A Simple Risk Index and Thrombolytic Treatment Response in Acute Ischemic Stroke

Importance  The Stroke Prognostication using Age and the NIH Stroke Scale index, created by combining age in years plus a National Institutes of Health (NIH) Stroke Scale score of 100 or higher (and hereafter referred to as the SPAN-100 index), is a simple risk score for estimating clinical outcomes for patients with acute ischemic stroke (AIS). The association between this index and response to intravenous thrombolysis for AIS has not been properly evaluated.

Objective  To assess the relationship between SPAN-100 index status and outcome following treatment with intravenous thrombolysis for AIS.

Design, Setting, and Participants  Using the Virtual International Stroke Trials Archive (VISTA) database, an international repository of clinical trials data, we assessed the SPAN-100 index among 7093 patients with AIS who participated in 4 clinical trials from 2000 to 2006. The SPAN-100 index is considered positive if the sum of the age and the NIH Stroke Scale (a 15-item neurological examination scale with scores ranging from 0 to 42, with higher scores indicating more severe strokes) score is greater than or equal to 100. Multivariable logistic regression analyses were used to determine the independent association between SPAN-100 index status and 90-day outcomes.

Main Outcomes and Measures  The primary outcome was a composite of severe disability or death measured 90 days after stroke, and the secondary outcomes were death alone and a composite of no disability/modest disability.

Results  Of 7093 patients, 743 (10.5%) were SPAN-100 positive, and 2731 (38.5%) received intravenous thrombolysis. Compared with SPAN-100–negative patients, SPAN-100–positive patients were more likely to experience a catastrophic outcome (adjusted odds ratio [AOR], 9.03 [95% CI, 6.68-12.21]) or death alone (AOR, 5.03 [95% CI, 4.06-6.23]) and less likely to experience a favorable outcome (AOR, 0.08 [95% CI, 0.06-0.13]). However, there was an interaction between SPAN-100 index status and thrombolysis treatment (P < .001) revealing a reduction in the likelihood of severe disability/death with thrombolytic treatment for SPAN-100–positive (AOR, 0.46 [95% CI, 0.29-0.71]) but not SPAN-100–negative patients (AOR, 0.96 [95% CI, 0.85-1.07]). Similar interactions between SPAN-100 index status and thrombolysis treatment were observed for the 2 secondary outcomes.

Conclusion and Relevance  Compared with the SPAN-100–negative patients with AIS, the SPAN-100–positive patients with AIS seem to have poorer 3-month outcomes but may derive greater benefit when treated with intravenous thrombolysis. The SPAN-100–positive patients are often excluded from AIS clinical trials but should probably not be denied thrombolysis treatment on the basis of such a profile alone.

To facilitate the consistent use of a prognostic index by providers caring for patients with acute ischemic stroke (AIS), a simple and practical index called the Stroke Prognostication using Age and NIH Stroke Scale, created by combining age in years plus an National Institutes of Health Stroke Scale (NIHSS) score of 100 or higher (and hereafter referred to as the SPAN-100 index), was developed to be applied especially to high-risk patients (ie, elderly patients with a moderate to severe stroke).1 When applied to a modest-sized sample of patients with AIS (n = 624), the SPAN-100 index was shown to be of value in estimating risk of intracerebral hemorrhage and clinical outcomes, at several follow-up time points, regardless of intravenous thrombolysis treatment.1However, the question of whether very elderly patients with very severe strokes (presumably with otherwise very poor outcomes) benefit from intravenous thrombolysis to a greater or lesser extent than other patients with AIS has not been specifically explored.2

In our study, we aimed to determine if the SPAN-100 index is indeed a useful practical prognostic variable/indicator for outcomes after AIS, and to assess if intravenous thrombolysis may decrease the risk of a disabling stroke or death among high-risk patients with an expected poor outcome.

JAMA Neurology 2014