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Abstract
Objective We aimed to compare adolescent mortality rates between different types of major trauma centre (MTC or level 1; adult, children’s and mixed).
Methods Data were obtained from TARN (Trauma Audit Research Network) from English sites over a 6-year period (2012–2018), with adolescence defined as 10–24.99 years. Results are presented using descriptive statistics. Patient characteristics were compared using the Kruskal-Wallis test with Dunn’s post-hoc analysis for pairwise comparison and χ2 test for categorical variables.
Results 21 033 cases met inclusion criteria. Trauma-related 30-day crude mortality rates by MTC type were 2.5% (children’s), 4.4% (mixed) and 4.9% (adult). Logistic regression accounting for injury severity, mechanism of injury, physiological parameters and ‘hospital ID’, resulted in adjusted odds of mortality of 2.41 (95% CI 1.31 to 4.43; p=0.005) and 1.85 (95% CI 1.03 to 3.35; p=0.041) in adult and mixed MTCs, respectively when compared with children’s MTCs. In three subgroup analyses the same trend was noted. In adolescents aged 14–17.99 years old, those managed in a children’s MTC had the lowest mortality rate at 2.5%, compared with 4.9% in adult MTCs and 4.4% in mixed MTCs (no statistical difference between children’s and mixed). In cases of major trauma (Injury Severity Score >15) the adjusted odds of mortality were also greater in the mixed and adult MTC groups when compared with the children’s MTC. Median length of stay (LoS) and intensive care unit LoS were comparable for all MTC types. Patients managed in children’s MTCs were less likely to have a CT scan (46.2% vs 62.8% mixed vs 64% adult).
Conclusions Children’s MTC have lower crude and adjusted 30-day mortality rates for adolescent trauma. Further research is required in this field to identify the factors that may have influenced these findings.
- paediatrics
- paediatric injury
- paediatric emergency medicine
- trauma
- majot trauma management
Data availability statement
Data are available upon reasonable request. Data are available upon reasonable request to the corresponding author.
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Key messages
What is already known on this subject
Trauma is a leading cause of mortality and morbidity in adolescence.
Adolescent trauma patients may be managed in either a children’s, mixed or adult trauma centre.
The current evidence base on outcomes by centre type is inconsistent. Some report a higher mortality in adolescent trauma patients managed in an adult and mixed major trauma centres (MTCs) when compared with children’s, while others have reported no difference.
What this study adds
Trauma Audit Research Network (TARN) data from English MTCs demonstrates lower crude and adjusted mortality rates for adolescent trauma patients attending a children’s MTC.
This association persists in cases of severe trauma (Injury Severity Score >15).
There was no difference in length of stay between MTC types (children’s, mixed or adult), although variation existed in CT rates and time from arrival to CT.
Introduction
In the UK, trauma accounts for 6 million ED attendances, 720 000 admissions and 17 000 deaths a year.1 Worldwide, approximately 5.8 million people die each year as a result of trauma, accounting for 10% of the world’s deaths.2 Trauma is the leading cause of death and acquired disability in adolescents, with road traffic collision (RTC) the most common mechanism.3 Regional major trauma networks, established in England in 2012 consist of major trauma centres (MTC; equivalent to level 1 trauma centres) and linked trauma units (TU; equivalent to level 2/3 trauma centres). In the current system configuration, the 27 MTCs, which receive the most seriously injured patients, are classified as adult (n=11; patients aged ≥16 years), children’s (n=5; patients <16 years) or mixed (n=11).
The WHO and UNICEF define adolescence as the age range 10–19 years, with ‘young people’ classified as those aged 10–24 years.4 5 Recent recommendations on the age range for adolescence state this should include those aged 10–24 years to better acknowledge ‘recognised shifts in events of biological growth and social role transitions’,6 a stance supported in the UK by the RCPCH.7 In the USA, youth violence prevention strategies are targeted to the 10–24 years age bracket.8
Adolescents are a unique cohort in that, dependent on age, they may be managed in either paediatric, adult or mixed trauma services. In England, ambulance services triage and convey patients under 16 years to a children’s MTC and those over 16 years to an adult MTC. A mixed MTC accepts patients of all ages. In rare circumstances, the age of an unconscious adolescent may be unclear and the patient may be conveyed to the incorrect trauma centre for their age by the ambulance service. While the principles of trauma management overlap between paediatric and adult guidelines, there exist subtle but important differences, including imaging strategies, the role of permissive hypotension and conservative management of abdominal organ injuries.9 10
It is not known whether these differing strategies impact outcomes in this cohort, or in what age groups differences may exist. There are no national published data comparing outcomes in this configuration for adolescent trauma between MTC types, and there are limited international studies. The majority come from the USA, a comparable trauma system to the UK, but findings are inconsistent. Some report higher mortality in adult and mixed MTCs compared with children’s MTCs, while others report no association.11–13
The primary aim of this study was to identify mortality rates for severely injured adolescents in England in different MTC types. The secondary aims were to describe length of stay (LoS), number of critical care days (intensive care unit (ICU) LoS), time to CT and the most senior clinician present at the initial resuscitation in MTC types.
Methods
Study design and setting
In this cross-sectional study we analysed data collected in the national Trauma Audit Research Network (TARN) database over a 6 years and 9 months period (1 April 2012 to 31 December 2018), with the commencement date selected to coincide with the implementation of trauma networks in England.14 The study was limited to English sites as there were no MTCs in Wales or Northern Ireland during the study period, and Scottish trauma data are captured elsewhere (Scottish Trauma Audit Group).
Study population
The TARN database includes patients of any age who sustain injury resulting in hospital admission for 3 days or greater, critical care admission, transfer to a tertiary/specialist centre or in-hospital death within 30 days. Injuries are assigned an Abbreviated Injury Scale (AIS) score, ranging from 1 (minor injury) to 6 (an injury that is thought to be ‘incompatible with life’).15 The Injury Severity Score (ISS), derived by adding the squares of the three highest scoring body regions, ranges from 1 to 75, with major trauma defined as ISS >15.14 Data are entered into the TARN database by local coordinators, using retrospective chart review methodology.
Datasets were included for all adolescent trauma episodes recorded in TARN with initial presentations to any MTC. Adolescence was defined as 10–24.99 years in line with international guidance.2 16 Prehospital deaths are not recorded by TARN. Cases that initially presented to TUs were excluded to reduce confounding from wider heterogeneity in initial management.
Outcomes
The primary outcome measure was mortality within 30 days of traumatic event, with comparison between children’s, adult and mixed MTCs. Secondary outcomes selected as measures of morbidity included length of stay and number of intensive care bed days. Intercentre comparison was undertaken for seniority of clinician managing initial management, and time taken for CT scanning where relevant.
Statistical analysis
In this analysis, the null hypothesis was that there was no difference in mortality rates between MTC types. Patient characteristics, when continuous, were compared using the Kruskal-Wallis test with Dunn’s post-hoc analysis for pairwise comparison and χ2 test for categorical variables. To allow for variation between sites, a logistic mixed effect (random intercept) regression was used. The logistic regression adjusted for mechanism of injury, GCS, ISS, systolic blood pressure (SBP), pulse rate, comorbidities and site institution with the inclusion of ‘hospital ID’. This is necessary to take into account the clustering of patients within each hospital to enable analysis of not only unexplained variance between patients but also between hospitals. Hosmer and Lemeshow (H-L) was used to test for goodness-of-fit and the C statistic by means of the area under the receiver operating curve (AROC) to assess the discriminating power of the statistical model. As TARN data are inputted retrospectively, required fields may not be recorded in the clinical notes. Missing data from the covariates were imputed using multiple imputation under the assumption of missingness at random mechanism and applying Rubin’s rule on the 10 imputed sets. The same statistical analysis was undertaken for all subanalyses. All the analyses were performed using Stata V.14 software (StataCorp).
We subcategorised the study cohort for three planned subanalyses for which we assessed crude and adjusted mortality comparing outcomes based on MTC type (children’s, mixed and adult). In the first subgroup analysis, the cohort was split into two age ranges, 10–15.99 years and 16–24.99 years. In assessing trauma outcomes for the breadth of adolescences, from 10 to 24 years, concerns may be expressed about the validity of comparing trauma in a 10-year-old to a 24-year-old due to potential differences in physiology and mechanism of injury. In restricting the age range, a more homogenous population may be assessed. These age boundaries were selected to account for the cut-off age of 16 years for children’s versus adult MTCs. The second subanalysis focused on all adolescent trauma patients within the age group 14–17.99 years. This age range was selected pragmatically by consensus of the study team, to represent upper and lower boundaries that paediatric and adult services, respectively may feel comfortable accepting, and reflect reasonable presumed age deviations for those making decisions prehospital. A further planned subanalysis assessed patients specifically with major trauma (ISS >15) for the full cohort (age 10 years–24 years) and those aged 14–17.99 years. The same statistical analyses were performed on these subgroups to adjust for potential confounders.
Patient and public involvement
Patients or the public were not involved in the design, conduct, reporting or dissemination plans of this study.
Results
Demographic and injury pattern data
A total of 30 321 adolescent trauma cases were identified of which 21 033 fulfilled eligibility criteria for this analysis. Of these, 11 319 (54%) presented to a mixed MTC, 7937 (38%) to an adult MTC and 1777 (8%) to a children’s MTC (figure 1). 2569 (12.2 %) were aged 10–13.99 years, 4471 (21.3%) aged 14–17.99 years and 13 993 (66.5%) aged 18–24.99 years. Patients were predominantly male (77.9%) (table 1).
Total number of adolescent trauma cases coded by Trauma Audit Research Network (TARN) between 1 April 2012 to 31 December 2018. Subcategorised by type of major trauma centre (MTC) (children’s, mixed, adult).
Demographic and outcome data for adolescent trauma cases coded by Trauma Audit Research Network
The initial physiological parameters were similar between groups but did demonstrate statistically significant differences between MTC cohorts. These differences were unlikely to be clinically significant (table 1). Overall, across all three types of MTC, the most common comorbidities were asthma, mental health conditions, alcohol/drug abuse and epilepsy. In 80% (16 883) of the total cohort, the patient had no comorbidities. Patients presenting to children’s MTCs had fewer comorbidities.
The most common mechanism of injury was RTC (52.6%, n=11 058), with falls of any height accounting for 22.2% (4657). Falls <2 m height accounted for a larger proportion of children’s MTC cases (20.5%) compared with mixed (10%) and adult (9.5%) MTCs. Stabbings and shootings were less common in children’s MTCs (2.8%) and highest in mixed MTCs (14.5%) (table 2). Patients managed in children’s MTCs had a median ISS of 10, whereas those managed in mixed or adult MTCs had a median ISS of 14 and 16, respectively (p<0.001) (table 1). Anatomical regions with significant differences in median highest AIS between MTC types were the face, abdomen, pelvis and limbs (table 2).
Mechanism of injury, ISS and AIS for adolescent patients coded by Trauma Audit Research Network subcategorised by MTC type
Seniority leading resuscitation, LoS and time to CT
In most cases a consultant was present as the most senior clinician (table 1). Physicians in their first 4 years of training were the most senior clinician present in only a small proportion (<5%) of cases, but this was most common in adult MTCs. Median LoS and ICU LoS were comparable for all MTC types although differences met statistical significance (table 1).
Patients managed in children’s MTCs were less likely to have a CT scan, though the time taken to perform a CT was significantly longer in children’s MTCs than other MTC types (table 1).
Mortality
Overall trauma-related crude 30-day mortality was 4.4%, with significant differences in mortality rates between MTC types (children’s 2.5%; mixed 4.4%; adult 4.9%; p<0.0001; table 1). When adjustments were made using logistic regression accounting for ISS, MOI, GCS, SBP, pulse rate, comorbidity, pupil reactivity and the random effect ‘hospital ID’, odds of mortality compared with children’s MTCs were 2.41 (95% CI 1.31 to 4.43; p=0.005) and 1.85 (95% CI 1.03 to 3.35; p=0.041) in adult and mixed MTCs, respectively (table 3). The model showed a good C statistic (AROC) of 0.980 (95% CI 0.977 to 0.984) and the goodness of fit showed a non-significant H-L test (p=0.55), demonstrating that the model fits the data well.
Odds of mortality by MTC centre type for adolescent trauma patients (aged 10–24.99 years)
Subgroup analysis: 10–15.99 years
In the subgroup analysis of the 10–15.99 years old, those managed in a children’s MTC had the lowest mortality rate at 2.3%, compared with 3.5% in adult MTCs and 3.8% in mixed MTCs. In the adjusted analysis, the OR for mortality was higher in the mixed and adult MTCs in comparison to children’s MTCs (statistically significant for mixed only) (table 3).
Subgroup analysis: 16–24.99 years
In the subgroup analysis of the 16–24.99 years old cohort, there was significant variation in participants number between MTC’s (children’s MTC n=17, mixed MTC n=9153 and adult MTC n=7507; table 4). Those managed in a children’s MTC had the highest mortality rate at 17.7%, compared with 5% in adult MTCs and 4.6% in mixed MTCs. In the adjusted analysis, the OR for mortality was higher in adult and mixed MTC’s compared with children’s MTCs, but this did not meet statistical significance (table 3).
Number of patients attending each MTC type for age ranges 10–15.99 and 16–24.99, n (%)
Subgroup analysis: 14–17.99 years
In the subgroup analysis of the 14–17.99 years old, those managed in a children’s MTC had the lowest mortality rate at 2.5%, compared with 4.9% in adult MTCs and 4.4% in mixed MTCs. In the adjusted analysis, the OR for mortality was significantly higher in adult MTCs in comparison to children’s MTCs. There was no statistically significant difference between mixed MTCs in comparison to children’s MTCs (table 3).
Subgroup analysis: ISS >15 (major trauma) in adolescents (10–24.99 years)
Table 5 displays the 30-day crude and adjusted odds of mortality for major trauma (ISS >15). The adjusted odds of mortality are greater in the mixed and adult MTC groups when compared with the children’s MTC. This association is replicated in the 14–17.99 years subgroup for major trauma (table 5).
Odds of mortality for adolescent trauma patients (aged 10–24.99 years) with an ISS >15
Discussion
Using English trauma registry data, we have demonstrated lower 30-day crude mortality rates for adolescent trauma patients (10–24.99 years) attending children’s MTCs in comparison to adult or mixed MTCs. This association persisted after adjustment for potential confounding factors, and in subgroup analyses comparing outcomes for those with major trauma (ISS >15) and those aged 14–17.99 years (with or without major trauma).
When the cohort was divided into young (10–15.99 years) and older adolescence (16–24.99 years), the trend for an adjusted improved mortality rate in those attending children’s MTCs remained. In the young adolescent group (10–15.99 years), the adjusted odds of mortality were 2.2 times higher for those who attended a mixed MTC compared with a children’s MTC, which was statically significant. In the comparison of adult MTCs to children’s MTCs for the 10–15.99 years age group, the adjusted odds of mortality was 2.9, although this was not statically significant.
For the older adolescent cohort (16–24.99 years) those managed in a children’s MTC had the highest mortality rate at 17.7%, compared with 5% in adult MTCs and 4.6% in mixed MTCs. The adjusted odds of mortality however continue to favour children’s MTCs although this did not meet statistical significance. These data should be interpreted with caution due the variation in case numbers attending each MTC types (children’s MTC n=17, mixed MTC n=9153 and adult MTC n=7507).
Some young adolescents (10–15.99 years) and some old adolescents (16–24.99 years) presented to non-designated centres (in accordance to English hospital set up of adult and children’s MTCs), with 430 patients under 16 years of age treated in adult MTCs (9.9% of all aged <16 years) and 17 patients over 16 years attending a children’s MTC (0.1% of all aged 16–24.99 years). We hypothesis that this variation in protocol is multi-factorial, including errors in estimating the age in the prehospital setting. In some instances, including in cases of extremis, prehospital teams may divert from protocol to the nearest unit for life saving interventions. In those under 16 years deemed too unstable for safe transfer the prehospital team may attend the nearest children’s TU (which may also be an adult MTC).
Existing literature describing adolescent mortality secondary to trauma is predominantly from the USA, and outcomes appear contradictory across studies. A 2016 study which accessed the US National Trauma Data Bank described higher adjusted odds of mortality in adult MTCs (OR, 4.19; 95% CI 1.30 to 13.51) and mixed MTCs (OR, 6.68; 95% CI 2.03 to 21.99) compared with children’s MTCs.4 Other studies have reported no difference in mortality between centres for either penetrating or blunt trauma,13 lower crude mortality (but not adjusted mortality) in a children’s trauma centre compared with an adult trauma centre,17 and no difference in mortality by centre but a reduction in imaging, invasive procedures, and ICU LoS, and improved discharge to home in children’s trauma centres.18 One further study of patients with penetrating injuries (predominantly stabbing and gunshot wounds) performed a subgroup analysis on adolescents (defined as >12 years), finding no difference in mortality. This same study reported those <5 years old may have superior functional outcomes when treated at a paediatric trauma centre.12
Adolescents (10–24.99 years) who presented to a children’s MTC had a lower ISS compared with adult and mixed MTCs. Previous trauma studies report a correlation between an increasing ISS and higher mortality.19 In acknowledgement of this, we undertook statistical adjustments to account for the variation in ISS and also performed a subgroup analysis for those with major trauma (ISS >15). In both, the trend for a lower mortality rate in the children’s MTC remained, supporting the view that children’s MTCs manage adolescent trauma with good outcomes despite seeing a lower volume of cases. This is in contrast to evidence suggesting improved trauma outcomes in institutions with higher case volumes.20 21
Between groups, there were statistically significant differences in baseline physiological observations. However, there was no clinical significance to these differences, and this finding likely represents the slight variations in normal values that one would expect over the age range of this cohort.
There was some variation in practice between trauma centres. Those that attended a children’s MTC were less likely to have a consultant present. We hypothesise that this variation may be a consequence of differing patterns of conveyance to children’s MTCs rather than system configuration. Up to a third of major paediatric trauma cases are more likely to ‘self-present’ via parental transport rather than via ambulance, removing the prealert trauma call.22 Regarding imaging, trauma cases were less likely to have a CT if they presented to a children’s MTC, and if they had a CT, it took longer to perform when compared with other MTC types. This reduction in imaging is in keeping with other studies, with an assumption that the difference is a result of adherence to adult imaging principles.8 11 Studies have noted no difference in mortality when targeted imaging is undertaken when compared with whole body CT.23 One would assume that these secondary outcomes would potentially increase mortality in children’s MTCs and are unlikely to explain the variation in mortality outcomes that we noted.
There were some limitations to this study. TARN is the national trauma registry for the UK, with any analysis limited to prespecified fields. Adolescent trauma cases that do not meet TARN inclusion criteria but may have significant injuries were not captured for this analysis, potentially creating a skewed data set. The decision to exclude TUs and transfers from a TU to an MTC was taken pragmatically as the authors felt this question would be more appropriately explored separately, and because the accuracy and completeness of data may be lower than that submitted from MTCs. Thus a considerable proportion of trauma cases were not included, and although it is assumed that MTCs would have better outcomes, it is not inconceivable that TUs may have the lowest mortality. There was considerable variation in the number of cases that attended each centre type, with the lowest volume in the children’s MTCs. Although this variation was accounted for in the analysis it may have impacted on the results. The chosen age range of 10–24 years is consistent with the current adolescent literature, though comparisons of trauma between a 10-year-old and a 24-year-old may be challenging given variations in mechanism of injury and physiology. To address this, we undertook adjusted and subgroup analysis with a smaller age range (14–17.99 years) but there is the potential that other variables have not been considered that may have impacted our findings.
Further research is required in this field to identify the factors that may have influenced these results. These should be explored qualitatively through engagement with clinicians and adolescent representatives, and quantitatively with richer interrogation of existing data on the contribution of factors such as type of injury and resulting interventions. There may also be benefit in a larger prospective study, in which all adolescent trauma cases attending EDs (not just MTCs) are collated to facilitate more comprehensive analysis.
In summary we have demonstrated that in England, children’s MTCs have lower 30-day mortality rates for adolescent trauma than adult or mixed MTCs, and that this association remains following adjustment for potential confounding variables including severity of injury. Further research is required to understand factors influencing disparities in trauma-related mortality among adolescents who are cared for in non-children’s MTCs. We hope that the results of this study will play a part to highlight where adolescent trauma patients are best managed, inspire further work in this field and therefore impact on future health policy for this frequently overlooked demographic group.
Data availability statement
Data are available upon reasonable request. Data are available upon reasonable request to the corresponding author.
Ethics statements
Ethics approval
TARN has ethical approval (PIAG section 60) for research on the anonymised data that are stored securely on the University of Manchester server.
References
Footnotes
Handling editor Caroline Leech
Twitter @damian_roland, @mdlyttle
Contributors SM conceived the study. SM and OB undertook the data collection. OB performed the statistical analysis of the data. JE, HM, RB and SM interpreted the data and drafted the manuscript. All authors contributed substantially the study design and revision of the manuscript with supervision from DR, MDL and SM. All authors have approved the manuscript and agree to be accountable for the work.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests DR is a member of TARNLet (the Paediatric Working Group on behalf of TARN). OB is employed as a Medical Statistician for TARN.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Provenance and peer review Not commissioned; externally peer reviewed.