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

Abstract

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.

Stroke incidence in Indigenous, minority populations: a review of methods for studying stroke in Aboriginal and Torres Strait Islander Australians

“…The three studies described in this review were each conducted using different methodologies to obtain incident stroke numbers in Aboriginal Australians (numerators). The first study comprised "gold-standard" population-based methods to study stroke incidence in South Australia (Balabanski et al, 2023). The second involved a retrospective hospital-based study of stroke incidence and in-hospital deaths in Central Australia (Balabanski et al, 2020).…”

“…The second involved a retrospective hospital-based study of stroke incidence and in-hospital deaths in Central Australia (Balabanski et al, 2020). The third incorporated use of whole-of-population linked hospital and mortality data from South Australia, the Northern Territory and Western Australia (Balabanski et al, 2023). In all instances census population estimates were used as denominators.…”

“…The third study (Balabanski et al, 2023), comprising wholeof-population, person-linked hospitalization and death registry data from three jurisdictions (home to ∼20% of Australia's Aboriginal population) enabled capture of the largest number of Aboriginal people with stroke (n = 675), including fatal and non-fatal cases. This provided insights into stroke incidence by sex, jurisdiction, remoteness of residence and stroke type.…”

“…In this comparative review, we aimed to examine whether "gold-standard" stroke incidence study methods are appropriate for Indigenous, minority populations. We compared stroke incidence in three studies from the South Australia and Northern Territory Stroke (SAiNTS) Study of stroke epidemiology in Aboriginal Australians (Balabanski et al, 2018(Balabanski et al, , 2020(Balabanski et al, , 2023. All three studies were designed and undertaken in response to community priorities with Indigenous stakeholder and researcher oversight and governance to ensure the research was done for the benefit of Aboriginal Australians.…”