OP38 Alternative scenarios for projected prevalence of stroke and post-stroke dementia to 2046 in Ireland: a preliminary model-based analysis

Background Stroke and post-stroke dementia prevalence projections are key for informing health policy and planning. However, future trends in stroke incidence are uncertain. The Irish population is ageing rapidly, and stable age-specific incidence rates will result in large projected increases in prevalent stroke and consequent dementia. This study aims to evaluate alternative scenarios for future trends in age-specific stroke incidence, and estimate the impact on projected prevalence of stroke and post-stroke dementia in Ireland to 2046. Methods We used a probabilistic Markov model, previously developed by our group, to project and track incidence and prevalence of stroke and post-stroke dementia in the Irish population aged 40–89 years to 2046. Data sources included official population and hospital episode statistics, and national and international longitudinal cohort studies. Drawing on evidence from systematic reviews and recent observational studies, we extrapolated trends in stroke incidence from 1990 to 2019 to the period 2016 to 2046. We explored five scenarios – stable incidence over time, and annual declines in stroke incidence of 1.0%, 1.5%, 2.0% and 2.5%. Results In the stable age-specific incidence scenario, there will be a projected 79,863 stroke survivors aged 40–89 years in 2046 living in Ireland (95% uncertainty interval, UI = 75,845–83,8987) (23.4 per 1000 pop), an increase of 115% from 2016, due to changing population age structure. Of these, 14,996 (UI = 12,248–17,966) are projected to have dementia, a 217% increase from 2016. Assuming a 1.0% rate of annual decline in stroke incidence, there will be a projected 62,905 stroke survivors (95% UI = 59,407–66,298) in 2046, an increase of 70% from 2016. Of these, 12,415 (UI = 10,083–14,906) are projected to have dementia, a 161% increase from 2016. In the most optimistic scenario (annual decline of 2.5%), projected stroke prevalence will increase from 2016 to 2046 by 13.5% to 46,090 (95% UI = 43,641–48,970). Of these, 9,918 (UI = 7,963–12,189) are projected to have dementia, an 108% increase from 2016. Conclusion If age-specific stroke incidence rates remain stable in Ireland, there will be substantial increases in prevalent stroke and post-stroke dementia with consequent needs to expand services. If recent trends towards decline in stroke incidence continue, this increase in prevalence will be substantially reduced. Limitations include the inherent uncertainty regarding future trends, and use of international data where Irish data was not available. Strengths include use of best available evidence, extensive sensitivity analysis, and consideration of multiple scenarios.