Platform Presentation The Joint Annual Meeting of the Stroke Society of Australasia (SSA) and Smartstrokes 2023

Changes in stroke incidence among major ethnic groups in New Zealand between 1981- 2021 (#11)

Rita V Krishnamurthi 1 , Balakrishnan Nair 1 , Yogini Ratnasabapathy 2 , Anna Ranta 3 , Alan A Barber 4 , Suzanne Barker-Collo 5 , Craig Anderson 6 , Derrick Bennett 7 , Amanda Thrift 8 , Dominique Cadilhac 9 , Bruce Arroll 10 , Paul Brown 11 , El-Shadan Tautolo 12 , Varsha Parag 13 , Valery L Feigin 1
  1. National Institute for Stroke and Applied Neurosciences, AUT University, Auckland, Auckland, AUCKLAND, New Zealand
  2. Waitemata, Stroke Units, Geriatrics, Waitakere Hospital, Te Whatu Ora - Waitemata, Auckland, New Zealand
  3. Department of Medicine (Wellington) , University of Otago, Wellington , New Zealand
  4. Neurology, Auckland City Hospital, Auc
  5. School of Psychology, University of Auckland, Auckland, New Zealand
  6. Neurology & Mental Health , The George Institute for Global Health, Sydney, ACT , Australia
  7. Nuffield Department of Population Health, University of Oxford , Oxford, United Kingdom
  8. Department of Medicine , Monash University , Melbourne, ACT, Australia,
  9. Department of Medicine, Monash University, Clayton, ACT, Australia,
  10. General Practice and Primary Health Care, University of Auckland, Auckland, New Zealand,
  11. UCM Health Services Research and Policy , University of California , Merced , United States of America
  12. AUT Pacific Health Research Centre , Auckland University of Technology,, Auckland, New Zealand
  13. National Institute for Health Innovation (NIHI) , UniServices, The Univerisity of Auckland, Auckland, New Zealand

Background: Previous studies have provided evidence of ethnic disparities in stroke incidence in New Zealand (NZ). Continued surveillance in changes in stroke burden among major ethnic groups is crucial for informing tailored prevention and management guidelines.

Aims: We aimed to compare changes in stroke incidence over four decades among major ethnic groups from the Auckland Regional Community Stroke (ARCOS) studies.

Methods: The ARCOS studies are population-based studies conducted in Auckland, NZ, every decade since 1981 (ARCOS I-V). Stroke cases were identified with hot and cold pursuit through multiple case ascertainment methods. Prioritized ethnicity (self-identified) was used to obtain a single ethnicity with participants grouped as Europeans, Māori, Pacific, or Asian/other.

Results: In ARCOS V (2021), in absolute numbers, Europeans represented the highest proportion of stroke (56%), followed by Asian (22%), Pacific (13%) and Māori (8%). The average age (years) of stroke onset was youngest in Māori (60.7), and greatest in Europeans (75.1), similar to the gap seen since 1981.The overall age-standardised incidence of stroke (per 100,000 person-years [95% CI]) was 161 [152, 171]; 109 [102, 116] in Europeans, 176 [151, 205] for Māori, 190 [169, 213] in Pacific and 153 [140, 168] in Asian/other. Since 1981, stroke incidence increased 1.3-fold in Māori and Pacific peoples and reduced 0.7-fold in Europeans and 0.4-fold in Asians. However, in the last decade stroke incidence as well as absolute numbers more than doubled in Asian/other, while a trend towards decrease in incidence was seen in Pacific people.

Conclusion: Despite improved acute stroke care, ethnic disparities have persisted in NZ. Improved and tailored strategies specific to different ethnic groups are needed for primary prevention. The current ARCOS V results are preliminary and will be updated with 2023 Census data when available.