Determining the Optimal Methodology for Identifying Incident Stroke Deaths Using Administrative Datasets Within Australia.

BACKGROUND AND AIM: Quantifying stroke incidence and mortality is crucial for disease surveillance and health system planning. Administrative data offer a cost-effective alternative to "gold standard" population-based studies. However, the optimal methodology for establishing stroke deaths from administrative data remains unclear. We aimed to determine the optimal method for identifying stroke-related deaths in administrative datasets as the fatal component of stroke incidence, comparing counts derived using underlying and all causes of death (CoD). METHOD: Using whole-population multijurisdictional person-level linked data from hospital and death datasets from South Australia, the Northern Territory, and Western Australia, we identified first-ever stroke events between 2012 and 2015, using underlying CoD and all CoD to identify fatal stroke counts. We determined the 28-day case fatality for both counts and compared results with gold standard Australian population-based stroke incidence studies. RESULTS: The total number of incident stroke events was 16,150 using underlying CoD and 18,074 using all CoD. Case fatality was 24.7% and 32.7% using underlying and all CoD, respectively. Case fatality using underlying CoD was similar to that observed in four Australian "gold standard" population-based studies (20%-24%). CONCLUSIONS: Underlying CoD generates fatal incident stroke estimates more consistent with population-based studies than estimates based on stroke deaths identified from all-cause fields in death registers.

Incidence of Stroke in Indigenous Populations of Countries With a Very High Human Development Index: A Systematic Review.

BACKGROUND AND OBJECTIVES: Cardiovascular disease contributes significantly to disease burden among many Indigenous populations. However, data on stroke incidence in Indigenous populations are sparse. We aimed to investigate what is known of stroke incidence in Indigenous populations of countries with a very high Human Development Index (HDI), locating the research in the broader context of Indigenous health. METHODS: We identified population-based stroke incidence studies published between 1990 and 2022 among Indigenous adult populations of developed countries using PubMed, Embase, and Global Health databases, without language restriction. We excluded non-peer-reviewed sources, studies with fewer than 10 Indigenous people, or not covering a 35- to 64-year minimum age range. Two reviewers independently screened titles, abstracts, and full-text articles and extracted data. We assessed quality using "gold standard" criteria for population-based stroke incidence studies, the Newcastle-Ottawa Scale for risk of bias, and CONSIDER criteria for reporting of Indigenous health research. An Indigenous Advisory Board provided oversight for the study. RESULTS: From 13,041 publications screened, 24 studies (19 full-text articles, 5 abstracts) from 7 countries met the inclusion criteria. Age-standardized stroke incidence rate ratios were greater in Aboriginal and Torres Strait Islander Australians (1.7-3.2), American Indians (1.2), Sámi of Sweden/Norway (1.08-2.14), and Singaporean Malay (1.7-1.9), compared with respective non-Indigenous populations. Studies had substantial heterogeneity in design and risk of bias. Attack rates, male-female rate ratios, and time trends are reported where available. Few investigators reported Indigenous stakeholder involvement, with few studies meeting any of the CONSIDER criteria for research among Indigenous populations. DISCUSSION: In countries with a very high HDI, there are notable, albeit varying, disparities in stroke incidence between Indigenous and non-Indigenous populations, although there are gaps in data availability and quality. A greater understanding of stroke incidence is imperative for informing effective societal responses to socioeconomic and health disparities in these populations. Future studies into stroke incidence in Indigenous populations should be designed and conducted with Indigenous oversight and governance to facilitate improved outcomes and capacity building. REGISTRATION INFORMATION: PROSPERO registration: CRD42021242367.

A Review of Cardiac Surgical Procedures and Their Outcomes for Paediatric Rheumatic Heart Disease in Western Australia.

INTRODUCTION: Surgical intervention is an important treatment modality for advanced rheumatic heart disease (RHD). This study aimed to describe patient characteristics and outcomes from cardiac surgery for RHD in patients referred to the only tertiary paediatric hospital in Western Australia. METHODS: An analysis of patient characteristics and cardiac surgery outcomes in patients with RHD was undertaken, using data from clinical cardiac databases, medical notes, and correspondence from rural outreach clinics. RESULTS: 29 patients (59% female, 97% Aboriginal, Maori or Pacific Islander) underwent 41 valve interventions over 34 cardiac surgeries for RHD between 2000-2018. Median age at first surgery was 12.2 (range 4-16) years. Severe mitral regurgitation (MR) was the most common indication for primary surgery (62%), followed by mixed mitral regurgitation/aortic regurgitation (21%) and severe aortic regurgitation (17%). Mitral valve repair was the most common valve intervention (56%). Two patients had mitral valve replacement (MVR) at first operation, two patients had MVR at second operation and two had MVR at third operation. There was no early mortality. One patient required early (<30 days) reoperation for aortic valve repair failure. Two patients had late reoperations at 3.3 and 6.1 months after the first procedure for MR. Four (14%) patients experienced documented ARF recurrences. Late mortality occurred in 3 (10%) patients, all due to cardiac causes. On last follow-up echocardiogram 5 patients (17%) had moderate MR and none had severe MR. CONCLUSIONS: This is the first study to describe characteristics and outcomes in WA paediatric patients having surgery for RHD. Outcomes are comparable to similar studies, with favourable long-term survival.

Fracture Risk Increases After Stroke or Transient Ischemic Attack and Is Associated With Reduced Quality of Life.

BACKGROUND: Fractures are a serious consequence following stroke, but it is unclear how these events influence health-related quality of life (HRQoL). We aimed to compare annualized rates of fractures before and after stroke or transient ischemic attack (TIA), identify associated factors, and examine the relationship with HRQoL after stroke/TIA. METHODS: Retrospective cohort study using data from the Australian Stroke Clinical Registry (2009-2013) linked with hospital administrative and mortality data. Rates of fractures were assessed in the 1-year period before and after stroke/TIA. Negative binomial regression, with censoring at death, was used to identify factors associated with fractures after stroke/TIA. Respondents provided HRQoL data once between 90 and 180 days after stroke/TIA using the EuroQoL 5-dimensional 3-level instrument. Adjusted logistic regression was used to assess differences in HRQoL at 90 to 180 days by previous fracture. RESULTS: Among 13 594 adult survivors of stroke/TIA (49.7% aged ≥75 years, 45.5% female, 47.9% unable to walk on admission), 618 fractures occurred in the year before stroke/TIA (45 fractures per 1000 person-years) compared with 888 fractures in the year after stroke/TIA (74 fractures per 1000 person-years). This represented a relative increase of 63% (95% CI, 47%-80%). Factors associated with poststroke fractures included being female (incidence rate ratio [IRR], 1.34 [95% CI, 1.05-1.72]), increased age (per 10-year increase, IRR, 1.35 [95% CI, 1.21-1.50]), history of prior fracture(s; IRR, 2.56 [95% CI, 1.77-3.70]), and higher Charlson Comorbidity Scores (per 1-point increase, IRR, 1.18 [95% CI, 1.10-1.27]). Receipt of stroke unit care was associated with fewer poststroke fractures (IRR, 0.67 [95% CI, 0.49-0.93]). HRQoL at 90 to 180 days was worse among patients with prior fracture across the domains of mobility, self-care, usual activities, and pain/discomfort. CONCLUSIONS: Fracture risk increases substantially after stroke/TIA, and a history of these events is associated with poorer HRQoL at 90 to 180 days after stroke/TIA.

Incidence of Stroke in the Aboriginal and Non-Aboriginal Populations of Australia: A Data Linkage Study.

BACKGROUND: Most estimates of stroke incidence among Aboriginal and Torres Strait Islander (hereinafter Aboriginal) Australians are confined to single regions and include small sample sizes. We aimed to measure and compare stroke incidence in Aboriginal and non-Aboriginal residents across central and western Australia. METHODS: Whole-population multijurisdictional person-linked data from hospital and death datasets were used to identify stroke admissions and stroke-related deaths (2001-2015) in Western Australia, South Australia, and the Northern Territory. Fatal (including out-of-hospital deaths) and nonfatal incident (first-ever) strokes in patients aged 20-84 years were identified during the 4-year study period (2012-2015), using a 10-year lookback period to exclude people with prior stroke. Incidence rates per 100 000 population/year were estimated for Aboriginal and non-Aboriginal populations, age-standardized to the World Health Organization World Standard population. RESULTS: In a population of 3 223 711 people (3.7% Aboriginal), 11 740 incident (first-ever) strokes (20.6% regional/remote location of residence; 15.6% fatal) were identified from 2012 to 2015, 675 (5.7%) in Aboriginal people (73.6% regional/remote; 17.0% fatal). Median age of Aboriginal cases (54.5 years; 50.1% female) was 16 years younger than non-Aboriginal cases (70.3 years; 44.1% female; P<0.001), with significantly greater prevalence of comorbidities. Age-standardized stroke incidence in Aboriginal people (192/100 000 [95% CI, 177-208]) was 2.9-fold greater than in non-Aboriginal people (66/100 000 [95% CI, 65-68]) aged 20-84 years; fatal incidence was 4.2-fold greater (38/100 000 [95% CI, 31-46] versus 9/100 000 [95% CI, 9-10]). Disparities were particularly apparent at younger ages (20-54 years), where age-standardized stroke incidence was 4.3-fold greater in Aboriginal people (90/100 000 [95% CI, 81-100]) than non-Aboriginal people (21/100 000 [95% CI, 20-22]). CONCLUSIONS: Stroke occurred more commonly, and at younger ages, in Aboriginal than non-Aboriginal populations. Greater prevalence of baseline comorbidities was present in the younger Aboriginal population. Improved primary prevention is required. To optimize stroke prevention, interventions should include culturally appropriate community-based health promotion and integrated support for nonmetropolitan health services.

Rheumatic heart disease mortality in Indigenous and non-Indigenous Australians between 2010 and 2017.

OBJECTIVES: To generate contemporary age-specific mortality rates for Indigenous and non-Indigenous Australians aged <65 years who died from rheumatic heart disease (RHD) between 2013 and 2017, and to ascertain the underlying causes of death (COD) of a prevalent RHD cohort aged <65 years who died during the same period. METHODS: For this retrospective, cross-sectional epidemiological study, Australian RHD deaths for 2013-2017 were investigated by first, mortality rates generated using Australian Bureau of Statistics death registrations where RHD was a coded COD, and second COD analyses of death records for a prevalent RHD cohort identified from RHD register and hospitalisations. All analyses were undertaken by Indigenous status and age group (0-24, 25-44, 45-64 years). RESULTS: Age-specific RHD mortality rates per 100 000 were 0.32, 2.63 and 7.41 among Indigenous 0-24, 25-44 and 45-64 year olds, respectively, and the age-standardised mortality ratio (Indigenous vs non-Indigenous 0-64 year olds) was 14.0. Within the prevalent cohort who died (n=726), RHD was the underlying COD in 15.0% of all deaths, increasing to 24.6% when RHD was included as associated COD. However, other cardiovascular and non-cardiovascular conditions were the underlying COD in 34% and 43% respectively. CONCLUSION: Premature mortality in people with RHD aged <65 years has approximately halved in Australia since 1997-2005, most notably among younger Indigenous people. Mortality rates based solely on underlying COD potentially underestimates true RHD mortality burden. Further strategies are required to reduce the high Indigenous to non-Indigenous mortality rate disparity, in addition to optimising major comorbidities that contribute to non-RHD mortality.

Large Burden of Stroke Incidence in People with Cardiac Disease: A Linked Data Cohort Study.

Purpose: People with cardiac disease have 2-4 times greater risk of stroke than the general population. We measured stroke incidence in people with coronary heart disease (CHD), atrial fibrillation (AF) or valvular heart disease (VHD). Methods: We used a person-linked hospitalization/mortality dataset to identify all people hospitalized with CHD, AF or VHD (1985-2017), and stratified them as pre-existing (hospitalized 1985-2012 and alive at October 31, 2012) or new (first-ever cardiac hospitalization in the five-year study period, 2012-2017). We identified first-ever strokes occurring from 2012 to 2017 in patients aged 20-94 years and calculated age-specific and age-standardized rates (ASR) for each cardiac cohort. Results: Of the 175,560 people in the cohort, most had CHD (69.9%); 16.3% had multiple cardiac conditions. From 2012-17, 5871 first-ever strokes occurred. ASRs were greater in females than males in single and multiple condition cardiac groups, largely driven by rates in females aged ≥75 years, with stroke incidence in this age group being at least 20% greater in females than males in each cardiac subgroup. In females aged 20-54 years, stroke incidence was 4.9-fold greater in those with multiple versus single cardiac conditions. This differential declined with increasing age. Non-fatal stroke incidence was greater than fatal stroke in all age groups except in the 85-94 age group. Incidence rate ratios were up to 2-fold larger in new versus pre-existing cardiac disease. Conclusion: Stroke incidence in people with cardiac disease is substantial, with older females, and younger patients with multiple cardiac conditions, at elevated risk. These patients should be specifically targeted for evidence-based management to minimize the burden of stroke.

Corrigendum to: Evolution of non-fatal burden estimates for cardiovascular disease in Australia: a comparison of national and state-wide methodology of burden of disease.

Objective Burden of disease studies measure the impact of disease at the population level;however, methods and data sources for estimates of prevalence vary. Using a selection of cardiovascular diseases, we aimed to describe the implications of using different disease models and linked administrative data on prevalence estimation within three Australian burden of disease studies. Methods Three different methods (A = 2011 Australian Burden of Disease Study; B = 2015 Australian Burden of Disease Study; C = 2015 Western Australian Burden of Disease Study), which used linked data, were used to compare prevalence estimates of stroke, aortic aneurysm, rheumatic valvular heart disease (VHD) and non-rheumatic VHD. We applied these methods to 2015 Western Australian data, and calculated crude overall and age-specific prevalence for each condition. Results Overall, Method C produced estimates of cardiovascular prevalence that were lower than the other methods, excluding non-rheumatic VHD. Prevalence of acute and chronic stroke was up to one-third higher in Method A and B compared to Method C. Aortic aneurysms had the largest change in prevalence, with Method A producing an eight-fold higher estimate compared to Method C, but Method B was 10-20% lower. Estimates of VHD varied dramatically, with an up to six-fold change in prevalence in Method C due to substantial changes to disease models and the use of linked data. Conclusions Prevalence estimates require the best available data sources, updated disease models and constant review to inform government policy and health reform. Availability of nation-wide linked data will markedly improve future burden estimates.

Evolution of non-fatal burden estimates for cardiovascular disease in Australia: a comparison of national and state-wide methodology of burden of disease.

Objective Burden of disease studies measure the impact of disease at the population level;however, methods and data sources for estimates of prevalence vary. Using a selection of cardiovascular diseases, we aimed to describe the implications of using different disease models and linked administrative data on prevalence estimation within three Australian burden of disease studies. Methods Three different methods (A = 2011 Australian Burden of Disease Study; B = 2015 Australian Burden of Disease Study; C = 2015 Western Australian Burden of Disease Study), which used linked data, were used to compare prevalence estimates of stroke, aortic aneurysm, rheumatic valvular heart disease (VHD) and non-rheumatic VHD. We applied these methods to 2015 Western Australian data, and calculated crude overall and age-specific prevalence for each condition. Results Overall, Method C produced estimates of cardiovascular prevalence that were lower than the other methods, excluding non-rheumatic VHD. Prevalence of acute and chronic stroke was up to one-third higher in Method A and B compared to Method C. Aortic aneurysms had the largest change in prevalence, with Method A producing an eight-fold higher estimate compared to Method C, but Method B was 10-20% lower. Estimates of VHD varied dramatically, with an up to six-fold change in prevalence in Method C due to substantial changes to disease models and the use of linked data. Conclusions Prevalence estimates require the best available data sources, updated disease models and constant review to inform government policy and health reform. Availability of nation-wide linked data will markedly improve future burden estimates.

Starting the SToP trial: Lessons from a collaborative recruitment approach.

OBJECTIVE: Recruitment in research can be challenging in Australian Aboriginal contexts. We aimed to evaluate the SToP (See, Treat, Prevent skin infections) trial recruitment approach for Aboriginal families to identify barriers and facilitators and understand the utility of the visual resource used. METHODS: This qualitative participatory action research used purposive sampling to conduct six semi-structured interviews with staff and five yarning sessions with Aboriginal community members from the nine communities involved in the SToP trial that were audio recorded and transcribed verbatim before thematic analysis. FINDINGS: Community members valued the employment of local Aboriginal facilitators who used the flipchart to clearly explain the importance of healthy skin and the rationale for the SToP trial while conducting recruitment. A prolonged process, under-developed administrative systems and stigma of the research topic emerged as barriers. CONCLUSION: Partnering with a local Aboriginal organisation, employing Aboriginal researchers, and utilising flip charts for recruitment was seen by some as successful. Strengthening governance with more planning and support for recordkeeping emerged as future success factors. IMPLICATIONS FOR PUBLIC HEALTH: Our findings validate the importance of partnership for this critical phase of a research project. Recruitment strategies should be co-designed with Aboriginal research partners. Further, recruitment rates for the SToP trial provide a firm foundation for building partnerships between organisations and ensuring Aboriginal perspectives determine recruitment methods.

Children and adolescents are not small adults: toward a better understanding of multimorbidity in younger populations.

Multimorbidity is of an increasing importance for the health of both children and adults but research has hitherto focused on adult multimorbidity. Hence, public awareness, practice, and policy lack vital information about multimorbidity in childhood and adolescence. We convened an international and interdisciplinary group of experts from six nations to identify key priorities supported by published evidence to strengthen research for children and adolescent with multimorbidity. Future research is encouraged (1) to develop a conceptual framework to capture unique aspects of child and adolescent multimorbidity-including definitions, characteristic patterns of conditions for different age groups, its dynamic nature through childhood and adolescence, and understanding of severity and trajectories for different clusters of multiple chronic conditions, (2) to define new indices to classify the presence of multimorbidity in children and adolescents, (3) to improve the availability and linkage of data across countries, (4) to synthesize evidence on the global phenomenon of multimorbidity in childhood and adolescence and health inequalities, and (5) to involve children and adolescents in research relevant to their health.

Living with Rheumatic Heart Disease at the Intersection of Biomedical and Aboriginal Worldviews.

Rheumatic heart disease (RHD) significantly impacts the lives of First Nations Australians. Failure to eliminate RHD is in part attributed to healthcare strategies that fail to understand the lived experience of RHD. To rectify this, a PhD study was undertaken in the Northern Territory (NT) of Australia, combining Aboriginal ways of knowing, being and doing with interviews (24 participants from clinical and community settings) and participant observation to privilege Aboriginal voices, including the interpretations and experiences of Aboriginal co-researchers (described in the adjunct article). During analysis, Aboriginal co-researchers identified three interwoven themes: maintaining good feelings; creating clear understanding (from good information); and choosing a good djalkiri (path). These affirm a worldview that prioritises relationships, positive emotions and the wellbeing of family/community. The findings demonstrate the inter-connectedness of knowledge, choice and behaviour that become increasingly complex in stressful and traumatic health, socioeconomic, political, historical and cultural contexts. Not previously heard in the RHD domain, the findings reveal fundamental differences between Aboriginal and biomedical worldviews contributing to the failure of current approaches to communicating health messages. Mitigating this, Aboriginal co-researchers provided targeted recommendations for culturally responsive health encounters, including: communicating to create positive emotions; building trust; and providing family and community data and health messages (rather than individualistic).

The Allure of Big Data to Improve Stroke Outcomes: Review of Current Literature.

PURPOSE OF REVIEW: To critically appraise literature on recent advances and methods using "big data" to evaluate stroke outcomes and associated factors. RECENT FINDINGS: Recent big data studies provided new evidence on the incidence of stroke outcomes, and important emerging predictors of these outcomes. Main highlights included the identification of COVID-19 infection and exposure to a low-dose particulate matter as emerging predictors of mortality post-stroke. Demographic (age, sex) and geographical (rural vs. urban) disparities in outcomes were also identified. There was a surge in methodological (e.g., machine learning and validation) studies aimed at maximizing the efficiency of big data for improving the prediction of stroke outcomes. However, considerable delays remain between data generation and publication. Big data are driving rapid innovations in research of stroke outcomes, generating novel evidence for bridging practice gaps. Opportunity exists to harness big data to drive real-time improvements in stroke outcomes.

Healing Right Way: study protocol for a stepped wedge cluster randomised controlled trial to enhance rehabilitation services and improve quality of life in Aboriginal Australians after brain injury.

INTRODUCTION: Despite higher incidence of brain injury among Aboriginal compared with non-Aboriginal Australians, suboptimal engagement exists between rehabilitation services and Aboriginal brain injury survivors. Aboriginal patients often feel culturally insecure in hospital and navigation of services post discharge is complex. Health professionals report feeling ill-equipped working with Aboriginal patients. This study will test the impact of a research-informed culturally secure intervention model for Aboriginal people with brain injury. METHODS AND ANALYSIS: Design: Stepped wedge cluster randomised control trial design; intervention sequentially introduced at four pairs of healthcare sites across Western Australia at 26-week intervals.Recruitment: Aboriginal participants aged ≥18 years within 4 weeks of an acute stroke or traumatic brain injury.Intervention: (1) Cultural security training for hospital staff and (2) local, trial-specific, Aboriginal Brain Injury Coordinators supporting participants.Primary outcome: Quality-of-life using EuroQOL-5D-3L (European Quality of Life scale, five dimensions, three severity levels) Visual Analogue Scale score at 26 weeks post injury. Recruitment of 312 participants is estimated to detect a difference of 15 points with 80% power at the 5% significance level. A linear mixed model will be used to assess the between-condition difference.Secondary outcome measures: Modified Rankin Scale, Functional Independence Measure, Modified Caregiver Strain Index, Hospital Anxiety and Depression Scale at 12 and 26 weeks post injury, rehabilitation occasions of service received, hospital compliance with minimum care processes by 26 weeks post injury, acceptability of Intervention Package, feasibility of Aboriginal Brain Injury Coordinator role.Evaluations: An economic evaluation will determine the potential cost-effectiveness of the intervention. Process evaluation will document fidelity to study processes and capture changing contexts including barriers to intervention implementation and acceptability/feasibility of the intervention through participant questionnaires at 12 and 26 weeks. ETHICS AND DISSEMINATION: The study has approvals from Aboriginal, university and health services human research ethics committees. Findings will be disseminated through stakeholder reports, participant workshops, peer-reviewed journal articles and conference papers. TRIAL REGISTRATION NUMBER: ACTRN12618000139279.

Study protocol for a prospective process evaluation of a culturally secure rehabilitation programme for Aboriginal Australians after brain injury: the Healing Right Way project.

INTRODUCTION: Aboriginal and Torres Strait Islander (hereafter respectfully referred to as Aboriginal) people are Australia's First Peoples, having the longest continuous culture in the world and deep spiritual connections with ancestral land. Improvements in their health and well-being is a major policy goal of Australian governments, as the legacy of colonisation and disruption of cultural practices contribute to major health challenges. Lack of culturally secure services impacts participation of Aboriginal people in health services. Aboriginal people with a brain injury typically experience poor access to rehabilitation and support following hospital discharge. 'Healing Right Way' (HRW) is a randomised control trial aiming to improve access to interdisciplinary and culturally secure rehabilitation services for Aboriginal people after brain injury in Western Australia, improve health outcomes and provide the first best practice model. This protocol is for the process evaluation of the HRW trial. METHODS AND ANALYSIS: A prospective mixed methods process evaluation will use the Consolidated Framework for Implementation Research to evaluate implementation and intervention processes involved in HRW. Data collection includes qualitative and quantitative data from all sites during control and intervention phases, relating to three categories: (1) implementation of trial processes; (2) cultural security training; and (3) Aboriginal Brain Injury Coordinator role. Additional data elements collected from HRW will support the process evaluation regarding fidelity and intervention integrity. Iterative cross-sectional and longitudinal data synthesis will support the implementation of HRW, interpretation of findings and inform future development and implementation of culturally secure interventions for Aboriginal people. ETHICS AND DISSEMINATION: This process evaluation was reviewed by The University of Western Australia Human Research Ethics Committee (RA/4/20/4952). Evaluation findings will be disseminated via academic mechanisms, seminars at trial sites, regional Aboriginal health forums, peak bodies for Aboriginal health organisations and the Australian Indigenous HealthInfoNet (https://healthinfonet.ecu.edu.au/). TRIAL REGISTRATION NUMBER: ACTRN12618000139279.

The Incidence of Stroke in Indigenous Populations of Countries With a Very High Human Development Index: A Systematic Review Protocol.

Background and Aims: Despite known Indigenous health and socioeconomic disadvantage in countries with a Very High Human Development Index, data on the incidence of stroke in these populations are sparse. With oversight from an Indigenous Advisory Board, we will undertake a systematic review of the incidence of stroke in Indigenous populations of developed countries or regions, with comparisons between Indigenous and non-Indigenous populations of the same region, though not between different Indigenous populations. Methods: Using PubMed, OVID-EMBASE, and Global Health databases, we will examine population-based incidence studies of stroke in Indigenous adult populations of developed countries published 1990-current, without language restriction. Non-peer-reviewed sources, studies including <10 Indigenous People, or with insufficient data to determine incidence, will be excluded. Two reviewers will independently validate the search strategies, screen titles and abstracts, and record reasons for rejection. Relevant articles will undergo full-text screening, with standard data extracted for all studies included. Quality assessment will include Sudlow and Warlow's criteria for population-based stroke incidence studies, the Newcastle-Ottawa Scale for risk of bias, and the CONSIDER checklist for Indigenous research. Results: Primary outcomes include crude, age-specific and/or age-standardized incidence of stroke. Secondary outcomes include overall stroke rates, incidence rate ratio and case-fatality. Results will be synthesized in figures and tables, describing data sources, populations, methodology, and findings. Within-population meta-analysis will be performed if, and where, methodologically sound and comparable studies allow this. Conclusion: We will undertake the first systematic review assessing disparities in stroke incidence in Indigenous populations of developed countries. Data outputs will be disseminated to relevant Indigenous stakeholders to inform public health and policy research.

Can the CHA2 DS2 -VA schema be used to decide on anticoagulant therapy in Aboriginal and other Australians with non-valvular atrial fibrillation?

The Australasian guidelines recommend use of the CHA2 DS2 -VA schema to stratify ischaemic stroke risk in patients with non-valvular atrial fibrillation (N-VAF) and determine risk thresholds for recommending oral anticoagulant (OAC) therapy. However, the CHA2 DS2 -VA score has not been validated in a representative Australian population cohort with N-VAF, including in Aboriginal people who are known to have a higher age-adjusted stroke risk than other Australians. In a retrospective data-linkage study of 49 114 patients aged 24-84 years with N-VAF, 40.0% women and 2.5% Aboriginal, we found that patients with a CHA2 DS2 -VA score >2 had high annual stroke rates (>2%) that would justify OAC therapy. This occurred regardless of Aboriginal status. Non-Aboriginal patients with a CHA2 DS2 -VA score of 0 had a mean annual stroke rate of 0.4%, and hence were not likely to benefit from antithrombotic therapy. However, Aboriginal patients with a zero CHA2 DS2 -VA score had a significantly higher annual stroke rate of 0.9%, and could potentially obtain net clinical benefit from anticoagulation, primarily with the safer non-vitamin K antagonist OAC. We conclude that clinicians can confidently use the CHA2 DS2 -VA score to make decisions regarding anticoagulation in accordance with stroke risk in patients with N-VAF, except in Aboriginal people in whom the risk score was unable to identify those at truly low risk of stroke.

Investigating inequities in cardiovascular care and outcomes for Queensland Aboriginal and Torres Strait Islander people: protocol for a hospital-based retrospective cohort data linkage project.

INTRODUCTION: Cardiovascular disease (CVD) represents a significant burden of disease for Aboriginal and Torres Strait Islander people, a population that continues to experience a lower life expectancy than other Australians. The aim of the Better Cardiac Care Data Linkage project is to describe patient care pathways and to identify disparities in care and health outcomes between Aboriginal and Torres Strait Islander people and other Queensland residents diagnosed with CVD in the state of Queensland. METHODS: This is a population-based retrospective cohort study using linked regional, state and national health and administrative data collections to describe disparities in CVD healthcare in primary and secondary prevention settings and during hospitalisation. The CVD cohort will be identified from the Queensland Hospital Admitted Patient Data Collection for admissions that occurred between 1 July 2010 and 31 June 2016 and will include relevant International Classification of Disease codes for ischaemic heart disease, congestive heart failure, stroke, acute rheumatic fever and rheumatic heart disease. Person-level data will be linked by Data Linkage Queensland and the Australian Institute of Health and Welfare (AIHW) in accordance with ethical and public health approvals to describe the patient journey prior to, during and post the hospital admission. ANALYSIS: This project will focus largely on descriptive epidemiological measures and multivariate analysis of clinical care standards and outcomes for Aboriginal and Torres Strait Islander people compared with other Queenslanders, including identification of risk factors for suboptimal care and change over time. Variation in care pathways and patient outcomes will be compared by Indigenous status, sex, age group, remoteness of residence, year of index hospitalisation and socioeconomic status. Cox models for time-to-event data and mixed models or generalised estimating equations for longitudinal data will be used to measure change over time where temporal effects exist. ETHICS AND DISSEMINATION: Ethical approval has been granted by Human Research Ethics Committees of the Prince Charles Hospital (HREC/15/QPCH/289) and the AIHW (EO2016-1-233). The Northern Territory Department of Health and Menzies School of Health Research have also provided reciprocal ethical approval of the project (HREC 2019-3490). The deidentified results will be summarised in a report and shared with investigators, advisory groups, Queensland Health and key stakeholders. Findings will be disseminated through workshops, conferences and will be published in peer-reviewed journals.