StrokeCog Markov Model: Projected Prevalent and Incident Cases of Stroke and Poststroke Cognitive Impairment to 2035 in Ireland.

BACKGROUND AND PURPOSE: Cognitive impairment no dementia (CIND) and dementia are common stroke outcomes, with significant health and societal implications for aging populations. These outcomes are not included in current epidemiological models. We aimed to develop an epidemiological model to project incidence and prevalence of stroke, poststroke CIND and dementia, and life expectancy, in Ireland to 2035, informing policy and service planning. METHODS: We developed a probabilistic Markov model (the StrokeCog model) applied to the Irish population aged 40 to 89 years to 2035. Data sources included official population and hospital-episode statistics, longitudinal cohort studies, and published estimates. Key assumptions were varied in sensitivity analysis. Results were externally validated against independent sources. The model tracks poststroke progression into health states characterized by no cognitive impairment, CIND, dementia, disability, stroke recurrence, and death. RESULTS: We projected 69 051 people with prevalent stroke in Ireland in 2035 (22.0 per 1000 population [95% CI, 20.8-23.1]), with 25 274 (8.0 per 1000 population [95% CI, 7.1-9.0]) of those projected to have poststroke CIND, and 12 442 having poststroke dementia (4.0 per 1000 population [95% CI, 3.2-4.8]). We projected 8725 annual incident strokes in 2035 (2.8 per 1000 population [95% CI, 2.7-2.9]), with 3832 of these having CIND (1.2 per 1000 population [95% CI, 1.1-1.3]), and 1715 with dementia (0.5 per 1000 population [95% CI, 0.5-0.6]). Life expectancy for stroke survivors at age 50 was 23.4 years (95% CI, 22.3-24.5) for women and 20.7 (95% CI, 19.5-21.9) for men. CONCLUSIONS: This novel epidemiological model of stroke, poststroke CIND, and dementia draws on the best available evidence. Sensitivity analysis indicated that findings were robust to assumptions, and where there was uncertainty a conservative approach was taken. The StrokeCog model is a useful tool for service planning and cost-effectiveness analysis and is available for adaptation to other national contexts.

Poststroke Cognitive Impairment in Model-Based Economic Evaluation: A Systematic Review.

INTRODUCTION: Cognitive impairment (CI) is a frequent consequence of stroke and is associated with increased costs and reduced quality of life. However, its inclusion in model-based economic evaluation for stroke is limited. OBJECTIVE: To identify, review, and critically appraise current models of stroke for use in economic evaluation, and to identify applicability to modeling poststroke CI. METHODS: PubMed, EMBASE, and the NHS Economic Evaluations Database (NHS EED) were systematically searched for papers published from January 2008 to August 2018. Studies that described the development or design of a model of stroke progression intended for use in economic evaluation were included. Abstracts were screened, followed by full text review of potentially relevant articles. Models that included CI were retained for data extraction, and among the remainder, models that included both stroke recurrence and disability were also retained. Relevance and potential for adaptation for modeling CI were assessed using a standard questionnaire. RESULTS: Forty modeling studies were identified and categorized into 4 groups: Markov disability/recurrence (k = 29); CI (k = 2); discrete event simulation (k = 4), and other (k = 5). Only 2 modeling studies included CI as an outcome, and both focused on narrow populations at risk of intracranial aneurysm. None of the models allowed for disease progression in the absence of a stroke recurrence. None of the included studies carried out any sensitivity analysis in relation to model design or structure. CONCLUSIONS: Current stroke models used in economic evaluation are not adequate to model poststroke CI or dementia, and will require adaptation to be used for this purpose.