Oral Presentation Asia Pacific Stroke Conference 2024

Demographic disparities in the incidence and case fatality of subarachnoid haemorrhage: an 18-year nationwide study from New Zealand (107060)

Ilari Rautalin 1 2 , Rita V Krishnamurthi 1 , Craig S Anderson 3 4 , Alan Barber 5 6 , Suzanne Barker-Collo 7 , Derrick Bennett 8 9 , Ronald Boet 10 , Jason A Correia 11 12 , Jeroen Douwes 13 , Andrew Law 11 , Balakrishnan Nair 1 , Amanda G Thrift 14 , Braden Te Ao 15 , Bronwyn Tunnage 1 16 , Anna Ranta 17 , Valery Feigin 1
  1. The National Institute for Stroke and Applied Neurosciences, Auckland University of Technology, Auckland, New Zealand
  2. Department of Neurosurgery, Helsinki University Hospital, Helsinki, Finland
  3. The George Institute for Global Health, Faculty of Medicine, University of New South Wales, Sydney, Australia
  4. Department of Neurology, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
  5. Department of Medicine, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
  6. Department of Neurology, Auckland City Hospital, Auckland, New Zealand
  7. School of Psychology, The University of Auckland, Auckland, New Zealand
  8. Clinical Trial Service Unit and Epidemiological Studies Unit, Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom
  9. Medical Research Council Population Health Research Unit, Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom
  10. Surgical Services, St. George's Hospital, Christchurch, New Zealand
  11. Department of Neurosurgery, Auckland City Hospital, Auckland, New Zealand
  12. Neurosurgery Research Unit, Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
  13. Research Centre for Hauora and Health, Massey University, Wellington, New Zealand
  14. Department of Medicine, School of Clinical Sciences at Monash Health, Monash University, Melbourne, Australia
  15. Health Systems, School of Population Health, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
  16. Department of Paramedicine, Auckland University of Technology, Auckland, New Zealand
  17. Department of Medicine, University of Otago, Wellington, New Zealand

Background/Aims. Although the incidence and case-fatality of subarachnoid haemorrhage (SAH) vary within countries, few countries have reported nationwide rates, especially for multi-ethnic populations. We assessed the nationwide incidence and case-fatality of SAH in New Zealand (NZ) and explored variations by sex, district, ethnicity and time.

Methods. We used administrative health data from the national hospital discharge and cause-of-death collections to identify aneurysmal SAHs in NZ between 2001–2018. For validation, we compared these administrative data to those of two prospective Auckland Regional Community Stroke Studies. We subsequently estimated the incidence and case-fatality of SAH and calculated adjusted rate ratios (RR) with 95% confidence intervals to assess differences between sub-populations.

Results. Over 78,187,500 cumulative person-years, we identified 5,371 SAHs (95% sensitivity and 85% positive predictive values) resulting in an annual age-standardised nationwide incidence of 8.2/100,000. In total, 2,452 (46%) patients died within 30 days after SAH. Compared to European/others, Māori had greater incidence (RR=2.23 (2.08–2.39)) and case-fatality (RR=1.14 (1.06–1.22)), whereas SAH incidence was also greater in Pacific peoples (RR=1.40 (1.24–1.59)) but lesser in Asians (RR=0.79 (0.71–0.89). By domicile, age-standardised SAH incidence varied between 6.3–11.5/100,000 person-years and case fatality between 40–57%. Between 2001–2018, the SAH incidence of NZ decreased by 34% and the case fatality by 12%.

Conclusions. Since the incidence and case-fatality of SAH varies considerably between regions and ethnic groups, caution is advised when generalising findings from focused geographical locations for public health planning, especially in multi-ethnic populations.