Aneurysmal subarachnoid haemorrhage in Indigenous and non-Indigenous Australians: A retrospective study assessing patient characteristics and outcome

Introduction: Smoking and hypertension are prevalent among Indigenous Australians (Aboriginal and Torres Strait Islanders). We investigated if these risk factors suggest a greater rate of aneurysmal subarachnoid haemorrhage in Indigenous Australians (IA) compared to non-IA. Materials and methods: A retrospective cross-sectional study was performed on data retrieved from the Nationwide Hospital Morbidity Database for all aSAH cases in Australia between 2012 and 2018. Patient characteristics, radiological findings, aneurysm characteristics, treatment characteristics and discharge outcomes were assessed. Crude and age-adjusted incidences, trends of aSAH and case fatality rate over time were calculated. Results: A total of 12,286 patients were included (285 IA, 12,001 non-IA). Indigenous aSAH patients were significantly younger than non-IA, with 89.8 percent of IA younger than 65 years old (p < 0.001). Crude annual incidences were similar between the 2 cohorts, however age-adjusted incidence shows a RR = 1.4 at 45–59 years in IA patients, compared with their non-IA counterparts. 30-day mortality was similar between the two groups, at 25.3 and 26.9% for IA and non-IA groups, respectively. Conclusion: This 10 year nationwide retrospective study highlights a disparity between the crude and age-adjusted incidence of aSAH in IA compared to non-IA.