Stroke incidence and subtypes in Aboriginal people in remote Australia: a healthcare network population-based study

Abstract

OBJECTIVES: We aimed to compare the incidence, subtypes and aetiology of stroke, and in-hospital death due to stroke, between Aboriginal and non-Aboriginal people in Central Australia, a remote region of Australia where a high proportion Aboriginal people reside (40% of the population). We hypothesised that the rates of stroke, particularly in younger adults, would be greater in the Aboriginal population, compared with the non-Aboriginal population; we aimed to elucidate causes for any identified disparities. DESIGN: A retrospective population-based study of patients hospitalised with stroke within a defined region from 1 January 2011 to 31 December 2014. SETTING: Alice Springs Hospital, the only neuroimaging-capable acute hospital in Central Australia, serving a network of 50 healthcare facilities covering 672 000 km2. PARTICIPANTS: 161 residents (63.4% Aboriginal) of the catchment area admitted to hospital with stroke. PRIMARY AND SECONDARY OUTCOME MEASURES: Rates of first-ever stroke, overall (all events) stroke and in-hospital death. RESULTS: Of 121 residents with first-ever stroke, 61% identified as Aboriginal. Median onset-age (54 years) was 17 years younger in Aboriginal patients (p<0.001), and age-standardised stroke incidence was threefold that of non-Aboriginal patients (153 vs 51 per 100 000, incidence rate ratio 3.0, 95% CI 2 to 4). The rate ratios for the overall rate of stroke (first-ever and recurrent) were similar. In Aboriginal patients aged <55 years, the incidence of ischaemic stroke was 14-fold greater (95% CI 4 to 45), and intracerebral haemorrhage 19-fold greater (95% CI 3 to 142) than in non-Aboriginal patients. Crude prevalence of diabetes mellitus (70.3% vs 34.0%, p<0.001) and hypercholesterolaemia (68.9% vs 51.1%, p=0.049) was greater, and age-standardised in-hospital deaths were fivefold greater (35 vs 7 per 100 000, 95% CI 2 to 11) in Aboriginal patients than in non-Aboriginal patients. CONCLUSIONS: Stroke incidence (both subtypes) and in-hospital deaths for remote Aboriginal Australians are dramatically greater than in non-Aboriginal people, especially in patients aged <55 years.