Oral Presentation Australian and New Zealand Stroke Organisation Conference 2025

Trends in incidence and risk factors of major pathological types of stroke in the Auckland Regional Community Stroke (ARCOS) studies over three decades (122900)

Rita V Krishnamurthi 1 , Craig Anderson 2 , Bruce Arroll 3 , Alan A Barber 4 , Suzanne Barker-Collo 5 , Derrick Bennett 6 , Paul Brown 7 , Dominique Cadilhac 8 , Jeroen Douwes 9 , Daniel Exeter 10 , Balakrishnan Nair 1 , Varsha Parag 11 , Anna Ranta 12 , Yogini Ratnasabapathy 13 , Ilari Rautalin 1 , Andy Swain 14 , El-Shadan Tautolo 15 , Braden Te Ao 16 , Amanda Thrift 17 , Bronwyn Tunnage 1 , Valery L Feigin 1
  1. National Institute for Stroke and Applied Neurosciences, AUT University, Auckland, New Zealand
  2. The George Institute for Global Health; Neurology and Epidemiology, University of New South Wales; Royal Prince Alfred Hospital, , Sydney, New South Wales, Australia
  3. General Practice and Primary Health Care, University of Auckland, Auckland, New Zealand,
  4. Neurology, Auckland City Hospital, Auc
  5. School of Psychology, University of Auckland, Auckland, New Zealand
  6. Nuffield Department of Population Health, University of Oxford , Oxford, United Kingdom
  7. UCM Health Services Research and Policy , University of California , Merced , United States of America
  8. Department of Medicine, Monash University, Clayton, ACT, Australia,
  9. Research Centre for Hauora and Health, Massey university, Wellington, New Zealand
  10. Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
  11. National Institute for Health Innovation (NIHI) , UniServices, The Univerisity of Auckland, Auckland, New Zealand
  12. Department of Medicine (Wellington) , University of Otago, Wellington , New Zealand
  13. Waitemata, Stroke Units, Geriatrics, Waitakere Hospital, Te Whatu Ora - Waitemata, Auckland, New Zealand
  14. Research and Education, Kia Ora te Tangata - Wellington Free Ambulance, Wellington , New Zealand
  15. AUT Pacific Health Research Centre , Auckland University of Technology,, Auckland, New Zealand
  16. School of Population Health, The University of Auckland, Auckland, New Zealand
  17. Faculty of Medicine, Nursing and Health Sciences , Monash University, Clayton, , Victoria,, Australia

Background/Aims: Monitoring temporal trends in the incidence of pathological stroke types (ischemic stroke [IS], intracerebral haemorrhage [ICH], and subarachnoid haemorrhage [SAH]) is critical for determining progress on prevention. We report trends in incidence and associated risk across three decades in ARCOS.

Methods: ARCOS III-V (2002-2003), (2010-2011) and (2020-2021) respectively, were population-based studies of stroke incidence (ages >15 years) that captured all major pathological stroke types. Age-standardised incidence per 100,000 and incidence rate ratios (IRR) with 95% confidence intervals (CIs) using Poisson regression were calculated to assess trends by stroke type and risk factor profile.

Results: Among 1613 first-ever strokes in ARCOS-V, 78% were IS, 16% ICH, (5% SAH, and 0.004% undetermined. In ARCOS V, the age-standardised incidence was 98 [93-103], 20 [18-23], 8 [6-9] for IS, ICH and SAH respectively. There was no significant incidence change of first-ever IS (p=0.321) or SAH (p=0.321), but a significant increase in ICH (p=0.016) over time, particularly in males. Across ARCOS IV and V, the IRR was 1.0 for IS, 1.3 for ICH and 1.1 for SAH. The prevalence of high blood pressure remained similar over time. The prevalence of diabetes and myocardial infarction increased in IS, while the prevalence of smoking declined in IS and SAH (p<0.001). 

Conclusion: Changes in stroke incidence varied by type; increasing for ICH and SAH, but with no detectable change for IS. The prevalence of elevated blood pressure remains high across all stroke types and other risk factors are rising indicating that greater preventive efforts are needed.