The bronchodilator response as a predictor of inhaled corticosteroid responsiveness in asthmatic children with normal baseline spirometry

Bronchodilator response by interrupter technique to guide management of preschool wheeze

OBJECTIVE

We examined relationships between clinical features and pulmonary function before and after inhaled corticosteroid (ICS) treatment in wheezy preschool children, and specifically, whether measuring bronchodilator response (BDR) could predict benefit from ICS.

DESIGN

Clinical non-randomised intervention study SETTING: Secondary care.

PATIENTS

Preschool children (2 years to <6 years) with recurrent wheeze.

INTERVENTIONS

Inhaled beta-agonist, ICS.

OUTCOME MEASURES

We measured prebronchodilator and postbronchodilator interrupter resistance (Rint) and symptom scores at 0 (V1), 4 (V2) and 12 (V3) weeks. At V2, those with a predetermined symptom level commenced ICS. Modified Asthma Predictive Index (mAPI) and parental perception of response to bronchodilator were recorded. Response to ICS was defined as a reduction in daily symptom score of >0.26. Positive BDR was defined as fall in Rint of ≥0.26 kPa.s/L, ≥35% predicted or ≥1.25 Z Scores.

RESULTS

Out of 138 recruited children, 67 completed the full study. Mean (SD) prebronchodilator Rint at V2 was 1.22 (0.35) kPa.s/L, and fell after starting ICS (V3) to 1.09 (0.33) kPa.s/L (p<0.001), while mean (SD) daily symptom score fell from 0.56 (0.36) to 0.28 (0.36) after ICS (p<0.001). Positive Rint BDR before ICS (at V1 and/or V2), using all three threshold criteria, was significantly associated with response to ICS on symptom scores at V3 (p<0.05). mAPI was not significantly associated with response to ICS, and parents' perception of response to bronchodilator was not related to measured Rint BDR .

CONCLUSIONS

Rint BDR may be helpful in selecting which wheezy preschool children are likely to benefit from ICS.

Sex and gender in asthma

Asthma is a heterogenous disease, and its prevalence and severity are different in males versus females through various ages. As children, boys have an increased prevalence of asthma. As adults, women have an increased prevalence and severity of asthma. Sex hormones, genetic and epigenetic variations, social and environmental factors, and responses to asthma therapeutics are important factors in the sex differences observed in asthma incidence, prevalence and severity. For women, fluctuations in sex hormone levels during puberty, the menstrual cycle and pregnancy are associated with asthma pathogenesis. Further, sex differences in gene expression and epigenetic modifications and responses to environmental factors, including SARS-CoV-2 infections, are associated with differences in asthma incidence, prevalence and symptoms. We review the role of sex hormones, genetics and epigenetics, and their interactions with the environment in the clinical manifestations and therapeutic response of asthma.

Spirometric Changes in Bronchodilation Tests as Predictors of Asthma Diagnosis and Treatment Response in Patients with FEV1 ≥ 80% Predicted

BACKGROUND

Many patients with mild asthma are undiagnosed and untreated due to the low diagnostic sensitivity of bronchodilation test (BDT).

OBJECTIVE

To investigate whether airway reversibility in BDT and fractional exhaled nitric oxide (Feno) can predict the response to antiasthma therapy (RAT) in patients with suspected asthma.

METHODS

This open-label, prospective cohort study included patients with chronic recurrent asthma symptoms, normal FEV₁, and negative BDT results. Inhaled corticosteroids and long-acting β agonists were given for 4 weeks. A positive RAT was defined as improved symptoms and an increase of more than 200 mL in FEV₁ after inhaled corticosteroid/long-acting β agonist treatment. Lung tissues from another 19 patients who underwent pneumectomy for lung nodules were also analyzed.

RESULTS

Of 110 patients recruited, 102 completed the study. Patients in the positive RAT group had a higher Feno and greater absolute (Δ) and percent (Δ%) improvements in forced vital capacity, FEV₁, and forced expiratory flows (FEFs) in BDT than in the negative RAT group. The area under the curves of Feno, ΔFEV₁%, ΔFEF_25-75% (percent improvement in FEF at 25%-75% of forced vital capacity), and ΔFEF₇₅% (percent improvement in FEF at 75% of forced vital capacity) for positive RAT were 0.703, 0.824, 0.736, and 0.710, with cutoff values of 33 parts per billion and 3.50%, 15.26%, and 26.04%, respectively. A joint model of Feno and ΔFEV₁% increased the area under the curve to 0.880. Inflammatory cytokines were higher in the lung tissues of patients with predicted positive RAT than in those with predicted negative RAT.

CONCLUSIONS

ΔFEV₁% in BDT together with Feno predicted a positive RAT and an asthma diagnosis in patients with a normal FEV₁ and negative BDT. Evidence of pathological changes increases the credibility of the predictive model.

Asthma-Like Features and Anti-Asthmatic Drug Prescription in Children with Non-CF Bronchiectasis

Bronchiectasis and asthma may share some characteristics and some patients may have both conditions. The present study aimed to examine the rationale of prophylactic inhaled corticosteroids (ICS) prescription in children with bronchiectasis. Data of children with radiologically established bronchiectasis were retrospectively reviewed. Episodes of dyspnea and wheezing, spirometric indices, total serum IgE, blood eosinophil counts, sensitization to aeroallergens, and air-trapping on expiratory CT scans, were recorded. The study included 65 children 1.5–16 years old, with non-CF bronchiectasis. Episodes of dyspnea or wheezing were reported by 22 (33.8%) and 23 (35.4%), respectively. Skin prick tests to aeroallergens (SPTs) were positive in 15 (23.0%) patients. Mosaic pattern on CT scans was observed in 37 (56.9%) patients. Dyspnea, presence of mosaic pattern, positive reversibility test, and positive SPTs were significantly correlated with the prescription of ICS. The prescription of ICS in children with bronchiectasis is more likely when there are certain asthma-like characteristics. The difficulty to set the diagnosis of real asthma in cases of bronchiectasis may justify the decision of clinicians to start an empirical trial with ICS in certain cases.

Exogenous Surfactant as a Pulmonary Delivery Vehicle for Budesonide In Vivo

Background

Lung inflammation is associated with many respiratory conditions. Consequently, anti-inflammatory medications, like glucocorticoids, have become mainstay intrapulmonary therapeutics. However, their effectiveness for treating inflammation occurring in the alveolar regions of the lung is limited by suboptimal delivery. To improve the pulmonary distribution of glucocorticoids, such as budesonide to distal regions of the lung, exogenous surfactant has been proposed as an ideal delivery vehicle for such therapies. It was therefore hypothesized that fortifying an exogenous surfactant (BLES) with budesonide would enhance efficacy for treating pulmonary inflammation in vivo.

Methods

An intratracheal instillation of heat-killed bacteria was used to elicit an inflammatory response in the lungs of male and female rats. Thirty minutes after this initial instillation, either budesonide or BLES combined with budesonide was administered intratracheally. To evaluate the efficacy of surfactant delivery, various markers of inflammation were measured in the bronchoalveolar lavage and lung tissue.

Results

Although budesonide exhibited anti-inflammatory effects when administered alone, delivery with BLES enhanced those effects by lowering the lavage neutrophil counts and myeloperoxidase activity in lung tissue. Combining budesonide with BLES was also shown to reduce several other pro-inflammatory mediators. These results were shown across both sexes, with no observed sex differences.

Conclusion

Based on these findings, it was concluded that exogenous surfactant can enhance the delivery and efficacy of budesonide in vivo.

Asthma and Corticosteroid Responses in Childhood and Adult Asthma

Corticosteroids are the most effective treatment for asthma; inhaled corticosteroids (ICSs) are the first-line treatment for children and adults with persistent symptoms. ICSs are associated with significant improvements in lung function. The anti-inflammatory effects of corticosteroids are mediated by both genomic and nongenomic factors. Variation in the response to corticosteroids has been observed. Patient characteristics, biomarkers, and genetic features may be used to predict response to ICSs. The existence of multiple mechanisms underlying glucocorticoid insensitivity raises the possibility that this might indeed reflect different diseases with a common phenotype.

Effects of age, sex, race/ethnicity, and allergy status in obesity-related pediatric asthma

RATIONALE

Obesity in children increases the risk for new asthma. How age, sex, race/ethnicity, and allergy status affect the relationship between obesity and asthma is unclear. This study describes the relationship between high body mass index (BMI) and incident asthma.

METHODS

We conducted a retrospective cohort study to compare asthma incidence among normal weight, overweight, and obese 2 to 6, 7 to 11, and 12 to 17 year olds to define the effects of sex, race/ethnicity, and allergy status. Weight status was determined at baseline and asthma incidence was defined as ≥2 asthma encounters and ≥1 asthma prescriptions. We used multivariable Poisson regression to estimate adjusted incident asthma rates and risk ratios.

RESULTS

Data from 192 843 2 to 6 year olds, 157 284 7 to 11 year olds, and 157 369 12 to 17 year olds were included. The relative risks (95% confidence interval [CI]) of new asthma among obese children in 2 to 6 year olds, 7 to 11 year olds, and 12 to 17 year olds were 1.25 (1.15, 1.37), 1.49 (1.32, 1.69) and 1.40 (1.21, 1.63), respectively. Among children with underlying allergic rhinitis, obesity did not increase the risk of new asthma. In children without allergic rhinitis, the risk for obesity-related asthma was highest in 7 to 11 year olds (risk ratio = 1.50 95% CI, 1.33, 1.60). Before age 12, females had a higher risk for obesity-related asthma; but after age 12, obese males had a higher asthma risk (interaction P-value < .05).

CONCLUSION

Obesity is a major preventable risk factor for pediatric asthma that appears to vary along the pediatric age continuum and depends on sex, race/ethnicity and atopy status.

Two vs four puffs of albuterol: does dose change bronchodilator response?

Background

Reversible obstruction on spirometry may be used to diagnose asthma. As per 2005 American Thoracic Society (ATS) guidelines, our pulmonary center began using 360 µg (four puffs) of albuterol rather than 180 µg (two puffs) to determine reversibility on spirometry starting in 2009.

Hypothesis

We hypothesized that fewer patients would respond to two puffs of albuterol than four puffs during spirometric testing.

Methods

We retrospectively reviewed records from new asthmatics seen in Pediatric Pulmonary Clinic from March 2002 to April 2014 who performed reproducible spirometry. Patients were divided into two groups based on whether they had received two or four puffs of albuterol for bronchodilator assessment. A positive bronchodilator response was defined as an increase of ≥12% in forced expiratory volume in one second (FEV₁) or ≥25% in forced expiratory flow (FEF_25–75%). Data were expressed as percentages and mean ± standard error of the mean values. Chi-squared test and Student’s t-test were utilized.

Results

Data were collected for 240 patients; 115 patients received two puffs of albuterol and 125 patients received four puffs. There were no significant differences in baseline characteristics between the two groups. There were no differences following two puffs or four puffs in changes in FEV₁ (10.0±1.1% vs 10.5±1.1% predicted) or FEF_25–75% (30.2±2.9% vs 33.5±2.9% predicted). Moreover, there was no difference in ATS-defined bronchodilator response between the two groups.

Conclusion

Based on the mean change in FEV₁ and overall bronchodilator responsiveness, two puffs of albuterol were not inferior to four puffs in the determination of bronchodilator responsiveness in our pediatric asthmatic patients.

Being Overweight or Obese and the Development of Asthma

OBJECTIVES

Adult obesity is linked to asthma cases and is estimated to lead to 250 000 new cases yearly. Similar incidence and attributable risk (AR) estimates have not been developed for children. We sought to describe the relationship between overweight and obesity and incident asthma in childhood and quantify AR statistics in the United States for overweight and obesity on pediatric asthma.

METHODS

The PEDSnet clinical data research network was used to conduct a retrospective cohort study (January 2009-December 2015) to compare asthma incidence among overweight and/or obese versus healthy weight 2- to 17-year-old children. Asthma incidence was defined as ≥2 encounters with a diagnosis of asthma and ≥1 asthma controller prescription. Stricter diagnostic criteria involved confirmation by spirometry. We used multivariable Poisson regression analyses to estimate incident asthma rates and risk ratios and accepted formulas for ARs.

RESULTS

Data from 507 496 children and 19 581 972 encounters were included. The mean participant observation period was 4 years. The adjusted risk for incident asthma was increased among children who were overweight (relative risk [RR]: 1.17; 95% confidence interval [CI]: 1.10-1.25) and obese (RR: 1.26; 95% CI: 1.18-1.34). The adjusted risk for spirometry-confirmed asthma was increased among children with obesity (RR: 1.29; 95% CI: 1.16-1.42). An estimated 23% to 27% of new asthma cases in children with obesity is directly attributable to obesity. In the absence of overweight and obesity, 10% of all cases of asthma would be avoided.

CONCLUSIONS

Obesity is a major preventable risk factor for pediatric asthma.

A simple prediction tool for inhaled corticosteroid response in asthmatic children

Background

Inhaled corticosteroids are recommended as the first-line controller medication for childhood asthma owing to their multiple clinical benefits. However, heterogeneity in the response towards these drugs remains a significant clinical problem.

Methods

Children aged 5 to 18 years with mild to moderate persistent asthma were recruited into the Taiwanese Consortium of Childhood Asthma Study. Their responses to inhaled corticosteroids were assessed based on their improvements in the asthma control test and peak expiratory flow. The predictors of responsiveness were demographic and clinical features that were available in primary care settings. We have developed a prediction model using logistic regression and have simplified it to formulate a practical tool. We assessed its predictive performance using the area under the receiver operating characteristic curve.

Results

Of the 73 asthmatic children with baseline and follow-up outcome measurements for inhaled corticosteroids treatment, 24 (33%) were defined as non-responders. The tool we have developed consisted of three predictors yielding a total score between 0 and 5, which are comprised of the following parameters: the age at physician-diagnosis of asthma, sex, and exhaled nitric oxide. Sensitivity and specificity of the tool for prediction of inhaled corticosteroids non-responsiveness, for a score of 3, were 0.75 and 0.69, respectively. The areas under the receiver operating characteristic curve for the prediction tool was 0.763.

Conclusions

Our prediction tool represents a simple and low-cost method for predicting the response of inhaled corticosteroids treatment in asthmatic children.

The case for impulse oscillometry in the management of asthma in children and adults

OBJECTIVE

To provide a clinical rationale for including impulse oscillometry (IOS) as a part of standard office-based asthma assessment.

DATA SOURCES

PubMed and Google search, limited to English language and human disease, with the keywords IOS and asthma.

STUDY SELECTIONS

Articles included in this review were based on the expert opinion and previous publications by the authors.

RESULTS

In children, IOS was more useful than spirometry in identifying asthma and uncontrolled asthma and predicting loss of control and exacerbations. IOS predicts young children at risk for loss of lung function with age and the potential for early intervention to prevent further sequelae. In adults, peripheral airway impairment detected by IOS or spirometry (ie, forced expiratory flow between 25% and 75%) commonly occurs across severity, and each measure may be complementary in predicting loss of control even with normal forced expiratory volume in 1 second. Extrafine inhaled corticosteroids with or without long-acting β-agonists proved superior to standard particle aerosols in improving IOS-detected peripheral airway obstruction. Our data also suggest that currently available commercial reference values for lung resistance at 5 Hz and lung reactance at 5 Hz are applicable across diverse populations, but further studies are needed.

CONCLUSION

The findings of this review suggest that IOS can add value to traditional clinical and spirometric assessment and thus improve management of asthma in children and adults, as well as have the potential to detect early dysfunction of the peripheral airways, which may result in better outcomes.

Stress and Bronchodilator Response in Children with Asthma

RATIONALE

Stress is associated with asthma morbidity in Puerto Ricans (PRs), who have reduced bronchodilator response (BDR).

OBJECTIVES

To examine whether stress and/or a gene regulating anxiety (ADCYAP1R1) is associated with BDR in PR and non-PR children with asthma.

METHODS

This was a cross-sectional study of stress and BDR (percent change in FEV1 after BD) in 234 PRs ages 9-14 years with asthma. We assessed child stress using the Checklist of Children's Distress Symptoms, and maternal stress using the Perceived Stress Scale. Replication analyses were conducted in two cohorts. Polymorphisms in ADCYAP1R1 were genotyped in our study and six replication studies. Multivariable models of stress and BDR were adjusted for age, sex, income, environmental tobacco smoke, and use of inhaled corticosteroids.

MEASUREMENTS AND MAIN RESULTS

High child stress was associated with reduced BDR in three cohorts. PR children who were highly stressed (upper quartile, Checklist of Children's Distress Symptoms) and whose mothers had high stress (upper quartile, Perceived Stress Scale) had a BDR that was 10.2% (95% confidence interval, 6.1-14.2%) lower than children who had neither high stress nor a highly stressed mother. A polymorphism in ADCYAP1R1 (rs34548976) was associated with reduced BDR. This single-nucleotide polymorphism is associated with reduced expression of the gene for the β2-adrenergic receptor (ADRB2) in CD4(+) lymphocytes of subjects with asthma, and it affects brain connectivity of the amygdala and the insula (a biomarker of anxiety).

CONCLUSIONS

High child stress and an ADCYAP1R1 single-nucleotide polymorphism are associated with reduced BDR in children with asthma. This is likely caused by down-regulation of ADRB2 in highly stressed children.

Pediatric Pulmonology year in review 2014: Part 1

Our discipline and our journal cover an extremely broad range of research and scholarly topics related to children's respiratory disorders. To better meet the needs of our readership for updated perspectives on the rapidly expanding knowledge in our field, we here summarize the past year's publications in our major topic areas, as well as selected publications in these areas from the core clinical journal literature outside our own pages.

Effect of inhaled corticosteroids on bronchial asthma in Japanese athletes

BACKGROUND

Asthma has a higher prevalence in athlete populations such as Olympic athletes than in the general population. Correct diagnosis and management of asthma in athletes is important for symptom control and avoidance of doping accusations. However, few reports are available on asthma treatment in the athlete population in clinical practice. In this study, we focused on the clinical efficacy of inhaled corticosteroid (ICS) for asthma in a Japanese athlete population.

METHODS

The study subjects included athletes who visited the Niigata Institute for Health and Sports Medicine, Niigata, Japan for athletic tests and who were diagnosed with asthma on the basis of respiratory symptoms and positive results in a bronchodilator or bronchial provocation test such as exercise, hypertonic saline, or methacholine provocation. The athletes received ICS alone for at least 3 months, and the clinical background, sports type, and treatment efficacy were analyzed.

RESULTS

The study population comprised 80 athletes (59 men and 21 women) with a median age of 16.0 years. Regarding sports type, 28 athletes engaged in winter sports (35%), 22 in endurance sports (27.5%), and 25 in indoor sports (31.3%). Although ICS is the primary treatment in athlete asthma, 16.3% of the athletes showed an unsatisfactory response to treatment according to the Global Evaluation of Treatment Effectiveness (GETE). These subjects were characterized by a decreased response to methacholine and lower values for FEV1/FVC and type 2 helper T cell (Th2)-associated biomarkers relative to responsive athletes. In multivariate analysis, FEV1/FVC and the logarithm to the base 10 of the IgE level were independently associated with the ICS response.

CONCLUSIONS

These data suggest that ICS is effective for asthma in most athletes. However, certain asthmatic athletes are less responsive to ICS than expected. The pathogenesis in these subjects may differ from that of conventional asthma characterized by chronic allergic airway inflammation.