Validating the TeleStroke Mimic Score: A Prediction Rule for Identifying Stroke Mimics Evaluated Over Telestroke Networks

Abstract

Background and purpose: Up to 30% of acute stroke evaluations are deemed stroke mimics, and these are common in telestroke as well. We recently published a risk prediction score for use during telestroke encounters to differentiate stroke mimics from ischemic cerebrovascular disease derived and validated in the Partners TeleStroke Network. Using data from 3 distinct US and European telestroke networks, we sought to externally validate the TeleStroke Mimic (TM) score in a broader population.

Methods: We evaluated the TM score in 1930 telestroke consults from the University of Utah, Georgia Regents University, and the German TeleMedical Project for Integrative Stroke Care Network. We report the area under the curve in receiver-operating characteristic curve analysis with 95% confidence interval for our previously derived TM score in which lower TM scores correspond with a higher likelihood of being a stroke mimic.

Results: Based on final diagnosis at the end of the telestroke consultation, there were 630 of 1930 (32.6%) stroke mimics in the external validation cohort. All 6 variables included in the score were significantly different between patients with ischemic cerebrovascular disease versus stroke mimics. The TM score performed well (area under curve, 0.72; 95% confidence interval, 0.70-0.73; P<0.001), similar to our prior external validation in the Partners National Telestroke Network.

Conclusions: The TM score's ability to predict the presence of a stroke mimic during telestroke consultation in these diverse cohorts was similar to its performance in our original cohort. Predictive decision-support tools like the TM score may help highlight key clinical differences between mimics and patients with stroke during complex, time-critical telestroke evaluations.

Keywords: area under curve; cerebrovascular disorders; cohort studies; humans; risk.

Figure 1

Nomogram for predicting Telestroke stroke mimics using TM Score. TM Score = (Age multiplied by 0.2) + 6 (if history of atrial fibrillation) + 3 (if history of Hypertension) + 9 (if facial weakness) + 5 (if NIHSS > 14) – 6 (if history of seizure)

Figure 2

Response operator curve for the TM Score for external validation data from the 3 telestroke centers.