Aneurysmal subarachnoid haemorrhage in Māori and European New Zealanders - A comparative study

A retrospective analysis of 358 patients admitted to the neurosurgical unit at a tertiary referral centre in Aotearoa New Zealand between 2010 and 2017 was undertaken to describe the relationship of ethnicity to demographic, disease characteristic and outcome data in Māori and European New Zealanders experiencing aneurysmal subarachnoid haemorrhage (aSAH). Māori had a higher incidence (RR 1.38, p = 0.01; 95 % CI 1.08-1.77) and presented at a younger age (mean age difference of 5 years). Higher rates of smoking and hypertension were observed in the Māori population studied. However, these do not fully explain any other differences observed. There was no significant difference in clinical grade at presentation. However, despite experiencing lower rates of posterior circulation aneurysms (adjusted OR 0.33, p = 0.05) and radiological findings predicting highest risk of vasospasm i.e., Modified Rankin Scale 4 (OR 0.54, p = 0.02), Māori had a higher incidence of clinical vasospasm (adjusted OR 1.40, p = 0.048, 95 % CI 1.01-1.98). While there was no observed difference in mortality, Māori may experience lower rates of excellent neurological recovery and survive with greater disability compared to European New Zealanders. Overall, this study is suggestive of inequities between Māori and European New Zealanders and highlights the need for further investigation in this area.