Validation of simplified FABS scale to predict stroke mimics in a Chinese population undergoing intravenous thrombolysis

Abstract

Objectives: A large number of suspected stroke patients undergoing intravenous thrombolysis are stroke mimics (SMs). In this study, we sought to revise the FABS scale for screening and stratifying SMs from acute ischemic stroke (AIS) in a Chinese stroke population receiving fibrinolytic therapy.

Patients and methods: The simplified FABS (sFABS) scale includes 4 items with 1 point for each item present: absence of facial droop, negative history of atrial fibrillation, age <50years, systolic blood pressure <150mm Hg at presentation. We evaluated consecutive suspected stroke patients undergoing intravenous thrombolysis in our stroke center for validation of sFABS scale. Diagnosis of SMs was based on absence of acute ischemic lesions on first and second diffusion weight imaging sequence in addition to an alternate diagnosis at discharge.

Results: A total of 190 AIS patients and 28 SMs were included in this study from December 2015 to February 2017. The sFABS scale showed excellent discrimination (C statistic: 0.928, 95% CI: 0.887-0.969, P<0.001). The Hosmer and Lemeshow goodness of fit test showed that the sFABS scale also had a good calibration (Cox and Snell R²=0.294, Nagelkerke R²=0.549). The plot of observed versus predicted risk of SMs showed high correlation (Pearson correlation coefficient: 0.983) between observed and predicted risk in our registered stroke population.

Conclusion: The sFABS scale had excellent discrimination and good calibration abilities to predict SMs among a Chinese stroke population receiving tPA therapy. Further imaging evaluation may be necessary before the use of tPA if the sFABS score is higher.

Keywords: Diagnostic studies; Ischemic stroke; Prediction of outcome; Stroke mimics; Stroke scales; Tissue plasminogen activator.