Abstract P257: Cost-Effectiveness of Advanced Neuroimaging for Transient & Minor Neurological Events in the Emergency Department

Abstract

Background: Accurate diagnosis of patients with transient or minor neurological events is challenging with non-trivial rates of Emergency Department (ED) misdiagnosis reported. Recent studies suggest that advanced neuroimaging can improve diagnostic accuracy in presumed low-risk patients, but a cost-effective ED diagnostic evaluation strategy remains uncertain. We therefore evaluate two strategies designed to determine which patients with low-risk transient and minor neurological symptoms can be directly discharged from the ED. Methods: We constructed a decision-analytic model to evaluate two ED-based diagnostic evaluation strategies for patients with presumed low-risk transient or minor neurological symptoms: (1) obtain advanced neuroimaging (MRI brain and MRA head and neck) in the ED on every patient or (2) current ED standard of care of clinical evaluation and basic neuroimaging. The main probability variables were: proportion of patients with true ischemic events, specificity and sensitivity of each evaluation strategy, recurrent stroke rate, and direct healthcare costs. We calculated incremental cost-effectiveness ratios (ICER) and performed threshold analyses to evaluate diagnostic test parameters. Cost-effectiveness was defined as willingness to pay (WTP) <$100,000 USD per quality adjusted life year (QALY) gained. Results: Our primary and sensitivity analyses found that the advanced neuroimaging strategy more cost-effective than ED standard of care, the latter of which has an ICER exceeding the WTP threshold. The total cost of the advanced neuroimaging strategy was $3,210 with an effectiveness of 0.9397 whereas the total cost of the standard ED strategy was $4,338 with an effectiveness of 0.9399 in the primary model. Using threshold analyses, we found that potential superior diagnostic approaches to the advanced neuroimaging strategy would have to be >92% specific, >70% sensitive, and cost less than or equal to the standard of care strategy. Conclusion: In our decision-analytic model, obtaining advanced neuroimaging on all patients presenting with low-risk transient and minor neurological symptoms was the more cost-effective strategy as compared to current practice.