Early intervention for infantile and childhood asthma

Lung sound analysis for predicting recurrent wheezing in preschool children

Background

In young healthy children, assessing airflow limitation may be difficult because of narrowing of the airways, which is a pathology of asthma, and responsiveness to bronchodilators.

Objective

We investigated whether lung sound analysis could predict the development of recurrent wheezing (RW), which is one of the signs of asthma.

Methods

In healthy children aged 3 to 24 months, we recorded and analyzed lung sounds before and after inhalation of bronchodilators and conducted a questionnaire survey. The children were followed up and assessed for the development of RW at age 3 years.

Results

Of the 62 patients analyzed, 19 (30.6%) developed RW. The parameters ratio of power and frequency at 50% of the highest frequency of the dB power spectrum (RPF50) and ratio of power and frequency at 75% of the highest frequency of the dB power spectrum (RPF75), calculated by lung sound analysis, were lower in the RW group, with odds ratios of 0.77 (95% CI = 0.61-0.98) and 0.81 (95% CI = 0.66-0.99), respectively. The rate of change of lung sound analysis parameters after bronchodilator inhalation did not differ among the participants as a group; however, in the subgroup of children with a history of atopic dermatitis, the fourth area under the curve (B4) divided by the total area under the curve of 100 Hz to the highest frequency of the dB power spectrum (AT) and difference between the values of the ratio of power and frequency at 50% of the highest frequency of the dB power spectrum (ΔRPF50) were elevated in the RW group (P = .015 and P = .041, respectively). In the subgroup of children with total a IgE level greater than 20 kUA/L, the sensitivities and specificities for predicting the development of RW were 85.7% (95% CI = 48.7-99.3) and 68.8% (95% CI = 44.4-85.8), respectively, when the cutoff value of ΔRPF50 was set at 10.5%.

Conclusion

The method of lung sound analysis allows noninvasive assessment of the airway, including airway hypersensitivity, in young children and may predict the risk of development of RW.

Nebulized step-down budesonide vs. fluticasone in infantile asthma: A retrospective cohort study

The United States Food and Drug Administration has approved budesonide in infantile asthma but nebulization of infants under budesonide has the risk of relapse of asthma. The objective of the present study was to compare the effectiveness and safety of fluticasone step-down treatment with budesonide step-down treatment in infantile asthma. The data of 778 infants with confirmed asthma were included in the analysis. Infants who had received nebulized 500 µg budesonide twice daily for 6 weeks followed by 250 µg budesonide twice daily for 6 weeks were included in the BS group (n=389), while infants who had received nebulized 250 µg fluticasone twice daily for 6 weeks followed by 125 µg fluticasone twice daily for 6 weeks were included in the FC group (n=389). The data of lung function tests and a safety study were collected and analyzed. Budesonide treatment achieved a reduced specific airway resistance (sRaw; 1.28±0.11 vs. 1.21±0.10 kPa/sec; P<0.0001, q=13.45) and improved forced expiratory volume in 1 sec (FEV1; 0.977±0.068 vs. 0.997±0.085 l/sec; P<0.0001, q=5.54). In addition, fluticasone treatment achieved a reduced sRaw (1.27±0.1 vs. 1.23±0.11 kPa/sec, P<0.0001, q=7.39) and improved FEV1 (0.971±0.069 vs. 0.992±0.085 l/sec; P=0.0003, q=5.46). Of note, the efficacy of budesonide to reduce sRaw (P=0.008, q=3.69) and improve FEV1 (P<0.0001, q=6.93) was greater than that of fluticasone. The budesonide treatment group had more post-treatment symptom-free days than the fluticasone treatment group (165.56±23.15 vs. 112.21±9.45 days; P<0.0001). The step-down approach of budesonide nebulization may better support the functional and clinical outcomes with an increased number of post-treatment symptom-free days compared with fluticasone in infantile asthma (level of evidence, 3).

Question 3: Can we diagnose asthma in children under the age of 5 years?

The diagnosis of asthma in children under five years has been controversial due to changing concepts of what true asthma is in this age group. Previous diagnostic algorithms that used clinical indices to predict the persistence of asthma symptoms or phenotypes based on asthma triggers do not predict which children will benefit from asthma medication. A pragmatic approach to asthma diagnosis in this age group is based on identifying signs and symptoms of reversible airflow obstruction and documenting their response to asthma medication. Hopefully, this approach will provide clearer guidance to clinicians and improve asthma morbidity in these young children.

A systematic review of predictive models for asthma development in children

BACKGROUND

Asthma is the most common pediatric chronic disease affecting 9.6 % of American children. Delay in asthma diagnosis is prevalent, resulting in suboptimal asthma management. To help avoid delay in asthma diagnosis and advance asthma prevention research, researchers have proposed various models to predict asthma development in children. This paper reviews these models.

METHODS

A systematic review was conducted through searching in PubMed, EMBASE, CINAHL, Scopus, the Cochrane Library, the ACM Digital Library, IEEE Xplore, and OpenGrey up to June 3, 2015. The literature on predictive models for asthma development in children was retrieved, with search results limited to human subjects and children (birth to 18 years). Two independent reviewers screened the literature, performed data extraction, and assessed article quality.

RESULTS

The literature search returned 13,101 references in total. After manual review, 32 of these references were determined to be relevant and are discussed in the paper. We identify several limitations of existing predictive models for asthma development in children, and provide preliminary thoughts on how to address these limitations.

CONCLUSIONS

Existing predictive models for asthma development in children have inadequate accuracy. Efforts to improve these models' performance are needed, but are limited by a lack of a gold standard for asthma development in children.

Revisiting early intervention in adult asthma

The term "early intervention" with inhaled corticosteroids (ICS) in asthma is used in different ways, thereby causing confusion and misinterpretation of data. We propose that the term should be reserved for start of ICS therapy in patients with a diagnosis of asthma but within a short period of time after the first symptoms, not from the date of diagnosis. Prospective clinical studies suggest a time frame of 2 years for the term "early" from the onset of symptoms to starting anti-inflammatory treatment with ICS. The current literature supports early intervention with ICS for all patients with asthma including patients with mild disease, who often have normal or near-normal lung function. This approach reduces symptoms rapidly and allows patients to achieve early asthma control. Later introduction of ICS therapy may not reduce effectiveness in terms of lung function but delays asthma control and exposes patients to unnecessary morbidity. Results of nationwide intervention programmes support the early use of ICS, as it significantly minimises the disease burden. Acute asthma exacerbations are usually preceded by progressing symptoms and lung function decline over a period of 1-2 weeks. Treatment with an increased dose of ICS together with a rapid- and long-acting inhaled β2-agonist during this phase has reduced the risk of severe exacerbations.

Contributing factors to the development of childhood asthma: working toward risk minimization

Asthma is the most common chronic disease in childhood, and considerable research has been undertaken to find ways to prevent its development and reduce its prevalence. For such interventions to be successful, risk factors for asthma emergence should be identified and clearly defined. Data are robust for some of them, including atopy, viral infections and exposure to airborne irritants, whereas it is less conclusive for others, such as aeroallergen exposure and bacterial infections. Several interventions for asthma prevention, including avoidance and pharmacotherapy, have been attempted. However, most of them have furnished equivocal results. Various issues hinder the establishment of risk factors for asthma development and reduce the effectiveness of interventions, including the complexity of the disease and the fluidity of the developing systems in childhood. In this review, we revisit the evidence on pediatric asthma risk factors and prevention and discuss issues that perplex this field.

Pharmacodynamic genome-wide association study identifies new responsive loci for glucocorticoid intervention in asthma

Asthma is a chronic lung disease that has a high prevalence. The therapeutic intervention of this disease can be made more effective if genetic variability in patients' response to medications is implemented. However, a clear picture of the genetic architecture of asthma intervention response remains elusive. We conducted a genome-wide association study (GWAS) to identify drug response-associated genes for asthma, in which 909 622 SNPs were genotyped for 120 randomized participants who inhaled multiple doses of glucocorticoids. By integrating pharmacodynamic properties of drug reactions, we implemented a mechanistic model to analyze the GWAS data, enhancing the scope of inference about the genetic architecture of asthma intervention. Our pharmacodynamic model observed associations of genome-wide significance between dose-dependent response to inhaled glucocorticoids (measured as %FEV1) and five loci (P=5.315 × 10(-7) to 3.924 × 10(-9)), many of which map to metabolic genes related to lung function and asthma risk. All significant SNPs detected indicate a recessive effect, at which the homozygotes for the mutant alleles drive variability in %FEV1. Significant associations were well replicated in three additional independent GWAS studies. Pooled together over these three trials, two SNPs, chr6 rs6924808 and chr11 rs1353649, display an increased significance level (P=6.661 × 10(-16) and 5.670 × 10(-11)). Our study reveals a general picture of pharmacogenomic control for asthma intervention. The results obtained help to tailor an optimal dose for individual patients to treat asthma based on their genetic makeup.