Heterogeneity of Mild to Moderate Persistent Asthma in Children: Confirmation by Latent Class Analysis and Association with 1-Year Outcomes

BACKGROUND

Compared with adults, phenotypic characterization of children with asthma is still limited and it remains difficult to predict which children with asthma are at highest risk for poor outcomes.

OBJECTIVE

To identify latent classes in a large population of treatment-adherent children with mild to moderate asthma enrolled in clinical trials and determine whether latent class assignment predicts future lung function abnormalities and exacerbation rate.

METHODS

Latent class analysis was performed on 2593 children with mild to moderate asthma aged 5 18 years, with 19 variables encompassing demographic characteristics, medical history, symptoms, lung function, allergic sensitization, and type 2 inflammation. Outcomes included lung function and the annualized exacerbation rate at 12 months of follow-up.

RESULTS

Five latent classes were identified with differing demographic features, asthma control, sensitization, type 2 inflammatory markers, and lung function. Exacerbation rates were 1.30 ± 0.12 for class 1 (multiple sensitization with partially reversible airflow limitation), 0.90 ± 0.05 for class 2 (multiple sensitization with reversible airflow limitation), 0.87 ± 0.08 for class 3 (lesser sensitization with reversible airflow limitation), 0.87 ± 0.05 for class 4 (multiple sensitization with normal lung function), and 0.71 ± 0.06 for class 5 (lesser sensitization with normal lung function). Lung function abnormalities persisted in class 1 at 12 months.

CONCLUSIONS

Children with mild to moderate asthma are a heterogeneous group. Allergic sensitization and lung function may be particularly useful in identifying children at the greatest risk for future exacerbation. Additional studies are needed to determine whether latent classes correspond to meaningful phenotypes for the purpose of personalized treatment.

Challenges in managing difficult-to-treat asthma in children: Stop, look, and listen

It is recognized that asthma places a significant economic burden on the United States, with a total cost of $81.9 billion total costs including costs incurred by absenteeism and mortality. Severe asthma places a large burden of morbidity on children and their caregivers, including severe exacerbations, medication side effects, increased missed school days leading to impaired school performance, and lower caregiver quality of life. Therefore, we need to take a careful look at how we can make asthma care more efficient and cost effective, especially for those children with severe asthma. The 2019 American Thoracic Society symposium reported in this theme issue presented four aspects of managing severe asthma in children that merit attention including patient variables that affect severe asthma, understanding patient behaviors around medications, the appropriate use of bronchoscopy in diagnosis and management of severe asthma, and also the rational use of biologic therapy. This editorial will summarize key points in each of these reviews and prompt a more careful reading of each contribution.

An expert consensus framework for asthma remission as a treatment goal

With novel therapies in development, there is an opportunity to consider asthma remission as a treatment goal. In this Rostrum, we present a generalized framework for clinical and complete remission in asthma, on and off treatment, developed on the basis of medical literature and expert consensus. A modified Delphi survey approach was used to ascertain expert consensus on core components of asthma remission as a treatment target. Phase 1 identified other chronic inflammatory diseases with remission definitions. Phase 2 evaluated components of those definitions as well as published definitions of spontaneous asthma remission. Phase 3 evaluated a remission framework created using consensus findings. Clinical remission comprised 12 or more months with (1) absence of significant symptoms by validated instrument, (2) lung function optimization/stabilization, (3) patient/provider agreement regarding remission, and (4) no use of systemic corticosteroids. Complete remission was defined as clinical remission plus objective resolution of asthma-related inflammation and, if appropriate, negative bronchial hyperresponsiveness. Remission off treatment required no asthma treatment for 12 or more months. The proposed framework is a first step toward developing asthma remission as a treatment target and should be refined through future research, patient input, and clinical study.

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

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

Applying a biopsychosocial model to inner city asthma: Recent approaches to address pediatric asthma health disparities

Pediatric asthma in inner cities is often severe and children living in these urban locations with socioeconomic disadvantage experience greater asthma morbidity. There are many interconnected risk factors that individually, and in combination, enhance asthma morbidity. These include biologic factors innate to the child, such as genetics and allergen susceptibility, as well as factors related to the family and neighborhood context. The biopsychosocial model can be used to frame these risk factors and develop interventions specific to the inner city. Successful inner city asthma interventions exist and key characteristics include multi-tiered components that operate within the community to coordinate disease management resources between patients, families and health care systems.

Development and initial validation of the Asthma Severity Scoring System (ASSESS)

BACKGROUND

Tools for quantification of asthma severity are limited.

OBJECTIVE

We sought to develop a continuous measure of asthma severity, the Asthma Severity Scoring System (ASSESS), for adolescents and adults, incorporating domains of asthma control, lung function, medications, and exacerbations.

METHODS

Baseline and 36-month longitudinal data from participants in phase 3 of the Severe Asthma Research Program (NCT01606826) were used. Scale properties, responsiveness, and a minimally important difference were determined. External replication was performed in participants enrolled in the Severe Asthma Research Program phase 1/2. The utility of ASSESS for detecting treatment response was explored in participants undergoing corticosteroid responsiveness testing with intramuscular triamcinolone and participants receiving biologics.

RESULTS

ASSESS scores ranged from 0 to 20 (8.78 ± 3.9; greater scores reflect worse severity) and differed among 5 phenotypic groups. Measurement properties were acceptable. ASSESS was responsive to changes in quality of life with a minimally important difference of 2, with good specificity for outcomes of asthma improvement and worsening but poor sensitivity. Replication analyses yielded similar results, with a 2-point decrease (improvement) associated with improvements in quality of life. Participants with a 2-point or greater decrease (improvement) in ASSESS scores also had greater improvement in lung function and asthma control after triamcinolone, but these differences were limited to phenotypic clusters 3, 4, and 5. Participants treated with biologics also had a 2-point or greater decrease (improvement) in ASSESS scores overall.

CONCLUSIONS

The ASSESS tool is an objective measure that might be useful in epidemiologic and clinical research studies for quantification of treatment response in individual patients and phenotypic groups. However, validation studies are warranted.

Step-Up Therapy in Black Children and Adults with Poorly Controlled Asthma

BACKGROUND

Morbidity from asthma is disproportionately higher among black patients than among white patients, and black patients constitute the minority of participants in trials informing treatment. Data indicate that patients with inadequately controlled asthma benefit more from addition of a long-acting beta-agonist (LABA) than from increased glucocorticoids; however, these data may not be informative for treatment in black patients.

METHODS

We conducted two prospective, randomized, double-blind trials: one involving children and the other involving adolescents and adults. In both trials, the patients had at least one grandparent who identified as black and had asthma that was inadequately controlled with low-dose inhaled glucocorticoids. We compared combinations of therapy, which included the addition of a LABA (salmeterol) to an inhaled glucocorticoid (fluticasone propionate), a step-up to double to quintuple the dose of fluticasone, or both. The treatments were compared with the use of a composite measure that evaluated asthma exacerbations, asthma-control days, and lung function; data were stratified according to genotypic African ancestry.

RESULTS

When quintupling the dose of fluticasone (to 250 μg twice a day) was compared with adding salmeterol (50 μg twice a day) and doubling the fluticasone (to 100 μg twice a day), a superior response occurred in 46% of the children with quintupling the fluticasone and in 46% of the children with doubling the fluticasone and adding salmeterol (P = 0.99). In contrast, more adolescents and adults had a superior response to added salmeterol than to an increase in fluticasone (salmeterol-low-dose fluticasone vs. medium-dose fluticasone, 49% vs. 28% [P = 0.003]; salmeterol-medium-dose fluticasone vs. high-dose fluticasone, 49% vs. 31% [P = 0.02]). Neither the degree of African ancestry nor baseline biomarkers predicted a superior response to specific treatments. The increased dose of inhaled glucocorticoids was associated with a decrease in the ratio of urinary cortisol to creatinine in children younger than 8 years of age.

CONCLUSIONS

In contrast to black adolescents and adults, almost half the black children with poorly controlled asthma had a superior response to an increase in the dose of an inhaled glucocorticoid and almost half had a superior response to the addition of a LABA. (Funded by the National Heart, Lung, and Blood Institute; BARD ClinicalTrials.gov number, NCT01967173.).

Novel pediatric-automated respiratory score using physiologic data and machine learning in asthma

OBJECTIVES

Manual clinical scoring systems are the current standard used for acute asthma clinical care pathways. No automated system exists that assesses disease severity, time course, and treatment impact in pediatric acute severe asthma exacerbations.

WORKING HYPOTHESIS

machine learning applied to continuous vital sign data could provide a novel pediatric-automated asthma respiratory score (pARS) by using the manual pediatric asthma score (PAS) as the clinical care standard.

METHODS

Continuous vital sign monitoring data (heart rate, respiratory rate, and pulse oximetry) were merged with the health record data including a provider-determined PAS in children between 2 and 18 years of age admitted to the pediatric intensive care unit (PICU) for status asthmaticus. A cascaded artificial neural network (ANN) was applied to create an automated respiratory score and validated by two approaches. The ANN was compared with the Normal and Poisson regression models.

RESULTS

Out of an initial group of 186 patients, 128 patients met inclusion criteria. Merging physiologic data with clinical data yielded >37 000 data points for model training. The pARS score had good predictive accuracy, with 80% of the pARS values within ±2 points of the provider-determined PAS, especially over the mid-range of PASs (6-9). The Poisson and Normal distribution regressions yielded a smaller overall median absolute error.

CONCLUSIONS

The pARS reproduced the manually recorded PAS. Once validated and studied prospectively as a tool for research and for physician decision support, this methodology can be implemented in the PICU to objectively guide treatment decisions.

Symptoms and perception of airway obstruction in asthmatic patients: Clinical implications for use of reliever medications

BACKGROUND

Asthma causes the unpleasant sensation of breathlessness (dyspnea) caused by airway obstruction. Patients with poor perception of airway obstruction are at risk of delay in seeking medical attention and undertreatment, which can lead to avoidable deaths. Conversely, those with heightened perception are at risk of overtreatment and iatrogenic adverse effects with reliever medications, anxiety, and unnecessary use of health care resources.

OBJECTIVE

We sought to review evidence about symptom misperception in asthmatic patients and how to identify and manage affected patients, particularly with regard to reliever medications.

METHODS

We conducted a systematic literature search for studies of perception of airway function in asthmatic patients. We searched the OVID (Medline and Medline [R] in process [PubMed]), Embase, and Adisearch/Odyssey databases, restricting our search to human studies published in English from 1990-2018, with no restrictions on age, sex, or racial origin.

RESULTS

We found that both underperception and overperception assessed during induced bronchoconstriction or bronchodilation or during changes in airway resistance were common across all age groups and that aging, disease severity, smoking, sex, ethnicity, psychologic factors, and medication are all associated with differences in perception. Importantly, airway inflammation was associated with impaired perception and a history of severe or near-fatal asthma. We also identified knowledge gaps, such as whether an individual patient's perception varies over time and the influence perception has on patients' use of reliever medication.

CONCLUSION

We found that abnormal perception of airway obstruction has important clinical implications for the management of patients with asthma.

Safety of tiotropium Respimat® in black or African-American patients with symptomatic asthma

BACKGROUND

Black patients with asthma have a higher disease burden and greater morbidity compared with other racial/ethnic groups. Tiotropium Respimat^®, as add-on to at least inhaled corticosteroids (ICS), improves lung function and asthma control and reduces asthma exacerbation risk in patients, with a safety profile comparable with placebo. This study aimed to assess the safety of tiotropium Respimat^®, compared with placebo, in black or African-American patients.

METHODS

Data were pooled from 12 randomized, placebo-controlled, parallel-group, Phase II or III trials from the global Boehringer Ingelheim program with once-daily tiotropium Respimat^® (5 μg or 2.5 μg). Trial participants had symptomatic persistent asthma with a broad range of severities and were aged 1-75 years. The safety results of black or African-American patients were compared with the overall trial population.

RESULTS

Of the 5165 patients treated with tiotropium or placebo, 3.2% were black or African American. For both doses of tiotropium, the proportion of patients reporting adverse events (AEs) was approximately 10% lower compared with placebo and was generally comparable with the proportion of patients reporting AEs in all groups of the overall population. The number of investigator-assessed drug-related AEs, AEs leading to trial drug discontinuation or serious AEs reported by patients was low and comparable between treatment groups and with the overall population.

CONCLUSION

Tiotropium Respimat^® appears to be a generally safe add-on bronchodilator treatment option to ICS with or without other controllers in pediatric and adult black or African-American patients with asthma.

CLINICAL TRIAL IDENTIFIERS

NCT01634113, NCT01634139, NCT01634152, NCT01257230, NCT01277523, NCT01316380, NCT00350207, NCT01172808, NCT01172821, NCT01340209, NCT00772538, NCT00776984.

Tiotropium add-on therapy is safe and reduces seasonal worsening in paediatric asthma patients

There remains an unmet need for effective, well-tolerated therapeutic options in paediatric patients with not fully controlled asthma, for whom safety is of paramount importance.Data were pooled from five randomised, double-blind, placebo-controlled studies evaluating tiotropium 5 or 2.5 µg versus placebo add-on therapy in patients with symptomatic asthma aged 1-17 years. Analysis included adverse events (AEs) and serious AEs (SAEs) reported throughout and for 30 days following treatment.Of 1691 patients treated, 1119 received tiotropium. Reporting of AEs was low and comparable across all groups: tiotropium 5 µg (51%), tiotropium 2.5 µg (51%) and placebo (54%). Reporting of drug-related AEs, those leading to discontinuation and SAEs was also low and balanced between treatment groups, irrespective of age, disease severity or sex. The number of AEs related to asthma symptoms and exacerbations was lower with tiotropium (5 µg) than with placebo, particularly during the seasonal peaks of these AEs.This comprehensive analysis of a large safety database allowed subgroup analyses that are often impractical with individual trials and provides further support for the safety of once-daily tiotropium Respimat add-on therapy in paediatric patients with symptomatic asthma.

Steroid variability in pediatric inpatient asthmatics: survey on provider preferences of dexamethasone versus prednisone

Objective: Our hospital's pediatric Emergency Department (ED) began using dexamethasone for treating asthma exacerbations after ED studies showed non-inferiority of dexamethasone compared to prednisone. However, providers have not reached consensus on optimal inpatient steroid regimen. This study evaluates provider preference for inpatient steroid treatment.Methods: A survey was distributed to providers who care for inpatient pediatric asthmatics. Respondents answered questions about steroid choice and timing. Data were summarized as percentages; bivariate comparisons were analyzed with Pearson's chi-squared test.Results: Ninety-two providers completed the survey (60% response rate). When patients received dexamethasone in the ED, subsequent inpatient management was variable: 44% continued dexamethasone, 14% switched to prednisone, 2% said no additional steroids, and 40% said it depended on the scenario. Hospitalists were more likely to continue dexamethasone than pulmonologists (61% and 15%, respectively; p < .001). Factors that influenced providers to switch to prednisone in the inpatient setting included severity of exacerbation (73%) and asthma history (47%). Fifty-one percent felt uncomfortable using dexamethasone because of "minimal data to support [its] use inpatient." In case-based questions, 28% selected dexamethasone dosing intervals outside the recommended range. Thirteen percent reported experiencing errors in clinical practice.Conclusions: Use of dexamethasone in the ED for asthma exacerbations has led to uncertainty in inpatient steroid prescribing practices. Providers often revert to prednisone, especially in severe asthma exacerbations, possibly due to experience with prednisone and limited research on dexamethasone in the inpatient setting. Further research comparing the effectiveness of dexamethasone to prednisone in inpatient asthmatic children with various severities of illness is needed.

Mometasone or Tiotropium in Mild Asthma with a Low Sputum Eosinophil Level

BACKGROUND

In many patients with mild, persistent asthma, the percentage of eosinophils in sputum is less than 2% (low eosinophil level). The appropriate treatment for these patients is unknown.

METHODS

In this 42-week, double-blind, crossover trial, we assigned 295 patients who were at least 12 years of age and who had mild, persistent asthma to receive mometasone (an inhaled glucocorticoid), tiotropium (a long-acting muscarinic antagonist), or placebo. The patients were categorized according to the sputum eosinophil level (<2% or ≥2%). The primary outcome was the response to mometasone as compared with placebo and to tiotropium as compared with placebo among patients with a low sputum eosinophil level who had a prespecified differential response to one of the trial agents. The response was determined according to a hierarchical composite outcome that incorporated treatment failure, asthma control days, and the forced expiratory volume in 1 second; a two-sided P value of less than 0.025 denoted statistical significance. A secondary outcome was a comparison of results in patients with a high sputum eosinophil level and those with a low level.

RESULTS

A total of 73% of the patients had a low eosinophil level; of these patients, 59% had a differential response to a trial agent. However, there was no significant difference in the response to mometasone or tiotropium, as compared with placebo. Among the patients with a low eosinophil level who had a differential treatment response, 57% (95% confidence interval [CI], 48 to 66) had a better response to mometasone, and 43% (95% CI, 34 to 52) had a better response to placebo (P = 0.14). In contrast 60% (95% CI, 51 to 68) had a better response to tiotropium, whereas 40% (95% CI, 32 to 49) had a better response to placebo (P = 0.029). Among patients with a high eosinophil level, the response to mometasone was significantly better than the response to placebo (74% vs. 26%) but the response to tiotropium was not (57% vs. 43%).

CONCLUSIONS

The majority of patients with mild, persistent asthma had a low sputum eosinophil level and had no significant difference in their response to either mometasone or tiotropium as compared with placebo. These data provide equipoise for a clinically directive trial to compare an inhaled glucocorticoid with other treatments in patients with a low eosinophil level. (Funded by the National Heart, Lung, and Blood Institute; SIENA ClinicalTrials.gov number, NCT02066298.).

Seasonal variation in asthma exacerbations in the AUSTRI and VESTRI studies

Seasonal peaks in asthma exacerbations are well described, as is the age-dependent nature of the magnitude of these peaks [1]. Children with asthma experience seasonal peaks in exacerbation frequency, which vary according to geographical location and climate [1–3]. Previous studies have examined the effect of season on the efficacy of pharmacological interventions. The anti-immunoglobulin-E monoclonal antibody omalizumab showed an increase in treatment benefits compared with placebo in the autumn and spring versus summer months in children, adolescents and young adults with allergic asthma in the USA [4]. In contrast, the anti-interleukin-5 monoclonal antibody mepolizumab showed no effect of seasonal differences in adolescents and adults with severe eosinophilic asthma [5].

Seasonal variation in the benefit of LABA/ICS versus ICS on asthma exacerbation rate is observed in children.http://ow.ly/pcZF30o8hHk

Time for Allergists to Consider the Role of Mouse Allergy in Non-Inner City Children with Asthma

Mouse allergen is endemic in the inner cities of the United States, with research predominantly in the Northeastern United States. A recent practice parameter notes the effect of mouse exposure in asthma in inner cities. However, studies are emerging that find a role of mouse allergen in non-inner cities as well. Mouse sensitization is associated with mouse allergen exposure and has been linked with adverse asthma outcomes including increased asthma symptoms, poorer lung function, and increased risk of exacerbations. There are commercially available extracts for testing for mouse sensitization although they are not standardized. Pest management studies have had varying results, but with decreased allergen exposure, there is a trend toward improved asthma outcomes. Physicians should be aware of the potential for rodent exposure and sensitization and consider screening for mouse allergy in asthmatic children, especially if they are located in the inner city, have poorly controlled asthma, or have a history of mouse infestation in their location. Evidence is emerging that this allergen should be considered in non-inner-city asthmatics as well. Finally, advocacy efforts are necessary to ensure that removal of this allergen is accomplished, when possible, in the environments of asthmatic children sensitized to mouse.

Tiotropium Is Efficacious in 6- to 17-Year-Olds with Asthma, Independent of T2 Phenotype

BACKGROUND

Tiotropium add-on therapy has demonstrated efficacy and safety in 6- to 17-year-olds with symptomatic asthma despite treatment with inhaled corticosteroids (ICSs), with or without additional controllers. Pediatric patients often have a significant allergic component to their asthma.

OBJECTIVE

To explore whether responses to tiotropium add-on were influenced by patients' type 2 status, assessed by serum IgE levels and blood eosinophil counts.

METHODS

Data from 2 phase III trials in symptomatic moderate asthma (CanoTinA-asthma; RubaTinA-asthma) and 2 phase III trials in symptomatic severe asthma (VivaTinA-asthma; PensieTinA-asthma) were pooled by severity. Patients were treated with tiotropium 5 μg, tiotropium 2.5 μg, or placebo (2 puffs once daily via Respimat inhaler), as add-on to ICSs, with or without additional controllers. Modeling of efficacy outcomes was performed over the whole range of baseline IgE levels and blood eosinophil counts, and the treatment effect of the tiotropium doses was presented graphically.

RESULTS

Improvements with tiotropium in peak FEV₁ within 3 hours postdose, trough FEV₁, forced expiratory flow at 25% to 75% of the pulmonary volume, and FEV₁/forced vital capacity responses were generally consistent across the range of baseline IgE levels and blood eosinophil counts. Risk of exacerbations and improvement in Asthma Control Questionnaire responder rates with tiotropium were also largely independent of IgE levels or eosinophil counts.

CONCLUSIONS

This exploratory analysis suggests that improvements with tiotropium as add-on to ICSs, with or without additional controllers, in 6- to 17-year-olds with symptomatic asthma do not vary according to systemic markers of T2 inflammation, namely, total IgE and blood eosinophil counts.

Can early intervention in pediatric asthma improve long-term outcomes? A question that needs an answer

OBJECTIVE

Although many children with asthma do not experience persistence into adulthood, recent studies have suggested that poorly controlled asthma in childhood may be associated with significant airflow obstruction in adulthood. However, data regarding disease progression are lacking, and clinicians are not yet able to predict the course of a child's asthma. The goal of this article was to assess the current understanding of childhood asthma treatment and progression and to highlight gaps in information that remain.

DATA SOURCES

Nonsystematic PubMed literature search and authors' expertise.

STUDY SELECTION

Articles were selected at the authors' discretion based on areas of interest in childhood asthma treatment and progression into adulthood.

RESULTS

Uncontrolled asthma in early childhood can potentially have lasting effects on lung development, but it is unclear whether traditional interventions in very young children preserve lung function. Although not all children respond to standard interventions, certain asthma phenotypes have been identified that can help to understand which children may respond to a particular treatment.

CONCLUSION

Clinicians should monitor children's asthma control and pulmonary function over time to assess the long-term impact of an intervention and to minimize the effect of uncontrolled asthma, especially exacerbations, on lung development. New biologic therapies have shown promise in treating adults with severe, uncontrolled asthma, and some of these therapies are approved in the United States for children as young as age 6. However, knowledge gaps regarding the efficacy and safety of these treatments in younger children hamper our understanding of their effect on long-term outcomes.