Diagnostic performance of the expanded National Institutes of Health Stroke Scale for the assessment of anterior and posterior circulation strokes.
The main limitation of the National Institutes of Health Stroke Scale (NIHSS) is the underestimation of clinical severity in posterior circulation (PC) strokes, which has been hypothesized to contribute to diagnostic delay and to reduce eligibility for reperfusion treatments in some patients. We aimed to evaluate the diagnostic performance of a previously developed modified version of the NIHSS, the Expanded NIHSS (e-NIHSS), for clinical assessment and outcome prediction in patients with anterior circulation (AC) and PC strokes.
Prospective observational study of 249 consecutive stroke patients admitted to a Comprehensive Stroke Center during 1 year. NIHSS and e-NIHSS were administered by two independent examiners within 48 h of onset. The primary outcome measure was an unfavorable outcome, defined as a modified Rankin Scale score of 3 to 6 at 3 months. The discriminative performance of the e-NIHSS to predict unfavorable outcome was evaluated by calculating the area under the receiver operating characteristic curve (AUC-ROC).
The inter-rater reliability of the e-NIHSS between the two independent observers was excellent (intraclass correlation coefficient, 0.992 [95% CI 0.990-0.994]). The mean e-NIHSS score was higher than the mean classical NIHSS score (p < 0.001). An unfavourable outcome at 3 months was detected in 113 (45%) patients. The e-NIHSS showed a discriminative performance to predict unfavorable functional outcome comparable to the classical NIHSS for the total amount of strokes (AUC-ROC of the e-NIHSS for the first observer, 0.867 [95% CI, 0.823-0.911]; AUC-ROC of the e-NIHSS for the second observer, 0.871 [95% CI, 0.827-0.914]; AUC-ROC of the classical NIHSS, 0.849 [95% CI, 0.802-0.897]), AC strokes (AUC-ROC of the e-NIHSS for the first observer, 0.886 [95% CI, 0.841-0.932]; AUC-ROC of the e-NIHSS for the second observer, 0.892 [95% CI, 0.848-0.936]; AUC-ROC of the classical NIHSS, 0.870 [95% CI, 0.821-0.920]), and PC strokes (AUC-ROC of the e-NIHSS for the first observer, 0.800 [95% CI, 0.685-0.916]; AUC-ROC of the e-NIHSS for the second observer, 0.791 [95% CI, 0.672-0.910]; AUC-ROC of the classical NIHSS, 0.804 [95% CI, 0.689-0.920]). Net reclassification improvement, integrated discrimination improvement, and decision curve analysis showed a modest apparent incremental prognostic benefit of the e-NIHSS over the classical NIHSS in the whole cohort and in AC strokes, but not in PC strokes.
Compared to the classical NIHSS, the e-NIHSS showed a similar discriminative performance to predict 3-month functional outcome, capturing and quantifying additional PC-relevant clinical signs not fully represented in the classical NIHSS, with excellent inter-rater reliability.
Prospective observational study of 249 consecutive stroke patients admitted to a Comprehensive Stroke Center during 1 year. NIHSS and e-NIHSS were administered by two independent examiners within 48 h of onset. The primary outcome measure was an unfavorable outcome, defined as a modified Rankin Scale score of 3 to 6 at 3 months. The discriminative performance of the e-NIHSS to predict unfavorable outcome was evaluated by calculating the area under the receiver operating characteristic curve (AUC-ROC).
The inter-rater reliability of the e-NIHSS between the two independent observers was excellent (intraclass correlation coefficient, 0.992 [95% CI 0.990-0.994]). The mean e-NIHSS score was higher than the mean classical NIHSS score (p < 0.001). An unfavourable outcome at 3 months was detected in 113 (45%) patients. The e-NIHSS showed a discriminative performance to predict unfavorable functional outcome comparable to the classical NIHSS for the total amount of strokes (AUC-ROC of the e-NIHSS for the first observer, 0.867 [95% CI, 0.823-0.911]; AUC-ROC of the e-NIHSS for the second observer, 0.871 [95% CI, 0.827-0.914]; AUC-ROC of the classical NIHSS, 0.849 [95% CI, 0.802-0.897]), AC strokes (AUC-ROC of the e-NIHSS for the first observer, 0.886 [95% CI, 0.841-0.932]; AUC-ROC of the e-NIHSS for the second observer, 0.892 [95% CI, 0.848-0.936]; AUC-ROC of the classical NIHSS, 0.870 [95% CI, 0.821-0.920]), and PC strokes (AUC-ROC of the e-NIHSS for the first observer, 0.800 [95% CI, 0.685-0.916]; AUC-ROC of the e-NIHSS for the second observer, 0.791 [95% CI, 0.672-0.910]; AUC-ROC of the classical NIHSS, 0.804 [95% CI, 0.689-0.920]). Net reclassification improvement, integrated discrimination improvement, and decision curve analysis showed a modest apparent incremental prognostic benefit of the e-NIHSS over the classical NIHSS in the whole cohort and in AC strokes, but not in PC strokes.
Compared to the classical NIHSS, the e-NIHSS showed a similar discriminative performance to predict 3-month functional outcome, capturing and quantifying additional PC-relevant clinical signs not fully represented in the classical NIHSS, with excellent inter-rater reliability.
Authors
Forlivesi Forlivesi, Balbarini Balbarini, Bigliardi Bigliardi, D'Amico D'Amico, Rosafio Rosafio, Vandelli Vandelli, Dell'Acqua Dell'Acqua, Casoni Casoni, Meletti Meletti, Cavazzuti Cavazzuti, Zini Zini
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