Pediatric asthma phenotypes

Characteristics of Allergic, Eosinophilic, and Overlapping Asthma Phenotypes Among Pediatric Patients with Current Asthma: A Cross-Sectional Study from Saudi Arabia

Purpose

Asthma is one of the most common chronic diseases affecting 10%-30% of children in Saudi Arabia. Although data exist on adult asthma phenotyping and endotyping in Saudi Arabia, little is known about asthma phenotypes in Saudi children.

Patients and Methods

This cross-sectional study enrolled pediatric patients diagnosed with bronchial asthma and followed in the pediatric pulmonology clinic of the Abha Maternity and Children Hospital between August 2021 and May 2023.

Results

A total of 321 children (aged 5-14 years) were analyzed. The population was classified into allergic [169 (52.6%)], eosinophilic [144 (44.9%)], and overlapping allergic and eosinophilic asthma [97 (30.2%)] phenotypes. Regarding asthma severity, 35.5%, 50.2%, and 14.3% were classified as mild, moderate, and severe, respectively. Of the 321 patients in the study, 124 (38.6%) had at least one asthma exacerbation that required hospitalization. The number of reported missed school days in the previous year was 1571 days [190 (59.2%) patients reported at least one missed school day]. The factors associated with the likelihood of uncontrolled asthma for all study participants included: emergency room (ER) visit last year (OR = 3.7, 95% CI:0.6-15.9]), overlapping eosinophilic and allergic (OR = 3.2, 95% CI = 1.8-5.9), and allergic phenotype (OR = 2.7, 95% CI = 1.3-5.4). The level of asthma control differed significantly among the three asthma phenotypes (p = 0.037).

Conclusion

Allergic asthma is the most prevalent asthma phenotype in this study, followed by the eosinophilic phenotype. The research has also shown that several factors predict uncontrolled asthma, including a family history of asthma, previous admission to the PICU, and previous hospitalization ever. There is, therefore, a definite need for multicenter cohort studies to better understand the phenotypes and endotypes of childhood asthma, as it could offer therapeutic and prognostic relevance.

Residential bacteria and fungi identified by high-throughput sequencing and childhood respiratory health

The objective of this study was to examine and compare environmental microbiota from dust and children's respiratory health outcomes at ages seven and twelve. At age seven, in-home visits were conducted for children enrolled in the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS). Floor dust was collected and analyzed for bacterial (16 S rRNA gene) and fungal (internal transcribed spacer region) microbiota. Respiratory outcomes, including physician-diagnosed asthma, wheeze, rhinitis, and aeroallergen sensitivity were assessed by physical examination and caregiver-report at ages seven and twelve. The associations between dust microbiota and respiratory outcomes were evaluated using Permanova, DESeq, and weighted quantile sum (WQS) regression models. Four types of WQS regression models were run to identify mixtures of fungi or bacteria that were associated with the absence or presence of health outcomes. For alpha or beta diversity of fungi and bacteria, no significant associations were found with respiratory health outcomes. DESeq identified specific bacterial and fungal indicator taxa that were higher or lower with the presence of different health outcomes. Most individual indicator fungal species were lower with asthma and wheeze and higher with aeroallergen positivity and rhinitis, whereas bacterial data was less consistent. WQS regression models demonstrated that a combination of species might influence health outcomes. Several heavily weighted species had a strong influence on the models, and therefore, created a microbial community that was associated with the absence or presence of asthma, wheeze, rhinitis, and aeroallergen+. Weights for specific species within WQS regression models supported indicator taxa findings. Health outcomes might be more influenced by the composition of a complex mixture of bacterial and fungal species in the indoor environment than by the absence or presence of individual species. This study demonstrates that WQS is a useful tool in evaluating mixtures in relation to potential health effects.

Management of asthma exacerbations in the paediatric population: a systematic review

Background

Asthma exacerbations in children is one of the most common medical conditions requiring urgent visits to primary healthcare providers or emergency departments, and even hospitalisations. Currently, there is significant variation in the management of asthma exacerbations expressed in guideline recommendations versus clinical practice. This disconnect affects diagnostic and treatment decisions for the clinician and patient.

Objective

We systematically reviewed the available guidelines providing recommendations for diagnostic and therapeutic management of asthma exacerbations in the paediatric population.

Methods

A systematic review of the literature for guidelines published between January 2009 and October 2019 was conducted, using a protocol registered with the international prospective register of systematic reviews (PROSPERO CRD42020221562).

Results

16 asthma exacerbation clinical practice guidelines for children were included. Despite general agreement between guidelines on the definition of asthma exacerbation, there was great variability in the definition of disease severity and assessment of asthma control. This systematic review also highlighted a paucity of recommendations for criteria for hospitalisation and discharge. Many guidelines scored poorly when measured for stakeholder involvement and editorial independence.

Conclusion

Comprehensive and updated guidelines compliant with international standards for clinical guidelines may significantly improve clinical practice quality, promote evidence-based recommendations and provide uniformity of treatment between countries.

There is wide variation in the management of asthma exacerbations in children. This systematic review suggests that updated guidelines aligned with international standards for clinical guidelines may improve uniformity of treatment and clinical practice quality.https://bit.ly/32Pgdiz

Identifying wheezing phenotypes in a pediatric Turkish cohort

OBJECTIVE

Characterization of wheezing phenotypes in children might help to identify the underlying mechanisms through which asthma occurs. In our study, we aimed to describe wheezing phenotypes in Turkish children and to identify risk factors according to phenotypes.

METHODS

651 wheezy children were evaluated and 5 wheezing phenotypes were described according to age of onset, atopy and persistence at 6 years of age and risk factors were identified.

RESULTS

Distribution of wheezing phenotypes was transient early wheeze (TEW)(34.9%) non-atopic wheeze (NAW) (18%), atopic wheeze (AW) (22.3%), intermediate onset wheeze (IOW) (11.1%), late onset wheeze (LOW) (11.7%). LOW, AW, and IOW were associated with, father's, sibling's and family's atopy (p:0.001) whereas LOW and AW were associated with mother's asthma and atopy as well as family's asthma (p < 0.05). Atopic dermatitis and allergic rhinitis were common of patients with LOW, AW, and IOW (p < 0.05). İnfection was the major trigger for TEW and NAW whereas multiple triggers were common of AW, LOW, and IOW. Allergens were mostly associated with AW, IOW and LOW. Aeroallergen-specific IgE positivity was mostly with AW, IOW, and LOW phenotype. Skin prick tests showed multiple allergen sensitivity in IOW, LOW groups and mostly single allergen in AW phenotype. Modified asthma predictive index (mAPI) positivity was high in all groups except TEW and NAW.

CONCLUSIONS

With this study we classified five wheeze phenotypes and found that atopy and family's atopy history, maternal asthma were strongly associated with AW, LOW, and IOW phenotypes which were usually effected by allergens or multiple triggers.

A systematic review of asthma case definitions in 67 birth cohort studies

BACKGROUND

Birth cohort studies are a valuable source of information about potential risk factors for childhood asthma. To better understand similarities and variations in findings between birth cohort studies, the methodologies used to measure asthma require consideration.

OBJECTIVE

To review and appraise the definitions of "asthma" used in birth cohort studies.

METHODS

A literature search, conducted in December 2017 in the MEDLINE database and birth cohort repositories, identified 1721 citations published since 1990. Information extracted included: study name, year of publication, sample size, sample age, prevalence of asthma (%), study region, source of information about asthma, measured outcome, and asthma case definition. A meta-analysis evaluated whether asthma prevalence in cohorts from Europe and North America varied by the studies' definition of asthma and by their data sources.

RESULTS

The final review included 67 birth cohorts, of which 48 (72%) were from Europe, 14 (21%) from North America, 3 (5%) from Oceania, 1 (1%) from Asia and 1 (1%) from South America. We identified three measured outcomes: "asthma ever", "current asthma", and "asthma" without further specification. Definitions of "asthma ever" were primarily based upon an affirmative parental response to the question whether the child had ever been diagnosed with asthma by a physician. The most frequently used definition of "current asthma" was "asthma ever" and either asthma symptoms or asthma medications in the last 12 months. This definition of "current asthma" was used in 16 cohorts. There was no statistically significant difference in the pooled asthma prevalence in European and North American cohorts that used questionnaire alone versus other data sources to classify asthma.

CONCLUSION

There is substantial heterogeneity in childhood asthma definitions in birth cohort studies. Standardisation of asthma case definitions will improve the comparability and utility of future cohort studies and enable meta-analyses.

Economic Burden of Pediatric Asthma in Turkey: A Cost of Illness Study from Payer Perspective

OBJECTIVES

To estimate economic burden of pediatric asthma in Turkey from payer perspective.

MATERIALS AND METHODS

This cost of illness study was based on identification of per patient annual direct medical costs for the management of pediatric asthma in Turkey from payer perspective. Average per patient direct medical cost was calculated based on cost items related to outpatient visits, laboratory and radiological tests, hospitalizations and interventions, drug treatment and equipment, and co-morbidities/complications.

RESULTS

Based on total annual per patient costs calculated for outpatient admission ($113.14), laboratory-radiological tests ($35.94), hospitalizations ($725.92), drug treatment/equipment ($212.90) and co-morbidities/complications ($144.62) cost items, total per patient annual direct medical cost related to management of pediatric asthma was calculated to be $1,232.53 from payer perspective. Hospitalizations and interventions (58.9%) was the main cost driver. Direct cost for managing controlled and uncontrolled pediatric asthma were calculated to be $530.17 [key cost driver: drugs/equipment (40.0%)] and $1,023.16 [key cost driver: hospitalization/interventions (59.0%)], respectively.

CONCLUSION

Our findings indicate that managing patients with pediatric asthma pose a considerable burden to health economics in Turkey, with hospitalizations identified as the main cost driver and two-fold cost increment in case of uncontrolled disease.

Personalized Medicine and Pediatric Asthma

Asthma is a heterogeneous disorder described by a large number of clinical features. A growing body of literature on more specific asthma phenotypes provides evidence for a phenotype-based approach to management in which specific therapies are recommended based on patient and disease characteristics. This understanding, coupled with an increase in the number of available therapies for children with asthma, as well as emerging therapies and phenotypic markers, will allow for improved asthma management in the future.

The Tempest: Difficult to Control Asthma in Adolescence

Severe asthma is associated with significant morbidity and is a highly heterogeneous disorder. Severe asthma in adolescence has some unique elements compared with the features of severe asthma a medical provider would see in younger children or adults. A specific focus on psychological issues and adherence highlights some of the challenges in the management of asthma in adolescents. Treatment of adolescents with severe asthma now includes 3 approved biologic phenotype-directed therapies. Therapies available to adults may be beneficial to adolescents with severe asthma. Research into predictors of specific treatment response by phenotypes is ongoing. Optimal treatment strategies are not yet defined and warrant further investigation.

Phenotypes of allergic diseases in children and their application in clinical situations

Allergic diseases, including allergic rhinitis, asthma, and atopic dermatitis, are common heterogeneous diseases that encompass diverse phenotypes and different pathogeneses. Phenotype studies of allergic diseases can facilitate the identification of risk factors and their underlying pathophysiology, resulting in the application of more effective treatment, selection of better treatment responses, and prediction of prognosis for each phenotype. In the early phase of phenotype studies in allergic diseases, artificial classifications were usually performed based on clinical features, such as triggering factors or the presence of atopy, which can result in the biased classification of phenotypes and limit the characterization of heterogeneous allergic diseases. Subsequent phenotype studies have suggested more diverse phenotypes for each allergic disease using relatively unbiased statistical methods, such as cluster analysis or latent class analysis. The classifications of phenotypes in allergic diseases may overlap or be unstable over time due to their complex interactions with genetic and encountered environmental factors during the illness, which may affect the disease course and pathophysiology. In this review, diverse phenotype classifications of allergic diseases, including atopic dermatitis, asthma, and wheezing in children, allergic rhinitis, and atopy, are described. The review also discusses the applications of the results obtained from phenotype studies performed in other countries to Korean children. Consideration of changes in the characteristics of each phenotype over time in an individual’s lifespan is needed in future studies.

Longitudinal Phenotypes of Respiratory Health in a High-Risk Urban Birth Cohort

RATIONALE

Characterization of patterns of wheezing and allergic sensitization in early life may allow for identification of specific environmental exposures impacting asthma development.

OBJECTIVES

To define respiratory phenotypes in inner-city children and their associations with early-life environmental exposures.

METHODS

Data were collected prospectively from 442 children in the URECA (Urban Environment and Childhood Asthma) birth cohort through age 7 years, reflecting symptoms (wheezing), aeroallergen sensitization, pulmonary function, and body mass index. Latent class mixed models identified trajectories of wheezing, allergic sensitization, and pulmonary function. Cluster analysis defined nonoverlapping groups (termed phenotypes). Potential associations between phenotypes and early-life environmental exposures were examined.

MEASUREMENTS AND MAIN RESULTS

Five phenotypes were identified and mainly differentiated by patterns of wheezing and allergic sensitization (low wheeze/low atopy; low wheeze/high atopy; transient wheeze/low atopy; high wheeze/low atopy; high wheeze/high atopy). Asthma was most often present in the high-wheeze phenotypes, with greatest respiratory morbidity among children with frequent wheezing and allergic sensitization. These phenotypes differentially related to early-life exposures, including maternal stress and depression, antenatal environmental tobacco smoke, house dust microbiome, and allergen content (all P < 0.05). Prenatal smoke exposure, maternal stress, and depression were highest in the high-wheeze/low-atopy phenotype. The high-wheeze/high-atopy phenotype was associated with low household microbial richness and diversity. Early-life aeroallergen exposure was low in high-wheeze phenotypes.

CONCLUSIONS

Patterns of wheezing, allergic sensitization, and lung function identified five respiratory phenotypes among inner-city children. Early-life environmental exposure to stress, depression, tobacco smoke, and indoor allergens and microbes differentially associate with specific phenotypes.

Pediatric asthma comprises different phenotypic clusters with unique nasal microbiotas

BACKGROUND

Pediatric asthma is the most common chronic childhood disease in the USA, currently affecting ~ 7 million children. This heterogeneous syndrome is thought to encompass various disease phenotypes of clinically observable characteristics, which can be statistically identified by applying clustering approaches to patient clinical information. Extensive evidence has shown that the airway microbiome impacts both clinical heterogeneity and pathogenesis in pediatric asthma. Yet, so far, airway microbiotas have been consistently neglected in the study of asthma phenotypes. Here, we couple extensive clinical information with 16S rRNA high-throughput sequencing to characterize the microbiota of the nasal cavity in 163 children and adolescents clustered into different asthma phenotypes.

RESULTS

Our clustering analyses identified three statistically distinct phenotypes of pediatric asthma. Four core OTUs of the pathogenic genera Moraxella, Staphylococcus, Streptococcus, and Haemophilus were present in at least 95% of the studied nasal microbiotas. Phyla (Proteobacteria, Actinobacteria, and Bacteroidetes) and genera (Moraxella, Corynebacterium, Dolosigranulum, and Prevotella) abundances, community composition, and structure varied significantly (0.05 < P ≤ 0.0001) across asthma phenotypes and one of the clinical variables (preterm birth). Similarly, microbial networks of co-occurrence of bacterial genera revealed different bacterial associations across asthma phenotypes.

CONCLUSIONS

This study shows that children and adolescents with different clinical characteristics of asthma also show different nasal bacterial profiles, which is indicative of different phenotypes of the disease. Our work also shows how clinical and microbial information could be integrated to validate and refine asthma classification systems and develop biomarkers of disease.

Asthma Endotyping and Biomarkers in Childhood Asthma

Childhood asthma represents a heterogeneous challenging disease, in particular in its severe forms. The identification of different asthma phenotypes has stimulated research in underlying molecular mechanisms, such as the endotypes, and paved the way to the search for related specific biomarkers, which may guide diagnosis, management, and predict response to treatment. A limited number of biomarkers are currently available in clinical practice in the pediatric population, mostly reflecting type 2-high airway inflammation. The identification of biomarkers of childhood asthma is an active area of research that holds a potential great clinical utility and may represent a step forward toward tailored management and therapy: the so-called Precision Medicine. The aim of the present review is to provide an updated overview of asthma endotyping, mostly focusing on novel noninvasive biomarkers in childhood asthma.

Moving toward consensus on diagnosis and management of severe asthma in children

Children with severe asthma continue to experience symptoms despite long-term treatment with high doses of corticosteroids. Moreover, the heterogeneous nature of asthma and the presence of several phenotypes have limited our ability to develop an optimized management strategy for these patients. Adequate management of severe asthma in children necessitates a detailed understanding of what makes asthma difficult to control, knowledge of the causal factors, review of diagnosis for accurate identification of pediatric patients with severe asthma and a precise definition of the phenotypes to be able to better target the therapy. Advancement in all these aspects is likely to improve childhood asthma treatment in the future. Although our understanding of severe pediatric asthma has grown in recent years, there remains a lack of consensus and clarity around critical aspects of this condition. This review attempts to present a harmonized view on the definition of severe asthma in the pediatric age group, identification of phenotypes and diagnosis, the inflammatory cascade, pharmacological and non-pharmacological treatment strategies, considerations for follow-up and referral to specialists, and disease prevention strategies.

Persistent asthma phenotype related with late-onset, high atopy, and low socioeconomic status in school-aged Korean children

BACKGROUND

Treatment guidelines for asthma have been established based on asthma severity; there are limitations in the identification of underlying pathophysiology and prediction of prognosis in heterogeneous phenotypes of asthma. Although the complex interactions between environmental and genetic factors affect the development and progression of asthma, studies on asthma phenotypes considering environmental factors are limited. This study aimed to identify asthma phenotypes using latent class analysis including environmental factors in school-age children.

METHODS

We included 235 children (6-8 years) with parent-reported, physician-diagnosed asthma from the Children's HEalth and Environmental Research (CHEER) study, which is a 4-year prospective follow-up study with 2-year intervals. At every survey, pulmonary function tests, methacholine challenge tests and blood tests with questionnaire were conducted.

RESULTS

Four asthma phenotypes were identified. Cluster 1 (22% of children) was characterized by high prevalence of atopy and mild symptoms; subjects in cluster 2 (17%) consisted of less atopy and normal lung function, but intermittent troublesome; cluster 3 (29%) experienced late-onset atopic troublesome asthma with decreased lung function in combination with low socioeconomic status; and cluster 4 was associated with early-onset and less-atopic infrequent asthma.

CONCLUSIONS

Late-onset, high atopy, and low socioeconomic status are associated with troublesome persistent asthma phenotype in school-age children. Environmental factors might be implicated in the clinical heterogeneity of asthma. Asthma phenotypes considering diverse factors might be more helpful in the identification of asthma pathogenesis and its prevention.

The Role of Sensitization to Allergen in Asthma Prediction and Prevention

The burden of asthma in childhood is considerable worldwide, although some populations are much more affected than others. Many attempts have been made by different investigators to identify the factors that could predict asthma development or persistence in childhood. In this review, the relation between atopic sensitization as an indicator of allergy and asthma in childhood will be discussed. Cross sectional studies, carried out in different countries, failed to show any firm correlation between asthma and atopic sensitization. Birth cohort mainly of infants at high risk for asthma and case-control studies showed that atopic sensitization was a risk factor for current asthma in children older than 6 years. In general, clear relations are observed mostly in affluent Western countries, whereas in less affluent countries, the picture is more heterogeneous. For the prediction of asthma development or persistence in school age children, other prerequisites should also be fulfilled such as family history of asthma and wheezing episodes at preschool age. Despite the conductance of different studies regarding the potential role of allergen avoidance for the primary prevention of childhood asthma, it does not seem that this approach is of benefit for primary prevention purposes. However, the identification of children at risk for asthma is of benefit as these subjects could be provided with the best management practices and with the appropriate secondary prevention measures.

[Prevalence and clinical characteristics of wheezing in children in the first year of life, living in Cuiabá, Mato Grosso, Brazil]

OBJECTIVE:

To evaluate the prevalence and the clinical characteristics of wheezing in infants aged 12 to 15 months in the city of Cuiabá, Mato Grosso State, Midwest Brazil.

METHODS:

Parents and/or guardians of infants were interviewed and completed a written standardized questionnaire of the Estudio Internacional de Sibilancia en Lactantes (EISL) - phase 3 at primary healthcare clinics at the same day of children vaccination or at home, from August of 2009 to November of 2010.

RESULTS:

1,060 parents and/or guardians completed the questionnaire, and 514 (48.5%) infants were male. Among the studied infants, 294 (27.7%) had at least one episode of wheezing during the first year of life, beggining at 5.8±3.0 months of age, with a predominance of male patients. The prevalence of occasional wheezing (<3 episodes of wheezing) was 15.0% and recurrent wheezing (≥3 episodes) was 12.7%. Among the infants with recurrent wheezing, the use of inhaled β2-agonist, oral corticosteroid, leukotriene receptor antagonist, as well as night symptoms, respiratory distress, and hospitalization due to severe episodes were significantly more frequent. Physician-diagnosed asthma was observed in 28 (9.5%) of the wheezing infants. Among the wheezing infants, 80 (27.7%) were diagnosed with pneumonia, of whom 33 (11.2%) required hospitalization; neverthless, no differences between occasional and recurrent wheezing infants were found.

CONCLUSIONS:

The prevalence of recurrent wheezing and physician-diagnosed asthma in infants were lower compared with those observed in other Brazilian studies. Recurrent wheezing had early onset and high morbity.

Moving towards precision care for childhood asthma

PURPOSE OF REVIEW

Asthma guidelines recognize the presence of different asthma endotypes and phenotypes but treatment recommendations are limited to age groups rather than phenotypes, as the phenotype literature is regarded as emerging evidence. This review will examine the current evidence regarding the management of asthma in school age children (5-18 years old) by endotype and phenotype.

RECENT FINDINGS

A number of studies have examined the effect of endotypes and phenotypes on response to conventional asthma therapy, omalizumab and specific allergen immunotherapy, and response in children with severe asthma. Emerging therapies, namely biologics and immunomodulators, have attracted considerable attention and appear to have favorable effects in adults with asthma, but additional pediatric studies are needed.

SUMMARY

The optimal treatment strategy for children with asthma is not yet defined and likely dependent on many patient and disease characteristics. Much of the phenotypic response literature presented in this review was constrained by a limited number of pediatric and adult studies available and as such should be regarded as preliminary. Better definition of asthma phenotypes and better targeting of therapy based on individual patient phenotypes are likely to improve asthma treatment in the future.

Risk factors for recurrent wheezing--International Study of Wheezing in Infants (EISL) phase 3

BACKGROUND

We aimed to identify factors associated with recurrent wheezing (RW) in infants in the first year of life living in the Southern region of São Paulo city and participating in the "Estudio Internacional de Sibilancias en Lactantes (EISL)" - phase 3 (P3).

METHODS

1335 parents of infants who were attended in primary care health units in the Southern region of São Paulo city from 2009 to 2010 answered the EISL-P3 written questionnaire. The wheezing group was stratified in accordance to the frequency of wheezing episodes as occasional wheezing (OW, less than three episodes), or RW (three or more episodes). Wheezing-associated factors were evaluated using multivariate analysis and were expressed as odds ratio (OR) and 95% confidence interval (95%CI).

RESULTS

The most relevant factors related to OW were pneumonia (OR=3.10, 95%CI=1.68-5.73), hospitalisation due to pneumonia (OR=2.88, 95%CI=1.26-6.56) and recurrent upper respiratory infection (URI, OR=1.87, 95%CI=1.25-2.81). Regarding RW, recurrent URI (OR=5.34, 95%CI=3.83-7.45), pneumonia (OR=4.06, 95%CI=2.87-5.74) and asthmatic siblings (OR=3.02, 95%CI=1.67-5.45) were the most significantly associated factors.

CONCLUSIONS

In the present study, we found that recurrent URI, positive history of pneumonia and familiar history of asthma were the most relevant factors associated with RW. The precocious knowledge of these factors can enable the identification of the probable asthmatic infants and can improve both prevention strategies and treatment of these patients.

Evaluation and treatment of critical asthma syndrome in children

The heterogeneity of asthma is illustrated by the significantly different features of pediatric asthma compared to adult asthma. One phenotype of severe asthma in pediatrics includes atopy, lack of reduction in lung function, and absence of gender bias as the main characteristics. Included in the NIH NAEPP EPR-3 are recommendations for the treatment and management of severe pediatric asthma and critical asthma syndrome, such as continuous nebulization treatments, intubation and mechanical ventilation, heliox, and magnesium sulfate. In addition, epinephrine, intravenous immunoglobulin, intravenous montelukast, extracorporeal membrane oxygenation, and many biological modulators currently under investigation are additional current and/or future treatment modalities for the severe pediatric asthmatic. But, perhaps the most important strategy for managing the severe asthmatic is preventative treatment, which can significantly decrease impairment and risk, particularly for severe acute exacerbations requiring emergency care and/or hospitalization. In order for preventative therapy to be successful, several challenges must be met, including selecting the correct therapy for each patient and then ensuring compliance or adherence to a treatment plan. The heterogeneity of asthma renders the former difficult in that not all patients will respond equally to the same treatment; the latter is only helpful if the correct treatment is employed. Strategies to ensure compliance include education of caregivers and patients and their families. As newer medications are introduced, options for individualized or customized medicine increase, and this may pave the way for significant decreases in morbidity and mortality in severe pediatric asthma.

Personalized medicine in children with asthma

Personalized medicine for children with asthma aims to provide a tailored management of asthma, which leads to faster and better asthma control, has less adverse events and may be cost saving. Several patient characteristics, lung function parameters and biomarkers have been shown useful in predicting treatment response or predicting successful reduction of asthma medication. As treatment response to the main asthma therapies is partly genetically determined, pharmacogenetics may open the way for personalized medicine in children with asthma. However, the number of genes identified for the various asthma drug response phenotypes remains small and randomized controlled trials are lacking. Biomarkers in exhaled breath or breath condensate remain promising but did not find their way from bench to bedside yet, except for the fraction of exhaled nitric oxide. E-health will most likely find its way to clinical practice and most interventions are at least non-inferior to usual care. More studies are needed on which interventions will benefit most individual children.

Prevalence and clinical characteristics of wheezing in children in the first year of life, living in Cuiabá, Mato Grosso, Brazil

OBJECTIVE: To evaluate the prevalence and the clinical characteristics of wheezing in infants aged 12 to 15 months in the city of Cuiabá, Mato Grosso State, Midwest Brazil.METHODS: Parents and/or guardians of infants were interviewed and completed a written standardized questionnaire of the Estudio Internacional de Sibilancia en Lactantes (EISL) - phase 3 at primary healthcare clinics at the same day of children vaccination or at home, from August of 2009 to November of 2010.RESULTS: 1,060 parents and/or guardians completed the questionnaire, and 514 (48.5%) infants were male. Among the studied infants, 294 (27.7%) had at least one episode of wheezing during the first year of life, beggining at 5.8±3.0 months of age, with a predominance of male patients. The prevalence of occasional wheezing (<3 episodes of wheezing) was 15.0% and recurrent wheezing (≥3 episodes) was 12.7%. Among the infants with recurrent wheezing, the use of inhaled β2-agonist, oral corticosteroid, leukotriene receptor antagonist, as well as night symptoms, respiratory distress, and hospitalization due to severe episodes were significantly more frequent. Physician-diagnosed asthma was observed in 28 (9.5%) of the wheezing infants. Among the wheezing infants, 80 (27.7%) were diagnosed with pneumonia, of whom 33 (11.2%) required hospitalization; neverthless, no differences between occasional and recurrent wheezing infants were found.CONCLUSIONS: The prevalence of recurrent wheezing and physician-diagnosed asthma in infants were lower compared with those observed in other Brazilian studies. Recurrent wheezing had early onset and high morbity.

Optimum predictors of childhood asthma: persistent wheeze or the Asthma Predictive Index?

BACKGROUND

The Asthma Predictive Index (API) and persistent wheezing phenotypes are associated with childhood asthma, but previous studies have not assessed their ability to predict objectively confirmed asthma.

OBJECTIVE

To determine whether the University of Cincinnati API Index (ucAPI) and/or persistent wheezing at age 3 can accurately predict objectively confirmed asthma at age 7.

METHODS

Data from the Cincinnati Childhood Allergy and Air Pollution Study, a high-risk prospective birth cohort, was used. Asthma was defined as parent-reported or physician-diagnosed asthma objectively confirmed by a change in FEV1 of ≥12% after bronchodilator or a positive methacholine challenge (PC20 ≤ 4 mg/mL); or as prior treatment with daily asthma controller medication(s). Multivariate logistic regression was used to investigate the relationship between confirmed asthma at age 7 and a positive ucAPI (adapted and modified from prior published API definitions) and persistent wheezing at age 3.

RESULTS

At age 7, 103 of 589 children (17.5%) satisfied the criteria for asthma. Confirmed asthma at age 7 was significantly associated with a positive ucAPI (adjusted odds ratio [aOR] 13.3 [95% CI, 7.0-25.2]; P < .01) and the persistent wheezing phenotype (aOR 9.8 [95% CI, 4.9-19.5]; P < .01) at age 3. Allergic persistent wheezing was associated with a significantly higher risk of asthma (aOR 10.4 [95% CI, 4.1-26.0]; P < .01) than nonallergic persistent wheezing (aOR 5.4 [95% CI, 2.04-14.06]; P < .01).

CONCLUSION

Both a positive ucAPI and persistent wheeze at age 3 were associated with objectively confirmed asthma at age 7; however, the highest risk was associated with ucAPI. These results demonstrate the ucAPI as a clinically useful tool for predicting future asthma in school-age children.

Childhood wheeze phenotypes show less than expected growth in FEV1 across adolescence

RATIONALE

Better characterization of childhood wheeze phenotypes using newer statistical methods provides a basis for addressing the heterogeneity of childhood asthma. Outcomes of these phenotypes beyond childhood are unknown.

OBJECTIVES

To determine if adolescent respiratory symptoms, lung function, and changes in lung function over adolescence differ by childhood wheeze phenotypes defined through latent class analysis.

METHODS

A prospective birth cohort (Melbourne Atopy Cohort Study) followed 620 high allergy-risk children, recording respiratory symptoms and spirometry at 12 and 18 years. Regression analyses identified relationships between wheeze phenotypes (never/infrequent, early transient, early persistent, intermediate onset, and late onset) and lung function, change in lung function (12-18 yr), respiratory symptoms, and asthma. The baseline classification was never/infrequent wheeze.

MEASUREMENTS AND MAIN RESULTS

Deficits in expected growth of lung function, measured by change in prebronchodilator FEV1 between 12 and 18 years, were found for early persistent (reduced 290 ml; 95% confidence interval [CI], 82-498), intermediate-onset (reduced 210 ml; 95% CI, 62-359), and late-onset wheeze (reduced 255 ml; 95% CI, 69-442). Intermediate-onset wheezers had persistent FEV1 deficit after bronchodilator at 18 years (reduced 198 ml; 46,350). Current asthma risk was increased for all phenotypes except early transient, which was also not associated with lung function deficits at 12 or 18 years.

CONCLUSIONS

Persistent wheeze phenotypes in childhood were associated with reduced growth in prebronchodilator FEV1 over adolescence. Intermediate-onset wheezers showed irreversible airflow limitation by 18 years. Conversely, early transient wheeze was a benign condition with no sequelae for respiratory health by age 18.

A preliminary investigation of anti-reflux intervention for gastroesophageal reflux related childhood-to-adult persistent asthma

BACKGROUND

Childhood-to-adult persistent asthma is usually considered to be an atopic disease. However gastroesophageal reflux may also play an important role in this phenotype of asthma, especially when it is refractory to pulmonary medicine.

METHODS

Fifty-seven consecutive GERD patients who had decades of childhood-to-adult persistent asthmatic symptoms refractory to pulmonary medication were enrolled. GERD was assessed by a symptom questionnaire, endoscopy, reflux monitoring, and manometry, and treated by Stretta radiofrequency (SRF) or laparoscopic Nissen fundoplication (LNF). The outcomes were followed up with a questionnaire for an average of 3.3 ± 1.1 years.

RESULTS

Upper esophageal sphincter hypotonia, lower esophageal sphincter (LES) hypotonia, shortened LES, and esophageal body dyskinesia were demonstrated by esophagus manometry in 50.9%, 43.9%, 35.1%, and 45.6% of the patients, respectively. The symptom scores for heartburn, regurgitation, coughing, wheezing, and chest tightness significantly decreased from 5.8 ± 2.0, 5.6 ± 2.0, 7.3 ± 1.6, 8.4 ± 1.2, and 8.1 ± 1.5, to 1.2 ± 1.8, 1.1 ± 1.6, 2.8 ± 2.5, 3.8 ± 2.7, and 3.9 ± 2.7, respectively, after anti-reflux treatment (P < 0.001).

CONCLUSIONS

Esophagus dysfunction is high in childhood-to-adult persistent asthmatic patients with GERD. SRF and LNF are both effective for esophagus symptoms as well as persistent asthmatic symptoms for these patients. GER may relate with asthmatic symptoms in some patients. Evaluating asthmatic patients for possible treatment of the underlying cause, such as GERD, may improve symptoms and prevent disease persistence.

Onset and persistence of respiratory/allergic symptoms in preschoolers: new insights from the PARIS birth cohort

BACKGROUND

The natural course of childhood asthma and allergy is complex and not fully understood. We aimed to identify phenotypes based upon the time course of respiratory/allergic symptoms throughout preschool years.

METHODS

As part of the PARIS cohort, symptoms of wheezing, dry night cough, rhinitis and dermatitis were collected annually from birth to age 4 years. K-means clustering was used to group into phenotypes children with similar symptoms trajectories over the study period. Associations of phenotypes with IgE sensitization and risk factors were studied using multinomial logistic regression.

RESULTS

Besides a group with low prevalence of symptoms considered as reference (n = 1236, 49.0%), four distinct respiratory/allergic phenotypes were identified: two transient [transient rhinitis phenotype (n = 295, 11.7%), transient wheeze phenotype (n = 399, 15.8%)], without any relation with IgE sensitization, and two persistent [cough/rhinitis phenotype (n = 284, 11.3%), dermatitis phenotype (n = 308, 12.2%)], associated with IgE sensitization. Transient rhinitis phenotype was only associated with tobacco smoke exposure, which could irritate the airways. Transient wheeze phenotype was related to male sex and contact with other children (older siblings, day care attendance). Lastly, risk factors for both IgE-associated phenotypes encompassed parental history of allergy, potential exposure to allergens and stress, known to be associated with the development of allergic diseases.

CONCLUSION

This study provides evidence for the existence of different respiratory/allergic phenotypes before school age. The fact that they differ in terms of sensitization and risk factors reinforces the plausibility of distinct phenotypes, potentially linked to irritation and infections for the transient phenotypes and to allergy for the persistent phenotypes.

A twin study of early-childhood asthma in Puerto Ricans

BACKGROUND

The relative contributions of genetics and environment to asthma in Hispanics or to asthma in children younger than 3 years are not well understood.

OBJECTIVE

To examine the relative contributions of genetics and environment to early-childhood asthma by performing a longitudinal twin study of asthma in Puerto Rican children ≤ 3 years old.

METHODS

678 twin infants from the Puerto Rico Neo-Natal Twin Registry were assessed for asthma at age 1 year, with follow-up data obtained for 624 twins at age 3 years. Zygosity was determined by DNA microsatellite profiling. Structural equation modeling was performed for three phenotypes at ages 1 and 3 years: physician-diagnosed asthma, asthma medication use in the past year, and ≥ 1 hospitalization for asthma in the past year. Models were additionally adjusted for early-life environmental tobacco smoke exposure, sex, and age.

RESULTS

The prevalences of physician-diagnosed asthma, asthma medication use, and hospitalization for asthma were 11.6%, 10.8%, 4.9% at age 1 year, and 34.1%, 40.1%, and 8.5% at 3 years, respectively. Shared environmental effects contributed to the majority of variance in susceptibility to physician-diagnosed asthma and asthma medication use in the first year of life (84%-86%), while genetic effects drove variance in all phenotypes (45%-65%) at age 3 years. Early-life environmental tobacco smoke, sex, and age contributed to variance in susceptibility.

CONCLUSION

Our longitudinal study in Puerto Rican twins demonstrates a changing contribution of shared environmental effects to liability for physician-diagnosed asthma and asthma medication use between ages 1 and 3 years. Early-life environmental tobacco smoke reduction could markedly reduce asthma morbidity in young Puerto Rican children.

Polygenic risk and the development and course of asthma: an analysis of data from a four-decade longitudinal study

BACKGROUND

Genome-wide association studies (GWAS) have discovered genetic variants that predispose individuals to asthma. To integrate these new discoveries with emerging models of asthma pathobiology, we aimed to test how genetic discoveries relate to developmental and biological characteristics of asthma.

METHODS

In this prospective longitudinal study, we investigated a multilocus profile of genetic risk derived from published GWAS of asthma case status. We then tested associations between this genetic risk score and developmental and biological characteristics of asthma in participants enrolled in a population-based long-running birth cohort, the Dunedin Multidisciplinary Health and Development Study (n=1037). We used data on asthma onset, asthma persistence, atopy, airway hyper-responsiveness, incompletely reversible airflow obstruction, and asthma-related school and work absenteeism and hospital admissions obtained during nine prospective assessments spanning the ages of 9 to 38 years. Analyses included cohort members of European descent from whom genetic data had been obtained.

FINDINGS

Of the 880 cohort members included in our analysis, those at higher genetic risk developed asthma earlier in life than did those with lower genetic risk (hazard ratio [HR] 1·12, 95% CI 1·01-1·26). Of cohort members with childhood-onset asthma, those with higher genetic risk were more likely to develop life-course-persistent asthma than were those with a lower genetic risk (relative risk [RR] 1·36, 95% CI 1·14-1·63). Participants with asthma at higher genetic risk more often had atopy (RR 1·07, 1·01-1·14), airway hyper-responsiveness (RR 1·16, 1·03-1·32), and incompletely reversible airflow obstruction (RR 1·28, 1·04-1·57) than did those with a lower genetic risk. They were also more likely to miss school or work (incident rate ratio 1·38, 1·02-1·86) and be admitted to hospital (HR 1·38, 1·07-1·79) because of asthma. Genotypic information about asthma risk was independent of and additive to information derived from cohort members' family histories of asthma.

INTERPRETATION

Our findings confirm that GWAS discoveries for asthma are associated with a childhood-onset phenotype. Genetic risk assessments might be able to predict which childhood-onset asthma cases remit and which become life-course-persistent, who might develop impaired lung function, and the burden of asthma in terms of missed school and work and hospital admissions, although these predictions are not sufficiently sensitive or specific to support immediate clinical translation.

FUNDING

US National Institute on Aging and UK Medical Research Council.

The prevalence of wheezing and its association with body mass index and abdominal obesity in children

OBJECTIVE

To evaluate the relative importance of body mass index (BMI) and abdominal obesity in the prevalence of wheezing in Brazilian children.

MATERIALS AND METHODS

This is a cross-sectional study of male and female students, 6-12 years old, from the public elementary schools of São Francisco do Conde, Bahia, Northeast Brazil. Reports of wheezing in the past 12 months were collected using a questionnaire from the International Study of Asthma and Allergies in Childhood Program (ISAAC) phase III, adapted to Portuguese. Anthropometric, demographic, and socioeconomic information was collected. Multivariate logistic regression analyses were used to assess the associations of interest.

RESULTS

Of the children surveyed, 10.6% reported wheezing. Excess weight was observed in 16.2%, 10.5%, and 7.9% of the sample, measured by BMI, waist circumference (WC), and the waist-to-height ratio (WHtR), respectively. The percentage of patients with wheezing attributable to BMI ≥ 85th percentile (8.2%) slightly exceeded those identified with abdominal obesity, WC ≥ 80th percentile (7.3%) and WHtR > 0.5 (7.1%).

CONCLUSION

The results suggest that an excess of fat deposits, either in the abdominal region or elsewhere in the body, increased the risk of wheezing. Since obesity is an important public health problem worldwide, control of this problem may partially reduce the occurrence of wheezing in youth.