Cost-effectiveness of short-protocol emergency brain MRI after negative non-contrast CT for minor stroke detection

Daniel Puhr-Westerheide,Philipp M Kazmierczak,Matthias P Fabritius,Eva Gresser,Clemens C Cyran,Matthias Klein,Konstantin Dimitriadis,Paul Reidler,Wolfgang G Kunz,Jens Ricke,Olga Solyanik,Matthias F Froelich

doi:10.1007/s00330-021-08222-z

Abstract

ObjectivesTo investigate the cost-effectiveness of supplemental short-protocol brain MRI after negative non-contrast CT for the detection of minor strokes in emergency patients with mild and unspecific neurological symptoms.MethodsThe economic evaluation was centered around a prospective single-center diagnostic accuracy study validating the use of short-protocol brain MRI in the emergency setting. A decision-analytic Markov model distinguished the strategies “no additional imaging” and “additional short-protocol MRI” for evaluation. Minor stroke was assumed to be missed in the initial evaluation in 40% of patients without short-protocol MRI. Specialized post-stroke care with immediate secondary prophylaxis was assumed for patients with detected minor stroke. Utilities and quality-of-life measures were estimated as quality-adjusted life years (QALYs). Input parameters were obtained from the literature. The Markov model simulated a follow-up period of up to 30 years. Willingness to pay was set to $100,000 per QALY. Cost-effectiveness was calculated and deterministic and probabilistic sensitivity analysis was performed.ResultsAdditional short-protocol MRI was the dominant strategy with overall costs of $26,304 (CT only: $27,109). Cumulative calculated effectiveness in the CT-only group was 14.25 QALYs (short-protocol MRI group: 14.31 QALYs). In the deterministic sensitivity analysis, additional short-protocol MRI remained the dominant strategy in all investigated ranges. Probabilistic sensitivity analysis results from the base case analysis were confirmed, and additional short-protocol MRI resulted in lower costs and higher effectiveness.ConclusionAdditional short-protocol MRI in emergency patients with mild and unspecific neurological symptoms enables timely secondary prophylaxis through detection of minor strokes, resulting in lower costs and higher cumulative QALYs.Key Points• Short-protocol brain MRI after negative head CT in selected emergency patients with mild and unspecific neurological symptoms allows for timely detection of minor strokes.• This strategy supports clinical decision-making with regard to immediate initiation of secondary prophylactic treatment, potentially preventing subsequent major strokes with associated high costs and reduced QALY.• According to the Markov model, additional short-protocol MRI remained the dominant strategy over wide variations of input parameters, even when assuming disproportionally high costs of the supplemental MRI scan.

Highlights

Ischemic stroke is one of the leading causes of severe disability and a major cause for cardiovascular mortality worldwide [1,2,3]
Major strokes are preceded by minor strokes or transient ischemic attacks (TIA) in approximately 15–30%, with 40% of these precursor events occurring within 7 days and about 20% within 24 h before a major ischemic stroke [6, 7]
Additional short-protocol MRI remained the dominant strategy even when assuming a rate of missed minor strokes of as low as 20% in patients not undergoing short-protocol MRI (Fig. 3B)

Summary

Introduction

Ischemic stroke is one of the leading causes of severe disability and a major cause for cardiovascular mortality worldwide [1,2,3]. Up to 65% of all acute ischemic events leading patients to seek medical attention are minor strokes or TIAs [9]. Urgent identification of these patients and immediate initiation of secondary prophylaxis lead to a risk reduction of 80 to 90% with regard to subsequent major strokes [9,10,11]. Timely diagnosis of minor strokes is of foremost importance for rapid initiation of secondary prophylaxis and prevention of major stroke

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Conclusion