Temporal trends and socioeconomic differences in acute respiratory infection hospitalisations in children: an intercountry comparison of birth cohort studies in Western Australia, England and Scotland

Health service utilisation for acute respiratory infections in infants graduating from the neonatal intensive care unit: a population-based cohort study

BACKGROUND

Despite advances in neonatal intensive care, babies admitted to Neonatal Intensive Care Units (NICU) suffer from adverse outcomes. We aim to describe the longer-term respiratory infectious morbidity of infants discharged from NICU using state-wide population-based linked data in Western Australia.

STUDY DESIGN

We used probabilistically linked population-based administrative data to analyse respiratory infection morbidity in a cohort of 23,784 infants admitted to the sole tertiary NICU, born 2002-2013 with follow up to 2015. We analysed incidence rates of secondary care episodes (emergency department presentations and hospitalisations) by acute respiratory infection (ARI) diagnosis, age, gestational age and presence of chronic lung disease (CLD). Poisson regression was used to investigate the differences in rates of ARI hospital admission between gestational age groups and those with CLD, after adjusting for age at hospital admission.

RESULTS

From 177,367 child-years at risk (i.e., time that a child could experience an ARI outcome), the overall ARI hospitalisation rate for infants and children aged 0-8 years was 71.4/1000 (95% confidence interval, CI: 70.1, 72.6), with the highest rates in infants aged 0-5 months (242.9/1000). For ARI presentations to emergency departments, equivalent rates were 114/1000 (95% CI: 112.4, 115.5) and 337.6/1000, respectively. Bronchiolitis was the most common diagnosis among both types of secondary care, followed by upper respiratory tract infections. Extremely preterm infants (< 28 weeks gestation at birth) were 6.5 (95% CI: 6.0, 7.0) times more likely and those with CLD were 5.0 (95% CI: 4.7, 5.4) times more likely to be subsequently admitted for ARI than those in NICU who were not preterm or had CLD after adjusting for age at hospital admission.

CONCLUSIONS

There is an ongoing burden of ARI in children who graduate from the NICU, especially those born extremely preterm, that persists into early childhood. Early life interventions to prevent respiratory infections in these children and understanding the lifelong impact of early ARI on later lung health are urgent priorities.

Parents' awareness of antimicrobial resistance: a qualitative study utilising the Health Belief Model in Perth, Western Australia

OBJECTIVE

This study aimed to determine local factors that promote or prevent parents' responsible use of antibiotics for their children in Perth, Western Australia.

METHODS

The Health Belief Model was used to guide this study. Four focus group discussions were conducted, with 26 participants. Participants were recruited purposively through a parent group organisation. The Framework Method was utilised to analyse the data.

RESULTS

Participants agreed that antimicrobial resistance (AMR) is a serious health problem. However, participants admitted that they lacked awareness of AMR, inhibiting their ability to assess the risks of developing AMR infections among their children. Participants knew the indications and risks of antibiotic use but still viewed antibiotics as a time-saving solution that minimised disruption to their routine. Participants' previous experiences in managing their children's illness increased their confidence and linked their positive and negative experiences with their general practitioners in their judicious use of antibiotics.

CONCLUSIONS

While parents demonstrated awareness of the indications of antibiotics, they continue to lack AMR awareness and overvalue antibiotics.

IMPLICATIONS FOR PUBLIC HEALTH

The findings highlight that incorporating parent empowerment and participation in decision-making regarding antibiotics use, and maintaining a positive relationship with healthcare providers, were important strategies to encourage the appropriate use of antibiotics.

Environmental risk factors associated with respiratory diseases in children with socioeconomic disadvantage

Children are more vulnerable to environmental exposures determinant of respiratory diseases due to their dynamic developmental physiology. Whereas social determinants of health are also associated with a higher risk of these diseases in children exposed to environmental risk factors, most studies incorporate them as covariates in the statistical analysis rather than focusing on specific vulnerable populations. In this study a systematic review searched and selected studies of respiratory diseases in children with socioeconomic disadvantage to identify the environmental risk factors associated with these diseases. The review followed the PRISMA protocol to identify eleven eligible studies of children with socioeconomic conditions that included low income and low socioeconomic status, overcrowding, adults with low education level and Indigenous status. Infectious respiratory diseases, asthma, rhinitis and mortality due to respiratory diseases were associated with risk factors such as biomass fuel use, tobacco smoking, particulate matter, coal dust and other pollutants including ozone, nitrogen dioxide and sulphur dioxide. The most common associations were between respiratory infections and household air pollution and asthma with indoor and outdoor air pollution. The findings support previous reports on these associations and suggest that specific vulnerabilities such as indigenous children and living with adults with low socioeconomic status and education level increase the risk of respiratory diseases. These populations can be given special attention to prioritize public health interventions to lower the burden of disease of respiratory diseases in children.

Maternal prenatal stress exposure and sex-specific risk of severe infection in offspring

Background

Maternal stressful life events during pregnancy have been associated with immune dysregulation and increased risk for asthma and atopy in offspring. Few studies have investigated whether prenatal stress is associated with increased overall or specific infectious diseases in childhood, nor explored sex differences. We sought to examine the relationship between the nature and timing of maternal stress in pregnancy and hospitalisation with infection in offspring.

Methods

Between 1989 and 1992, exposure data on stressful life events were collected from pregnant women (Gen1) in the Raine Study at 18 and 34 weeks’ gestation and linked to statutory state-wide hospital morbidity data. We examined associations between the number, category and timing of maternal prenatal stress events and overall and clinical groups of offspring (Gen2) infection-related hospitalisation until age 16 years, adjusting for maternal age, education, and smoking in pregnancy in addition to the presence of siblings at birth.

Results

Of 2,141 offspring with complete stress in pregnancy data available, 1,089 had at least one infection-related hospitalisation, with upper respiratory tract infections the most common (n = 556). Each additional stressful life event during pregnancy was associated with increased risk in male offspring for hospitalisation with all infection types. There was little evidence of these associations in girls.

Conclusions

Increased exposure to stressful life events in utero is associated with sex-specific infection-related hospitalisations in childhood. Prenatal stress may adversely affect early immune development for boys and increase the risk of more severe infections. Mechanistic understanding would inform preventative interventions.

Developing a national birth cohort for child health research using a hospital admissions database in England: The impact of changes to data collection practices

BACKGROUND

National birth cohorts derived from administrative health databases constitute unique resources for child health research due to whole country coverage, ongoing follow-up and linkage to other data sources. In England, a national birth cohort can be developed using Hospital Episode Statistics (HES), an administrative database covering details of all publicly funded hospital activity, including 97% of births, with longitudinal follow-up via linkage to hospital and mortality records. We present methods for developing a national birth cohort using HES and assess the impact of changes to data collection over time on coverage and completeness of linked follow-up records for children.

METHODS

We developed a national cohort of singleton live births in 1998-2015, with information on key risk factors at birth (birth weight, gestational age, maternal age, ethnicity, area-level deprivation). We identified three changes to data collection, which could affect linkage of births to follow-up records: (1) the introduction of the "NHS Numbers for Babies (NN4B)", an on-line system which enabled maternity staff to request a unique healthcare patient identifier (NHS number) immediately at birth rather than at civil registration, in Q4 2002; (2) the introduction of additional data quality checks at civil registration in Q3 2009; and (3) correcting a postcode extraction error for births by the data provider in Q2 2013. We evaluated the impact of these changes on trends in two outcomes in infancy: hospital readmissions after birth (using interrupted time series analyses) and mortality rates (compared to published national statistics).

RESULTS

The cohort covered 10,653,998 babies, accounting for 96% of singleton live births in England in 1998-2015. Overall, 2,077,929 infants (19.5%) had at least one hospital readmission after birth. Readmission rates declined by 0.2% percentage points per annual quarter in Q1 1998 to Q3 2002, shifted up by 6.1% percentage points (compared to the expected value based on the trend before Q4 2002) to 17.7% in Q4 2002 when NN4B was introduced, and increased by 0.1% percentage points per annual quarter thereafter. Infant mortality rates were under-reported by 16% for births in 1998-2002 and similar to published national mortality statistics for births in 2003-2015. The trends in infant readmission were not affected by changes to data collection practices in Q3 2009 and Q2 2013, but the proportion of unlinked mortality records in HES and in ONS further declined after 2009.

DISCUSSION

HES can be used to develop a national birth cohort for child health research with follow-up via linkage to hospital and mortality records for children born from 2003 onwards. Re-linking births before 2003 to their follow-up records would maximise potential benefits of this rich resource, enabling studies of outcomes in adolescents with over 20 years of follow-up.

Hospital Admission Trends for Bronchiolitis in Scotland, 2001-2016: A National Retrospective Observational Study

BACKGROUND

Bronchiolitis is the commonest cause of respiratory related hospital admissions in young children. This study aimed to describe temporal trends in bronchiolitis admissions for children under 2 years of age in Scotland by patient characteristics, socioeconomic deprivation, and duration of admission.

METHODS

The national hospital admissions database for Scotland was used to extract data on all bronchiolitis admissions (International Classification of Disease, Tenth Revision, code J21) in children <2 years of age from 2001 to 2016. Deprivation quintiles were classified using the 2011 Scottish Index of Multiple Deprivation.

RESULTS

Over the 15-year study period, admission rates for children under 2 years old increased 2.20-fold (95% confidence interval [CI], 1.4-3.6-fold) from 17.2 (15.9-18.5) to 37.7 (37.4-38.1) admissions per 1000 children per year. Admissions peaked in infants aged 1 month, and in those born in the 3 months preceding the peak bronchiolitis month-September, October, and November. Admissions from the most-deprived quintile had the highest overall rate of admission, at 40.5 per 1000 children per year (95% CI, 39.5-41.5) compared with the least-deprived quintile, at 23.0 admissions per 1000 children per year (22.1-23.9). The most-deprived quintile had the greatest increase in admissions over time, whereas the least-deprived quintile had the lowest increase. Zero-day admissions, defined as admission and discharge within the same calendar date, increased 5.3-fold (5.1-5.5) over the study period, with the highest increase in patients in the most-deprived quintile.

CONCLUSIONS

This study provides baseline epidemiological data to aid policy makers in the strategic planning of preventative interventions. With the majority of bronchiolitis caused by respiratory syncytial virus (RSV), and several RSV vaccines and monoclonal antibodies currently in clinical trials, understanding national trends in bronchiolitis admissions is an important proxy for determining potential RSV vaccination strategies.