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Hospital admissions for unintentional poisoning in preschool children in England; 2000–2011
  1. Cordelle N A Mbeledogu,
  2. Elizabeth V Cecil,
  3. Christopher Millett,
  4. Sonia Saxena
  1. Department of Primary Care and Public Health, School of Public Health, Imperial College London, London, UK
  1. Correspondence to Dr Cordelle N A Mbeledogu, Department of Primary Care and Public Health, School of Public Health, Imperial College London, 3rd Floor Reynolds Building, Charing Cross Campus, London W6 8RP, UK; doctorcordelle{at}gmail.com

Abstract

We conducted a population based time-trend analysis of all unplanned admissions to National Health Service hospitals for poisoning in preschool children (aged <5 years) in England, between 2000 and 2011. Hospital admission rates for poisoning (medicinal and non-medicinal) decreased overall from 179 per 100 000 in 2000 to 139 per 100 000 in 2011 (rate ratio 0.77, 95% CI 0.74 to 0.81). The relative risk of hospital admission from the most deprived quintile compared with the least deprived quintile reduced from 2.37 (95% CI 2.15 to 2.60) in 2001 to 1.54 (95% CI 1.40 to 1.70) in 2011. Poisoning admissions in preschool children have decreased by 23% over the past decade. Although social gradients have narrowed, those from the most deprived areas are at higher risk of poisoning, and may benefit from targeted schemes of home safety education in deprived areas.

  • Accident & Emergency
  • Injury Prevention
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What is already known on this topic

  • Children aged less than 5 years are especially vulnerable to unintentional poisoning in the home.

  • Childhood poisonings in the UK were on the decline in the 1990s, but remain a significant public health problem, particularly among children from deprived backgrounds.

What this study adds

  • Admission rates for all poisoning have decreased overall since 2000/2001, except for poisoning admissions due to soaps and detergents which have doubled.

  • The social gradient in admission rates has decreased over the past decade but children from the most deprived areas are still 50% more at risk.

Introduction

Unintended poisonings in children cause considerable morbidity and health resource use in the UK and worldwide.1 Preschool children are particularly vulnerable to unintentional poisoning, usually in their own homes. Children from the most deprived areas are at significantly greater risk than more affluent children.2

The success of public health interventions for childhood poisoning, such as the enforcement of child resistant closures (CRCs), led to low numbers of poisoning deaths, Emergency Department (ED) attendances and hospital admissions.1 However wider availability of over–the-counter medicines and chemical products may have influenced incidence of poisonings at home. For example, poison control centres in the UK and USA have recently raised concerns about toxic reactions from exposure to liquid detergent capsules (liquitabs) in young children.3

There are no recent studies examining overall trends in unintentional poisoning in the UK. We examined changes in the sociodemographic profile of children admitted to hospitals in England, for poisoning in children less than 5 years of age over the past decade.

Methods

Study design and data

We extracted data for all unplanned admissions for children less than 5 years of age between financial years 2000/2001 and 2011/2012, for National Health Service (NHS) hospitals in England from the Hospital Episodes Statistics database. Our main outcome measure was hospital admission rates for unintentional poisonings defined using the coded primary diagnosis for admission (International Classification of Diseases, 10th revision, codes T36 to T65), but excluded a few codes for unlikely causes of household toxicity (T61 to T64). Population data came from midyear population estimates based on the census, produced by the Office for National Statistics. We ascribed area based deprivation measures to each child using their postcode of residence and the Index of Multiple Deprivation.

Statistical analysis

We calculated annual hospital admission rates for each type of poisoning using national midyear population estimates for each year by age and sex. We computed rate ratios with 95% CIs to compare rates at the beginning and end of the study period and used the Mantel-Haenszel test for homogeneity to test for significance of any difference across the years. The relative risk of hospital admission from the most deprived quintile to the least deprived quintile was calculated for each year. We investigated trends in risk of admission by deprivation level using logistic regression. All analyses were conducted in STATA V.11.2.

Results

There were 54 757 admissions to English hospitals for poisoning in children aged less than 5 years, between 2000/2001 and 2011/2012. Of these, 77% of admissions were due to medicinal poisoning, of which 38% were non-opioid analgesics (30% paracetamol, 6% non-steroidal anti-inflammatory drugs, 1% aspirin). Soaps and detergents were implicated in 2% of poisoning admissions. Hospital admission rates decreased overall between 2000/2001 and 2011/2012 from 178.8 to 138.5/100 000 children (rate ratio (RR) 0.77, 95% CI 0.74 to 0.81), but increased between 2009 and 2011 (RR 1.12, 95% CI 1.07 to 1.17). The most common poisons leading to hospital admission are presented in table 1.

Table 1

Hospital admission numbers and rates for poisoning in children under 5 years of age from 2000/2001 to 2011/2012

Over the study period from 2000 to 2011, admission rates decreased for medicinal poisoning (RR 0.80, 95% CI 0.77 to 0.84), organic solvents (RR 0.51, 95% CI 0.44 to 0.59), gases (RR 0.60, 95% CI 0.47 to 0.77), pesticides (RR 0.71, 95% CI 0.52 to 0.97) and alcohol (RR 0.59, 95% CI 0.41 to 0.85). However, the admission rate for soaps and detergents doubled (RR 2.11, 95% CI 1.47 to 3.09).

Hospital admission rates for all poisoning among children in the most deprived quintile decreased from 253.6 per 100 000 in 2001 to 163.9 per 100 000 in 2011 (RR 0.65, 95% CI 0.60 to 0.69). In the least deprived quintile there was a non-significant decrease from 107.2 per 100 000 to 106.1 per 100 000 (RR 0.99, 95% CI 0.88 to 1.11). The relative risk of hospital admission from the most deprived quintile compared with the least deprived quintile reduced from 2.37 (95% CI 2.15 to 2.60) in 2001 to 1.54 (95% CI 1.40 to 1.70) in 2011. The variation in trends for risk of admission by level of deprivation (figure 1) was tested with an interaction term between deprivation and year. The interaction was significant for the most deprived and the fourth most deprived quintiles (p<0.001) suggesting that the relative risk of admission in these groups compared with the least deprived quintile reduced over time.

Figure 1

Trends in relative risk of hospital admission for poisoning in children less than 5 years of age by quintile of deprivation, 2001–2011.

Discussion

Hospital admission rates for poisoning in children aged less than 5 years in England decreased by 23% for all poisoning and 20% for medicinal poisoning between 2000 and 2011. However admissions due to poisoning by soaps and detergents doubled over this time frame. Although social gradients have narrowed, the relative risk of poisoning admissions for children in the most deprived areas compared with the least deprived areas is still 54% higher.

To our knowledge, this is the largest study of hospital admissions due to poisoning in preschool children in the UK. Other studies have looked at ED attendances or smaller populations. We are not aware of any national changes in coding practice that would influence the trends in recorded admissions seen in this study.

There are limitations inherent in the use of coding for classification. For example, some detergents may have been coded based on their chemical content such as ‘corrosive alkali’ rather than ‘soaps and detergents’. There is little granularity in the International Classification of Diseases (ICD) coding for non-medicinal poisoning, to allow detailed examination of poisonings due to these products. Our findings are consistent with similar declines in hospital admission rates for poisoning in children reported in other developed countries.4 These trends may not reflect all poisonings such as less toxic events resulting in ED attendances. In the USA there has been a rise in reports to call centres and ED attendances for medicinal poisoning, on the backdrop of an increase in sales and prescriptions,5 despite the comprehensive Poisons Prevention Act.

A higher rate of poisoning in children living in more deprived areas in the UK has been described,2 but ours is the first study to document a reduction in this disparity over time. Likely explanations for the observed falls in poisonings in young children in England include legislative change, public awareness and the impact of targeted public health education programmes. An interrupted time series study would be required to analyse the impact of specific interventions. Health service reorganisation is an unlikely explanation for this trend as hospital admissions in young children overall have increased over the past decade. The law regarding CRCs was extended to include non-reclosable containers such as blister packs between 2002 and 2003. However this still only applies to aspirin, paracetamol and iron. Furthermore blister packs that allow a child to access 8 or less units are considered ‘child-resistant’ by current standards. The wide availability of medicines that are not prescribed and issued in non-secure packaging may effectively be increasing exposure to potential poisons. The increase in hospital admission rates since 2009 revealed in our study, may be incidental but merits careful monitoring in view of the US trend. The UK National Poisons Information Service has reported a large number of enquiries about liquitabs since their introduction in 2001,3 and ED attendances for suspected poisoning involving laundry detergents doubled between 2000 and 2002 before the surveillance system was suspended. This could in part explain the observed increase in admissions for poisonings due to soaps and detergents.

In summary, poisoning admissions in preschool children have fallen and social gradients in England have narrowed. But increasing trends in medicinal poisoning and poisoning due to soaps and detergents are of concern and warrant close monitoring. The trends in the USA confirm that CRCs are not a substitute for safe storage and parental supervision.

References

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Footnotes

  • Contributors CNAM conceived and designed the study, analysed and interpreted data and wrote the manuscript. EVC collected data and contributed to data analysis. SS contributed to the study design and conception and edited the manuscript. CM contributed to the interpretation of the data and edited the manuscript. All authors contributed to and approved the final version of the manuscript. CNAM is the guarantor and is responsible for the overall content.

  • Funding SS and EC are funded by a National Institute for Health Research Career Development Fellowship (NIHR CDF-2011-04-048). CNAM is funded by the Higher Education Funding Council for England and the NIHR Collaborations for Leadership in Applied Health Research and Care (CLAHRC) programme. This article presents independent research commissioned by the National Institute for Health Research (NIHR) under the Collaborations for Leadership in Applied Health Research and Care (CLAHRC) programme for North West London. The views expressed in this publication are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health.

  • Competing interests None.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement This study uses routinely collected data from Hospital Episode Statistics available from the Health and Social Care Information Centre (http://www.hscic.gov.uk).

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