Oral Presentation Australian and New Zealand Stroke Organisation Conference 2025

Trends in stroke incidence among Aboriginal and non-Aboriginal Western Australians – did Closing-the-Gap policies make a difference? (122329)

Judy Katzenellenbogen 1 , Nita Sodhi-Berry 1 , Marwan Ahmed 1 , Angela dos Santos 2 , Anna Balabanski 3 , Graeme Hankey 1 , Timothy Kleinig 4 , Lee Nedkoff 1
  1. University of Western Australia, Crawley, WA, Australia
  2. Neurology, University of New South Wales, Sydney, NSW, Australia
  3. Neurology, Monash University, Melbourne, VIC, Australia
  4. Neurology, University of Adelaide, Adelaide, SA, Australia

Background:

Initiated in 2008, the Closing-the-Gap (CtG) policy focusses on overcoming Aboriginal socio-economic disadvantage to reduce health differentials. We investigated temporal trends in stroke incidence among Aboriginal and non-Aboriginal people living in Western Australia (WA) 2003-2020 to explore population-level impacts of CtG Policy on stroke burden.

Methods:

Linked statewide hospital and death records identified first-ever stroke events (18-year lookback) in WA residents 2003-2020. Annual age-standardised incidence rates (ASIRs) were calculated for younger (25-54-years) and older (55-84-years) Aboriginal and non-Aboriginal males and females. Age-adjusted annual percentage change for each group, and Aboriginal-to-non-Aboriginal incidence-rate-ratios (IRRs) were estimated from Poisson regression models for the pre-(2003-2008) and post-CtG (2011-2020) periods, acknowledging temporal bias in population denominators.

Results:

Aboriginal cases comprised 4.5% of 31,729 incident strokes, with 6-9-times greater ASIRs in both broad age-groups across the period than other Australians.

No significant trends were observed in either period among 25-54-year cohorts, except an increase in non-Aboriginal females post-CtG (+1.9%/yr (95%CI 0.0,+3.8)). Trends among all older cohorts suggest reductions pre-CtG; Aboriginal reductions were more substantial (particularly males) but non-significant. Post-CtG, further reductions only occurred among older non-Aboriginal females (-1.0%/yr, 95%CI=-1.9,-0.2), while incidence increased in non-Aboriginal males (+0.9%/yr, 95%CI=+0.1,+1.6). Post-CtG IRR were lower than pre-CtG for older males (3.6 vs. 6.4) and females (4.7 vs. 6.2).

Conclusion:

Stroke gains among Aboriginal and non-Aboriginal Australians occurred only in older people before CtG rollout, corresponding with shifts in anticoagulant use (early 2000s) and better stroke diagnosis/management. The Aboriginal-to-non-Aboriginal differential has not widened and has reduced for older ages.