Quantifying the hospitalised morbidity and mortality attributable to traumatic injury using a population-based matched cohort in Australia

Disadvantaged by More Than Distance: A Systematic Literature Review of Injury in Rural Australia

Rural populations experience injury-related mortality and morbidity rates 1.5 times greater than metropolitan residents. Motivated by a call for stronger epidemiological evidence around rural injuries to inform prevention, a systematic review of peer-reviewed literature published between January 2010 and March 2021 was undertaken to explore the epidemiology of rural injury and associated risk factors in Australia. A subsequent aim was to explore definitions of rurality used in injury prevention studies. There were 151 papers included in the review, utilizing 23 unique definitions to describe rurality. People living in rural areas were more likely to be injured, for injuries to be more severe, and for injuries to have greater resulting morbidity than people in metropolitan areas. The increase in severity reflects the mechanism of rural injury, with rural injury events more likely to involve a higher energy exchange. Risk-taking behavior and alcohol consumption were significant risk factors for rural injury, along with rural cluster demographics such as age, sex, high socio-economic disadvantage, and health-related comorbidities. As injury in rural populations is multifactorial and nonhomogeneous, a wide variety of evidence-based strategies are needed. This requires funding, political leadership for policy formation and development, and implementation of evidence-based prevention interventions.

Hospital service use following an injury hospitalisation for young males and females in a population-level matched retrospective cohort study

BACKGROUND

Children and young people who sustain injuries resulting in a hospital admission may experience adverse effects for months or years following the event. Understanding the attributable burden and health service needs is vital for public health planning as well as individual care provision. This study aims to identify the hospitalised morbidity associated with injury among young people by sex using a population-level matched cohort.

METHOD

A population-level matched case-comparison retrospective cohort study of young people aged ≤18 years hospitalised for an injury during 2005-2018 in New South Wales, Australia using linked birth, health, and mortality records. The comparison cohort was matched on age, gender and residential postcode. Adjusted rate ratios (ARR) were calculated for age group, injury severity and nature of injury by sex.

RESULTS

There were 122,660 (60.9%) males and 78,712 (39.1%) females aged ≤18 years hospitalised after sustaining an injury. Males (ARR 2.89; 95%CI 2.81-2.97) and females (ARR 2.79; 95%CI 2.68-2.90) who were hospitalised after an injury had a higher risk of subsequent hospital admission than their matched peers. Males (ARR 3.38; 95%CI 2.81-4.05) and females (ARR 3.41; 95%CI 2.72-4.26) with serious injuries had a higher risk of admission compared to peers. Males with dislocations, sprains and strains (ARR 3.40; 95%CI 3.03-3.82), burns (ARR 3.37; 95%CI 2.99-3.80), and fractures (ARR 3.20; 95%CI 3.07-3.33), and females with burns (ARR 3.84; 95%CI 3.40-4.33), dislocations, sprains and strains (ARR 3.54; 95%CI 2.96-4.23), and traumatic brain injury (ARR 3.39; 95%CI 3.01-3.82) had the highest risk of subsequent hospitalisation compared to peers.

CONCLUSION

Patient management and care extends beyond the injury admission as many young people face high levels of contact with health services in the months and years following injury. These findings will inform health service planning and trauma care management for young people and families affected by injury.

Chronic physical health conditions up to five years after serious orthopaedic injury

BACKGROUND

Information about the prevalence of chronic physical health conditions following serious orthopaedic injury is currently lacking in the general population and is essential for quantifying the burden of injury and improving outcomes.

OBJECTIVES

To determine the prevalence of chronic physical health conditions recorded within hospitalisations and emergency department presentations and associated factors five years following serious orthopaedic injury.

METHODS

We conducted a registry-based cohort study using data from the Victorian State Trauma Registry (2007-2016) linked with hospital admissions and ED presentations for 16,249 adults with serious orthopaedic injuries. We considered that people who were admitted to hospital or presented to an emergency department with a chronic physical health condition one to five years post-injury had "new-onset" conditions. We applied Kaplan-Meier failure curves and Cox proportional hazard regression models to determine factors associated with new-onset conditions.

RESULTS

There were 1420 people (11.0%) with at least one new-onset condition. Cancer (6.1%), cardiovascular disease (5.1%) and hypertension (6.2%) were the three most common "new-onset" chronic physical health conditions. Older adults, women, smokers, and people with mental health and alcohol and drug-related conditions had a higher risk of hospitalisation or emergency department presentation with new-onset conditions post-injury.

CONCLUSION

People with serious orthopaedic injuries experienced a significant additional burden of chronic physical health conditions up to five years after serious orthopaedic injury, posing a new challenge to post-trauma care. Early preventive interventions may be required in people with serious orthopaedic injuries to minimise modifiable risk factors such as smoking, excessive consumption of alcohol or drug use.

Community Opioid Dispensing after Injury (CODI): Protocol for a retrospective population-based cohort study (Preprint)

Background

There is an urgent need to reduce preventable deaths and hospitalizations from prescription opioid harms and minimize the negative effect opioid misuse can have on injured individuals, families, and the wider community. Data linkage between administrative hospitalization records for injured patients and community opioid dispensing can improve our understanding of the health and surgical trajectories of injured persons and generate insights into corresponding opioid dispensing patterns.

Objective

The Community Opioid Dispensing after Injury (CODI) study aims to link inpatient hospitalization data with opioid dispensing data to examine the distribution and predictive factors associated with high or prolonged community opioid dispensing among adults, for 2 years following an injury-related hospital admission.

Methods

This is a retrospective population-based cohort study of adults aged 18 years or older hospitalized with an injury in Queensland, Australia. The study involves the linkage of statewide hospital admissions, opioid prescription dispensing, and mortality data collections. All adults hospitalized for an injury between January 1, 2014, and December 31, 2015, will be included in the cohort. Demographics and injury factors are recorded at the time of the injury admission. Opioid dispensing data will be linked and extracted for 3 months prior to the injury admission date to 2 years after the injury separation date (last date December 31, 2017). Deaths data will be extracted for the 2-year follow-up period. The primary outcome measure will be opioid dispensing (frequency and quantity) in the 2 years following the injury admission. Patterns and factors associated with community opioid dispensing will be examined for different injury types, mechanisms, and population subgroups. Appropriate descriptive statistics will be used to describe the cohort. Regression models will be used to examine factors predictive of levels and duration of opioid use. Nonparametric methods will be applied when the data are not normally distributed.

Results

The project is funded by the Royal Brisbane and Women’s Hospital Foundation. As of November 2021, all ethics and data custodian approvals have been granted. Data extraction and linkage has been completed. Data management and analysis is underway with results relating to an analysis for blunt chest trauma patients expected to be published in 2022.

Conclusions

Little is currently known of the true prevalence or patterns of opioid dispensing following injury across Queensland. This study will provide new insights about factors associated with high and long-term opioid dispensing at a population level. This information is essential to inform targeted public policy and interventions to reduce the risk of prolonged opioid use and dependence for those injured. The novel work undertaken for this project will be vital to planning, delivering, monitoring, and evaluating health care services for those injured. The findings of this study will be used to inform key stakeholders as well as clinicians and pain management services.

International Registered Report Identifier (IRRID)

RR1-10.2196/36357

Seven-year excess mortality, functional outcome and health status after trauma in Hong Kong

PURPOSE

The purpose was to investigate long-term health impacts of trauma and the aim was to describe the functional outcome and health status up to 7 years after trauma.

METHODS

We conducted a prospective, multi-centre cohort study of adult trauma patients admitted to three regional trauma centres with moderate or major trauma (ISS ≥ 9) in Hong Kong (HK). Patients were followed up at regular time points (1, 6 months and 1, 2, 3, 4, 5, 6, and 7 years) by telephone using extended Glasgow Outcome Scale (GOSE) and the Short-Form 36 (SF36). Observed annual mortality rate was compared with the expected mortality rate estimated using the HK population cohort. Linear mixed model (LMM) analyses examined the changes in SF36 with subgroups of age ≥ 65 years, ISS > 15, and GOSE ≥ 5 over time.

RESULTS

At 7 years, 115 patients had died and 48% (138/285) of the survivors responded. The annual mortality rate (AMR) of the trauma cohort was consistently higher than the expected mortality rate from the general population. Forty-one percent of respondents had upper good recovery (GOSE = 8) at 7 years. Seven-year mean PCS and MCS were 45.06 and 52.06, respectively. LMM showed PCS improved over time in patients aged < 65 years and with baseline GOSE ≥ 5, and the MCS improved over time with baseline GOSE ≥ 5. Higher mortality rate, limited functional recovery and worse physical health status persisted up to 7 years post-injury.

CONCLUSION

Long-term mortality and morbidity should be monitored for Asian trauma centre patients to understand the impact of trauma beyond hospital discharge.

Excess Mortality Among Adults Hospitalized With Traumatic Brain Injury in Australia: A Population-Based Matched Cohort Study

OBJECTIVE

To quantify and describe excess mortality attributable to traumatic brain injury (TBI) during the 12 months after hospitalization.

DESIGN

Population-based matched cohort study using linked hospital and mortality data.

SETTING

Australia.

PARTICIPANTS

Individuals 18 years and older who were hospitalized with a principal diagnosis of TBI in 2009 (n = 6929) and matched noninjured individuals randomly selected from the electoral roll (n = 6929).

MAIN MEASURES

Survival distributions were compared using a Kaplan-Meier plot with a log-rank test. Mortality rate ratios (MRRs) were computed using Cox proportional hazard regression with and without controlling for demographic characteristics and preexisting health status.

RESULTS

Individuals with TBI experienced significantly worse survival during the 12 months after hospitalization (χ = 640.9, df = 1, P < .001), and were more than 7.5 times more likely to die compared with their noninjured counterparts (adjusted MRR, 7.76; 95% confidence interval, 6.07-9.93). TBI was likely to be a contributory factor in 87% of deaths in the TBI cohort. Excess mortality was higher among males, younger age groups, and those with more severe TBI.

CONCLUSION

Excess mortality is high among individuals hospitalized with TBI and most deaths are attributable to the TBI. Increased primary and secondary preventive efforts are warranted to reduce the mortality burden of TBI.

Risk analysis and clinical outcomes of intraoperative periprosthetic fractures: a retrospective study of 481 bipolar hemiarthroplasties

BACKGROUND

Intraoperative periprosthetic fractures (IPF) are a well-described complication following hip hemiarthroplasty. Our aims were to identify risk factors that characterize IPF and to investigate postoperative mobility.

METHODS

We retrospectively reviewed 481 bipolar hemiarthroplasties for displaced femoral neck fractures; of which, 421 (87.5%) were performed without cement, from January 2013 to March 2018. Data on the patients' demographics, comorbidities, femoral canal geometry (Dorr canal type, Canal Flare Index), surgeon's experience (junior vs. senior surgeon), and timing of surgery (daytime vs. on-call duty) were obtained. In patients with intraoperative fractures, further information was obtained. Patient mobility was assessed using matched-pair analysis. Mobility was classified according to the NHFD mobility score. The chi-square test, Fisher's exact test, and Fisher-Freeman-Halton exact test were used for comparison between categorical variables, while the Mann-Whitney U test was used for continuous variables. The data analysis was performed using SPSS.

RESULTS

Of 481 procedures, 34 (7.1%) IPFs were encountered. The Dorr canal type C was identified as a significant risk factor (p = .004). Other risk factors included female sex (OR 2.30, 95% CI .872-6.079), stovepipe femur (OR 1.749, 95% CI .823-3.713), junior surgeon (OR 1.204, 95% CI .596-2.432), and on-call-duty surgery (OR 1.471, 95% CI .711-3.046), although none showed a significant difference. Of 34 IPFs, 25 (73.5%) were classified as Vancouver type A. The treatment of choice was cerclage wiring. Within the 12 matched pairs identified, the postoperative mobility was slightly worse for the IPF group (delta = .41).

CONCLUSIONS

IPF is a serious complication with bipolar hemiarthroplasty. The identification of risk factors preoperatively, in particular femur shape, is crucial and should be incorporated into the decision-making process.

Evaluation of approximate comparison methods on Bloom filters for probabilistic linkage

INTRODUCTION

The need for increased privacy protection in data linkage has driven the development of privacy-preserving record linkage (PPRL) techniques. A popular technique using Bloom filters with cryptographic analyses, modifications, and hashing variations to optimise privacy has been the focus of much research in this area. With few applications of Bloom filters within a probabilistic framework, there is limited information on whether approximate matches between Bloom filtered fields can improve linkage quality.

OBJECTIVES

In this study, we evaluate the effectiveness of three approximate comparison methods for Bloom filters within the context of the Fellegi-Sunter model of recording linkage: Sørensen-Dice coefficient, Jaccard similarity and Hamming distance.

METHODS

Using synthetic datasets with introduced errors to simulate datasets with a range of data quality and a large real-world administrative health dataset, the research estimated partial weight curves for converting similarity scores (for each approximate comparison method) to partial weights at both field and dataset level. Deduplication linkages were run on each dataset using these partial weight curves. This was to compare the resulting quality of the approximate comparison techniques with linkages using simple cut-off similarity values and only exact matching.

RESULTS

Linkages using approximate comparisons produced significantly better quality results than those using exact comparisons only. Field level partial weight curves for a specific dataset produced the best quality results. The Sørensen-Dice coefficient and Jaccard similarity produced the most consistent results across a spectrum of synthetic and real-world datasets.

CONCLUSION

The use of Bloom filter similarity comparisons for probabilistic record linkage can produce linkage quality results which are comparable to Jaro-Winkler string similarities with unencrypted linkages. Probabilistic linkages using Bloom filters benefit significantly from the use of similarity comparisons, with partial weight curves producing the best results, even when not optimised for that particular dataset.

Burn induced nervous system morbidity among burn and non-burn trauma patients compared with non-injured people

OBJECTIVE

Burns cause acute damage to the peripheral nervous system with published reports identifying that neurological changes after injury remain for a prolonged period. To shed some light on potential mechanisms, we assessed injury etiology and patterns of nervous system morbidity after injury by comparing long-term hospital admissions data of burns patients and other non-burn trauma patients with uninjured people.

METHODS

Linked hospital and death data of a burn patient cohort (n=30,997) in Western Australia during the period 1980-2012 were analysed along with two age and gender frequency matched comparison cohorts: non-burn trauma patients (n=28,647) and; non-injured people (n=123,399). The number of annual NS disease admissions and length of stay (LOS) were used as outcome measures. Multivariable negative binomial regression modelling was used to derive adjusted incidence rate ratios and 95% confidence intervals (IRR, 95% CI) and adjusted Cox regression models and hazard ratios (HR) were used to examine time to first nervous system admission after burn and incident admission rates.

RESULTS

The most common peripheral nervous system condition identified in each cohort (burn, non-burn trauma, uninjured) were episodic and paroxysmal disorders followed by nerve root and plexus disorders and polyneuropathies/peripheral NS conditions. Significantly elevated admission rates for NS conditions (IRR, 95% CI) were found for the burn (2.20, 1.86-2.61) and non-burn trauma (1.85, 1.51-2.27), compared to uninjured. Peripheral nervous system admission rates after injury (IRR, 95% CI) were significantly higher regardless of age at time of injury for the burn (<15years: 1.97, 1.49-2.61; 15-45: 2.70, 2.016-3.55; ≥45year: 1.62, 1.33-1.97) and non-burn trauma cohorts (<15years: 1.91, 1.55-2.35; 15-45: 1.94, 1.51-2.49; ≥45year: 1.42, 1.18-1.72), when compared to the uninjured. Significantly higher rates of incident NS hospitalisations were found for the burn cohort vs. uninjured cohort for a period of 15-years after discharge (0-5 years: HR, 95% CI: 1.97, 1.75-2.22; 5-15 years; HR, 95% CI: 1.44, 1.28-1.63). The non-burn trauma cohort had significantly higher incident nervous system admissions for 10 years after discharge (0-30 days: HR, 95% CI: 4.75, 2.44-9.23; 30days to 1-year HR, 95% CI: 2.95, 2.34-3.74; 1-5 years; HR, 95% CI: 1.47, 1.26-1.70; 5-10 years; HR, 95% CI: 1.34, 1.13-1.58).

CONCLUSIONS

Results suggest that injury patients are at increased risk of peripheral nervous system morbidity after discharge for a prolonged period of time. The time patterns associated with incident nervous system conditions suggest possible differences in underlying pathology and long-term patient care needs. Further research is needed to elucidate the underlying neuropathology.

A retrospective cohort study to compare post-injury admissions for infectious diseases in burn patients, non-burn trauma patients and uninjured people

Background

Injury triggers a range of systemic effects including inflammation and immune responses. This study aimed to compare infectious disease admissions after burn and other types of injury using linked hospital admissions data.

Methods

A retrospective longitudinal study using linked health data of all patients admitted with burns in Western Australia (n = 30,997), 1980–2012, and age and gender frequency matched cohorts of people with non-burn trauma (n = 28,647) and no injury admissions (n = 123,399). Analyses included direct standardisation, negative binomial regression and Cox proportional hazards regression.

Results

Annual age-standardised infectious disease admission rates were highest for the burn cohort, followed by the non-burn trauma and uninjured cohorts. Age-standardised admission rates by decade showed different patterns across major categories of infectious diseases, with the lower respiratory and skin and soft tissue infections the most common for those with burns and other open trauma. Compared with the uninjured, those with burns had twice the admission rate for infectious disease after discharge (incident rate ratio (IRR), 95% confidence interval (CI): 2.04, 1.98–2.11) while non-burn trauma experienced 1.74 times higher rates (95%CI: 1.68–1.81). The burn cohort experienced 10% higher rates of first-time admissions after discharge when compared with the non-burn trauma (hazard ratio (HR), 95%CI: 1.10, 1.05–1.15). Compared with the uninjured cohort, incident admissions were highest during the first 30 days after discharge for burns (HR, 95%CI: 5.18, 4.15–6.48) and non-burn trauma (HR, 95%CI: 5.06, 4.03–6.34). While incident rates remained high over the study period, the magnitude decreased with increasing time from discharge: burn vs uninjured: HR, 95%CI: 30 days to 1 year: 1.69, 1.53–1.87; 1 to 10 years: 1.40, 1.33–1.47; 10 years to end of study period: 1.16, 1.08–1.24; non-burn trauma vs uninjured: HR, 95%CI: 30 days to 1 year: 1.71, 1.55–1.90; 1 to 10 years: 1.30, 1.24–1.37; 10 years to end of study period: 1.09, 1.03–1.17).

Conclusions

Burns and non-burn trauma patients had higher admission rates for infectious diseases compared with age and gender matched uninjured people. The pattern of annual admission rates for major categories of infectious diseases varied across injury groups. Overall, the burn cohort experienced the highest rates for digestive, lower respiratory and skin and soft tissue infections. These results suggest long-term vulnerability to infectious disease after injury, possibly related to long-term immune dysfunction.

Self-harm hospitalised morbidity and mortality risk using a matched population-based cohort design

OBJECTIVE

Prior and repeated self-harm hospitalisations are common risk factors for suicide. However, few studies have accounted for pre-existing comorbidities and prior hospital use when quantifying the burden of self-harm. The aim is to quantify hospitalisation in the 12 months preceding and re-hospitalisation and mortality risk in the 12 months post a self-harm hospitalisation.

METHOD

A population-based matched cohort using linked hospital and mortality data for individuals ⩾18 years from four Australian jurisdictions. A non-injured comparison cohort was matched on age, gender and residential postcode. Twelve-month pre- and post-index self-harm hospitalisations and mortality were examined.

RESULTS

The 11,597 individuals who were hospitalised following self-harm in 2009 experienced 21% higher health service use in the 12 months pre and post the index admission and a higher mortality rate (2.9% vs 0.3%) than their matched counterparts. There were 133 (39.0%) deaths within 2 weeks of hospital discharge and 342 deaths within 12 months of the index hospitalisation in the self-harm cohort. Adjusted rate ratios for hospital readmission were highest for females (2.86; 95% confidence interval: [2.33, 2.52]) and individuals aged 55-64 years (3.96; 95% confidence interval: [2.79, 5.64]).

CONCLUSION

Improved quantification of the burden of self-harm-related hospital use can inform resource allocation for intervention and after-care services for individuals at risk of repeated self-harm. Better assessment of at-risk self-harm behaviour, appropriate referrals and improved post-discharge care, focusing on care continuity, are needed.

Diabetes mellitus after injury in burn and non-burned patients: A population based retrospective cohort study

OBJECTIVE

To compare hospitalisations for diabetes mellitus (DM) after injury experienced by burn patients, non-burn trauma patients and people with no record of injury admission, adjusting for socio-demographic, health and injury factors.

METHODS

Linked hospital and death data for a burn patient cohort (n=30,997) in Western Australia during the period 1980-2012 and two age and gender frequency matched comparison cohorts: non-burn trauma patients (n=28,647); non-injured people (n=123,399). The number of DM admissions and length of stay were used as outcome measures. Multivariate negative binomial regression was used to derive adjusted incidence rate ratios and 95% confidence intervals (IRR, 95%CI) for overall post-injury DM admission rates. Multivariate Cox regression models and hazard ratios (HR) were used to examine time to first DM admission and incident admission rates after injury discharge.

RESULTS

The burn cohort (IRR, 95%: 2.21, 1.80-2.72) and other non-burn trauma cohort (IRR, 95%CI: 1.63, 1.24-2.14) experienced significantly higher post-discharge admission rates for DM than non-injured people. Compared with the non-burn trauma cohort, the burn cohort experienced a higher rate of post-discharge DM admissions (IRR, 95%CI: 1.40, 1.07-1.84). First-time DM admissions were significantly higher during first 5-years after-injury for the burn cohort compared with the non-burn trauma cohort (HR, 95%CI: 2.00, 1.31-3.05) and non-injured cohort (HR, 95%CI: 1.96, 1.46-2.64); no difference was found >5years (burn vs. non-burn trauma: HR, 95%CI: 0.88, 0.70-1.12; burn vs non-injured: 95%CI: 1.08 0.82-1.41). No significant difference was found when comparing the non-burn trauma and non-injured cohorts (0-5 years: HR, 95%CI: 1.03, 0.71-1.48; >5years: HR. 95%CI: 1.11, 0.93-1.33).

CONCLUSIONS

Burn and non-burn trauma patients experienced elevated rates of DM admissions after injury compared to the non-injured cohort over the duration of the study. While burn patients were at increased risk of incident DM admissions during the first 5-years after the injury this was not the case for non-burn trauma patients. Sub-group analyses showed elevated risk in both adult and pediatric patients in the burn and non-burn trauma. Detailed clinical data are required to help understand the underlying pathogenic pathways triggered by burn and non-burn trauma. This study identified treatment needs for patients after burn and non-burn trauma for a prolonged period after discharge.

Mortality risk among older Australians hospitalised with hip fracture: a population-based matched cohort study

With an ageing population, the burden of hip fractures is expected to increase in the coming decades. Older individuals with hip fracture are more than 3.5 times more likely to die within 12 months compared to non-injured individuals. The main priority for reducing mortality should be prevention of hip fracture.

PURPOSE

The aim of this study is to quantify and describe the 12-month mortality of older persons presenting to hospitals in Australia with a hip fracture.

METHODS

Population-based matched cohort study using linked hospital and mortality data from four Australian states (New South Wales, Queensland, South Australia, and Tasmania). Individuals aged 65 years and older who had a hospital admission with a primary diagnosis of hip fracture in 2009 (n = 9748) and a matched comparison cohort of non-injured individual were selected from the electoral roll (n = 9748). The comparison group was matched 1:1 on age, sex, and postcode of residence. Adjusted mortality rate ratios (MRR) and attributable risk percent were calculated. Cox proportional hazard regression was used to examine the effect of risk factors on survival.

RESULTS

The hip fracture cohort experienced significantly worse survival at the 12-month post-fracture hospitalisation (P < 0.0001). Individuals with hip fracture were more than 3.5 times more likely to die within 12 months compared to their non-injured counterparts (MRR 3.62 [95%CI 3.23-4.05]). Hip fracture was likely to be a contributory factor in 72% of mortality within 12 months after the index hospital admission. Excess mortality risk at 12 months was higher in males than that in females and in the 65-74-year age group.

CONCLUSIONS

With an ageing population in Australia, the burden of hip fractures is expected to increase in the coming decades. Because incident hip fracture is the main predictor of subsequent mortality, the main priority for reducing excess mortality after hip fracture is primary and secondary prevention of hip fracture.

Patterns of health care use of injured adults: A population-based matched cohort study

BACKGROUND

Healthcare use by traumatically injured individuals prior to and subsequent to their injury are not often explored for different types of injuries. This study aims to describe health care use 12 months preceding and 12 months following a traumatic injury by injury type and injury severity.

METHOD

Hospital and mortality data from three Australian states were linked in a population-based matched cohort study. Individuals ≥18 years who had an injury-related hospital admission in 2009 were identified as the injured cohort. A comparison cohort of non-injured people, matched 1:1 on age, gender and postcode of residence, was randomly selected from the electoral roll. Twelve-month pre- and post-index injury health service use was examined. Rates, adjusted rate ratios and attributable risk proportions were calculated by injury type and severity.

RESULTS

The injury cohort experienced higher 12-month pre- and post-injury hospital admissions than the non-injured group. By 6 to 7 months post-injury, the injury cohort had largely returned to their pre-injury health service use levels, except for injuries involving dislocations, sprains and strains and injury to nerves and spinal cord. Hip fracture (17.69 per 100 person-months) and poisoning (16.09 per 100 person-months) had the highest rates of post-injury hospitalisation in the injured cohort. The adjusted rate ratios (ARR) for post-injury hospitalisation were highest for poisoning (ARR: 3.77; 95% CI: 3.38-4.21) and injury to nerves and spinal cord (ARR: 2.73; 95% CI: 2.27-3.28). Poisoning also had the highest ARR for post-injury LOS (ARR: 5.31; 95% CI: 4.51-6.27).

CONCLUSIONS

After sustaining a traumatic injury, many individuals are readmitted to hospital and require ongoing care up to 12 months post-injury. That injured individuals post-injury largely return to their pre-index injury hospital use by 6 to 7 months could imply a return to pre-injury function and/or that other measures of health service use should be explored. Trauma services should consider long-term follow-up and support services for seriously injured patients post-hospital discharge.

Higher mortality risk among injured individuals in a population-based matched cohort study

BACKGROUND

Improved understanding of long-term mortality attributable to injury is needed to accurately inform injury burden studies. This study aims to quantify and describe mortality attributable to injury 12 months after an injury-related hospitalisation in Australia.

METHOD

A population-based matched cohort study using linked hospital and mortality data from three Australian states during 2008-2010 was conducted. The injured cohort included individuals ≥18 years who had an injury-related hospital admission in 2009. A comparison cohort of non-injured people was obtain by randomly selecting from the electoral roll. This comparison group was matched 1:1 on age, gender and postcode of residence. Pre-index injury health service use and 12-month mortality were examined. Adjusted mortality rate ratios (MRR) and attributable risk were calculated. Cox proportional hazard regression was used to examine the effect of risk factors on survival.

RESULTS

Injured individuals were almost 3 times more likely to die within 12 months following an injury (MRR 2.90; 95% CI: 2.76-3.04). Individuals with a traumatic brain injury (MRR 7.58; 95% CI: 5.92-9.70) or injury to internal organs (MRR 7.38; 95% CI: 5.90-9.22) were 7 times more likely to die than the non-injured group. Injury was likely to be a contributory factor in 92% of mortality within 30 days and 66% of mortality at 12 months following the index injury hospital admission. Adjusted mortality rate ratios varied by type of cause-specific death, with MRR highest for injury-related deaths.

CONCLUSIONS

There are likely chronic consequences of sustaining a traumatic injury. Longer follow-up post-discharge is needed to consider deaths likely to be attributable to the injury. Better enumeration of long-term injury-related mortality will have the potential to improve estimates of injury burden.