Risk of Asthma in Late Preterm Infants: A Propensity Score Approach

Risk Factors Affecting Development and Persistence of Preschool Wheezing: Consensus Document of the Emilia-Romagna Asthma (ERA) Study Group

Wheezing at preschool age (i.e., before the age of six) is common, occurring in about 30% of children before the age of three. In terms of health care burden, preschool children with wheeze show double the rate of access to the emergency department and five times the rate of hospital admissions compared with school-age asthmatics. The consensus document aims to analyse the underlying mechanisms involved in the pathogenesis of preschool wheezing and define the risk factors (i.e., allergy, atopy, infection, bronchiolitis, genetics, indoor and outdoor pollution, tobacco smoke exposure, obesity, prematurity) and the protective factors (i.e., probiotics, breastfeeding, vitamin D, influenza vaccination, non-specific immunomodulators) associated with the development of the disease in the young child. A multidisciplinary panel of experts from the Emilia-Romagna Region, Italy, addressed twelve key questions regarding managing preschool wheezing. Clinical questions have been formulated by the expert panel using the PICO format (Patients, Intervention, Comparison, Outcomes). Systematic reviews have been conducted on PubMed to answer these specific questions and formulate recommendations. The GRADE approach has been used for each selected paper to assess the quality of the evidence and the degree of recommendations. Based on a panel of experts and extensive updated literature, this consensus document provides insight into the pathogenesis, risk and protective factors associated with the development and persistence of preschool wheezing. Undoubtedly, more research is needed to improve our understanding of the disease and confirm the associations between certain factors and the risk of wheezing in early life. In addition, preventive strategies must be promoted to avoid children's exposure to risk factors that may permanently affect respiratory health.

A diagnostic codes-based algorithm improves accuracy for identification of childhood asthma in archival data sets

OBJECTIVE

While a single but truncated ICD code (493) had been widely used for identifying asthma in asthma care and research, it significantly under-identifies asthma. We aimed to develop and validate a diagnostic codes-based algorithm for identifying asthmatics using Predetermined Asthma Criteria (PAC) as the reference.

METHODS

This is a retrospective cross-sectional study which utilized two different coding systems, the Hospital Adaptation of the International Classification of Diseases, Eighth Revision (H-ICDA) and the International Classification of Diseases, Ninth Revision (ICD-9). The algorithm was developed using two population-based asthma study cohorts, and validated in a validation cohort, a random sample of the 1976-2007 Olmsted County Birth Cohort. Performance of the diagnostic codes-based algorithm for ascertaining asthma status against manual chart review for PAC (gold standard) was assessed by determining both criterion and construct validity.

RESULTS

Among eligible 267 subjects of the validation cohort, 50% were male, 70% white, and the median age at last follow-up was 17 (interquartile range, 8.7-24.4) years. Asthma prevalence by PAC through manual chart review was 34%. Sensitivity and specificity of the codes-based algorithm for identifying asthma were 82% and 98% respectively. Associations of asthma-related risk factors with asthma status ascertained by the code-based algorithm were similar to those by the manual review.

CONCLUSIONS

The diagnostic codes-based algorithm for identifying asthmatics improves accuracy of identification of asthma and can be a useful tool for large scale studies in a setting without automated chart review capabilities.

A prenatally disrupted airway epithelium orchestrates the fetal origin of asthma in mice

BACKGROUND

Prenatal challenges such as maternal stress perception increase the risk and severity of asthma during childhood. However, insights into the trajectories and targets underlying the pathogenesis of prenatally triggered asthma are largely unknown. The developing lung and immune system may constitute such targets.

OBJECTIVE

Here we have aimed to identify the differential sex-specific effects of prenatal challenges on lung function, immune response, and asthma severity in mice.

METHODS

We generated bone marrow chimeric (BMC) mice harboring either prenatally stress-exposed lungs or a prenatally stress-exposed immune (hematopoietic) system and induced allergic asthma via ovalbumin. Next-generation sequencing (RNA sequencing) of lungs and assessment of airway epithelial barrier function in ovalbumin-sensitized control and prenatally stressed offspring was also performed.

RESULTS

Profoundly enhanced airway hyperresponsiveness, inflammation, and fibrosis were exclusively present in female BMC mice with prenatally stress-exposed lungs. These effects were significantly perpetuated if both the lungs and the immune system had been exposed to prenatal stress. A prenatally stress-exposed immune system alone did not suffice to increase the severity of these asthma features. RNA sequencing analysis of lungs from prenatally stressed, non-BMC, ovalbumin-sensitized females unveiled a deregulated expression of genes involved in asthma pathogenesis, tissue remodeling, and tight junction formation. It was also possible to independently confirm a tight junction disruption. In line with this, we identified an altered perinatal and/or postnatal expression of genes involved in lung development along with an impaired alveolarization in female prenatally stressed mice.

CONCLUSION

Here we have shown that the fetal origin of asthma is orchestrated by a disrupted airway epithelium and further perpetuated by a predisposed immune system.

Preterm birth is associated with higher prevalence of wheeze and asthma in a selected population of Japanese children aged three years

BACKGROUND

The present cross-sectional study investigated the associations between low birthweight (LBW), high birthweight, preterm birth (PTB), postterm birth, small for gestational age (SGA), and large for gestational age (LGA) and the prevalence of wheeze and asthma in Japanese children aged three years (age range, 33-54 months; mean age, 38.7 months).

METHODS

Study subjects were 6364 children. A questionnaire was used to collect all data. Wheeze and asthma were defined according to the criteria of the International Study of Asthma and Allergies in Childhood.

RESULTS

The prevalence values of wheeze and asthma were 19.5% and 7.7%, respectively. Of the 6364 subjects, 8.8% were classified as LBW (<2500g), 90.4% as normal birthweight, 0.8% as high birthweight (≥4000g), 4.8% as PTB (<37 weeks), 94.8% as term birth, 0.4% as postterm birth (≥42 weeks), 7.8% as SGA (<10th percentile), 82.5% as appropriate for gestational age, and 9.7% as LGA (>90th percentile). Compared with term birth, PTB was independently positively associated with wheeze and asthma: the adjusted ORs (95% CI) were 1.47 (1.11-1.92) and 1.52 (1.02-2.20), respectively. An independent positive association was shown between PTB and wheeze only in boys; the interaction between PTB and sex was significant. Such an interaction between PTB and sex was not seen for asthma. No evident associations were observed between LBW, high birthweight, postterm birth, SGA, or LGA and wheeze or asthma.

CONCLUSIONS

This is the first study in Japan to show that PTB, but not LBW or SGA, was significantly positively associated with childhood wheeze and asthma.

Effect of late preterm birth on lung clearance index and respiratory physiology in school-age children

BACKGROUND

We hypothesized that former late preterm (LP) children have abnormal pulmonary physiology parameters, including uneven ventilation distribution, due to premature disruption of normal lung development.

METHODS

A cross-sectional study evaluating former LP children at the age of 6 to 12 years as compared to term controls. Demographics and child's and family history of asthma/atopy/smoking were recorded. The outcome parameters were spirometry, multiple breath washout (MBW) measurement by lung clearance index (LCI), 6-minute walk test (6MWT), symptoms related to asthma and allergy, and Godin Leisure-Time Exercise Questionnaire.

RESULTS

Twenty-nine former LP were compared to 30 term-control children (mean age, 8.2 ± 1.7 and 8.8 ± 1.8 years, respectively). LP had reduced forced expiratory volume in the first second (FEV1) and forced vital capacity (FVC) compared to term controls (FEV1 1.59 ± 0.48 vs 1.80 ± 0.39 L, P = 0.005 and FVC 1.73 ± 0.45 vs 1.99 ± 0.49 L, P = 0.009). There were no differences between the two groups regarding FEV1/FVC, forced expiratory flow between 25 and 75 (FEF25-75), LCI (7.10 ± 0.79 vs 6.96 ± 0.75, P = 0.50), 6MW distance, and weekly leisure-activity score. Former LP children had more episodes of wheezing and greater use of asthma medication.

CONCLUSIONS

This pilot study suggests that LP have lower pulmonary function tests (PFTs) but not ventilation inhomogeneity measured by LCI or functional disturbance. It is unclear if the differences in PFTs are due to late prematurity by itself or are the consequence of maternal and neonatal factors associated with LP. Further larger studies are required to assess the long-term respiratory consequences of LP birth.

Respiratory morbidity, atopy and asthma at school age in preterm infants aged 32-35 weeks

Little is known about respiratory morbidity and asthma risk in preterm infants (PTIs) with a gestational age (GA) over 32 weeks. This was a prospective study carried out from birth to 7-8 years, comparing two groups: (a) PTIs (GAs 32 weeks + 1 day to 35 weeks + 0 days, without comorbidities) and (b) full-term infants (FTIs; GA ≥ 37 weeks). Risk and protective factors for bronchiolitis and asthma were identified. A total of 232 children (116/group) were included. Sixty-six (56.9%) PTIs and 43 (37.1%) FTIs presented bronchiolitis (p = 0.002). Recurrent wheezing was 52 (44.8%) on PTIs versus 36 (31.0%) on FTIs (p = 0.03). Asthma at school aged was 27 (23.3%) on PTIs and 8 (6.9%) on FTIs (p = 0.020). Asthma risk factors were only detected in group A.Conclusion: PTIs had a higher prevalence of bronchiolitis, recurrent wheezing and asthma; risk factors for asthma are the following: older siblings, allergic father, atopic dermatitis and antibiotic treatment in the first 3 years of life and prematurity itself, which also acted as protective factor for atopic dermatitis. What is known: • In recent decades, there has been a significant increase in the birth of premature babies and consequently, also in the pathologies secondary to the prematurity: a greater number of complications and disorders related to the development and maturation of many organs and systems, especially the respiratory system. Several studies, especially in full-term infants and very preterm infants, have tried to elucidate the risk factors that may influence the development of persistent or chronic respiratory problems such asasthma, but little is known about the aetiology of these disorders in the late or moderate preterm infants. Inthis group of children, the role played by certain factors (early use of antibiotics, chorioamnionitis, smokeexposure, paternal asthma, etc.) on late respiratory morbidity, or asthma, is inconclusive. • Moderate-to-late preterm infants are more predisposed to developing recurrent wheezing/asthma and should adopt control measures. What is new: • Our work provides data related to little-understood aspects of respiratory diseases in this group of late or moderate preterm infants (gestational age between 32 weeks plus 1 day and 35 weeks plus 0 days), by monitoring their evolution from birth to 7-8 years of age, compared with another group of full-term newborns. We aimed to establish the prevalence of bronchiolitis and recurrent wheezing in these children during their first years of life. • The prevalence of school-aged asthma and the risk factors for contracting it were also investigated.

Early childhood health and morbidity, including respiratory function in late preterm and early term births

Late preterm (LP) and early term (ET) infants have generally been considered in the same way as their healthy full term (FT) counterparts. It is only in the last decade that an increased risk of later poor health in children born LP has been recognised; evidence for health outcomes following ET birth is still emerging. However, reports are largely consistent in highlighting an increased risk, which lessens approaching FT but is measurable and persists into adolescence and beyond. The most thoroughly explored area to date is respiratory morbidity. This article reviews the body of available evidence for effects of LP birth on pulmonary function and ongoing morbidity, and other areas where an increased risk of health problems has been identified in this population. Implications for delivery of health care are considered and areas for further research are highlighted.

Early Identification of Childhood Asthma: The Role of Informatics in an Era of Electronic Health Records

Emerging literature suggests that delayed identification of childhood asthma results in an increased risk of long-term and various morbidities compared to those with timely diagnosis and intervention, and yet this risk is still overlooked. Even when children and adolescents have a history of recurrent asthma-like symptoms and risk factors embedded in their medical records, this information is sometimes overlooked by clinicians at the point of care. Given the rapid adoption of electronic health record (EHR) systems, early identification of childhood asthma can be achieved utilizing (1) asthma ascertainment criteria leveraging relevant clinical information embedded in EHR and (2) innovative informatics approaches such as natural language processing (NLP) algorithms for asthma ascertainment criteria to enable such a strategy. In this review, we discuss literature relevant to this topic and introduce recently published informatics algorithms (criteria-based NLP) as a potential solution to address the current challenge of early identification of childhood asthma.

Usefulness of asthma predictive index in ascertaining asthma status of children using medical records: An explorative study

BACKGROUND

Frequent wheezing in original asthma predictive index (API) was defined by parental report of recurrent wheezing within 1 year during the first 3 years of life. The nature of frequent wheezing in children, particularly aged over 3 years, has not been studied. We aimed to assess the frequency and interval of wheezing to define frequent wheezing in ascertaining asthma for children using medical records.

METHODS

Among children who participated in a previous study (n = 427), all wheezing episodes documented in medical records were collected for children who had ≥2 wheezing episodes PLUS met one major criterion or two minor criteria of API. We compared the distribution of known risk factors for asthma between subjects having two consecutive wheezing episodes with shorter interval (≤1 year) compared to those with longer interval (1 to 3 years).

RESULTS

A total of 62 children met API at median age of 2.3 years. During follow-up period (median age: 11.3 years), a total of 198 wheezing episodes were observed. 81% of wheezing intervals were within 3 years from the earlier wheezing episode, including 60% within 1 year. Children who met API based on 1-year interval (n = 40) vs 1- to 3-year interval (n = 13) appeared to be similar in regard to the known risk factors for asthma.

CONCLUSIONS

Our exploratory study finding suggests that children who had frequent wheezing episodes with longer interval (<3 years) need to be considered to be determined as asthma cases when API is applied to retrospective medical records. Prospective studies with a larger sample size need to replicate this finding.

Examining Early Childhood Health Outcomes of Children Born Late Preterm in Urban Manitoba

Objective The late preterm population [34-36 weeks gestational age (GA)] is known to incur increased morbidity in the infancy stage compared to the population born at term (39-41 weeks GA). This study aimed to examine the health of these children during their early childhood years, with specific attention to the role of socioeconomic status. Methods A retrospective cohort study was conducted using data from the Manitoba Centre for Health Policy, including all live-born children born at 34-36 and 39-41 weeks GA in urban Manitoba between 2000 and 2005 (n = 28,100). Multivariable logistic regression was used to examine the association of GA with early childhood morbidity after controlling for maternal, child and family level variables. Results The late preterm population was found to have significantly greater adjusted odds of lower respiratory tract infections in the preschool years (aOR = 1.59 [1.24, 2.04]) and asthma at school age (aOR = 1.33 [1.18, 1.47]) compared to the population born at term. The groups also differed in health care utilization at ages 4 (aOR = 1.19 [1.06,1.34]) and 7 years (aOR = 1.24 [1.09, 1.42]). Additional variables associated with poor outcomes suggest that social deprivation and GA simultaneously have a negative impact on early childhood development. Conclusions for Practice Adjustment for predictors of poor early childhood development, including socioeconomic status, were found to attenuate but not eliminate health differences between children born late preterm and children born at term. Poorer health outcomes that extend into childhood have implications for practice at the population level and suggest a need for further follow-up post discharge.

What accounts for the association between late preterm births and risk of asthma?

BACKGROUND

Although results of many studies have indicated an increased risk of asthma in former late preterm (LPT) infants, most of these studies did not fully address covariate imbalance.

OBJECTIVE

To compare the cumulative frequency of asthma in a population-based cohort of former LPT infants to that of matched term infants in their early childhood, when accounting for covariate imbalance.

METHODS

From a population-based birth cohort of children born 2002-2006 in Olmsted County, Minnesota, we assessed a random sample of LPT (34 to 36 6/7 weeks) and frequency-matched term (37 to 40 6/7 weeks) infants. The subjects were followed-up through 2010 or censored based on the last date of contact, with the asthma status based on predetermined criteria. The Kaplan-Meier method was used to estimate the cumulative incidence of asthma during the study period. Cox models were used to estimate the hazard ratio and 95% confidence interval for the risk of asthma, when adjusting for potential confounders.

RESULTS

LPT infants (n = 282) had a higher cumulative frequency of asthma than did term infants (n = 297), 29.9 versus 19.5%, respectively; p = 0.01. After adjusting for covariates associated with the risk of asthma, an LPT birth was not associated with a risk of asthma, whereas maternal smoking during pregnancy was associated with a risk of asthma.

CONCLUSION

LPT birth was not independently associated with a risk of asthma and other atopic conditions. Clinicians should make an effort to reduce exposure to smoking during pregnancy as a modifiable risk factor for asthma.

Outcomes of infants born near term

Most research on outcomes of preterm birth has centred on babies born at <32 weeks gestation and at highest risk of mortality and serious morbidity. Recent years have seen a dramatic increase in studies focusing on late preterm infants (34-36 weeks gestation). Early epidemiological studies demonstrated increased risks of mortality and adverse neonatal outcomes in this group, prompting further investigations. These increased risks have been confirmed and more recent studies have also included babies born at 37-38 weeks, now defined as 'early-term' births. It now seems that it is inappropriate to consider term and preterm as a dichotomy; gestational age rather represents a continuum in which risk and severity of adverse outcomes increase with decreasing gestational age, but where measurable effects can be detected even very close to full term. In this review, we summarise current evidence for the outcomes of infants born at late preterm and early-term gestations.