Article Text

Contribution of recurrent admissions in children and young people to emergency hospital admissions: retrospective cohort analysis of hospital episode statistics
1. Linda PMM Wijlaars1,
2. Pia Hardelid1,
3. Jenny Woodman1,
4. Janice Allister2,
5. Ronny Cheung3,
6. Ruth Gilbert1
1. 1Population, Policy and Practice Programme, UCL Institute of Child Health, London, UK
2. 2Clinical Innovation and Research, Royal College of General Practitioners, London, UK
3. 3Department of General Paediatrics, Evelina's Children Hospital, Guy's and St Thomas' NHS Trust, London, UK
1. Correspondence to Dr Linda Wijlaars, Population, Policy and Practice Programme, UCL Institute of Child Health, 30 Guildford Street, London WC1N 1EH, UK; linda.wijlaars{at}ucl.ac.uk

## Abstract

Objective To examine the contribution of recurrent admissions to the high rate of emergency admissions among children and young people (CYP) in England, and to what extent readmissions are accounted for by patients with chronic conditions.

Design All hospital admissions to the National Health Service (NHS) in England using hospital episode statistics (HES) from 2009 to 2011 for CYP aged 0–24 years. We followed CYP for 2 years from discharge of their first emergency admission in 2009. We determined the number of subsequent emergency admissions, time to next admission, length of stay and the proportion of injury and chronic condition admissions measured by diagnostic codes in all following admissions.

Conclusions Recurrent admissions contribute substantially to total emergency admissions. They often occur soon after discharge, and disproportionately affect CYP with chronic conditions. Policies aiming to discourage readmissions should consider whether they could undermine necessary inpatient care for children with chronic conditions.

• Epidemiology
• General Paediatrics
• Health services research

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### What is already known on this topic?

• Rates of emergency hospital admissions have been increasing year-on-year in children and young people (CYP).

• A substantial proportion (one in five) of emergency admissions is considered to be avoidable, especially those involving short-stay admissions.

• Of CYP requiring emergency admission to hospital, 32% had at least one recurrent emergency admission within 2 years. Recurrent emergency admissions accounted for 41% of all emergency admissions and 66% of emergency bed days.

• Emergency admissions recurred soon after discharge with one in four recurrent admissions occurring within 30 days.

• Recurrent emergency admissions occurred overwhelmingly in CYP affected by chronic conditions.

## Introduction

Interventions are needed to reduce the need for emergency admissions and ensure that patients are treated in the most appropriate setting.3–5 National policy initiatives include financial incentives, such as the 30-day emergency readmission rule, which partially redirects funds previously accrued by hospitals for emergency admissions to be reinvested by National Health Service (NHS) commissioners into specific joint activities that aim to reduce the demand on emergency services.6 However, there is a lack of evidence about the extent to which recurrent admissions account for the high and increasing rates of admission in children.

Recent research has focused on identifying which admissions are potentially avoidable.1 ,2 One study, focusing on ambulatory care sensitive conditions, has estimated that approximately 20% of emergency are preventable,7 but has not considered admission patterns of CYP over time. The contribution of underlying chronic conditions has also not been determined.1 ,8 As hospital care is expensive and strains resources, identifying characteristics of patients who are recurrently admitted could inform preventative and cost-reducing measures. We used national hospitalisation data from 2009 to 2012 to determine the proportion of emergency admissions in CYP that are recurrent, how soon after discharge admissions recurred, and what proportion of admissions were accounted for by CYP affected by chronic conditions.

## Methods

### Data source

We analysed hospital admissions to the NHS in England using hospital episode statistics (HES)9 from April 2009 to March 2012 for CYP aged 0–24 years. The HES database records all inpatient admissions, including day cases, to the NHS in England. We tracked patients longitudinally using a unique identifier (HES-ID), which is derived by the Health & Social Care Information Centre from the patient's NHS number, postcode, date of birth and sex.10

### Population

A detailed description of how we identified admissions is given in online supplementary appendix A. We identified admissions as continuous periods in hospital that could consist of several episodes (period of hospital stay under a single consultant). We considered admissions that occurred within a day of each other and admissions that included a transfer as a single admission.11

CYP were included if they had a valid recording of sex, and were aged up to 24 years. Analyses were stratified by age groups (<1 year, 1–4 years, 5–9 years, 10–14 years, 15–19 years and 20–24 years) that broadly reflect developmental or socialisation stages.

We categorised admissions as elective or emergency by assessing the admission method (see online supplementary appendix A). For infants, we considered only emergency admissions that occurred at least 7 days after the date of postnatal discharge.

We classified admissions using International Classification of Diseases V.10 (ICD-10) codes recorded in any of up to 20 diagnostic fields in discharge records in HES. We used ICD-10 code lists to identify admissions for injury or for pregnancy-related reasons. CYP with a chronic condition diagnosis code were identified by scanning diagnostic codes recorded in any emergency or elective admission during the 2 years.11

### Analyses

#### Cohort of CYP with first emergency admission in 2009

We defined a cohort of CYP (0–24 years) who had an emergency or elective admission in the 2009 financial year, and counted all subsequent emergency and elective admissions in the 2 years after discharge (see online supplementary eFigure 1). We calculated admission rates per 100 person-years using mid-year population estimates for 2009,12 and estimated yearly prevalence of recurrent admissions as the number of CYP with recurrent admissions as a proportion of the number of CYP with at least one emergency admission in 2009 as a denominator (n recurrent admissions/all admissions). Analyses were stratified by age group, based on the child or young person's age at index admission.

#### Sensitivity analysis

We conducted a sensitivity analysis to assess whether results differed in retrospect, looking back 2 years from an index admission. Taking the last emergency admission in 2011 for CYP aged 2–24 years, we determined the number of emergency admissions in the preceding 2 years.

All analyses were performed using Stata/SE V.12.1.

## Results

In 2009, 869 885 children had at least one emergency admission, resulting in a further 939 710 admissions (of which 600 322, or 64%, were emergency admissions) during the 2-year follow-up period (see online supplementary eTable 1). We excluded 0.5% of children with inconsistent records. Of the 869 885, 32% had at least one recurrent emergency admission, accounting for 41% of all emergency admissions, including the index admission.

Emergency index admissions were followed by a high burden of emergency admissions (rates ranged from 33 to 54 per 100 person-years between age groups) during the first year after admission. The frequency of elective admissions was particularly high for children with an elective index admission (rates ranged from 55 to 73 per 100 person-years, see online supplementary eTable 1). Rates for both emergency and elective admissions decreased during the second year.

Incidence rates for emergency admissions were highest for children <1 year old, lowest for children aged 5–14 years, thereafter increasing for young people aged 15–24 years (figure 1). Rates for emergency admissions were higher for boys up to age 14 years and for girls from age 15. In contrast, incidence rates for elective admissions were similar for all age groups (see figure 1 and online supplementary eTable 1).

Figure 1

Proportion of children and young people (CYP) who had at least one emergency or elective admission in 2009 by age and sex.

Figure 2

Number of recurrent emergency admissions over 2 years by age group and sex. Percentages on the right indicate the proportion of total admissions over a 2-year period (measured from index admission discharge) made up by recurrent admissions. ♂, males; ♀, females.

After index admission discharge, the next emergency admission (shown in red in figure 3 and online supplementary figure 2) occurred within 30 days in 26% of boys and girls across all six age groups (see figure 3 and online supplementary eTable 3). Second recurrent admissions occurred predominantly between 6 and 10 months after discharge from index admission.

Figure 3

Time to next admission from discharge date of index admission for first (red), second (yellow) and third (green) recurrent admission by sex and age group. A=<1 year; B=20–24 years. Percentages represent proportion of first recurrent admission that occurred in the first month after discharge from index admission. Left Y-axis (in red) applies to first recurrent admissions, right Y-axis (in blue) applies to second and third recurrent admissions.

Overall, recurrent admissions accounted for 66% of bed days (see online supplementary eTable 3). Despite making up only 4% of the total population, CYP with four or more recurrent emergency admissions (see online supplementary eTable 2) accounted for 25% of the total number of bed days in hospital.

A high proportion of CYP with multiple recurrent admissions had chronic conditions (figure 4). While 41% of CYP had a chronic condition recorded at their index emergency admission, as many as 96% of emergency admissions that were fourth or higher order admissions included a chronic condition code. Overall, CYP affected by chronic conditions accounted for 76% of recurrent admissions. While injuries were a common reason for emergency admissions at their index admission (22%), injuries were recorded for relatively few recurrent admissions (<12%, see online supplementary eTable 4)

Figure 4

Proportion of recurrent admissions over 2 years in children and young people (CYP) affected by a chronic condition by age group and sex.

Looking back from 2011, there were 689 112 CYP aged 2–24 years who had an emergency admission in 2011, 26% of whom had had previous emergency admissions between 2009 and 2011.

## Discussion

Recurrent admissions contribute substantially to total emergency admission rates, especially for CYP affected by chronic conditions who account for 76% of recurrent admissions. During the 2 years following their index admission, 32% of CYP had recurrent admissions, which accounted for 41% of total admissions during this period and 66% of bed days. We found similar numbers of recurrent admissions in our sensitivity analysis. Current health and social care policy, driving towards integrated care, needs to prioritise effective strategies to meet the needs of these CYP.

To our knowledge, this is the first report on the contribution of recurrent admissions in England. Other studies have found similar rates of emergency and elective admissions as we have demonstrated.1 ,13 ,14 Minor inconsistencies in rates are due to differences in methodologies used. Similar to our results, Berry et al's study of US paediatric hospitals found a small group of high-impact users. We found that 4% of patients had four or more admissions over a 2-year period, whereas they found that over a 1-year period, 3% of patients had four or more admissions.15 Moreover, we found that this group of high-impact patients accounts for a similar proportion of bed days (25% vs 19% for our vs Berry et al's results) and similar numbers had chronic conditions recorded (96% vs 89%), despite using slightly different code list to identify chronic conditions. At an average cost of £273 (€330, US$457) for an excess bed day,16 hospital stay alone (not accounting for procedures or treatments) for this group accounts for £322 million in England (€394 million,$545 million).

A strength of our study is that we did not make assumptions about the appropriateness of admissions as other papers have attempted.1 ,2 ,8 While primary diagnoses, as used in these studies, might represent the acute indication that required admission, chronic conditions could complicate cases that, at first sight, may appear to be manageable in primary care. Since potentially complex cases are reduced to a number of ICD diagnosis codes and other coded HES data in predefined fields, we aimed to use as much of the data available rather than focusing only on the first diagnosis code. Although inference about appropriateness goes beyond the available data, our finding that the large majority of children who were readmitted had a chronic condition suggested this group had complex needs.

A weakness is that we confined our analyses to hospital admissions, and did not include emergency department visits or community care. We captured just part of the healthcare use of high-impact users. However, as inpatient care represents the most expensive healthcare costs, our results are likely to be representative (though an underestimate) of total healthcare use. Moreover, the number of recurrent admissions included was dependent on the time window sampled: rates would likely be even higher if we were to include time beyond the 2-year window we used in this study. We did not present analyses by deprivation group.

### Implications

Recurrent admissions in CYP represent a significant proportion of hospital inpatient care with an overwhelming majority occurring in those affected by chronic conditions. From the data available, we are unable to judge whether this recurrence is avoidable, or whether CYP could be treated in more appropriate healthcare settings in the community.

Further research is also needed to determine whether the needs of CYP who are readmitted to hospital could be better met in the community without the need for a hospital stay. This involves understanding the characteristics of CYP with multiple recurrent admissions, for instance: what types of chronic conditions are most related with recurrent admissions and the reasons for readmission, but also the number and timings of contact with primary care that occur after hospital discharge. Research using national administrative healthcare data that links primary care with hospital services offers an efficient resource for identifying regional variation in rates of GP and hospital contact and for comparing models of integrated paediatric care that are emerging across the country.

Services also need to consider the impact across the transition to adult care has on the NHS. We found an increase in recurrent admissions with age in young people with chronic conditions, which may reflect a fall off of paediatric services as young people fail to appropriately transition to adult services. A recent report by the Care Quality Commission stressed the importance of transition planning and need for a ‘key accountable individual’ to take the lead on this.24 There are new incentives for GP practices demonstrating that they have nominated a particular GP for each known young or elderly person with chronic illness. Service planning and service evaluation for emergency healthcare need to go beyond the first point of healthcare access and address the trajectory of healthcare needs across the life course of CYP.

• ## Supplementary Data

This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.

## Footnotes

• Correction notice This paper has been amended since it was published Online First. In the abstract, line 5 of the results the number “600322” is a mistake. The sentence now reads: “After discharge from the index admission, 274,986 (32%) of children were readmitted within 2 years, 26% of these readmissions occurring within 30 days of discharge.”

• Contributors RG and LPMMW conceived the paper and the statistical analysis plan. LPMMW cleaned and analysed the data, and drafted and revised the paper. RG acquired the data and is the guarantor. PH contributed to the design of the study, interpretation of results and revised the paper. JW, JA and RC helped interpret the data and revised the paper. All authors commented on the analyses and report, and read and approved the final manuscript.

• Funding Department of Health.

• Competing interests All authors have completed the ICMJE uniform disclosure form at http://www.icmje.org/coi_disclosure.pdf and declare: LPMMW was supported by funding from the Department of Health Policy Research Programme through funding to the Policy Research Unit in the Health of Children, Young People and Families (grant reference number 109/0001). This is an independent report commissioned and funded by the Department of Health. The views expressed are not necessarily those of the Department. RG is supported by awards establishing the Farr Institute of Health Informatics Research at University College London Partners from the Medical Research Council and a consortium of funders (MR/K006584/1). No financial relationships with any organisations that might have an interest in the submitted work in the previous 3 years; no other relationships or activities that could appear to have influenced the submitted work.

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

• Data sharing statement Additional data can be accessed in the appendices. Source data can be accessed by researchers applying to the Health and Social Care Information Centre for England.

• Transparency declaration The lead author affirms that this manuscript is an honest, accurate and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.