Baseline NIH Stroke Scale is an inferior predictor of functional outcome in the era of acute stroke intervention

It took you how many decades to figure out that the NIHSS subjective stroke scale is worthless? You can't do a goddamn thing with it; map recovery protocols to a objective starting point. Survivors don't care about predictions. They want results! When are YOU going to provide RESULTS?

Baseline NIH Stroke Scale is an inferior predictor of functional outcome in the era of acute stroke intervention 

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Michael E Reznik, Shadi Yaghi, Mahesh V Jayaraman, ...

First Published June 29, 2018 Research Article

https://doi.org/10.1177/1747493018783759

Article information

Abstract

Background and aims

Baseline National Institutes of Health Stroke Scale (NIHSS) scores have frequently been used for prognostication after ischemic stroke. With the increasing utilization of acute stroke interventions, we aimed to determine whether baseline NIHSS scores are still able to reliably predict post-stroke functional outcome.

Methods

We retrospectively analyzed prospectively collected data from a high-volume tertiary-care center. We tested strength of association between NIHSS scores at baseline and 24 h with discharge NIHSS using Spearman correlation, and diagnostic accuracy of NIHSS scores in predicting favorable outcome at three months (defined as modified Rankin Scale 0–2) using receiver operating characteristic curve analysis with area under the curve.

Results

There were 1183 patients in our cohort, with median baseline NIHSS 8 (IQR 3–17), 24-h NIHSS 4 (IQR 1–11), and discharge NIHSS 2 (IQR 1–8). Correlation with discharge NIHSS was r = 0.60 for baseline NIHSS and r = 0.88 for 24-h NIHSS. Of all patients with follow-up data, 425/1037 (41%) had favorable functional outcome at three months. Receiver operating characteristic curve analysis for predicting favorable outcome showed area under the curve 0.698 (95% CI 0.664–0.732) for baseline NIHSS, 0.800 (95% CI 0.772–0.827) for 24-h NIHSS, and 0.819 (95% CI 0.793–0.845) for discharge NIHSS; 24 h and discharge NIHSS maintained robust predictive accuracy for patients receiving mechanical thrombectomy (AUC 0.846, 95% CI 0.798–0.895; AUC 0.873, 95% CI 0.832–0.914, respectively), while accuracy for baseline NIHSS decreased (AUC 0.635, 95% CI 0.566–0.704).

Conclusion

Baseline NIHSS scores are inferior to 24 h and discharge scores in predicting post-stroke functional outcomes, especially in patients receiving mechanical thrombectomy.

Keywords Stroke, ischemic stroke, outcome, stroke intervention

Introduction

Baseline National Institutes of Health Stroke Scale (NIHSS) scores obtained at hospital admission are used to predict outcome after ischemic stroke,^1–4 and serve as the foundation for more complex prognostic scoring tools.⁵ However, most of these studies were performed prior to widespread implementation of mechanical thrombectomy (MT) as standard of care for select patients with acute ischemic stroke and large vessel occlusion. Though some more recent studies have suggested that NIHSS scores at 24–48 h may hold promise as prognostic tools,^6,7 they used data which predate MT, and did not compare the utility of later time-points with baseline NIHSS scores.
We hypothesized that in the current era of acute stroke intervention, baseline NIHSS scores were no longer optimal for predicting long-term functional outcome with a high degree of accuracy, compared to scores obtained post-intervention. We therefore designed this retrospective study using prospectively collected data from a tertiary-care referral center that performs a high volume of acute stroke interventions to test our hypothesis.