<0.0001).

Conclusions

The findings of this study suggest that patients with uncontrolled asthma and a diminished health-related quality of life had an increased risk of exacerbations in the future. Defining these risk factors associated with AE is important as it will identify these at the highest risk to patients and may guide future interventions.

Challenges in uncontrolled asthma in pediatrics: important considerations for the clinician

INTRODUCTION

Despite symptoms control being the primary focus of asthma management according to guidelines, uncontrolled asthma is still an issue worldwide, leading to huge costs and asthma deaths at all ages. In childhood, poor asthma control can be even more harmful, as it can irreversibly compromise the children's lung function and the whole family's well-being.

AREAS COVERED

Given the problem extent, this review aims to discuss the leading modifiable causes of uncontrolled asthma in Pediatrics, giving some practical insights regarding the critical role of families and the main tools for monitoring control and drug adherence, even at a distance. The most recent GINA documents were used as the primary reference, along with the latest evidence regarding the management of asthma control and the impact of the COVID-19 pandemic on asthma.

EXPERT OPINION

In managing pediatric asthma, a multidisciplinary, multi-determinant, personalized approach is needed, actively involving families, schools, and other specialists. In addition to current strategies for implementing control, electronic health strategies, new validated asthma control tools, and the identification of novel inflammatory biomarkers could lead to increasingly tailored therapies with greater effectiveness in reaching asthma control.

Environmental and clinical data utility in pediatric asthma exacerbation risk prediction models

BACKGROUND

Asthma exacerbations are triggered by a variety of clinical and environmental factors, but their relative impacts on exacerbation risk are unclear. There is a critical need to develop methods to identify children at high-risk for future exacerbation to allow targeted prevention measures. We sought to evaluate the utility of models using spatiotemporally resolved climatic data and individual electronic health records (EHR) in predicting pediatric asthma exacerbations.

METHODS

We extracted retrospective EHR data for 5982 children with asthma who had an encounter within the Duke University Health System between January 1, 2014 and December 31, 2019. EHR data were linked to spatially resolved environmental data, and temporally resolved climate, pollution, allergen, and influenza case data. We used xgBoost to build predictive models of asthma exacerbation over 30-180 day time horizons, and evaluated the contributions of different data types to model performance.

RESULTS

Models using readily available EHR data performed moderately well, as measured by the area under the receiver operating characteristic curve (AUC 0.730-0.742) over all three time horizons. Inclusion of spatial and temporal data did not significantly improve model performance. Generating a decision rule with a sensitivity of 70% produced a positive predictive value of 13.8% for 180 day outcomes but only 2.9% for 30 day outcomes.

CONCLUSIONS

EHR data-based models perform moderately wellover a 30-180 day time horizon to identify children who would benefit from asthma exacerbation prevention measures. Due to the low rate of exacerbations, longer-term models are likely to be most clinically useful.

TRIAL REGISTRATION

Not applicable.

Asthma Attacks in Children-Challenges and Opportunities

Asthma is the most common chronic disease of childhood worldwide, and is responsible for significant morbidity and mortality in children and young people (CYP). Given the inherent dangers of a child experiencing even a single asthma attack, it is essential to identify and manage modifiable risk factors at every clinical opportunity. Following an attack, there is an opportunity to prevent future attacks by assessing compliance and optimizing asthma control. Careful questioning will allow physicians to identify asthma triggers, barriers to good asthma control, and health beliefs or socioeconomic obstacles that may have contributed to this attack. The vast majority of children with asthma can achieve good symptom control with appropriate use of low-dose inhaled corticosteroids.

FeNO in Asthma

Asthma is a common disease affecting 350 million people worldwide, which is characterized by airways inflammation and hyperreactivity. Historically diagnosis and treatment have been mainly based on symptoms, which have the potential to result in misdiagnosis and inappropriate treatment. Nitric oxide (NO) is exhaled in human breath and is a marker of airways inflammation. Levels of NO are increased in the exhaled breath of patients with type 2 asthma and fractional exhaled nitric oxide (FeNO) provides an objective biomarker of airway inflammation. FeNO testing is an accessible, noninvasive, and easy-to-use test. Cut-off values have been established by the American Thoracic Society (ATS), the Global Initiative for Asthma (GINA), and the National Institute for Health and Care Excellence (NICE) but vary between guidance. FeNO levels have been shown to be predictive of blood and sputum eosinophil levels but should not be used in isolation and current guidance emphasizes the importance of incorporating clinical symptoms and testing when utilizing FeNO results. The inclusion of FeNO testing can increase diagnostic accuracy of asthma, while high levels in asthmatic patients can help predict response to inhaled corticosteroids (ICS) and suppression of levels with ICS to monitor adherence. FeNO levels are also a predictor of asthma risk with increased exacerbation rates and accelerated decline in lung function associated with high levels as well as having an emerging role in predicting response to some biologic therapies in severe asthma. FeNO testing is cost-effective and has been shown, when combined with clinical assessment, to improve asthma management.

Treatment Decisions in Children with Asthma in a Real-Life Clinical Setting: The Swiss Paediatric Airway Cohort

BACKGROUND

Asthma treatment should be modified according to symptom control and future risk, but there are scarce data on what drives treatment adjustments in routine tertiary care.

OBJECTIVE

We studied factors that drive asthma treatment adjustment in pediatric outpatient clinics.

METHODS

We performed a cross-sectional analysis of the Swiss Paediatric Airway Cohort, a clinical cohort of 0- to 16-year-old children seen by pediatric pulmonologists. We collected information on diagnosis, treatment, lung function, and FeNO from hospital records; and on symptoms, sociodemographic, and environmental factors from a parental questionnaire. We used reported symptoms to classify asthma control and categorized treatment according to the 2020 Global Initiative for Asthma guidelines. We used multivariable logistic regression to study factors associated with treatment adjustment (step-up or down vs no change).

RESULTS

We included 551 children diagnosed with asthma (mean age, 10 years; 37% female). At the clinical visit, most children were prescribed Global Initiative for Asthma step 3 (35%). Compared with previsit treatment, 252 children remained on the same step (47%), 227 were stepped up (42%), and 58 were stepped down (11%). Female sex (adjusted odds ratio [aOR] = 1.61; 95% confidence interval [CI], 1.05-2.47), poor asthma control (aOR = 3.08; 95% CI, 1.72-5.54), and lower FEV₁ Z-score (aOR = 0.70; 95% CI, 0.56-0.86 per one Z-score increase) were independently associated with treatment step-up, and low FeNO (aOR = 2.34; 95% CI, 1.23-4.45) was associated with treatment step-down, with marked heterogeneity between clinics.

CONCLUSIONS

In this tertiary care real-life study, we identified main drivers for asthma treatment adjustment. These findings may help improve both asthma management guidelines and clinical practice.

Neighborhoods, Caregiver Stress, and Children's Asthma Symptoms

BACKGROUND

Neighborhood and caregiver characteristics have each been linked to children's asthma outcomes, but less is known about how caregiver psychosocial functioning may explain the link between neighborhood characteristics and asthma outcomes.

OBJECTIVE

To examine associations between neighborhood safety, caregiver stress and depressive symptoms, and children's asthma outcomes, and to evaluate whether caregiver stress and depressive symptoms mediate the relationship between neighborhood safety and asthma outcomes.

METHODS

We analyzed baseline data from a prospective cohort study of the effects of a housing mobility program on children's asthma-related outcomes. Age- and sex-adjusted models evaluated associations of neighborhood safety, and caregiver stress and depressive symptoms, with children's asthma symptoms and exacerbations.

RESULTS

Participants were 140 low-income children with persistent asthma (98% Black participants; 53% males; mean age, 9.0 years) with an average of 7.1 ± 5.3 maximum symptom days per 2 weeks. Lower neighborhood safety, and higher caregiver stress and depressive symptoms, were associated with higher asthma symptoms, but not exacerbations, in adjusted models (eg, for neighborhood safety, maximum symptom days: odds ratio, 1.41; 95% CI, 1.07-1.88; for caregiver stress, maximum symptom days: odds ratio, 1.08; 95% CI, 1.01-1.15; for depressive symptoms, maximum symptom days: odds ratio, 1.05; 95% CI, 1.00-1.11). Exploratory analyses suggested that caregiver stress partially mediated associations between neighborhood safety and asthma symptoms for children in unsafe neighborhoods.

CONCLUSIONS

Neighborhood safety was associated with children's asthma symptoms independent from caregiver stress and depressive symptoms, although for children in unsafe neighborhoods, caregiver stress may partially mediate this association. Findings suggest the importance of targeting multiple systems to improve children's asthma outcomes.

Pediatric Asthma Exacerbation in Children with Suspected and Confirmed Coronavirus Disease 2019 (COVID-19): An Observational Study from Saudi Arabia

Background

Most asthma exacerbations are caused by viral respiratory infections such as rhinovirus, coronaviruses, influenza viruses, and many others. While there have been data about the impact of COVID-19 on adult asthma, much remains unknown about the impact of COVID-19 on childhood asthma.

Methods

This retrospective cohort study included all pediatric patients aged 2 to 12 years who were admitted to Abha Maternity and Children Hospital for acute asthma exacerbation between June 1, 2020, and May 31, 2021, and underwent testing for SARS-CoV-2 using nasopharyngeal real-time polymerase chain reaction.

Results

Sixty children hospitalized with the diagnosis of asthma were included in the study. Out of these patients, 10 (16.7%) were diagnosed with COVID-19. The enrolled patients were between 2 and 12 years, with a median age of five years (interquartile range, 3.8), and 58% were males (35/60). Cough, shortness of breath, and hypoxia were the most common presenting symptoms and signs. Severe asthma was more prevalent among positive COVID-19 compared with negative COVID-19 patients (60 vs 20%; P= 0.016). In addition, chronic asthma for more than five years was more prevalent among positive COVID-19 than negative COVID-19 patients (60 vs 40%, P= 0.305). Fifty-five percent of the enrolled patients had eosinophilic asthma using a 300cells/μL threshold. None of the children required invasive respiratory support (ventilation through an endotracheal tube or tracheostomy), but 12 patients (21.7%) required respiratory support via high-flow nasal cannula. The total days of hospitalization in either PICU or pediatric general ward did not differ between the two groups. All patients were discharged, and there were no reports of serious morbidity or mortality.

Conclusion

Eosinophilic asthma was the most prevalent asthma phenotype in the study group. Furthermore, there was no difference in the presenting symptoms of an asthma flare-up, laboratory indicators, and hospitalization outcomes (critical care admission and hospital stay) between asthmatics with and without a COVID-19 diagnosis.

The predictive value of impulse oscillometry for asthma exacerbations in childhood: A systematic review and meta-analyses

OBJECTIVE

Several studies have explored the predictive value of impulse oscillometry (IOS) for asthma exacerbations in childhood, but its specific parameters are still unclear. Therefore, we designed this meta-analysis to determine the related indicators of acute asthma attacks.

METHODS

A comprehensive literature search was performed on July 9, 2020 based on PubMed, Embase, and Web of Science database. Weighted mean differences (WMDs) were calculated using fixed- or random-effects models.

RESULTS

A total of 615 patients from six trials were included in this analysis. IOS may be a useful tool to predict asthma exacerbations. And the results showed that R5 (WMD = -1.21, 95% CI: -1.55 to -0.87, p < .001), Fres (WMD = -1.34, 95% CI: -2.03 to -0.65, p = .018), and AX (WMD = -7.35, 95% CI: -9.94 to -4.76, p < .001) had significant correlation with asthma exacerbations. In addition, X5 may also predict the acute attack of asthma (WMD = 0.81, 95% CI: 0.56 to 1.01, p < .001).

CONCLUSIONS

R5, AX, Fres, and X5 may be able to identify the risk of an acute attack of asthma. Besides, our research further demonstrated that peripheral airway injury may play an important role in the acute attack of asthma.

The Predictive Role of Biomarkers and Genetics in Childhood Asthma Exacerbations

Asthma exacerbations are associated with significant childhood morbidity and mortality. Recurrent asthma attacks contribute to progressive loss of lung function and can sometimes be fatal or near-fatal, even in mild asthma. Exacerbation prevention becomes a primary target in the management of all asthmatic patients. Our work reviews current advances on exacerbation predictive factors, focusing on the role of non-invasive biomarkers and genetics in order to identify subjects at higher risk of asthma attacks. Easy-to-perform tests are necessary in children; therefore, interest has increased on samples like exhaled breath condensate, urine and saliva. The variability of biomarker levels suggests the use of seriate measurements and composite markers. Genetic predisposition to childhood asthma onset has been largely investigated. Recent studies highlighted the influence of single nucleotide polymorphisms even on exacerbation susceptibility, through involvement of both intrinsic mechanisms and gene-environment interaction. The role of molecular and genetic aspects in exacerbation prediction supports an individual-shaped approach, in which follow-up planning and therapy optimization take into account not only the severity degree, but also the risk of recurrent exacerbations. Further efforts should be made to improve and validate the application of biomarkers and genomics in clinical settings.

Predicting Severe Asthma Exacerbations in Children: Blueprint for Today and Tomorrow

Severe asthma exacerbations are the primary cause of morbidity and mortality in children with asthma. Accurate prediction of children at risk for severe exacerbations, defined as those requiring systemic corticosteroids, emergency department visit, and/or hospitalization, would considerably reduce health care utilization and improve symptoms and quality of life. Substantial progress has been made in identifying high-risk exacerbation-prone children. Known risk factors for exacerbations include demographic characteristics (ie, low income, minority race/ethnicity), poor asthma control, environmental exposures (ie, aeroallergen exposure/sensitization, concomitant viral infection), inflammatory biomarkers, genetic polymorphisms, and markers from other "omic" technologies. The strongest risk factor for a future severe exacerbation remains having had one in the previous year. Combining risk factors into composite scores and use of advanced predictive analytic techniques such as machine learning are recent methods used to achieve stronger prediction of severe exacerbations. However, these methods are limited in prediction efficiency and are currently unable to predict children at risk for impending (within days) severe exacerbations. Thus, we provide a commentary on strategies that have potential to allow for accurate and reliable prediction of children at risk for impending exacerbations. These approaches include implementation of passive, real-time monitoring of impending exacerbation predictors, use of population health strategies, prediction of severe exacerbation responders versus nonresponders to conventional exacerbation management, and considerations for preschool-age children who can be especially high risk. Rigorous prediction and prevention of severe asthma exacerbations is needed to advance asthma management and improve the associated morbidity and mortality.

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.

Impact of antipyretics on acute asthma exacerbation during respiratory infection-A nationwide population-based study

BACKGROUND

Antipyretics are frequently used in pediatric practice. Both acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs) have been reported to increase the risk of asthma exacerbation. The study investigated antipyretic use during respiratory infection in children and analyzed the risk of acetaminophen and NSAID for severe asthma exacerbation (AE) in asthmatic children in Taiwan.

METHODS

We used the data from the National Health Insurance Research Database in 2005. There were 27,095 pediatric asthmatic patients having at least one respiratory infection episode, and 27,095 age- and sex-matched non-asthmatic children with respiratory infection served as controls. These patients were divided into groups with acetaminophen use, NSAID cyclooxygenase-1 (COX-1) use, and no antipyretic use. The rate of AE occurrence within the first 7 days after respiratory infection diagnosis was compared among the groups.

RESULTS

During a single episode of respiratory infection, asthmatic patients used fewer antipyretics than controls (48.51% vs. 55.50%, p < 0.001). No difference was observed in the risk of AE occurrence within 7 days after respiratory infection between antipyretic users and antipyretic nonusers (22/13,144 [0.167%] vs. 12/13,951 [0.086%], p = 0.058). Compared with asthmatic children using acetaminophen, those using no antipyretic and COX-1 have lower risks for AE (OR: 0.26, 95% CI: 0.12-0.54, p < 0.001; and OR: 0.14, 95% CI: 0.03-0.61, p = 0.009).

CONCLUSION

In asthmatic children, the rate of AE after a single respiratory infection episode was around 0.144%. The risk of AE was higher in those who took acetaminophen.

Advances in understanding and reducing the burden of severe asthma in children

Severe asthma in children is rare, accounting for only a small proportion of childhood asthma. After addressing modifiable factors such as adherence to treatment, comorbidities, and adverse exposures, children whose disease is not well controlled on high doses of medication form a heterogeneous group of severe asthma phenotypes. Over the past decade, considerable advances have been made in understanding the pathophysiology of severe therapy-resistant asthma in children. However, asthma attacks and hospital admissions are frequent and mortality is still unacceptably high. Strategies to modify the natural history of asthma, prevent severe exacerbations, and prevent lung function decline are needed. Mechanistic studies have led to the development of several biologics targeting type 2 inflammation. This growing pipeline has the potential to reduce the burden of severe asthma; however, detailed assessment and characterisation of each child with seemingly severe asthma is necessary so that the most effective and appropriate management strategy can be implemented. Risk stratification, remote monitoring, and the integration of multiple data sources could help to tailor management for the individual child with severe asthma.

Asthma attacks in children are always preceded by poor asthma control: myth or maxim?

Some, but not all, asthma exacerbations in children are preceded by poor asthma control https://bit.ly/3muIy6h.

Predicting asthma exacerbation by impulse oscillometry evaluation of small airway function and fractional exhaled nitric oxide in preschool children

OBJECTIVE

To study impulse oscillometry (IOS) indices of peripheral airway function and FeNO as predictors of future loss of asthma control in preschool children.

METHODS

Patients aged 3 to 6 years who were actively being treated for asthma and children without asthma were enrolled in the study. Participants had no change in medication on visit 1 and returned for a follow-up visit within 8 to 12 weeks. At the first visit, nursing assessment, symptom history, IOS analysis, FeNO, and physician evaluation were repeated.

RESULTS

Fifty-one (64.6%) subjects had lost asthma control (UC-Group) and 28 (35.4%) subjects had maintained asthma control (C-Group) at their follow-up visit. Thirty-two children without asthma were enrolled in the study as a normal control group (N-Group). R5, R5-20, AX, and Z5 values were all significantly higher in subjects whose symptoms remained uncontrolled compared with those in the controlled asthma group (P < .01) and also significantly higher than those in the normal control group (P < .01). FeNO showed no significant difference between the UC-Group and C-Group (P = .399). Four indices-R5, R5-20, AX, and Z5-had an estimated area under the curve (AUC) of greater than 0.8 and were thus easily able to distinguish the UC-Group from the C-Group.

CONCLUSIONS

AX had the highest overall AUC (0.884) of the investigated parameters, and the optimal cut-off point of 37.435 cm H₂ O/L was able to predict future loss of asthma control in preschool children.

Precision medicine in childhood asthma

PURPOSE OF REVIEW

Childhood asthma is a heterogeneous disease and many children have uncontrolled disease. Therefore an individualized approach is needed to improve asthma outcomes in children. Precision medicine using clinical characteristics, biomarkers, and the rapidly involving field of genomics and pharmacogenomics aims to achieve asthma control and reduce future risks with less side-effects in individual children with asthma.

RECENT FINDINGS

It is not yet possible to select treatment options on clinical characteristics. Novel monoclonal antibodies are efficacious in patients with severe, eosinophilic asthma. Reduced lung function growth and early decline is a prevalent finding in children with persistent asthma. Pharmacogenetic studies have identified children at risk for cortisol suppression when using inhaled corticosteroids.

SUMMARY

Clinical characteristics and simple biomarkers like eosinophils, IgE, and the fraction of exhaled nitric oxide may be used in clinical practice for a basic precision medicine approach, deciding which children will have the best chance to respond to inhaled corticosteroids and to the biologicals omalizumab and mepolizumab.Further application of pharmacogenomics and breathomics needs additional studies before they can be applied as tools for precision medicine in individual children with asthma.

Clinical utility of exhaled nitric oxide fraction in the management of asthma and COPD

Exhaled nitric oxide fraction (F_ENO) values can be easily measured using portable analysers and are a surrogate marker of airway eosinophilia. F_ENO may be useful in diagnosing and monitoring conditions characterised by airway eosinophilia, i.e. asthma and possibly COPD. Many factors other than asthma and COPD affect F_ENO, especially atopy, which is associated with elevated F_ENO. One guideline recommends that F_ENO should be used as part of the diagnostic pathway for asthma diagnosis in adults and children aged >5 years. The role of F_ENO in monitoring asthma is even less clear, and most guidelines do not recommend its use outside of specialist asthma clinics. Currently, F_ENO is not recommended for diagnosis or monitoring of COPD. Although F_ENO is starting to find a place in the management of asthma in children and adults, considerably more research is required before the potential of F_ENO as an objective measurement in asthma and COPD can be realised.

Exhaled nitric oxide fraction (F_ENO) may be a useful test for diagnosing asthma in adults and in children but is currently not recommended for monitoring all patients with asthma or COPD 
http://bit.ly/2lmjXpm

Bronchodilator Dose Responsiveness in Children and Adolescents: Clinical Features and Association with Future Asthma Exacerbations

BACKGROUND

Bronchodilator reversibility measures are often associated with poor asthma outcomes in children. Whether bronchodilator dose responsiveness is similarly useful in children is unclear.

OBJECTIVE

We hypothesized that children and adolescents requiring higher doses of bronchodilator to achieve maximal bronchodilation would have unique risk factors and increased risk of future exacerbation.

METHODS

Children (6-11 years, N = 299) and adolescents (12-21 years, N = 331) with confirmed asthma underwent clinical phenotyping procedures and a test of maximal bronchodilation with escalating doses of albuterol sulfate up to 720 mcg. Outcome measures were assessed at 12 months and included exacerbations treated with systemic corticosteroids, emergency department (ED) visits, and hospitalizations for asthma.

RESULTS

A total of 6.7% of children and 9.3% of adolescents had poor bronchodilator dose responsiveness, defined as attainment of maximal forced expiratory volume in 1 second with 720 mcg albuterol. Risk factors included type 2 inflammation, prior exacerbations, and greater asthma severity; historical pneumonia and tobacco exposure were also risk factors in children. Children and adolescents with poor bronchodilator dose responsiveness did not have increased current symptoms or impaired quality of life, but had approximately 2-fold increased odds of exacerbation or ED visit and approximately 3-fold increased odds of hospitalization by 12 months, independent of airflow obstruction.

CONCLUSIONS

Bronchodilator dose responsiveness may be useful for phenotyping and may be of utility in practice and future studies focused on asthma outcomes or quantification of treatment responses. In children and adolescents, this phenotype of poor bronchodilator responsiveness may be associated with periods of relatively stable disease yet marked airway constriction in response to triggers, including tobacco smoke, respiratory infections/pneumonia, and aeroallergens.

Severe childhood asthma exacerbations: Is treatment response variability in the genes?

Worldwide, asthma is one of the most common causes of medical emergency in children. Failed acute management events comprise a large part of the annual healthcare costs of asthma. These severe exacerbations requiring hospitalization likely also contribute to permanent remodeling and impaired lung function in later life. Various studies have uncovered clinical, environmental, and genetic risk factors for severe asthma and exacerbations that cannot be acutely managed and require hospitalization. Tse and colleagues extend their previous work by adding important new insights into the determinants of failed ED management of pediatric asthma. Using a candidate gene approach and stepwise regression, they identified three SNPs in two candidate genes: IL33, rs7037276, rs1342326 and SPATS2L, rs295137, which when aggregated together significantly increased the odds for ED management failure, with each risk allele increasing failure odds by 83% (95% CI, 36–145%). When these genes markers were combined with validated clinical predictors of acute asthma management failure (viral infection, poor baseline pediatric respiratory assessment measure score, oxygen saturation <92%, fever >38.3°C, and presence of symptoms between episodes) the resulting ability to predict acute management failure was significantly improved (ROC curve=0.82). As discussed in this editorial and the discussion by Tse et al, these novel genetic markers provide new avenues of research for management of acute exacerbations. As the syndrome of asthma continues to be better characterized into multiple endo-phenotypes, we are likely to find that personalized treatment is necessary not only for control of asthma but also for acute rescue of exacerbations.

Asthma exacerbation trajectories and their predictors in children with incident asthma

BACKGROUND

Asthma exacerbation trajectories in children after incident asthma diagnosis are understudied.

OBJECTIVE

To identify trajectories of asthma exacerbation and predictors of these trajectories in children with incident asthma.

METHODS

Children from the National Longitudinal Survey of Children and Youth, Canada, with incident asthma were followed-up for up to 12 years during childhood. Latent class growth modeling was used to identify distinct asthma exacerbation trajectory groups. Multinomial logistic regression was performed to identify predictors of trajectory group membership.

RESULTS

The mean age at asthma diagnosis among 403 children was 5.9 years. Three distinct trajectories were identified: low increasing (21.3% of children), medium decreasing (45.8% of children), and high decreasing (32.8% of children). Asthma attack probability increased gradually after diagnosis in low increasing group, decreased from moderate level after diagnosis to almost zero probability at the end of follow-up in the medium decreasing group, and decreased after diagnosis but remained higher in the high decreasing group than the other 2 groups at 12 years after diagnosis. Children having more siblings at home were more likely to belong to the medium decreasing and high decreasing trajectory groups, whereas children older at asthma diagnosis were less likely to belong to the medium decreasing and high decreasing trajectory groups than the low increasing trajectory group.

CONCLUSION

Our results suggest that children with incident asthma follow 3 distinct trajectories of asthma exacerbations after asthma diagnosis. The trajectory group with initial moderate exacerbation probability has better long-term prognosis.

Exploring the Utility of Noninvasive Type 2 Inflammatory Markers for Prediction of Severe Asthma Exacerbations in Children and Adolescents

BACKGROUND

Noninvasive markers of type 2 inflammation are needed to identify children and adolescents who might benefit from personalized biologic therapy.

OBJECTIVE

We hypothesized that blood eosinophil counts would predict 1 or more acute visits for asthma and that prediction could be improved with the addition of a second, noninvasive type 2 inflammatory biomarker.

METHODS

Children and adolescents 5 to 21 years (N = 589) with an asthma exacerbation necessitating systemic corticosteroid treatment in the previous year completed a characterization visit and telephone calls at 6 and 12 months. The primary outcome was an acute visit for asthma with receipt of systemic corticosteroids. Acute visits were verified by medical record review. Exploratory outcomes included time to first acute visit and hospitalization.

RESULTS

Acute visits occurred in 106 (35.5%) children and 72 (24.8%) adolescents. Elevated blood eosinophils were associated with increased odds and shorter time to first acute visit, but optimal cut-points differed by age (≥150 vs ≥300 cells/μL for children vs adolescents, respectively). The addition of a second marker of type 2 inflammation did not improve prediction in children, but increased the odds and hazard of an acute visit up to 16.2% and 11.9%, respectively, in adolescents. Similar trends were noted for hospitalizations.

CONCLUSIONS

Blood eosinophils and other noninvasive markers of type 2 inflammation may be useful in the clinical assessment of children and adolescents with asthma. However, features of type 2 inflammation vary by age. Whether children and adolescents also respond differently to management of type 2 inflammation is unclear and warrants further evaluation.

Asthma exacerbation prediction: recent insights

PURPOSE OF REVIEW

Asthma attacks are frequent in children with asthma and can lead to significant adverse outcomes including time off school, hospital admission and death. Identifying children at risk of an asthma attack affords the opportunity to prevent attacks and improve outcomes.

RECENT FINDINGS

Clinical features, patient behaviours and characteristics, physiological factors, environmental data and biomarkers are all associated with asthma attacks and can be used in asthma exacerbation prediction models. Recent studies have better characterized children at risk of an attack: history of a severe exacerbation in the previous 12 months, poor adherence and current poor control are important features which should alert healthcare professionals to the need for remedial action. There is increasing interest in the use of biomarkers. A number of novel biomarkers, including patterns of volatile organic compounds in exhaled breath, show promise. Biomarkers are likely to be of greatest utility if measured frequently and combined with other measures. To date, most prediction models are based on epidemiological data and population-based risk. The use of digital technology affords the opportunity to collect large amounts of real-time data, including clinical and physiological measurements and combine these with environmental data to develop personal risk scores. These developments need to be matched by changes in clinical guidelines away from a focus on current asthma control and stepwise escalation in drug therapy towards inclusion of personal risk scores and tailored management strategies including nonpharmacological approaches.

SUMMARY

There have been significant steps towards personalized prediction models of asthma attacks. The utility of such models needs to be tested in the ability not only to predict attacks but also to reduce them.

Understanding the importance of key risk factors in predicting chronic bronchitic symptoms using a machine learning approach

BACKGROUND

Chronic respiratory symptoms involving bronchitis, cough and phlegm in children are underappreciated but pose a significant public health burden. Efforts for prevention and management could be supported by an understanding of the relative importance of determinants, including environmental exposures. Thus, we aim to develop a prediction model for bronchitic symptoms.

METHODS

Schoolchildren from the population-based southern California Children's Health Study were visited annually from 2003 to 2012. Bronchitic symptoms over the prior 12 months were assessed by questionnaire. A gradient boosting model was fit using groups of risk factors (including traffic/air pollution exposures) for all children and by asthma status. Training data consisted of one observation per participant in a random study year (for 50% of participants). Validation data consisted of: (1) a random (later) year in the same participants (within-participant); (2) a random year in participants excluded from the training data (across-participant).

RESULTS

At baseline, 13.2% of children had asthma and 18.1% reported bronchitic symptoms. Models performed similarly within- and across-participant. Previous year symptoms/medication use provided much of the predictive ability (across-participant area under the receiver operating characteristic curve (AUC): 0.76 vs 0.78 for all risk factors, in all participants). Traffic/air pollution exposures added modestly to prediction as did body mass index percentile, age and parent stress.

CONCLUSIONS

Regardless of asthma status, previous symptoms were the most important predictors of current symptoms. Traffic/air pollution variables contribute modest predictive information, but impact large populations. Methods proposed here could be generalized to personalized exacerbation predictions in future longitudinal studies to support targeted prevention efforts.

Advances in the aetiology, management, and prevention of acute asthma attacks in children

Acute attacks of wheeze or asthma are among the most common reasons for paediatric hospital attendance, and the incidence of severe attacks in the UK is among the highest in Europe. Although most attacks are driven by infection, there are important differences in the underlying pathophysiology of asthma and wheeze between preschool and school-aged children. Allergen sensitisation, airway eosinophilia, and type 2 inflammation predominate in older children, whereas phenotypes in preschool children are variable, often including non-atopic episodes driven by neutrophilic infection. Currently, a universal approach is adopted towards management, but there is a need to make objective assessments of airway function, inflammation, and infection, both during the attack and during stable periods, to identify treatable traits and to target therapy if outcomes are to be improved. An assessment of the risk factors that led to the attack and early, focused follow-up are essential to ensure attacks never occur again.

Life Cycle of Childhood Asthma: Prenatal, Infancy and Preschool, Childhood, and Adolescence

Asthma is a heterogeneous developmental disorder influenced by complex interactions between genetic susceptibility and exposures. Wheezing in infancy and early childhood is highly prevalent, with a substantial minority of children progressing to established asthma by school age, most of whom are atopic. Adolescence is a time of remission of symptoms with persistent lung function deficits. The transition to asthma in adulthood is not well understood.

Pharmacogenetics of inhaled long-acting beta2-agonists in asthma: A systematic review

BACKGROUND

Long-acting beta2-agonists (LABA) are recommended in asthma therapy; however, not all asthma patients respond well to LABA. We performed a systematic review on genetic variants associated with LABA response in patients with asthma.

METHODS

Articles published until April 2017 were searched by two authors using PubMed and EMBASE. Pharmacogenetic studies in patients with asthma and LABA response as an outcome were included.

RESULTS

In total, 33 studies were included in this systematic review; eight focused on children (n = 6051). Nineteen studies were clinical trials, while 14 were observational studies. Studies used different outcomes to define LABA response, for example, lung function measurements (FEV₁ , PEF, MMEF, FVC), exacerbations, quality of life, and asthma symptoms. Most studies (n = 30) focused on the ADRB2 gene, encoding the beta2-adrenergic receptor. Thirty studies (n = 14 874) addressed ADRB2 rs1042713, 7 ADRB2 rs1042714 (n = 1629), and 3 ADRB2 rs1800888 (n = 1892). The association of ADRB2 rs1042713 and rs1800888 with LABA response heterogeneity was successfully replicated. Other variants were only studied in three studies but not replicated. One study focused on the ADCY9 gene. Five studies and a meta-analysis found an increased risk of exacerbations in pediatrics using LABA carrying one or two A alleles (OR 1.52 [1.17; 1.99]). These results were not confirmed in adults.

CONCLUSIONS

ADRB2 rs1042713 variant is most consistently associated with response to LABA in children but not adults. To assess the clinical value of ADRB2 rs1042713 in children with asthma using LABA, a randomized clinical trial with well-defined outcomes is needed.

Treatment of allergic rhinitis reduces acute asthma exacerbation risk among asthmatic children aged 2-18 years

BACKGROUND/PURPOSE

Asthma and allergic rhinitis (AR) frequently coexist in the same individuals in childhood and adolescence. We evaluated whether AR had an impact on acute exacerbation (AE) and whether intranasal corticosteroid (INCS) and second-generation antihistamines (SGH) for AR modified the association of AR with AE in asthmatics aged 2-6 years and 7-18 years.

METHODS

Using the National Health Research Institutes (NHRI) Database 2005 of Taiwan, we investigated patients who had been diagnosed with asthma in the years 2000 through 2012 and who had then been followed-up with for at least one year. The risk factors of AE were evaluated using multiple Cox proportional hazards regression analysis.

RESULTS

The incidence of AE was higher in the preschool group than the older group (adj. HR: 1.68, 95% CI: 1.44-1.95). The AR with INCS and/or SGH group was found to have a lower risk of AE than the non-AR group (adj. HR: 0.32, 0.44 and 0.30), but the AR without treatment group did not have a significant difference with the non-AR group. After propensity score matching, the use of INCS and/or SGH was associated with a significant reduction in the occurrence of AE among AR patients aged 2-6 years old (adj. HR: 0.38, 0.57 and 0.45) and 7-18 years old (adj. HR: 0.50, 0.52 and 0.35).

CONCLUSION

The preschool patients had a higher incidence of AE than the older patients in general. Adequate treatment with INCS and/or SGH in asthma with AR patients is important for reducing the incidence of AE of asthma.

Change in FEV1 and Feno Measurements as Predictors of Future Asthma Outcomes in Children

BACKGROUND

Repeated measurements of spirometry and fractional exhaled nitric oxide (Feno) are recommended as part of the management of childhood asthma, but the evidence base for such recommendations is small. We tested the hypothesis that reducing spirometric indices or increasing Feno will predict poor future asthma outcomes.

METHODS

A one-stage individual patient data meta-analysis used data from seven randomized controlled trials in which Feno was used to guide asthma treatment; spirometric indices were also measured. Change in %FEV₁ and % change in Feno between baseline and 3 months were related to having poor asthma control and to having an asthma exacerbation between 3 and 6 months after baseline.

RESULTS

Data were available from 1,112 children (mean age, 12.6 years; mean %FEV₁, 94%). A 10% reduction in %FEV₁ between baseline and 3 months was associated with 28% increased odds for asthma exacerbation (95% CI, 3-58) and with 21% increased odds for having poor asthma control (95% CI, 0-45) 6 months after baseline. A 50% increase in Feno between baseline and 3 months was associated with 11% increase in odds for poor asthma control 6 months after baseline (95% CI, 0-16). Baseline Feno and %FEV₁ were not related to asthma outcomes at 3 months.

CONCLUSIONS

Repeated measurements of %FEV₁ that are typically within the "normal" range add to clinical risk assessment of future asthma outcomes in children. The role of repeated Feno measurements is less certain because large changes were associated with small changes in outcome risk.

Susceptibility to exacerbations in Black adults with asthma

OBJECTIVE

Exacerbations account for much of the morbidity in asthma. In a large intervention study, we sought to test the hypothesis that a Black adult exacerbation-prone phenotype - a group of Black people with asthma who are at high risk of repeat exacerbation within one year - exists in asthma independent of clinical control.

METHODS

We analyzed exacerbation risk factors in 536 self-identified Black Americans with asthma eligible for, or on, Step 3 National Asthma Education and Prevention Program (NAEPP) therapy who participated in a randomized 6-18 month trial of tiotropium versus long acting beta agonist as add-on therapy to inhaled corticosteroids. Exacerbations were defined as events treated by oral or systemic corticosteroids. Clinical control was assessed by a validated asthma control questionnaire (ACQ5).

RESULTS

Exacerbations became more likely with loss of clinical control. The mean baseline ACQs for exacerbators and non-exacerbators were 2.41 and 1.91, respectively (p < 0.001). The strongest independent factor associated with exacerbations across all ACQ levels was an exacerbation in the preceding year (adjusted OR 3.26; p < 0.001). The severity of prior exacerbations did not correlate with the likelihood of a future exacerbation. Lower baseline FEV1/FVC was also associated with increased risk of exacerbations.

CONCLUSIONS

Even though exacerbations increase with loss of clinical control, an exacerbation susceptibility phenotype exists in Black adults with asthma, independent of clinical control. This phenotype requires precision therapeutic targeting.

Predictors of repeated acute hospital attendance for asthma in children: A systematic review and meta-analysis

BACKGROUND

Asthma attacks are common and have significant physical, psychological, and financial consequences. Improving the assessment of a child's risk of subsequent asthma attacks could support front-line clinicians' decisions on augmenting chronic treatment or specialist referral. We aimed to identify predictors for emergency department (ED) or hospital readmission for asthma from the published literature.

METHODS

We searched MEDLINE, EMBASE, AMED, PsycINFO, and CINAHL with no language, location, or time restrictions. We retrieved observational studies and randomized controlled trials (RCT) assessing factors (personal and family history, and biomarkers) associated with the risk of ED re-attendance or hospital readmission for acute childhood asthma.

RESULTS

Three RCTs and 33 observational studies were included, 31 from Anglophone countries and none from Asia or Africa. There was an unclear or high risk of bias in 14 of the studies, including 2 of the RCTs. Previous history of emergency or hospital admissions for asthma, younger age, African-American ethnicity, and low socioeconomic status increased risk of subsequent ED and hospital readmissions for acute asthma. Female sex and concomitant allergic diseases also predicted hospital readmission.

CONCLUSION

Despite the global importance of this issue, there are relatively few high quality studies or studies from outside North America. Factors other than symptoms are associated with the risk of emergency re-attendance for acute asthma among children. Further research is required to better quantify the risk of future attacks and to assess the role of commonly used biomarkers.

Passive Nocturnal Physiologic Monitoring Enables Early Detection of Exacerbations in Children with Asthma. A Proof-of-Concept Study

RATIONALE

Asthma management depends on prompt identification of symptoms, which challenges both patients and providers. In asthma, a misapprehension of health between exacerbations can compromise compliance. Thus, there is a need for a tool that permits objective longitudinal monitoring without increasing the burden of patient compliance.

OBJECTIVES

We sought to determine whether changes in nocturnal physiology are associated with asthma symptoms in pediatric patients.

METHODS

Using a contactless bed sensor, nocturnal heart rate (HR), respiratory rate, relative stroke volume, and movement in children with asthma 5-18 years of age (n = 16) were recorded. Asthma symptoms and asthma control test (ACT) score were reported every 2 weeks. Random forest model was used to identify physiologic parameters associated with asthma symptoms. Elastic net regression was used to identify variables associated with ACT score.

MEASUREMENTS AND MAIN RESULTS

The model on the full cohort performed with sensitivity of 47.2%, specificity of 96.3%, and accuracy of 87.4%; HR and respiratory parameters were the most important variables in this model. The model predicted asthma symptoms 35% of the time on the day before perception of symptoms, and 100% of the time for a select subject for which the model performed with greater sensitivity. Multivariable and bivariable analyses demonstrated significant association between HR and respiratory rate parameters and ACT score.

CONCLUSIONS

Nocturnal physiologic changes correlate with asthma symptoms, supporting the notion that nocturnal physiologic monitoring represents an objective diagnostic tool capable of longitudinally assessing disease control and predicting asthma exacerbations in children with asthma at home.

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

Current understanding of risk factors for asthma attacks in children is based on studies of small but well-characterised populations or pharmaco-epidemiology studies of large but poorly characterised populations. We describe an observational study of factors linked to future asthma attacks in large number of well-characterised children. From two UK primary care databases (Clinical Practice Research Datalink and Optimum Patient Care research Database), a cohort of children was identified with asthma aged 5–12 years and where data were available for ≥2 consecutive years. In the “baseline” year, predictors included treatment step, number of attacks, blood eosinophil count, peak flow and obesity. In the “outcome” year the number of attacks was determined and related to predictors. There were 3776 children, of whom 525 (14%) had ≥1 attack in the outcome year. The odds ratio (OR) for one attack was 3.7 (95% Confidence Interval (CI) 2.9, 4.8) for children with 1 attack in the baseline year and increased to 7.7 (95% CI 5.6, 10.7) for those with ≥2 attacks, relative to no attacks. Higher treatment step, younger age, lower respiratory tract infections, reduced peak flow and eosinophil count >400/μL were also associated with small increases in OR for an asthma attack during the outcome year. In this large population, several factors were associated with a future asthma attack, but a past history of attacks was most strongly associated with future attacks. Interventions aimed at reducing the risk for asthma attacks could use primary care records to identify children at risk for asthma attacks.

A past history of asthma attacks in young children is a strong predictor for future attacks and should be factored into treatment regimes. Childhood asthma attacks take considerable toll on sufferers and their carers, yet risk factors for future attacks are unclear. David Price at the Observational and Pragmatic Research Institute in Singapore and co-workers searched UK primary care databases to find at least two years’ worth of consecutive data on children with asthma aged 5 to 12. The team analyzed data from 3,776 children. Their results showed that past attacks are the strongest predictor for future attacks; of 638 patients who experienced more than one asthma attack during the first year, 240 (38%) had attacks in the second year. Other risk factors included reduced peak flow, lower respiratory tract infections and younger age.

At-risk children with asthma (ARC): a systematic review

Introduction

Asthma attacks are responsible for considerable morbidity and may be fatal. We aimed to identify and weight risk factors for asthma attacks in children (5–12 years) in order to inform and prioritise care.

Methods

We systematically searched six databases (May 2016; updated with forward citations January 2017) with no language/date restrictions. Two reviewers independently selected studies for inclusion, assessed study quality and extracted data. Heterogeneity precluded meta-analysis. Weighting was undertaken by an Expert Panel who independently assessed each variable for degree of risk and confidence in the assessment (based on study quality and size, effect sizes, biological plausibility and consistency of results) and then achieved consensus by discussion. Assessments were finally presented, discussed and agreed at a multidisciplinary workshop.

Results

From 16 109 records, we included 68 papers (28 cohort; 4 case-control; 36 cross-sectional studies). Previous asthma attacks were associated with greatly increased risk of attack (ORs between 2.0 and 4.1). Persistent symptoms (ORs between 1.4 and 7.8) and poor access to care (ORs between 1.2 and 2.3) were associated with moderately/greatly increased risk. A moderately increased risk was associated with suboptimal drug regimen, comorbid atopic/allergic disease, African-American ethnicity (USA), poverty and vitamin D deficiency. Environmental tobacco smoke exposure, younger age, obesity and low parental education were associated with slightly increased risk.

Discussion

Assessment of the clinical and demographic features identified in this review may help clinicians to focus risk reduction management on the high-risk child. Population level factors may be used by health service planners and policymakers to target healthcare initiatives.

Trial registration number

CRD42016037464.

The use of pharmacogenomics, epigenomics, and transcriptomics to improve childhood asthma management: Where do we stand?

Asthma is a complex multifactorial disease and it is the most common chronic disease in children. There is a high variability in response to asthma treatment, even in patients with good adherence to maintenance treatment, and a correct inhalation technique. Distinct underlying disease mechanisms in childhood asthma might be the reason of this heterogeneity. A deeper knowledge of the underlying molecular mechanisms of asthma has led to the recent development of advanced and mechanism-based treatments such as biologicals. However, biologicals are recommended only for patients with specific asthma phenotypes who remain uncontrolled despite high dosages of conventional asthma treatment. One of the main unmet needs in their application is lack of clinically available biomarkers to individualize pediatric asthma management and guide treatment. Pharmacogenomics, epigenomics, and transcriptomics are three omics fields that are rapidly advancing and can provide tools to identify novel asthma mechanisms and biomarkers to guide treatment. Pharmacogenomics focuses on variants in the DNA, epigenomics studies heritable changes that do not involve changes in the DNA sequence but lead to alteration of gene expression, and transcriptomics investigates gene expression by studying the complete set of mRNA transcripts in a cell or a population of cells. Advances in high-throughput technologies and statistical tools together with well-phenotyped patient inclusion and collaborations between different centers will expand our knowledge of underlying molecular mechanisms involved in disease onset and progress. Furthermore, it could help to select and stratify appropriate therapeutic strategies for subgroups of patients and hopefully bring precision medicine to daily practice.

Pharmacogenetic and pharmacogenomic considerations of asthma treatment

INTRODUCTION

Pharmacogenetic and pharmacogenomic approaches are already utilized in some areas, such as oncology and cardiovascular disease, for selecting appropriate patients and/or establishing treatment and dosing guidelines. This is not true in asthma although many patients have different responses to drug treatment due to genetic factors. Areas covered: Several genetic factors that affect the pharmacotherapeutic responses to asthma medications, such as β₂-AR agonists, corticosteroids, and leukotriene modifiers and could contribute to significant between-person variability in response are described. Expert opinion: An expanding number of genetic loci have been associated with therapeutic responses to asthma drugs but the individual effect of one single-nucleotide polymorphism is partial. In fact, epigenetic changes can modify genetic effects in time-, environment-, and tissue-specific manners, genes interact together in networks, and nongenetic components such as environmental exposures, gender, nutrients, and lifestyle can significantly interact with genetics to determine the response to therapy. Therefore, well-designed randomized controlled trials or observational studies are now mandatory to define if response to asthma medications in individual patients can be improved by using pharmacogenetic predictors of treatment response. Meanwhile, routine implementation of pharmacogenetics and pharmacogenomics into clinical practice remains a futuristic, far-off challenge for many clinical practices.

Shared decision making and time to exacerbation in children with asthma

Objective: Although shared decision making (SDM) is a promising approach for improving outcomes for patients with chronic diseases, no evidence currently supports the use of SDM to delay asthma exacerbations. We evaluated the impact of an SDM intervention implemented by providers in a real-world setting on time to exacerbation in children with asthma. Methods: This study used a prospective cohort observed between 2011 and 2013 at five primary care practices that serve vulnerable populations (e.g., Medicaid and uninsured patients) in Charlotte, NC. Patients aged 2 to 17 receiving SDM were matched to those receiving usual care using propensity scores. Time to asthma exacerbation (asthma hospitalization, emergency department visit or oral steroid prescription in the outpatient setting) was compared between groups using Kaplan-Meier curves and conditional Cox proportional hazards models. Results: The cohort included 746 children, 60.5% male and 54.2% African American, with a mean age of 8.6 years. Of these, 625 received usual care and 121 received SDM. The final analysis included 100 matched pairs of children. Kaplan-Meier curves showed longer exacerbation-free time for patients in the SDM intervention compared to those in usual care (p = 0.005). The difference in risk of experiencing an exacerbation was marginally significant between the two groups (HR = 0.56, 95% C.I. = 0.29-1.08, p = 0.08). Conclusions: SDM was found to delay exacerbations among children with asthma. Clinicians should consider incorporating patient preferences in treatment decisions through SDM as a means for longer exacerbation-free time among children with poor asthma control.

Differences in airway remodeling and airway inflammation among moderate-severe asthma clinical phenotypes

Background

To identify asthma clinical phenotypes using cluster analysis and improve our understanding of heterogeneity in asthma.

Methods

Clustering approaches were applied to 203 patients who were diagnosed with asthma in XinHua Hospital (January 2012 to December 2015). One hundred and twenty patients underwent multi-slice spiral computed tomography (MSCT) examination and 30 underwent bronchial mucosal biopsy for evaluation of airway remodeling and airway inflammation among the phenotypes.

Results

Four groups were identified. Patients in cluster 1 (n=52) had early onset atopic asthma and patients in cluster 2 (n=65) had small airway obstruction and atopic asthma. Cluster 3 (n=52) was a unique group of patients with late-onset and non-atopic asthma. Patients in cluster 4 (n=34) had severe airflow obstruction and obvious airway remodeling as observed on MSCT (P<0.05). According to the immunohistochemistry of IL-5 and IL-17 (P<0.05), the results of clusters 1 and 2 may be attributable to the Th2 immune response, whereas those of clusters 3 and 4 to the Th17 immune response.

Conclusions

Four distinct clinical phenotypes of asthma were identified by cluster analysis. The results of the MSCT and pathological examinations may suggest specific pathogeneses among the phenotypes.

Early life antibiotic use and the risk of asthma and asthma exacerbations in children

BACKGROUND

The use of antibiotic therapy early in life might influence the risk of developing asthma. Studies assessing the influence of early life antibiotic use on the risk of asthma exacerbations are limited, and the results are inconsistent. Therefore, the aim of this study was to assess the association between use of antibiotic during the first 3 years of life and the risk of developing childhood asthma and the occurrence of asthma exacerbations.

METHODS

Data from four large childhood cohorts were used; two population-based cohorts to study the risk of developing asthma: Generation R (n=7393, The Netherlands) and SEATON (n=891, Scotland, UK), and two asthma cohorts to assess the risk of asthma exacerbations: PACMAN (n=668, The Netherlands) and BREATHE (n=806, Scotland, UK). Odds ratios (ORs) were derived from logistic regression analysis within each database followed by pooling the results using a fixed- or random-effect model.

RESULTS

Antibiotic use in early life was associated with an increased risk of asthma in a meta-analysis of the Generation R and SEATON data (OR: 2.18, 95% CI: 1.04-4.60; I² : 76.3%). There was no association between antibiotic use in early life and risk of asthma exacerbations later in life in a meta-analysis of the PACMAN and BREATHE data (OR: 0.93, 95% CI: 0.65-1.32; I² : 0.0%).

CONCLUSION

Children treated with antibiotic in the first 3 years of life are more likely to develop asthma, but there is no evidence that the exposure to antibiotic is associated with increased risk of asthma exacerbations.

Rationale and design of the multiethnic Pharmacogenomics in Childhood Asthma consortium

AIM

International collaboration is needed to enable large-scale pharmacogenomics studies in childhood asthma. Here, we describe the design of the Pharmacogenomics in Childhood Asthma (PiCA) consortium.

MATERIALS & METHODS

Investigators of each study participating in PiCA provided data on the study characteristics by answering an online questionnaire.

RESULTS

A total of 21 studies, including 14,227 children/young persons (58% male), from 12 different countries are currently enrolled in the PiCA consortium. Fifty six percent of the patients are Caucasians. In total, 7619 were inhaled corticosteroid users. Among patients from 13 studies with available data on asthma exacerbations, a third reported exacerbations despite inhaled corticosteroid use. In the future pharmacogenomics studies within the consortium, the pharmacogenomics analyses will be performed separately in each center and the results will be meta-analyzed.

CONCLUSION

PiCA is a valuable platform to perform pharmacogenetics studies within a multiethnic pediatric asthma population.

Can we predict fall asthma exacerbations? Validation of the seasonal asthma exacerbation index

BACKGROUND

A Seasonal Asthma Exacerbation Predictive Index (saEPI) was previously reported based on 2 prior National Institute of Allergy and Infectious Diseases Inner City Asthma Consortium trials.

OBJECTIVE

This study sought to validate the saEPI in a separate trial designed to prevent fall exacerbations with omalizumab therapy.

METHODS

The saEPI and its components were analyzed to characterize those who had an asthma exacerbation during the Preventative Omalizumab or Step-Up Therapy for Fall Exacerbations (PROSE) study. We characterized those inner-city children with and without asthma exacerbations in the fall period treated with guidelines-based therapy (GBT) in the absence and presence of omalizumab.

RESULTS

A higher saEPI was associated with an exacerbation in both the GBT alone (P < .001; area under the curve, 0.76) and the GBT + omalizumab group (P < .01; area under the curve, 0.65). In the GBT group, younger age at recruitment, higher total IgE, higher blood eosinophil percentage and number, and higher treatment step were associated with those who had an exacerbation compared with those who did not. In the GBT + omalizumab group, younger age at recruitment, increased eosinophil number, recent exacerbation, and higher treatment step were also associated with those who had an exacerbation. The saEPI was associated with a high negative predictive value in both groups.

CONCLUSIONS

An exacerbation in children treated with GBT with or without omalizumab was associated with a higher saEPI along with higher markers of allergic inflammation, treatment step, and a recent exacerbation. Those that exacerbated on omalizumab had similar features with the exception of some markers of allergic sensitization, indicating a need to develop better markers to predict poor response to omalizumab therapy and alternative treatment strategies for children with these risk factors. The saEPI was able to reliably predict those children unlikely to have an asthma exacerbation in both groups.

Impulse Oscillometry as a Predictor of Asthma Exacerbations in Young Children

BACKGROUND

In a post-hoc analysis of a pediatric asthma study, we identified the predictors of asthma exacerbations (AEs) and related them to forced expiratory volume (FEV1), the FEV1/FVC ratio, and bronchial hyperresponsiveness (BHR).

OBJECTIVES

We sought to detect predictors of AEs in a prospective study that utilizes impulse oscillometry (IOS) and to compare the results to previously determined predictors.

METHODS

A moderate AE was defined as an increased use of salbutamol during coughing episodes. Pulmonary function and BHR were measured during symptom- and medication-free periods. Additionally, allergen testing and IOS were included. To calculate the sensitivity and specificity of AE detection, a receiver-operating characteristic (ROC) curve was plotted, and accuracy was measured with the area under the ROC curve (AUC). A logistic regression analysis was used to predict the probability of an exacerbation.

RESULTS

Seventy-five pediatric patients (4-7 years of age) with intermittent asthma were included. In 69 patients, the following cut-off values demonstrated the best sensitivity and specificity combination for predicting an AE: FEV1 103.2% (AUC 0.62), BHR (PD20methacholine) 0.13 mg (AUC 0.61), and, in 54 children, Rrs5 0.78 kPa × l-1 × s (AUC 0.80). Logistic regression analysis demonstrated that the combination of all parameters predicted the individual risk of AEs with an accuracy of 86%.

CONCLUSIONS

IOS, a simple method, predicted the probability of AEs in young children. Airway resistance, measured by IOS, was superior to FEV1 and methacholine testing. The current data suggest that peripheral airway obstruction is present during symptom-free periods and that these children more likely experience AEs.