The burden and prognostic significance of suspected sepsis in the prehospital setting: A state-wide population-based cohort study

OBJECTIVE

Despite high in-hospital mortality, the epidemiology of prehospital suspected sepsis presentations is not well described. This retrospective cohort study aimed to quantify the burden of such presentations, and to determine whether such a diagnosis was independently associated with longer-term mortality.

METHODS

Retrospective, observational population-based cohort study examining all adult prehospital presentations in Victoria, between January 2015 and June 2019, who required subsequent in-hospital assessment. Linked data were extracted from clinical and administrative datasets. Demographics, illness severity, prehospital treatment and mortality were compared between prehospital suspected sepsis and non-sepsis patients. Multivariable logistic regression was used to determine the adjusted association between prehospital assessment (suspected sepsis vs non-sepsis) and 6-month mortality.

RESULTS

A total of 1 218 047 patients were included. The age-adjusted incidence rate of prehospital suspected sepsis was 65 cases per 100 000 person-years. Those with prehospital suspected sepsis were older (74 vs 62 years), more frequently male (55% vs 47%), with greater physiological derangement. Intravenous cannulas were more often inserted prehospital (60% vs 29%). Crude in-hospital mortality was 6.5-fold higher in the prehospital suspected sepsis group (11.8% vs 1.8%), and by 6 months, 22.6% had died. After adjustment for demographics, illness severity, comorbidity, treatment and hospital location, a diagnosis of prehospital suspected sepsis was associated with a 35% higher likelihood of 6-month mortality (OR 1.35, 95% CI 1.29-1.41).

CONCLUSIONS

The burden of prehospital suspected sepsis in the Australian setting is significant, with paramedics identifying patients at high-risk of poor longer-term outcomes. This implies the need to consider improved care pathways for this highly vulnerable group.

Antidepressant Exposure and DNA Methylation: Insights from a Methylome-Wide Association Study

Importance

Understanding antidepressant mechanisms could help design more effective and tolerated treatments.

Objective

Identify DNA methylation (DNAm) changes associated with antidepressant exposure.

Design

Case-control methylome-wide association studies (MWAS) of antidepressant exposure were performed from blood samples collected between 2006-2011 in Generation Scotland (GS). The summary statistics were tested for enrichment in specific tissues, gene ontologies and an independent MWAS in the Netherlands Study of Depression and Anxiety (NESDA). A methylation profile score (MPS) was derived and tested for its association with antidepressant exposure in eight independent cohorts, alongside prospective data from GS.

Setting

Cohorts; GS, NESDA, FTC, SHIP-Trend, FOR2107, LBC1936, MARS-UniDep, ALSPAC, E-Risk, and NTR.

Participants

Participants with DNAm data and self-report/prescription derived antidepressant exposure.

Main Outcomes and Measures

Whole-blood DNAm levels were assayed by the EPIC/450K Illumina array (9 studies, N exposed = 661, N unexposed = 9,575) alongside MBD-Seq in NESDA (N exposed = 398, N unexposed = 414). Antidepressant exposure was measured by self- report and/or antidepressant prescriptions.

Results

The self-report MWAS (N = 16,536, N exposed = 1,508, mean age = 48, 59% female) and the prescription-derived MWAS (N = 7,951, N exposed = 861, mean age = 47, 59% female), found hypermethylation at seven and four DNAm sites (p < 9.42x10 -8 ), respectively. The top locus was cg26277237 ( KANK1, p self-report = 9.3x10 -13 , p prescription = 6.1x10 -3 ). The self-report MWAS found a differentially methylated region, mapping to DGUOK-AS1 ( p adj = 5.0x10 -3 ) alongside significant enrichment for genes expressed in the amygdala, the "synaptic vesicle membrane" gene ontology and the top 1% of CpGs from the NESDA MWAS (OR = 1.39, p < 0.042). The MPS was associated with antidepressant exposure in meta-analysed data from external cohorts (N studies = 9, N = 10,236, N exposed = 661, f3 = 0.196, p < 1x10 -4 ).

Conclusions and Relevance

Antidepressant exposure is associated with changes in DNAm across different cohorts. Further investigation into these changes could inform on new targets for antidepressant treatments.

3 Key Points

Question: Is antidepressant exposure associated with differential whole blood DNA methylation?Findings: In this methylome-wide association study of 16,536 adults across Scotland, antidepressant exposure was significantly associated with hypermethylation at CpGs mapping to KANK1 and DGUOK-AS1. A methylation profile score trained on this sample was significantly associated with antidepressant exposure (pooled f3 [95%CI]=0.196 [0.105, 0.288], p < 1x10 -4 ) in a meta-analysis of external datasets. Meaning: Antidepressant exposure is associated with hypermethylation at KANK1 and DGUOK-AS1 , which have roles in mitochondrial metabolism and neurite outgrowth. If replicated in future studies, targeting these genes could inform the design of more effective and better tolerated treatments for depression.

Healthcare and economic cost burden of emergency medical services treated non-traumatic shock using a population-based cohort in Victoria, Australia

OBJECTIVES

We aimed to assess the healthcare costs and impact on the economy at large arising from emergency medical services (EMS) treated non-traumatic shock.

DESIGN

We conducted a population-based cohort study, where EMS-treated patients were individually linked to hospital-wide and state-wide administrative datasets. Direct healthcare costs (Australian dollars, AUD) were estimated for each element of care using a casemix funding method. The impact on productivity was assessed using a Markov state-transition model with a 3-year horizon.

SETTING

Patients older than 18 years of age with shock not related to trauma who received care by EMS (1 January 2015-30 June 2019) in Victoria, Australia were included in the analysis.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome assessed was the total healthcare expenditure. Secondary outcomes included healthcare expenditure stratified by shock aetiology, years of life lived (YLL), productivity-adjusted life-years (PALYs) and productivity losses.

RESULTS

A total of 21 334 patients (mean age 65.9 (±19.1) years, and 9641 (45.2%) females were treated by EMS with non-traumatic shock with an average healthcare-related cost of $A11 031 per episode of care and total cost of $A280 million. Annual costs remained stable throughout the study period, but average costs per episode of care increased (Ptrend=0.05). Among patients who survived to hospital, the average cost per episode of care was stratified by aetiology with cardiogenic shock costing $A24 382, $A21 254 for septic shock, $A19 915 for hypovolaemic shock and $A28 057 for obstructive shock. Modelling demonstrated that over a 3-year horizon the cohort lost 24 355 YLLs and 5059 PALYs. Lost human capital due to premature mortality led to productivity-related losses of $A374 million. When extrapolated to the entire Australian population, productivity losses approached $A1.5 billion ($A326 million annually).

CONCLUSION

The direct healthcare costs and indirect loss of productivity among patients with non-traumatic shock are high. Targeted public health measures that seek to reduce the incidence of shock and improve systems of care are needed to reduce the financial burden of this syndrome.

Refining ambulance clinical response models: The impact on ambulance response and emergency department presentations

OBJECTIVE

The ambulance service in Victoria, Australia implemented a revised clinical response model (CRM) in 2016 which was designed to increase the diversion of low-acuity Triple Zero (000) calls to secondary telephone triage and reduce emergency ambulance dispatches. The present study evaluates the influence of the revised CRM on emergency ambulance response times and ED presentations.

METHODS

A retrospective study of emergency calls for ambulance between 1 January 2015 and 31 December 2018. Ambulance data were linked with ED presentations occurring up to 48 h after contact. Interrupted time series analyses were used to evaluate the impact of the revised CRM.

RESULTS

A total of 2 365 529 calls were included. The proportion allocated a Code 1 (time-critical, lights/sirens) dispatch decreased from 56.6 to 41.0% after implementation of the revised CRM. The proportion of calls not receiving an emergency ambulance increased from 10.4 to 19.6%. Interrupted time series analyses demonstrated an improvement in Code 1 cases attended within 15 min (Key Performance Indicator). However, for patients with out-of-hospital cardiac arrest or requiring lights and sirens transport to hospital, there was no improvement in response time performance. By the end of the study period, there was also no difference in the proportion of callers presenting to ED when compared with the estimated proportion assuming the revised CRM had not been implemented.

CONCLUSION

The revised CRM was associated with improved Code 1 response time performance. However, there was no improvement in response times for high acuity patients, and no change in the proportion of callers presenting to ED.

Characteristics and Outcomes of Patients Referred to a General Practitioner by Victorian Paramedics

OBJECTIVE

Many patients who are attended by paramedics do not require conveyance to an emergency department (ED). Our study focuses on comparing the characteristics and outcomes of patients who were advised to follow up with a general practitioner (GP) by an attending paramedic with those of patients who were discharged at scene or transported to hospital.

METHODS

This was a retrospective data linkage cohort study of ambulance, ED, hospital admission, and death records for all adults attended by paramedics in Victoria, Australia between the 1st of January 2015 and 30th of June 2019. Patients were excluded if they presented in cardiac arrest, resided in a residential aged care facility, or were receiving palliative care services. Outcomes of interest included reattendance by ambulance, ED presentation; and, a high acuity outcome which we defined as a patient who (1) presented to ED and received an Australasian Triage Scale of category 1 (Resuscitation) or 2 (Emergency) AND was admitted to a ward OR (2) was admitted to an Intensive Care Unit, Coronary Care Unit or Catheter laboratory (regardless of triage category) OR (3) died. Outcomes of interest were considered within 48-h of initial EMS attendance.

RESULTS

A total of 1,777,950 cases were included in the study of which 3.1% were referred to a GP, 9.0% were discharged at scene without a follow-up recommendation, and 87.9% were transported to hospital. Patients referred to a GP were more likely than those discharged at scene to subsequently present to an ED within 48 h of their attendance (5.3% vs 3.8%). However, GP referral was not associated with any change to high acuity outcome (0.3% vs 0.2%) or ambulance reattendance (6.0% vs 6.0%) compared to discharge at scene. The only factors that were associated with ambulance reattendance, ED presentation, and a high acuity outcome were male gender and elevated temperature.

CONCLUSIONS

Despite increasing low and medium-acuity casework in this EMS system, paramedic referral to a GP is not common practice. Referring a patient to a GP did not reduce the likelihood of patients experiencing a high acuity outcome or recalling an ambulance within 48 h, suggesting opportunity exists to refine paramedic to GP referral practices.

Impact of socioeconomic status on presentation, care quality and outcomes of patients attended by emergency medical services for dyspnoea: a population-based cohort study

BACKGROUND

Low socioeconomic status (SES) has been linked to poor outcomes in many conditions. It is unknown whether these disparities extend to individuals presenting with dyspnoea. We aimed to evaluate the relationship between SES and incidence, care quality and outcomes among patients attended by emergency medical services (EMS) for dyspnoea.

METHODS

This population-based cohort study included consecutive patients attended by EMS for dyspnoea between 1 January 2015 and 30 June 2019 in Victoria, Australia. Data were obtained from individually linked ambulance, hospital and mortality datasets. Patients were stratified into SES quintiles using a composite census-derived index.

RESULTS

A total of 262 412 patients were included. There was a stepwise increase in the age-adjusted incidence of EMS attendance for dyspnoea with increasing socioeconomic disadvantage (lowest SES quintile 2269 versus highest quintile 889 per 100 000 person years, ptrend<0.001). Patients of lower SES were younger and more comorbid, more likely to be from regional Victoria or of Aboriginal or Torres Strait Islander heritage and had higher rates of respiratory distress. Despite this, lower SES groups were less frequently assigned a high acuity EMS transport or emergency department (ED) triage category and less frequently transported to tertiary centres or hospitals with intensive care unit facilities. In multivariable models, lower SES was independently associated with lower acuity EMS and ED triage, ED length of stay>4 hours and increased 30-day EMS reattendance and mortality.

CONCLUSION

Lower SES was associated with a higher incidence of EMS attendances for dyspnoea and disparities in several metrics of care and clinical outcomes.

Association of socioeconomic status in the incidence, quality-of-care metrics, and outcomes for patients with cardiogenic shock in a pre-hospital setting

AIMS

The relationship between lower socioeconomic status (SES) and poor cardiovascular outcomes is well described; however, there exists a paucity of data exploring this association in cardiogenic shock (CS). This study aimed to investigate whether any disparities exist between SES and the incidence, quality of care or outcomes of CS patients attended by emergency medical services (EMS).

METHODS AND RESULTS

This population-based cohort study included consecutive patients transported by EMS with CS between 1 January 2015 and 30 June 2019 in Victoria, Australia. Data were collected from individually linked ambulance, hospital, and mortality datasets. Patients were stratified into SES quintiles using national census data produced by the Australian Bureau of Statistics.A total of 2628 patients were attended by EMS for CS. The age-standardized incidence of CS amongst all patients was 11.8 [95% confidence interval (95% CI), 11.4-12.3] per 100 000 person-years, with a stepwise increase from the highest to lowest SES quintile (lowest quintile 17.0 vs. highest quintile 9.7 per 100 000 person-years, P-trend < 0.001). Patients in lower SES quintiles were less likely to attend metropolitan hospitals and more likely to be received by inner regional and remote centres without revascularization capabilities. A greater proportion of the lower SES groups presented with CS due to non-ST elevation myocardial infarction (NSTEMI) or unstable angina pectoris (UAP), and overall were less likely to undergo coronary angiography. Multivariable analysis demonstrated an increased 30-day all-cause mortality rate in the lowest three SES quintiles when compared with the highest quintile.

CONCLUSION

This population-based study demonstrated discrepancies between SES status in the incidence, care metrics, and mortality rates of patients presenting to EMS with CS. These findings outline the challenges in equitable healthcare delivery within this cohort.

Dose Escalation in Esophageal Cancer: Comparing Pre-Accrual and On-Trial Target Volume Delineation in the UK SCOPE2 Trial

PURPOSE/OBJECTIVE(S)

The ongoing UK SCOPE2 trial evaluates radiotherapy (RT) dose escalation and PET-guided systemic therapy in esophageal cancer, and has an accompanying RT trials quality assurance (RTTQA) program, evolved through the preceding SCOPE trials. We compare pre-accrual with on-trial individual case review (ICR) target volume delineation (TVD).

MATERIALS/METHODS

Prior to recruitment, centers were required to undertake TVD exercises using 3D/4D DICOM datasets with relevant clinical details and a RT planning guidance document (RPGD) provided. Contours were then compared against the RTTQA team-defined gold standard. Exceptions were those who had satisfied QA requirements for a previous esophageal RT trial (NeoSCOPE). For ICRs, prospective reviews (prior RT start, PRs) were undertaken for each center's first submission, plus high-dose cases submitted pending formal safety review. Additional PRs were undertaken at the RTTQA team's discretion. Timely retrospective reviews (within 2 weeks of RT start, TRR) were also undertaken for a random 10% sample. TVDs were assessed for compliance using predefined criteria and the RPGD. Resubmission was requested at reviewer's discretion, usually due to unacceptable variation (UV) from protocol. Clarification was sought before contour approval/resubmission request if appropriate. Review outcomes were then evaluated. PTV6000 was new to SCOPE2, along with a greater emphasis on use of 4DCT than in prior SCOPE trials.

RESULTS

A total of 85 pre-accrual cases from 33 UK centers were reviewed, of which 20 (24%) were resubmissions, and 50 (59%) were accepted. 99 TVD UVs were observed in 49 cases, most commonly in CTVB (42/99, 42%), which included editing for normal structures and elective lymph node regions, followed by ITV (4D cases only, 14/52, 27%) and PTV6000 (13/99, 13%). 121 ICRs from 31 UK centers were available for review. 87 (72%) were PRs and 34 (28%) TRRs. 43 (36%) completed the relevant SCOPE2 exercise. 19 (16%) were resubmissions, and 82 (68%) were accepted. 72 UVs were observed in 45 ICRs; again, most commonly in CTVB (34/72, 48%), PTV6000 (high dose arm only, 11/46, 24%) and ITV (4D only, 5/26, 19%). Of the 45 cases where a UV was recorded, 16 (36%) had completed the relevant SCOPE2 pre-accrual. Comparing area of UV on SCOPE2 pre-accrual cases and ICRs, 3 (19%) contours contained the same (2 = CTVB, 1 = PTV6000), 5 (31%) contained different and 8 (50%) had no UVs at pre-accrual. The rate of UV was significantly lower for ICR than for pre-accrual submissions (0.60 and 1.16 respectively, p = 0.001).

CONCLUSION

Significantly fewer UVs in ICR compared with pre-accrual supports a robust, educational RTTQA program through national collaboration and evolving trial series. CTVB, along with newer volumes of ITV and PTV6000, were recurring UV domains and should inform RPGD development and RTTQA for ongoing recruitment and future trials.

Risk-standardized mortality metric to monitor hospital performance for chest pain presentations

AIMS

Risk-standardized mortality rates (RSMR) have been used to monitor hospital performance in procedural and disease-based registries, but limitations include the potential to promote risk-averse clinician decisions and a lack of assessment of the whole patient journey. We aimed to determine whether it is feasible to use RSMR at the symptom-level to monitor hospital performance using routinely collected, linked, clinical and administrative data of chest pain presentations.

METHODS AND RESULTS

We included 192 978 consecutive adult patients (mean age 62 years; 51% female) with acute chest pain without ST-elevation brought via emergency medical services (EMS) to 53 emergency departments in Victoria, Australia (1/1/2015-30/6/2019). From 32 candidate variables, a risk-adjusted logistic regression model for 30-day mortality (C-statistic 0.899) was developed, with excellent calibration in the full cohort and with optimism-adjusted bootstrap internal validation. Annual 30-day RSMR was calculated by dividing each hospital's observed mortality by the expected mortality rate and multiplying it by the annual mean 30-day mortality rate. Hospital performance according to annual 30-day RSMR was lower for outer regional or remote locations and at hospitals without revascularisation capabilities. Hospital rates of angiography or transfer for patients diagnosed with non-ST elevation myocardial infarction (NSTEMI) correlated with annual 30-day RSMR, but no correlations were observed with other existing key performance indicators.

CONCLUSION

Annual hospital 30-day RSMR can be feasibly calculated at the symptom-level using routinely collected, linked clinical, and administrative data. This outcome-based metric appears to provide additional information for monitoring hospital performance in comparison with existing process of care key performance measures.

Chest pain epidemiology and care quality for Aboriginal and Torres Strait Islander peoples in Victoria, Australia: a population-based cohort study from 2015 to 2019

Background

This study examined chest pain epidemiology and care quality for Aboriginal and Torres Strait Islander ('Indigenous') patients presenting to hospital via emergency medical services (EMS) with chest pain.

Methods

State-wide population-based cohort study of consecutive patients attended by ambulance for acute chest pain with individual linkage to emergency, hospital admission and mortality data in the state of Victoria, Australia from January 2015 to June 2019. Multivariable models were used to assess for differences in pre-hospital and hospital adherence to care quality, process measures and clinical outcomes.

Findings

From 204,969 EMS attendances for chest pain, 3890 attendances (1.9%) identified as Aboriginal or Torres Strait Islander. Age-standardized incidence rates were higher overall for Indigenous people (3128 vs. 1147 per 100,000 person-years, incidence rate ratio 2.73, 95% CI 2.72-2.74), this difference being particularly striking for younger patients, women, and those residing in outer regional areas. In multivariable models, adherence to care quality and process measures was lower for attendances involving Indigenous people. In the pre-hospital setting, Indigenous people were less likely to be provided intravenous access or analgesia. In the hospital setting, Indigenous people were less likely to be seen by emergency clinicians within target time and less likely to transferred following myocardial infarction to a revascularization capable centre.

Interpretation

Incidence of acute chest pain presentations is high among Indigenous people in Victoria, Australia. Opportunities to improve the quality of care for Indigenous Australians presenting with acute chest pain are identified.

Funding

National Health and Medical Research Council, National Heart Foundation.

Observation versus intervention for incidental common bile duct stones at intraoperative cholangiogram: a systematic review

BACKGROUND

The natural history of incidental common bile duct stones (CBDS) is poorly understood. Current evidence is conflicting, with several studies suggesting the majority may pass spontaneously. Despite this, guidelines recommend routine removal even if asymptomatic. This study aimed to systematically review the outcomes of expectant management for CBDS detected on operative cholangiography during cholecystectomy.

METHODS

MEDLINE, Embase and CINAHL databases were systematically searched. Participants were adult patients with CBDS identified by intraoperative cholangiography. Intervention was regarded as any perioperative effort to remove common bile duct stones, including endoscopic retrograde cholangiopancreatography (ERCP), laparoscopic and open bile duct exploration. This was compared to observation. Outcomes of interest included rates of spontaneous stone passage, success of duct clearance and complications. Risk of bias was assessed using the ROBINS-I tool.

RESULTS

Eight studies were included. All studies were non-randomized, heterogeneous and at serious risk of bias. In patients observed after a positive IOC, 20.9% went on to have symptomatic retained stones. In patients directed to ERCP for positive IOC, persistent CBDS were found in 50.6%. Spontaneous passage was not associated with stone size. Meta-analysis is dominated by the results from one large database, which recommends intervention for incidental stones, despite low rates of persistent stones seen at postoperative ERCP.

CONCLUSIONS

Further evidence is required before a definitive recommendation on observation can be made. There is some evidence that asymptomatic stones may be safely observed. In clinical scenarios where the risks of biliary intervention are considered high, a conservative strategy could be more widely considered.

Variation in Health Care Processes, Quality and Outcomes According to Day and Time of Chest Pain Presentation via Ambulance

BACKGROUND

Previous studies examining temporal variations in cardiovascular care have largely been limited to assessing weekend and after-hours effects. We aimed to determine whether more complex temporal variation patterns might exist in chest pain care.

METHODS

This was a population-based study of consecutive adult patients attended by emergency medical services (EMS) for non-traumatic chest pain without ST elevation in Victoria, Australia between 1 January 2015 and 30 June 2019. Multivariable models were used to assess whether time of day and week stratified into 168 hourly time periods was associated with care processes and outcomes.

RESULTS

There were 196,365 EMS chest pain attendances; mean age 62.4 years (standard deviation [SD] 18.3) and 51% females. Presentations demonstrated a diurnal pattern, a Monday-Sunday gradient (Monday peak) and a reverse weekend effect (lower rates on weekends). Five temporal patterns were observed for care quality and process measures, including a diurnal pattern (longer emergency department [ED] length of stay), an after-hours pattern (lower angiography or transfer for myocardial infarction, pre-hospital aspirin administration), a weekend effect (shorter ED clinician review, shorter EMS off-load time), an afternoon/evening peak period pattern (longer ED clinician review, longer EMS off-load time) and a Monday-Sunday gradient (ED clinician review, EMS offload time). Risk of 30-day mortality was associated with weekend presentation (Odds ratio [OR] 1.15, p=0.001) and morning presentation (OR 1.17, p<0.001) while risk of 30-day EMS reattendance was associated with peak period (OR 1.16, p<0.001) and weekend presentation (OR 1.07, p<0.001).

CONCLUSIONS

Chest pain care demonstrates complex temporal variation beyond the already established weekend and after-hours effect. Such relationships should be considered during resource allocation and quality improvement programs to improve care across all days and times of the week.

Healthcare cost burden of acute chest pain presentations

BACKGROUND

This study aimed to estimate the direct healthcare cost burden of acute chest pain attendances presenting to ambulance in Victoria, Australia, and to identify key cost drivers especially among low-risk patients.

METHODS

State-wide population-based cohort study of consecutive adult patients attended by ambulance for acute chest pain with individual linkage to emergency and hospital admission data in Victoria, Australia (1 January 2015-30 June 2019). Direct healthcare costs, adjusted for inflation to 2020-2021 ($A), were estimated for each component of care using a casemix funding method.

RESULTS

From 241 627 ambulance attendances for chest pain during the study period, mean chest pain episode cost was $6284, and total annual costs were estimated at $337.4 million ($68 per capita per annum). Total annual costs increased across the period ($310.5 million in 2015 vs $384.5 million in 2019), while mean episode costs remained stable. Cardiovascular conditions (25% of presentations) were the most expensive (mean $11 523, total annual $148.7 million), while a non-specific pain diagnosis (49% of presentations) was the least expensive (mean $3836, total annual $93.4 million). Patients classified as being at low risk of myocardial infarction, mortality or hospital admission (Early Chest pain Admission, Myocardial infarction, and Mortality (ECAMM) score) represented 31%-57% of the cohort, with total annual costs estimated at $60.6 million-$135.4 million, depending on the score cut-off used.

CONCLUSIONS

Total annual costs for acute chest pain presentations are increasing, and a significant proportion of the cost burden relates to low-risk patients and non-specific pain. These data highlight the need to improve the cost-efficiency of chest pain care pathways.

Chest Pain Management Using Prehospital Point-of-Care Troponin and Paramedic Risk Assessment

Importance

Prehospital point-of-care troponin testing and paramedic risk stratification might improve the efficiency of chest pain care pathways compared with existing processes with equivalent health outcomes, but the association with health care costs is unclear.

Objective

To analyze whether prehospital point-of-care troponin testing and paramedic risk stratification could result in cost savings compared with existing chest pain care pathways.

Design, Setting, and Participants

In this economic evaluation of adults with acute chest pain without ST-segment elevation, cost-minimization analysis was used to assess linked ambulance, emergency, and hospital attendance in the state of Victoria, Australia, between January 1, 2015, and June 30, 2019.

Interventions

Paramedic risk stratification and point-of-care troponin testing.

Main Outcomes and Measures

The outcome was estimated mean annualized statewide costs for acute chest pain. Between May 17 and June 25, 2022, decision tree models were developed to estimate costs under 3 pathways: (1) existing care, (2) paramedic risk stratification and point-of-care troponin testing without prehospital discharge, or (3) prehospital discharge and referral to a virtual emergency department (ED) for low-risk patients. Probabilities for the prehospital pathways were derived from a review of the literature. Multivariable probabilistic sensitivity analysis with 50 000 Monte Carlo iterations was used to estimate mean costs and cost differences among pathways.

Results

A total of 188 551 patients attended by ambulance for chest pain (mean [SD] age, 61.9 [18.3] years; 50.5% female; 49.5% male; Indigenous Australian, 2.0%) were included in the model. Estimated annualized infrastructure and staffing costs for the point-of-care troponin pathways, assuming a 5-year device life span, was $2.27 million for the pathway without prehospital discharge and $4.60 million for the pathway with prehospital discharge (incorporating virtual ED costs). In the decision tree model, total annual cost using prehospital point-of-care troponin and paramedic risk stratification was lower compared with existing care both without prehospital discharge (cost savings, $6.45 million; 95% uncertainty interval [UI], $0.59-$16.52 million; lower in 94.1% of iterations) and with prehospital discharge (cost savings, $42.84 million; 95% UI, $19.35-$72.26 million; lower in 100% of iterations).

Conclusions and Relevance

Prehospital point-of-care troponin and paramedic risk stratification for patients with acute chest pain could result in substantial cost savings. These findings should be considered by policy makers in decisions surrounding the potential utility of prehospital chest pain risk stratification and point-of-care troponin models provided that safety is confirmed in prospective studies.

Epidemiology, outcomes and predictors of mortality in patients transported by ambulance for dyspnoea: A population-based cohort study

OBJECTIVES

There are currently limited data to inform the management of patients transported by emergency medical services (EMS) with dyspnoea. We aimed to describe the incidence, aetiology and outcomes of patients transported by EMS for dyspnoea using a large population-based sample and to identify factors associated with 30-day mortality.

METHODS

Consecutive EMS attendances for dyspnoea in Victoria, Australia from January 2015 to June 2019 were included. Data were individually linked to hospital and mortality records to determine incidence, diagnoses, and outcomes. Factors associated with 30-day mortality were assessed using multivariable logistic regression.

RESULTS

During the study period, there were 2 505 324 cases attended by EMS, of whom 346 228 (14%) met inclusion criteria for dyspnoea. The incidence of EMS attendances for dyspnoea was 1566 per 100 000 person-years, and was higher in females, older patients and socially disadvantaged areas. Of the 271 204 successfully linked cases (median age 76 years; 51% women), 79% required hospital admission with a 30-day mortality of 9%. The most common final diagnoses (and 30-day mortality rates) were lower respiratory tract infection (13%, mortality 11%), chronic obstructive pulmonary disease (13%, mortality 6.4%), heart failure (9.1%, mortality 9.8%), arrhythmias (3.9%, mortality 4.4%), acute coronary syndromes (3.9%, mortality 9.5%) and asthma (3.2%, mortality 0.5%). Predictors of mortality included older age, male sex, pre-existing chronic kidney disease, heart failure or cancer, abnormal respiratory status or vital signs and pre-hospital intubation.

CONCLUSION

Dyspnoea is a common presentation with a broad range of causes and is associated with high rates of hospitalisation and death.

Age as a predictor of clinical outcomes and determinant of therapeutic measures for emergency medical services treated cardiogenic shock

BACKGROUND

The impact of age on outcomes in cardiogenic shock (CS) is poorly described in the pre-hospital setting. We assessed the impact of age on outcomes of patients treated by emergency medical services (EMS).

METHODS

This population-based cohort study included consecutive adult patients with CS transported to hospital by EMS. Successfully linked patients were stratified into tertiles by age (18-63, 64-77, and > 77 years). Predictors of 30-day mortality were assessed through regression analyses. The primary outcome was 30-day all-cause mortality.

RESULTS

A total of 3523 patients with CS were successfully linked to state health records. The average age was 68 ± 16 years and 1398 (40%) were female. Older patients were more likely to have comorbidities including pre-existing coronary artery disease, hypertension, dyslipidemia, diabetes mellitus, and cerebrovascular disease. The incidence of CS was significantly greater with increasing age (incidence rate per 100,000 person years 6.47 [95% CI: 6.1-6.8] in age 18-63 years, 34.34 [32.4-36.4] in age 64-77 years, 74.87 [70.6-79.3] in age > 77 years, P < 0.001). There was a step-wise increase in the rate of 30-day mortality with increasing age tertile. After adjustment, compared to the lowest age tertile, patients aged > 77 years had increased risk of 30-day mortality (adjusted hazard ratio = 2.26 [95% CI: 1.96-2.60]). Older patients were less likely to receive inpatient coronary angiography.

CONCLUSION

Older patients with EMS-treated CS have significantly higher rates of short-term mortality. The reduced rates of invasive interventions in older patients underscore the need for further development of systems of care to improve outcomes for this patient group.

Spring and latch dynamics can act as control pathways in ultrafast systems

Ultrafast movements propelled by springs and released by latches are thought limited to energetic adjustments prior to movement, and seemingly cannot adjust once movement begins. Even so, across the tree of life, ultrafast organisms navigate dynamic environments and generate a range of movements, suggesting unrecognized capabilities for control. We develop a framework of control pathways leveraging the non-linear dynamics of spring-propelled, latch-released systems. We analytically model spring dynamics and develop reduced-parameter models of latch dynamics to quantify how they can be tuned internally or through changing external environments. Using Lagrangian mechanics, we test feedforward and feedback control implementation via spring and latch dynamics. We establish through empirically-informed modeling that ultrafast movement can be controllably varied during latch release and spring propulsion. A deeper understanding of the interconnection between multiple control pathways, and the tunability of each control pathway, in ultrafast biomechanical systems presented here has the potential to expand the capabilities of synthetic ultra-fast systems and provides a new framework to understand the behaviors of fast organisms subject to perturbations and environmental non-idealities.

Outcomes of paediatric patients who are not transported to hospital by Emergency Medical Services: a data linkage study

BACKGROUND

Data on the safety of non-transport decisions for paediatric patients attended by Emergency Medical Services (EMS) are lacking. We describe the characteristics and outcomes of paediatric non-transported patients in Victoria, Australia.

METHODS

A retrospective data linkage study of consecutive paediatric (aged <18 years) non-transported patients between January 2015 and June 2019. Patients were linked to ED, hospital admission and death records. Multivariable logistic regression analyses were used to determine factors associated with EMS recontact, ED presentation, hospital admission and an adverse event (death/cardiac arrest, intensive care unit admission or highest ED triage category) within 48 hours of the initial emergency call.

RESULTS

In total, 62 975 non-transported patients were included. The mean age was 7.1 (SD 6.0) years and 48.9% were male. Overall, 2.2% recontacted the EMS within 48 hours, 13.7% self-presented to a public ED, 2.4% were admitted to hospital and 0.1% had an adverse event, including two deaths. Among patients with paramedic-initiated non-transport (excluding transport refusals and transport via other means), 5.6% presented to a public ED, 1.1% were admitted to hospital and 0.05% had an adverse event. In the overall population, an abnormal vital sign on initial assessment increased the odds of hospital admission and an adverse event. Among paramedic-initiated non-transports, cases occurring in the early hours of the morning (04:00-08:00 hours) were associated with increased odds of subsequent hospital admission, while the odds of ED presentation and hospital admission also increased with increasing prior exposure to non-transported cases.

CONCLUSION

Adverse events were rare among paramedic-initiated non-transport cases. Vital sign derangements and attendance by paramedics with higher prior exposure to non-transports were associated with poorer outcomes and may be used to improve safety.

Temperature-related chest pain presentations and future projections with climate change

BACKGROUND

Climate change has led to increased interest in studying adverse health effects relating to ambient temperatures. It is unclear whether incident chest pain is associated with non-optimal temperatures and how chest pain presentation rates might be affected by climate change.

METHODS

The study included ambulance data of chest pain presentations in Melbourne, Australia from 1/1/2015 to 30/6/2019 with linkage to hospital and emergency discharge diagnosis data. A time series quasi-Poisson regression with a distributed lag nonlinear model was fitted to assess the temperature-chest pain presentation associations overall and according to age, sex, socioeconomic status, and event location subgroups, with adjustment for season, day of the week and long-term trend. Future excess chest pain presentations associated with cold and heat were projected under six general circulation models under medium and high emission scenarios.

RESULTS

In 206,789 chest pain presentations, mean (SD) age was 61.2 (18.9) years and 50.3 % were female. Significant heat- and cold-related increased risk of chest pain presentations were observed for mean air temperatures above and below 20.8 °C, respectively. Excess chest pain presentations related to heat were observed in all subgroups, but appeared to be attenuated for older patients (≥70 years), patients of higher socioeconomic status (SES), and patients developing chest pain at home. We projected increases in heat-related chest pain presentations with climate change under both medium- and high-emission scenarios, which are offset by decreases in chest pain presentations related to cold temperatures.

CONCLUSIONS

Heat- and cold- exposure appear to increase the risk of chest pain presentations, especially among younger patients and patients of lower SES. This will have important implications with climate change modelling of chest pain, in particular highlighting the importance of risk mitigation strategies to minimise adverse health impacts on hotter days.

Temperature-related chest pain presentations and future projections with climate change

Background

Climate change has led to increased interest in studying adverse health effects relating to ambient temperatures. It is unclear whether incident chest pain is associated with non-optimal temperatures and how chest pain presentation rates might be affected by climate change.

Methods

The study included ambulance data of chest pain presentations in Melbourne, Australia from 1/1/2015 to 30/6/2019 with linkage to hospital and emergency discharge diagnosis data. A time series quasi-Poisson regression with a distributed lag nonlinear model was fitted to assess the temperature-chest pain presentation associations, after adjusting for season, day of the week and long-term trend. Future excess chest pain presentations associated with cold and heat were projected under six general circulation models under medium and high emission scenarios.

Results

In 206,789 chest pain presentations, mean (SD) age was 61.2 (18.9) years and 50.3% were female. Significant heat- and cold-related increased risk of chest pain presentations were observed for mean air temperatures above and below 20.8°C, respectively (Figure 1). Excess chest pain presentations related to heat were observed in all subgroups, but appeared to be attenuated for older patients (≥70 years) and patients of higher socioeconomic status (SES). We projected no significant change in net temperature-related chest pain presentations with climate change under medium- and high-emission scenarios, with increases in heat-related chest pain presentations offset by decreases in chest pain presentations related to cold temperatures.

Conclusions

Heat- and cold-exposure appear to increase risk of chest pain presentations, especially among younger patients and patients of lower SES. In Melbourne, Australia, chest pain presentations overall were not projected to increase with climate change, but increases in heat-related chest pain presentations highlight the importance of risk mitigation strategies to minimise adverse health impacts on hotter days.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Alfred Health.

Impact of ambulance off-load delays on mortality in patients with chest pain

Background

Ambulance off-load delays in transferring patient care to emergency departments (EDs) are increasingly common, but it is unclear whether clinical outcomes are impacted.

Methods

Population-based cohort study of ambulance attendances for non-traumatic chest pain transported to ED in Victoria, Australia (1/1/2015–30/6/2019) excluding patients transported to hospital with “lights and sirens” or triaged as ED category 1. Multivariable models were used to assess the relationship between ambulance off-load times and 30-day mortality and ambulance re-attendance for chest pain.

Results

The study included 213,544 ambulance attendances for chest pain (mean age 62 [SD 18] years; 51% female). Median ambulance off-load times increased across the study period from 21 minutes (interquartile range [IQR] 15–30) in 2015 to 24 minutes (IQR 17–37) in 2019. Patients were divided into tertiles according to off-load times with 69,247 patients included in tertile 1 (0–17 minutes), 73,109 patients in tertile 2 (18–28 minutes), and 71,188 patients in tertile 3 (&gt;28 minutes). In multivariable models, ambulance off-load delays were associated with higher unadjusted and adjusted rates of 30-day mortality (1.57% tertile 3 vs. 1.29% tertile 1, adjusted risk difference 0.28% [95% CI 0.16% - 0.42%], p&lt;0.001) and ambulance re-attendance for chest pain (9.89% tertile 3 vs. 8.59% tertile 1, adjusted risk difference 1.30% [95% CI 1.00% - 1.61%], p&lt;0.001). Similarly, in analysis using off-load times as a continuous variable with restricted cubic splines, a non-linear increase in adjusted odds ratio for mortality was observed (Figure 1).

Conclusions

Delays in ambulance off-load times appear to be associated with increased mortality and ambulance re-attendance risk among chest pain cohorts. This study has important policy implications given the increasing frequency of off-load delays in many healthcare settings.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Alfred health

Variation in health-care quality and outcomes according to time of chest pain presentation: a state-wide prospective cohort study

Background

Previous studies examining temporal variation in cardiovascular care have largely been limited to assessing weekend and after-hours effects whereby those presenting on the weekend or after-hours have a poorer outcome. However, emerging evidence suggests more complex patterns in patterns and outcomes may exist.

Purpose

We aimed to determine patterns of temporal variation in chest pain presentations and subsequent health-care quality and outcomes.

Methods

This was an observational, prospective-cohort study of adult patients aged 18 and over who were attended by emergency medical services for non-traumatic chest pain between 1 January 2015 and 30 June 2019 in Victoria, Australia. Major exclusion criteria included pre-hospital diagnosis of ST elevation myocardial infarction or an out of hospital cardiac arrest. The exposure variable was time of day and day of week stratified into 168 hourly time periods. The primary outcome measure was 30-day mortality.

Results

The study cohort comprised 196,365 ambulance attendances for acute non-traumatic chest pain; mean age 62.4 years (SD 18.3) and 99,497 (50.7%) females. Three temporal patterns were observed for chest pain presentations (Figure 1): (1) a diurnal pattern with a sharp increase in presentations from 8 am, peaking around midday, before decreasing into late evening with a nadir between 3–4 am, (2) a weekend effect where Saturday and Sunday had a relatively lower rate of presentations compared to during the week, and (3) a Monday – Sunday gradient where more presentations were likely earlier in the week, than later. Six patterns were identified across pre-hospital and hospital key performance indicators (KPI) (diurnal, in/after-hours, weekend effect, Monday – Sunday gradient, a peak period and morning vs afternoon/evening effect. Risk of 30-day mortality was associated with weekend presentation (OR 1.15, 95% CI 1.06–1.24, p=0.001) and morning presentation between midnight and midday (OR 1.17, 95% CI 1.09–1.25, p&lt;0.001) (Figure 2).

Conclusion

Chest pain presentations, care quality and outcomes demonstrate complex temporal variation beyond the already established weekend and after-hours effect. Such relationships should be considered during resource allocation and quality improvement programs in order to improve treatment quality across all days and times of the week.

Funding Acknowledgement

Type of funding sources: None.

The influence of ambulance offload time on 30-day risks of death and re-presentation for patients with chest pain

OBJECTIVE

To assess whether ambulance offload time influences the risks of death or ambulance re-attendance within 30 days of initial emergency department (ED) presentations by adults with non-traumatic chest pain.

DESIGN, SETTING

Population-based observational cohort study of consecutive presentations by adults with non-traumatic chest pain transported by ambulance to Victorian EDs, 1 January 2015 - 30 June 2019.

PARTICIPANTS

Adults (18 years or older) with non-traumatic chest pain, excluding patients with ST elevation myocardial infarction (pre-hospital electrocardiography) and those who were transferred between hospitals or not transported to hospital (eg, cardiac arrest or death prior to transport).

MAIN OUTCOME MEASURES

Primary outcome: 30-day all-cause mortality (Victorian Death Index data).

SECONDARY OUTCOME

Transport by ambulance with chest pain to ED within 30 days of initial ED presentation.

RESULTS

We included 213 544 people with chest pain transported by ambulance to EDs (mean age, 62 [SD, 18] years; 109 027 women [51%]). The median offload time increased from 21 (IQR, 15-30) minutes in 2015 to 24 (IQR, 17-37) minutes during the first half of 2019. Three offload time tertiles were defined to include approximately equal patient numbers: tertile 1 (0-17 minutes), tertile 2 (18-28 minutes), and tertile 3 (more than 28 minutes). In multivariable models, 30-day risk of death was greater for patients in tertile 3 than those in tertile 1 (adjusted rates, 1.57% v 1.29%; adjusted risk difference, 0.28 [95% CI, 0.16-0.42] percentage points), as was that of a second ambulance attendance with chest pain (adjusted rates, 9.03% v 8.15%; adjusted risk difference, 0.87 [95% CI, 0.57-1.18] percentage points).

CONCLUSIONS

Longer ambulance offload times are associated with greater 30-day risks of death and ambulance re-attendance for people presenting to EDs with chest pain. Improving the speed of ambulance-to-ED transfers is urgently required.

HOSPITAL CHARACTERISTICS ARE ASSOCIATED WITH CLINICAL OUTCOMES IN PATIENTS WITH CARDIOGENIC SHOCK

ABSTRACT

Background: Regionalized systems of care for the management of cardiogenic shock (CS) are increasingly being utilized. This study aims to assess whether receiving hospital characteristics such as the availability of 24-hour coronary angiography, on-site cardiac surgery, and annual treated CS volume influence outcomes in patients transferred by emergency medical services (EMS) to hospital with CS. Methods: This population-based cohort study included consecutive adult patients with CS who were transferred to hospital by EMS between January 1, 2015 and June 30, 2019 in Victoria, Australia. Data were obtained from individually linked ambulance, hospital, and state death index data sets. The primary outcome assessed was 30-day mortality stratified by the availability of 24-hour coronary angiography (cardiac center) at the receiving hospital. Results: A total of 3,217 patients were transferred to hospital with CS. The population had an average age of 67.9 +/- 16.1 years, and 1,289 (40.1%) were female. EMS transfer to a cardiac center was associated with significantly reduced rates of 30-day mortality (adjusted odds ratio [aOR], 0.78; 95% confidence interval [CI], 0.64-0.95), compared with noncardiac centers. Compared with the lowest annual CS volume quartile (<18 cases per year), hospitals in the highest volume quartile (>55 cases per year) had reduced risk of 30-day mortality (aOR, 0.71; 95% CI, 0.56-0.91). A stepwise reduction in the adjusted probability of 30-day mortality was observed in patients transferred by EMS to trauma level 1 centers (34.6%), compared with cardiothoracic surgical centers (39.0%), noncardiac surgical metropolitan (44.9%), and rural (51.3%) cardiac centers, all P < 0.05. Conclusion: Receiving hospital characteristics are associated with survival outcomes in patients with CS. These finding have important implications for establishing regionalized systems of care for patients with CS who are transferred to hospital by EMS.

Gender Disparities in Cardiogenic Shock Treatment and Outcomes

Cardiogenic shock is associated with a high risk for morbidity and mortality. The impact of gender on treatment and outcomes is poorly defined. This study aimed to evaluate whether gender influences the clinical management and outcomes of patients with prehospital cardiogenic shock. Consecutive adult patients with cardiogenic shock who were transferred to hospital by emergency medical services (EMS) between January 1, 2015 and June 30, 2019 in Victoria, Australia were included. Data were obtained from individually linked ambulance, hospital, and state death index datasets. The primary outcome assessed was 30-day mortality, stratified by patient gender. Propensity score matching was performed for risk adjustment. Over the study period a total of 3,465 patients were identified and 1,389 patients (40.1%) were women. Propensity score matching yielded 1,330 matched pairs with no differences observed in baseline characteristics, including age, initial vital signs, pre-existing co-morbidities, etiology of shock, and prehospital interventions. In the matched cohort, women had higher rates of 30-day mortality (44.7% vs 39.2%, p = 0.009), underwent less coronary angiography (18.3% vs 27.2%, p <0.001), and revascularization with percutaneous coronary intervention (8.9% vs 14.2%, p <0.001), compared with men. In conclusion, in this large population-based study, women with cardiogenic shock who were transferred by EMS to hospital had significantly worse survival outcomes and reduced rates of invasive cardiac interventions compared to men. These data underscore the urgent need for targeted public health measures to redress gender differences in outcomes and variation with clinical care for patients with cardiogenic shock.

Determining the sensitivity of emergency dispatcher and paramedic diagnosis of stroke: statewide registry linkage study

Introduction

Correctly identifying people with suspected stroke is essential for ensuring rapid treatment. Our aims were to determine the sensitivity of emergency dispatcher and paramedic identification of patients with stroke, the factors associated with correct identification, and whether there were any implications for hospital arrival times.

Methods

Observational study using patient‐level data from the Australian Stroke Clinical Registry (2015–2017) linked with ambulance and emergency department records for the state of Victoria. The registry diagnosis was the reference standard to compare with the provisional diagnoses made by emergency services personnel classified as “suspected” and “not suspected” stroke/transient ischemic attack (TIA). Multivariable logistic and quintile regressions were used to determine factors associated with correct identification and timely arrival to hospital.

Results

Overall, 4717 (64%) were matched to ambulance transport records (median age: 73 years, 43% female). Stroke/TIA was suspected in 56% of registrants by call‐takers and 69% by paramedics. Older patients (75+ years) (adjusted odds ratio [aOR]: 0.61; 95% confidence interval [CI]: 0.49–0.75), females (aOR: 0.86; 95% CI: 0.75–0.99), those with severe stroke or intracerebral hemorrhage were less often suspected as stroke. Cases identified as stroke had a shorter arrival time to hospital (unadjusted median minutes: stroke, 54 [43, 72] vs not stroke, 66 [51, 89]).

Conclusions

Emergency dispatchers and paramedics identified over half of patients with stroke in the prehospital setting. Important patient characteristics, such as being female and those having a severe stroke, were found that may enable refinement of prehospital ambulance protocols and dispatcher/paramedic education. Those correctly identified as stroke, arrived earlier to hospital optimizing their chances of receiving time‐critical treatments.

Development and validation of a comprehensive early risk prediction model for patients with undifferentiated acute chest pain

Aims

Existing risk scores for undifferentiated chest pain focus on excluding coronary events and do not represent a comprehensive risk assessment if an alternate serious diagnosis is present. This study aimed to develop and validate an all-inclusive risk prediction model among patients with undifferentiated chest pain.

Methods

We developed and validated a multivariable logistic regression model for a composite measure of early all-inclusive risk (defined as hospital admission excluding a discharge diagnosis of non-specific pain, 30-day all-cause mortality, or 30-day myocardial infarction [MI]) among adults assessed by emergency medical services (EMS) for non-traumatic chest pain using a large population-based cohort (January 2015 to June 2019). The cohort was randomly divided into development (146,507 patients [70%]) and validation (62,788 patients [30%]) cohorts.

Results

The composite outcome occurred in 28.4%, comprising hospital admission in 27.7%, mortality within 30-days in 1.8%, and MI within 30-days in 0.4%. The Early Chest pain Admission, MI, and Mortality (ECAMM) risk model was developed, demonstrating good discrimination in the development (C-statistic 0.775, 95% CI 0.772-0.777) and validation cohorts (C-statistic 0.765, 95% CI 0.761-0.769) with excellent calibration. Discriminatory performance for the composite outcome and individual components was higher than existing scores commonly used in undifferentiated chest pain risk stratification.

Conclusions

The ECAMM risk score model can be used as an all-inclusive risk stratification assessment of patients with non-traumatic chest pain without the limitation of a single diagnostic outcome. This model could be clinically useful to help guide decisions surrounding the need for non-coronary investigations and safety of early discharge.

Incidence, diagnoses and outcomes of ambulance attendances for chest pain: A population-based cohort study

AIMS

Non-traumatic chest pain is one of the most common reasons for calls for emergency assistance and places a significant burden on health services. This study aimed to determine age- and sex-specific incidences, diagnoses, and outcomes of patients with chest pain attended by paramedics using a large population-based sample.

METHODS

Consecutive emergency medical services (EMS) attendances for non-traumatic chest pain in Victoria, Australia from January 2015 to June 2019 were included. Data were individually linked to emergency, hospital admission and mortality records.

RESULTS

During the study period (representing 22,186,930 person-years), chest pain was the reason for contacting EMS in 257,017 of 2,736,570 attendances (9.4%). Overall incidence of chest pain attendances was 1,158 (per 100,000 person-years) with a higher incidence observed with increasing age, among females, among Aboriginal and Torres Strait Islanders, in regional settings, and in socially disadvantaged areas. The most common diagnoses were non-specific pain (46%; 30-day mortality 0.5%), non-ST elevation myocardial infarction (5.3%; mortality 1.3%), pneumonia (3.8%; mortality 3.9%), stable coronary syndromes (3.5%; mortality 0.8%), unstable angina (3.3%; mortality 1.3%), and ST-elevation myocardial infarction (2.8%; mortality 7.0%), while pulmonary embolism (0.7%; mortality 3.2%) and aortic pathologies (0.2%; mortality 22.2%) were rare.

CONCLUSIONS

Chest pain accounts for one in ten ambulance calls, and underlying causes are diverse, with substantial differences according to age and sex. Almost half of patients are discharged from hospital with a diagnosis of non-specific pain and low rates of mortality.

Association of Socioeconomic Status With Outcomes and Care Quality in Patients Presenting With Undifferentiated Chest Pain in the Setting of Universal Health Care Coverage

BACKGROUND

This study aimed to assess whether there are disparities in incidence rates, care, and outcomes for patients with chest pain attended by emergency medical services according to socioeconomic status (SES) in a universal health coverage setting.

METHODS AND RESULTS

This was a population‐based cohort study of individually linked ambulance, emergency, hospital admission, and mortality data in the state of Victoria, Australia, from January 2015 to June 2019 that included 183 232 consecutive emergency medical services attendances for adults with nontraumatic chest pain (mean age 62 [SD 18] years; 51% women) and excluded out‐of‐hospital cardiac arrest and ST‐segment–elevation myocardial infarction. Age‐standardized incidence of chest pain was higher for patients residing in lower SES areas (lowest SES quintile 1595 versus highest SES quintile 760 per 100 000 person‐years; P<0.001). Patients of lower SES were less likely to attend metropolitan, private, or revascularization‐capable hospitals and had greater comorbidities. In multivariable models adjusted for clinical characteristics and final diagnosis, lower SES quintiles were associated with increased risks of 30‐day and long‐term mortality, readmission for chest pain and acute coronary syndrome, lower acuity emergency department triage categorization, emergency department length of stay >4 hours, and emergency department or emergency medical services discharge without hospital admission and were inversely associated with use of prehospital ECGs and transfer to a revascularization‐capable hospital for patients presenting to non‐percutaneous coronary intervention centers.

CONCLUSIONS

In this study, lower SES was associated with a higher incidence of chest pain presentations to emergency medical services and differences in care and outcomes. These findings suggest that substantial disparities for socioeconomically disadvantaged chest pain cohorts exist, even in the setting of universal health care access.

Incidence and Outcomes of Nontraumatic Shock in Adults Using Emergency Medical Services in Victoria, Australia

IMPORTANCE

Nontraumatic shock is a challenging clinical condition, presenting urgent and unique demands in the prehospital setting. There is a paucity of data assessing its incidence, etiology, and clinical outcomes.

OBJECTIVE

To assess the incidence, etiology, and clinical outcomes of patients treated by emergency medical services (EMS) with nontraumatic shock using a large population-based sample.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study included consecutive adult patients with shock not related to trauma who received care by EMS between January 1, 2015, and June 30, 2019, in Victoria, Australia. Data were obtained from individually linked ambulance, hospital, and state death index data sets. During the study period there were 2 485 311 cases attended by EMS, of which 16 827 met the study's inclusion criteria for shock.

MAIN OUTCOMES AND MEASURES

The primary outcome was 30-day mortality. Secondary outcomes included length of hospital stay, emergency department discharge disposition, rates of coronary angiography and revascularization procedures, and the use of mechanical circulatory support.

RESULTS

A total of 12 695 patients were successfully linked, with a mean (SD) age of 65.7 (19.1) years; 6411 (50.5%) were men. The overall population-wide incidence of EMS-treated prehospital shock was 76 (95% CI, 75-77) per 100 000 person-years. An increased incidence was observed in men (79 [77-81] per 100 000 person-years), older patients (eg, aged 70-79 years: 177 [171-183] per 100 000 person-years), regional locations (outer regional or remote: 100 [94-107] per 100 000 person-years), and in areas with increased socioeconomic disadvantage (lowest socioeconomic status quintile: 92 [89-95] per 100 000 person-years). Patients with hospital outcome data were stratified into shock etiologies; 3615 (28.5%) had cardiogenic shock: 3998 (31.5%), septic shock; 1457 (11.5%), hypovolemic shock; and 3625 (28.6%), other causes of shock. Nearly one-third of patients (4158 [32.8%]) were deceased at 30 days. In multivariable analyses, increased age (all etiologies: hazard ratio [HR], 1.04; 95% CI, 1.03-1.04), female sex (cardiogenic shock: HR, 1.26; 95% CI, 1.12-1.42), increased initial heart rate (all etiologies: 1.01; 95% CI, 1.00-1.01), prehospital intubation (all etiologies: HR, 3.93; 95% CI, 3.48-4.44), and preexisting comorbidities (eg, chronic kidney disease, all etiologies: HR, 1.25; 95% CI, 1.10-1.42) were independently associated with 30-day mortality, while higher socioeconomic status (all etiologies: HR, 0.96; 95% CI, 0.94-0.98) and increased initial systolic blood pressure (all etiologies: HR, 0.99; 95% CI, 0.99-0.99) were associated with lower risk.

CONCLUSIONS AND RELEVANCE

This population-level cohort study found that EMS-treated nontraumatic shock was a common condition, with a high risk of morbidity and mortality regardless of etiology. It disproportionately affected men, older patients, patients in regional areas, and those with social disadvantage. Further studies are required to assess how current systems of care can be optimized to improve outcomes.

Linking Ambulance Records with Hospital and Death Index Data to Evaluate Patient Outcomes

Objective

Linkage of electronic administrative datasets is becoming increasingly common, offering a powerful resource for research and analysis. However, routine linkage of prehospital data with emergency department (ED) presentation and hospital admission datasets is rare. We describe a methodology used to link ambulance data with hospital ED presentations, admissions, and death records, and examine potential biases between matched and unmatched patients.

Methods

Iterative deterministic linkage methodologies were employed to link clinical, operational, and secondary triage ambulance data to ED presentations, hospital admissions, and death records in Victoria, Australia. Descriptive analyses and standardised differences were used to examine potential biases between matched and unmatched patients.

Results

A total of 2,813,913 ambulance records were available for linkage. Of the patients that were transported to a public ED (n=1,753,268), 83.3% matched with an ED record. Only small differences were observed between matched and unmatched patients for sex, year, time of day and attending crew type. The data elements with the largest standardised differences were patient age (0.25) and paramedic diagnosis (0.25). Matched patients were older (mean ± standard deviation: 55.6±25.7 vs 49.0±26.0 years) and more likely to have a paramedic-suspected cardiac, respiratory, neurological, or gastrointestinal/genitourinary condition, suspected infection/sepsis, or pain.

Conclusion

This linked dataset will facilitate a large body of research into prehospital care and patient outcomes. Although future analysis of matched patients should acknowledge the linkage error rate, our findings suggest that results are likely to be generalisable to the broader ambulance population.

Linking Data From the Australian Stroke Clinical Registry With Ambulance and Emergency Administrative Data in Victoria

Objective: In Australia, approximately 3 in 4 people with acute stroke use an ambulance. Few examples of merging ambulance clinical records, hospital government data, and national registry data for stroke exist. We sought to understand the advantages of using linked datasets for describing the full clinical journey of people with stroke and the possibility of investigating their long-term outcomes based on pre-hospital management of stroke. Method: Patient-level data from the Australian Stroke Clinical Registry (AuSCR) (January 2013-October 2017) were linked with Ambulance Victoria (AV) records and Victorian Emergency Minimum Dataset (VEMD). Probabilistic iterative matching on personal identifiers were used and records merged with a project specific identification number. Results: Of the 7,373 episodes in the AuSCR and 6,001 in the AV dataset; 4,569 (62%) were matched. Unmatched records that were positive for “arrival by ambulance” in the AuSCR and VEMD (no corresponding record in AV) were submitted to AV. AV were able to identify 148/435 additional records related to these episodes. The final cohort included 4,717 records (median age: 73 years, female 42%, ischemic stroke 66%). Conclusion: The results of the data linkage provides greater confidence for use of these data for future research related to pre-hospital management of stroke.

Ambulance management of patients with penetrating truncal trauma and hypotension in Melbourne, Australia

OBJECTIVE

Penetrating truncal trauma with hypotension is uncommon in Australia. Current pre-hospital clinical practice guidelines based on overseas studies recommend expedited transport to definitive trauma care and that i.v. fluid should only be administered to maintain palpable blood pressure.

METHODS

A retrospective review included all adult patients with penetrating truncal trauma and hypotension (systolic blood pressure <90 mmHg) attended by emergency medical services in Victoria between January 2006 and December 2018. Patient pre-hospital characteristics and hospital outcomes are described using descriptive statistics. Predictors of fluid resuscitation and mortality were examined using logistic regression analyses.

RESULTS

Between 2006 and 2018 there were 101 hypotensive, penetrating truncal injury major trauma patients in Melbourne, Victoria transported by road ambulance to a major trauma service. The median age of these patients was 38 years (interquartile range [IQR] 27-50) and 85% were male. Median scene time was 16.6 min (IQR 12-26) and median pre-hospital time was 53.0 min (IQR 38-66). Intravenous fluid resuscitation was given in 54.5% of cases. The mechanism of injury was stabbing in 91.1% and gunshot wound in 8.9%. Urgent surgery was required in 72.3% of cases, 32.7% of patients were admitted to the intensive care unit and there were eight deaths (8.3%).

CONCLUSION

Penetrating truncal trauma with hypotension is rare in Melbourne, Australia with most patients having the injury caused by stabbing rather than shooting. Compared with outcomes reported in the USA and Europe, the mortality rate is low.