Long-term mortality among older adults with burn injury: a population-based study in Australia.

OBJECTIVE: To assess if burn injury in older adults is associated with changes in long-term all-cause mortality and to estimate the increased risk of death attributable to burn injury. METHODS: We conducted a population-based matched longitudinal study - based on administrative data from Western Australia's hospital morbidity data system and death register. A cohort of 6014 individuals who were aged at least 45 years when hospitalized for a first burn injury in 1980-2012 was identified. A non-injury comparison cohort, randomly selected from Western Australia's electoral roll (n = 25 759), was matched to the patients. We used Kaplan-Meier plots and Cox proportional hazards regression to analyse the data and generated mortality rate ratios and attributable risk percentages. FINDINGS: For those hospitalized with burns, 180 (3%) died in hospital and 2498 (42%) died after discharge. Individuals with burn injury had a 1.4-fold greater mortality rate than those with no injury (95% confidence interval, CI: 1.3-1.5). In this cohort, the long-term mortality attributable to burn injury was 29%. Mortality risk was increased by both severe and minor burns, with adjusted mortality rate ratios of 1.3 (95% CI: 1.1-1.9) and 2.1 (95% CI: 1.9-2.3), respectively. CONCLUSION: Burn injury is associated with increased long-term mortality. In our study population, sole reliance on data on in-hospital deaths would lead to an underestimate of the true mortality burden associated with burn injury.

An Australian study of long-term hospital admissions and costs comparing patients with unintentional burns and uninjured people.

BACKGROUND: The objective of this study was to describe and quantify the long-term hospital service use (HSU) after burn injury and associated costs in a population-based cohort of patients with unintentional burns and compare with uninjured people. METHODS: This retrospective population-based cohort study analysed de-identified linked health administrative data of all unintentional burns patients (n = 10,460) between 2000 and 2012 in Western Australia and a matched uninjured comparison cohort (n = 42,856). HSU after burn injury (annual admission counts and cumulative length of stay) was examined. HSU costs were based on the Australian Refined Diagnosis Related Groups (AR-DRGs) code on each record. Generalised linear models were used to examine and quantify associations between burn injury and long-term HSU and associated costs. RESULTS: There were 48,728 hospitalisations after burn occurring within the study period in the burn cohort; in the uninjured comparison cohort, there were 53,244 post-study index hospitalisations. Of those in the burn cohort, 63.9% (n = 6828) had a further hospitalisation after burn injury; this compared with 40.4% (n = 17,297) in the uninjured cohort. After adjustment for socio-demographic and pre-existing health conditions the burn cohort had 2.48 times the hospitalisation rate compared to the uninjured cohort (95% CI: 2.33-2.65). The cost of post-index hospitalisations in the burn cohort totalled to $AUS248.3 million vs $AUS240.8 million in the uninjured cohort. After adjustment, the burn cohort had hospital costs 2.77 times higher than the uninjured controls (95% CI: 2.58-2.98). CONCLUSIONS: After adjustment for covariates, burn patients experienced greater hospital use for a prolonged period after the initial injury compared with uninjured people. The mean cost per episode of care was generally higher for members of the burn cohort compared to the uninjured cohort indicating either more complicated admissions or admissions for more expensive conditions.

Retrospective cohort study of health service use for cardiovascular disease among adults with and without a record of injury hospital admission.

OBJECTIVE: To quantify postinjury cardiovascular-related health service use experienced by mid to older aged adults hospitalised for injury, compared with uninjured adults. Additionally, to explore the effect of beta-blocker medications on postinjury cardiovascular hospitalisations among injury patients, given the potential cardioprotective effects of beta blockers. DESIGN: A retrospective cohort study using linked administrative and survey data. PARTICIPANTS: Records of 35 026 injured and 60 823 uninjured matched adults aged over 45 from New South Wales, Australia, who completed the 45 and up survey. PRIMARY AND SECONDARY OUTCOME MEASURES: Admission rates and cumulative lengths of stay for cardiovascular hospitalisations, and prescription rates for cardiovascular medications. Negative binomial and Cox proportional hazards regression modelling were used to generate incident rate ratios (IRRs) and HR. RESULTS: Compared with the uninjured, those with injury had a 19% higher adjusted rate of postinjury cardiovascular admissions (IRR 1.19, 95% CI 1.14 to 1.25), spent 40% longer in hospital for ardiovascular disease (IRR 1.40, 95% CI 1.26 to 1.57) and had slightly higher cardiovascular prescription rates (IRR 1.04, 95% CI 1.02 to 1.06), during study follow-up. Those in the injury cohort that used beta blockers both prior to and after injury (continuous) appeared to have reduced need for post-injury cardiovascular hospitalisation (IRR 1.09, 95% CI 1.17 to 1.42) compared with those commencing on beta blockers after injury (after 30 days: IRR 1.69, 95% CI 1.37 to 2.08). CONCLUSIONS: Apparent increased postinjury hospitalisation rates and prolonged length of stay related to cardiovascular disease suggest that injury patients may require clinical support for an extended period after injury. Additionally, injury patients who were on continuous beta blocker treatment appeared to have lower need for post-injury cardiovascular hospitalisations. However, the data do not allow us to draw clear conclusions and further clinical research is required.

Identification of Differentially Methylated CpG Sites in Fibroblasts from Keloid Scars.

As a part of an abnormal healing process of dermal injuries and irritation, keloid scars arise on the skin as benign fibroproliferative tumors. Although the etiology of keloid scarring remains unsettled, considerable recent evidence suggested that keloidogenesis may be driven by epigenetic changes, particularly, DNA methylation. Therefore, genome-wide scanning of methylated cytosine-phosphoguanine (CpG) sites in extracted DNA from 12 keloid scar fibroblasts (KF) and 12 control skin fibroblasts (CF) (six normal skin fibroblasts and six normotrophic fibroblasts) was conducted using the Illumina Human Methylation 450K BeadChip in two replicates for each sample. Comparing KF and CF used a Linear Models for Microarray Data (Limma) model revealed 100,000 differentially methylated (DM) CpG sites, 20,695 of which were found to be hypomethylated and 79,305 were hypermethylated. The top DM CpG sites were associated with TNKS2, FAM45B, LOC723972, GAS7, RHBDD2 and CAMKK1. Subsequently, the most functionally enriched genes with the top 100 DM CpG sites were significantly (p ≤ 0.05) associated with SH2 domain binding, regulation of transcription, DNA-templated, nucleus, positive regulation of protein targeting to mitochondrion, nucleoplasm, Swr1 complex, histone exchange, and cellular response to organic substance. In addition, NLK, CAMKK1, LPAR2, CASP1, and NHS showed to be the most common regulators in the signaling network analysis. Taken together, these findings shed light on the methylation status of keloids that could be implicated in the underlying mechanism of keloid scars formation and remission.

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 population-based comparison study of the mental health of patients with intentional and unintentional burns.

BACKGROUND: A number of studies report high prevalence of mental health conditions among burn patients. However there is a need to understand differences in the temporal relationship between mental health conditions and intentional and unintentional burns to hasten psychological prevention and intervention. This study aims to compare the socio-demographic profile, burn characteristics and pre- and post-burn psychiatric morbidity of burn patients by intent-of-injury. METHODS: De-identified linked hospital, death and mental health (MH) case registry data of burn patients hospitalised in Western Australia between 1 January 1980 and 30 June 2012 were analysed. Crude (observed) post-burn rates of mental health admissions were generated by burn intent-of-injury. Descriptive statistics were performed to compare the characteristics of the burn patients. RESULTS: A total of 30,997 individuals were hospitalised for a first burn; 360 (1.2%) had self-harm burns and 206 (0.7%) assault burns. Over the study period, admission rates for assault burns increased by 4.8% per year (95% confidence interval (CI) 3.1-6.5%) and self-harm burns increased 6.9% per year (95% CI 4.8-9.1%). Self-harm and assault burns occurred mainly among those aged 15 to 44 years (median age, interquartile range (IQR): self-harm 30 years, 22-40; assault 31 years, 23-38). Those with self-harm burns had a longer index hospital stay (median (IQR): self-harm 15 days (5-35) vs 4 days (1-11) assault vs 4 days (1-10) unintentional) and higher in-hospital mortality (7.2% self-harm vs 1.9% assault burns vs 0.8% unintentional). More than half (55.0%) of self-harm burns had a prior hospitalisation (5-year lookback) for a MH condition vs 10.7% of assault burns and 2.8% of unintentional burns. Crude post-burn rates of MH admissions per 100 person-years (PY) by intent-of-burn subgroups: self-harm 209 per 100 PY, assault burns 11 per 100 PY and unintentional burns 3 per 100 PY. CONCLUSIONS: Intentional burn patients experienced significantly higher pre- and post-burn mental health morbidity along with significant adverse outcome in comparison with unintentional burns. Early psychological assessment and intervention could help in improving the MH of these patients.

Long-term mental health outcomes after unintentional burns sustained during childhood: a retrospective cohort study.

BACKGROUND: Burns are a devastating injury that can cause physical and psychological issues. Limited data exist on long-term mental health (MH) after unintentional burns sustained during childhood. This study assessed long-term MH admissions after paediatric burns. METHODS: This retrospective cohort study included all children (< 18 years) hospitalised for a first burn (n = 11,967) in Western Australia, 1980-2012, and a frequency matched uninjured comparison cohort (n = 46,548). Linked hospital, MH and death data were examined. Multivariable negative binomial regression modelling was used to generate incidence rate ratios (IRR) and 95% confidence intervals (CI). RESULTS: The burn cohort had a significantly higher adjusted rate of post-burn MH admissions compared to the uninjured cohort (IRR, 95% CI: 2.55, 2.07-3.15). Post-burn MH admission rates were twice as high for those younger than 5 years at index burn (IRR, 95% CI 2.06, 1.54-2.74), three times higher for those 5-9 years and 15-18 years (IRR, 95% CI: 3.21, 1.92-5.37 and 3.37, 2.13-5.33, respectively) and almost five times higher for those aged 10-14 (IRR, 95% CI: 4.90, 3.10-7.76), when compared with respective ages of uninjured children. The burn cohort had higher admission rates for mood and anxiety disorders (IRR, 95% CI: 2.79, 2.20-3.53), psychotic disorders (IRR, 95% CI: 2.82, 1.97-4.03) and mental and behavioural conditions relating to drug and alcohol abuse (IRR, 95% CI: 4.25, 3.39-5.32). CONCLUSIONS: Ongoing MH support is indicated for paediatric burn patients for a prolonged period after discharge to potentially prevent psychiatric morbidity and associated academic, social and psychological issues.

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.

A population-based retrospective cohort study to assess the mental health of patients after a non-intentional burn compared with uninjured people.

BACKGROUND: The objective of this study was to describe and quantify mental health (MH) admissions experienced by patients with unintentional burns subsequent to their injury. METHODS: A retrospective population-based cohort study that used de-identified linked hospital, death and mental health in-patient case registry data of all burn patients hospitalised for unintentional burns (n=10,460) between 2000 and 2012 in Western Australia and an age and gender matched uninjured comparison cohort (n=42,856). Cohorts had a median age at study index of 26 years with males comprising 66% of each cohort. MH admissions for 5 years before and after the injury were examined. Negative binomial and Cox proportional hazards regressions were adjusted for socio-demographic and pre-existing health conditions and used to quantify associations between burns and MH hospitalisations. RESULTS: In the burn cohort during the 5-year post-burn period, 4% had a MH admission, 2% were admitted for self-harm, and 3% were admitted for a behavioural disorder caused by drugs/alcohol. Significantly elevated adjusted admission rates for MH conditions were observed for the burn cohort compared with the uninjured cohort (IRR, 95% CI: 4.89, 3.52-6.79). Increased MH admission rates were found for all age groups but were most pronounced in those younger than 18 years of age at time of burn (IRR, 95% CI: 6.28, 3.00-13.14), followed by those aged 18-60 (5.14, 3.59-7.35) and those over 60 years (IRR, 95% CI: 2.97, 1.38-6.39) compared to the uninjured cohort. Gender-specific analyses showed significant differences for male (IRR, 95% CI: 4.48, 3.05-6.59) and female burn patients (IRR, 95% CI: 6.00, 3.62-9.92), compared to uninjured. The burn cohort had higher adjusted first time admissions for MH conditions (HR, 95% CI: 3.55, 2.72-4.64), mood and anxiety disorders (HR, 95% CI: 3.77, 2.81-5.08), psychotic disorders (HR, 95% CI: 3.55, 1.99-6.15) and behavioural disorders related to alcohol/drugs (HR, 95% CI: 4.75, 3.09-7.28) for five years after the initial burn. CONCLUSIONS: Patients hospitalised for unintentional burns had significantly higher MH admission rates after discharge than that observed for an uninjured cohort. Ongoing mental health support is clearly indicated for many burns patients for a prolonged period after discharge.

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.

Is there an association between the use of oral contraception and depressive symptoms in young Australian women?

PURPOSE: The purpose of this study was to explore the relationship between oral contraceptive pill (OCP) use and the experience of depressive symptoms among a representative sample of young Australian women. METHODS: The study sample comes from the Australian Longitudinal Study on Women's Health. Analysis was confined to women in the youngest cohort who responded to Survey 2, which was conducted in 2000 (n=9688) when they were aged between 22 and 27 years, and to Survey 3, which was conducted in 2003 (n=9081) when they were aged between 25 and 30 years. RESULTS: After adjusting for potential confounders, the odds of a nonuser experiencing depressive symptoms is not significantly different from that of an OCP user [odds ratio=1.05; 95% confidence interval (95% CI)=0.90-1.21]. Women who used OCP for reasons other than contraception were 1.32 (95% CI=1.07-1.62) times as likely to be depressed than women who used OCP for contraception. The percentage of women who reported experiencing depressive symptoms declined as the number of years of OCP use increased (p=.009). CONCLUSIONS: The results of this study suggest that, after adjusting for confounders, there is no independent effect of OCP use on depressive symptoms in young Australian women.

Geographic distribution of burn in an Australian setting.

OBJECTIVE: To investigate the geographic distribution and temporal trends of burn admissions in an Australian setting. METHODS: Health administrative data of all persons hospitalised for a first burn in Western Australia for the period 2000-2012 were used. Crude and standardised incident rates were generated for each region. Maps of crude rates were generated for state regions and postcode-suburbs of Perth, the capital city. Standardised incidence rates were generated for Western Australia, total and regions, and for sub-cohorts defined by age (<20years; ≥20 years), TBSA burn severity and major causes of burns (fire, scalds and contact). Negative binomial regression was used to examine temporal changes and generate incidence rate ratios (IRR) with 95% confidence intervals (CI). RESULTS: Perth had the lowest burn admission rate per population; clusters of suburbs of lower social advantage and higher immigrant settlement were identified as being at high risk. While the highest observed admission rates were found in Kimberley and Goldfields (remote) regions, after adjustment for the regional demographic structures, the Wheatbelt and Mid-West (rural) regions were found to have the highest adjusted rates of burn admissions. Significant annual declines in admission rates were found for the Kimberley, Pilbara and Goldfields (remote regions); however, stable admission rates were identified for all other regions. CONCLUSIONS: The Mid-West and Wheatbelt rural regions were found to have the highest risk of burn admissions raising concerns about farming-related injury. Safety awareness and burn prevention strategies need to be continued, with specific attention to these high risk areas, to reduce burn admissions in Western Australia.

Burn leads to long-term elevated admissions to hospital for gastrointestinal disease in a West Australian population based study.

BACKGROUND: While the most obvious impact of burn is on the skin, systemic responses also occur after burn, including intestinal inflammation. The objective of this study was to assess if burns are associated with increased long-term admissions for gastrointestinal diseases. METHODS: A population-based longitudinal study using linked hospital morbidity and death data from Western Australia was undertaken of adults aged at least 15 years when hospitalized for a first burn (n=20,561) in 1980-2012. A frequency matched non-injury comparison cohort was randomly selected from Western Australia's birth registrations and electoral roll (n=80,960). Crude admission rates and summed days in hospital for digestive diseases were calculated. Negative binomial and Cox proportional hazards regression modeling were used to generate incidence rate ratios (IRR) and hazard ratios (HR), respectively. RESULTS: After adjustment for demographic factors and pre-existing health status, the burn cohort had 1.54 times (95% confidence interval (CI): 1.47-1.62) as many admissions and almost three times the number of days in hospital with a digestive system diagnosis (IRR, 95% CI: 2.90, 2.60-3.25) than the uninjured cohort. Significantly elevated adjusted post-burn incident rates were identified, with the risk decreasing with increasing time: in the first month (HR, 95% CI: 3.02, 1.89-4.82), from one month to five years (HR, 95% CI: 1.42, 1.31-1.54), and from five to twenty years after burn (HR, 95% CI: 1.13, 1.06-1.20). CONCLUSIONS: Findings of increased hospital admission rates and prolonged length of hospital stay for gastrointestinal diseases in the burn cohort provide evidence to support that burns have effects that persist long after the initial injury.

Burns and long-term infectious disease morbidity: A population-based study.

BACKGROUND: There is a growing volume of data that indicates that serious injury suppresses immune function, predisposing individuals to infectious complications. With recent evidence showing long-term immune dysfunction after less severe burn, this study aimed to investigate post-burn infectious disease morbidity and assess if burn patients have increased long-term hospital use for infectious diseases. METHODS: A population-based longitudinal study using linked hospital morbidity and death data from Western Australia for all persons hospitalised for a first burn (n=30,997) in 1980-2012. A frequency matched non-injury comparison cohort was randomly selected from Western Australia's birth registrations and electoral roll (n=123,399). Direct standardisation was used to assess temporal trends in infectious disease admissions. Crude annual admission rates and length of stay for infectious diseases were calculated. Multivariate negative binomial and Cox proportional hazards regression modeling were used to generate adjusted incidence rate ratios (IRR) and hazard ratios (HR), respectively. RESULTS: After adjustment for demographic factors and pre-existing health status, the burn cohort had twice (IRR, 95% confidence interval (CI): 2.04, 1.98-2.22) as many admissions and 3.5 times the number of days in hospital (IRR, 95%CI: 3.46, 3.05-3.92) than the uninjured cohort for infectious diseases. Higher rates of infectious disease admissions were found for severe (IRR, 95%CI: 2.37, 1.89-2.97) and minor burns (IRR, 95%CI: 2.22, 2.11-2.33). Burns were associated with significantly increased incident admissions: 0-30days (HR, 95%CI: 5.18, 4.15-6.48); 30days-1year (HR, 95%CI: 1.69, 1.53-1.87); 1-10 years (HR, 95%CI: 1.40:1.33-1.47); >10years (HR, 95%CI: 1.16, 1.08-1.24). Respiratory, skin and soft tissue and gastrointestinal infections were the most common. The burn cohort had a 1.75 (95%CI: 1.37-2.25) times greater rate of mortality caused by infectious diseases during the 5-year period after discharge than the uninjured cohort. CONCLUSIONS: These findings suggest that burn has long-lasting effects on the immune system and its function. The increase in infectious disease in three different epithelial tissues in the burn cohort suggests there may be common underlying pathophysiology. Further research to understand the underlying mechanisms are required to inform clinical interventions to mitigate infectious disease after burn and improve patient outcomes.

Burn Injury Leads to Increased Long-Term Susceptibility to Respiratory Infection in both Mouse Models and Population Studies.

BACKGROUND: Burn injury initiates an acute inflammatory response that subsequently drives wound repair. However, acute disruption to the immune response is also common, leading to susceptibility to sepsis and increased morbidity and mortality. Despite increased understanding of the impact of burn injury on the immune system in the acute phase, little is known about long-term consequences of burn injury on immune function. This study was established to determine whether burn injury has long-term clinical impacts on patients' immune responses. METHODS: Using a population-based retrospective longitudinal study and linked hospital morbidity and death data from Western Australia, comparative rates of hospitalisation for respiratory infections in burn patients and a non-injured comparator cohort were assessed. In addition, a mouse model of non-severe burn injury was also used in which viral respiratory infection was induced at 4 weeks post-injury using a mouse modified version of the Influenza A virus (H3NN; A/mem/71-a). RESULTS AND CONCLUSIONS: The burn injured cohort contained 14893 adult patients from 1980-2012 after removal of those patients with evidence of smoke inhalation or injury to the respiratory tract. During the study follow-up study a total of 2,884 and 2,625 respiratory infection hospital admissions for the burn and uninjured cohorts, respectively, were identified. After adjusting for covariates, the burn cohort experienced significantly elevated admission rates for influenza and viral pneumonia (IRR, 95%CI: 1.73, 1.27-2.36), bacterial pneumonia (IRR, 95%CI: 2.05, 1.85-2.27) and for other types of upper and lower respiratory infections (IRR, 95% CI: 2.38, 2.09-2.71). In the mouse study an increased viral titre was observed after burn injury, accompanied by a reduced CD8 response and increased NK and NKT cells in the draining lymph nodes. This data suggests burn patients are at long-term increased risk of infection due to sustained modulation of the immune response.

Fracture admissions after burns: A retrospective longitudinal study.

BACKGROUND: Severe burn triggers systemic responses that result in reduced muscle mass and changes in bone formation, with recent evidence also suggesting systemic effects on bone after minor burns. The aim of this study was to assess if people hospitalised with a burn have increased admissions for fractures after discharge. METHODS: A population-based longitudinal study using linked hospital morbidity and death data from Western Australia was undertaken of all persons hospitalised for a first burn (n=30,997) during the period 1980-2012. Australian population-based annual rates for fracture admissions for the period 1993-2012 were obtained from the Australian Institute of Health and Welfare. Rates of hospital admissions for fractures in the burn cohort and the Australian population were standardised, using the direct method, to the age and gender structure of the Western Australian population at the 2006. Annual standardised fracture admission rates for the period 1993-2012 were graphed with estimated 95% confidence intervals. Age and gender specific fracture rates were also examined. RESULTS: A total of 4004 members of the burn cohort had at least one fracture admission for a total of 6096. The median (IQR) time to the first fracture admission after burn was 6.9 years (2.8-13.6) and the median age (IQR) at first fracture admission was 31 years (20-49). The burn cohort experienced admissions for fractures at a rate approximately twice that of the Australian population. While rates were generally higher for males in the burn cohort when compared with males in the Australian population, female burn patients had significantly higher rates over the entire study period when compared with the female Australian population. Elevated rates were observed for those younger than 20 years at the time of the burn admission; however, rates were significantly and consistently elevated during the study period for those 20 years and older at the time of the burn. CONCLUSIONS: Burn patients experienced significantly higher age and gender standardised rates of admissions for fractures after discharge from hospital for their index burn. Further prospective research is indicated to clarify any underlyling pathogenic processes linked to the burn that may increase a patient's risk of having a fracture serious enough to undergo admission.

Effects of Pediatric Burns on Gastrointestinal Diseases: A Population-Based Study.

The systemic responses triggered by burns have been shown to include effects on the gastrointestinal tract. However, it is not clear if these changes lead to long-term gastrointestinal morbidity in patients with burns. The aim of this study was to assess if pediatric burns are associated with increased hospital use for gastrointestinal diseases after discharge for the initial injury. A population-based longitudinal study was performed using linked hospital and death data from Western Australia for children younger than 15 years when hospitalized for a first burn injury (n = 10,436) between 1980 and 2012, along with a frequency-matched noninjury comparison cohort, randomly selected from Western Australia's birth registrations (n = 40,819). Crude admission rates and cumulative length of stay for digestive diseases were calculated. Negative binomial and Cox proportional hazards regression modeling were used to generate incidence rate ratios (IRRs) and hazard ratios, respectively. After discharge, the pediatric burn cohort experienced twice the rate of gastrointestinal disease admissions (IRR, 95% confidence interval [CI]: 2.03, 1.56-2.65), spent over twice as long in hospital (IRR, 95% CI: 2.23, 1.67-2.98), and had a higher rate of first-time or incident gastrointestinal disease admissions (hazard ratio, 95% CI: 1.18, 1.08-1.29) when compared with the uninjured cohort, after adjusting for demographic and preexisting health factors. Children who experience a burn injury hospitalization are at increased risk of postburn hospital service use for gastrointestinal diseases when compared with uninjured children.

Long term cardiovascular impacts after burn and non-burn trauma: A comparative population-based study.

OBJECTIVE: To compare post-injury cardiovascular disease (CVD) hospital admissions experienced by burn patients with non-burn trauma patients and people with no record of injury, adjusting for socio-demographic, health and injury factors. METHODS: Linked hospital and death data were analysed for a cohort of burn patients (n=30,997) hospitalised in Western Australia during the period 1980-2012 and age and gender frequency matched comparison cohorts (non-burn trauma: n=28,647; non-injured: n=123,399). The number and length of hospital stay for CVD admissions were used as outcome measures. Multivariate negative binomial regression was used to derive adjusted incidence rate ratios (IRR) and 95% confidence intervals (95%CI). Multivariate Cox regression models and hazard ratios (HR) were used to examine first time post-injury CVD admissions. RESULTS: The burn cohort had a higher rate of CVD (combined) admissions (IRR, 95%CI: 1.16: 1.08-1.24) and spent longer in hospital (IRR, 95%CI: 1.37, 1.13-1.66) than the non-burn trauma cohort. Both the burn cohort (IRR, 95%CI: 1.50, 1.40-1.60) and the non-burn trauma cohort (IRR, 95%CI: 1.29, 1.21-1.37) had higher adjusted rates of post-injury CVD admissions compared with the non-injured cohort. The burn cohort (HR, 95%CI: 2.27, 1.70-3.02) and non-burn trauma cohort (HR, 95%CI: 2.19, 1.66-2.87) experienced significantly elevated first time CVD admissions during the first 6 months after injury, decreasing in magnitude from 6 months to 5 years after injury (HR, 95%CI: burn vs. non-injured; 1.31, 1.16-1.48; non-burn trauma vs. non-injured; 1.16, 1.03-1.31); no significant difference in incident admission rates was found beyond 5 years (HR, 95%CI: burn vs. non-injured; 0.99, 0.92-1.07; non-burn trauma vs. non-injured; 1.00, 0.93-1.07). CONCLUSIONS: Burn and non-burn trauma patients experience elevated rates of post-injury CVD admissions for a prolonged period after the initial injury and are particularly at increased risk of incident CVD admissions during the first 5-years after the injury event. 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 injury patients, burn and non-burn, for a prolonged period after discharge.

Western Australia population trends in the incidence of acute myocardial infarction between 1993 and 2012.

BACKGROUND: Acute myocardial infarction (AMI) incidence has been declining throughout the developed world. Australia has been an outlier to this trend, with AMI incidence reportedly increasing. This study provides a detailed investigation on the incidence of acute myocardial infarction (AMI) in Western Australia overall, and by age, sex, level of geographic remoteness and socioeconomic status. METHODS: Individual level data was sourced from routinely collected hospital admissions and the Western Australian mortality register, providing coverage of the entire population. Hospital admissions were grouping into continuous inpatient stays to avoid double counting individual AMIs. The mortality register provided coverage of out of hospital AMI deaths. RESULTS: AMI incidence decreased in Western Australia from 1993 to 2012 by 1.2% per year (95% confidence interval (CI): -1.7 to -0.8). This decrease was concentrated in the 50-80 age group, with rates for those under 50 and over 80 remaining stable. AMI rates increased in both regional (Annual percentage change (APC), 95% (CI): 4.7, 3.7 to 5.7) and remote areas (APC, 95% CI: 4.6, 3.5 to 5.6). There was a large effect of socioeconomic status, with those from the lowest quintile having a 68% higher AMI incidence than those from the highest socioeconomic quintile. CONCLUSIONS: These results are generally in line with other developed nations. Previous findings of increased incidence Australia-wide appear likely the result of double-counting AMIs within hospitals, and excluding out of hospital deaths. Further focus is required on particular subpopulations showing increased incidence of AMI, such as those in regional and remote areas. Focus on primary care prevention of cardiovascular risk factors will likely be the most effective method to ensure reductions in AMI incidence in these populations.

Respiratory Morbidity After Childhood Burns: A 10-Year Follow-up Study.

BACKGROUND AND OBJECTIVE: The systemic responses triggered by burns and resuscitative measures may cause pulmonary damage and edema in the acute phase. These effects may occur in the absence of inhalation injury. Currently, there is a paucity of data on the recovery of the respiratory system postburn. This study aimed to examine 10-year hospital service use for respiratory morbidity in children with cutaneous burns and no smoke inhalation injury. METHODS: A population-based longitudinal study with 10-year follow-up using linked hospital and death from Western Australia for children <5 years when hospitalized for a first burn injury (n = 5290) between 1980 and 2012 and a frequency matched noninjury comparison cohort, randomly selected from Western Australia's birth registrations (n = 27 061). Multivariate negative binomial and Cox proportional hazards regression models were used to generate adjusted incidence rate ratios (IRR) and hazard ratios, respectively. RESULTS: After adjustment for demographic factors and preexisting health status, the burn cohort had higher rates of admissions for influenza and viral pneumonia (IRR, 1.78; 95% confidence interval [CI], 1.10-2.87), bacterial pneumonia (IRR, 1.34; 95% CI, 1.06-1.70), and other respiratory infections (IRR, 1.65; 95% CI, 1.43-1.90. No significant difference was found for other upper respiratory tract conditions (IRR, 1.10; 95% CI, 0.98-1.23) or chronic lower respiratory diseases (IRR, 0.99; 95% CI, 0.80-1.23) compared with the uninjured cohort. CONCLUSIONS: These findings demonstrated increased respiratory infection admissions after burns. These outcomes suggest that immune changes triggered by a burn injury may persist in some children for at least 10 years after wound healing.