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.