Abstract WP78: National Institutes Of Health Stroke Scale Correlates Well With Initial Intracerebral Hemorrhage Volume

Introduction: The US Centers for Medicare and Medicaid Services (CMS) currently publicly reports hospital-quality, risk-adjusted mortality measure for ischemic stroke but not intracerebral hemorrhage (ICH). The NIHSS, which is captured in CMS administrative claims data, is a candidate metric for use in ICH risk adjustment and has been shown to predict clinical outcome with accuracy similar to the ICH Score. Correlation between early NIHSS and initial ICH volume would further support use of the NIHSS for ICH risk adjustment. Methods: Among consecutive ICH patients enrolled in a large multicenter trial (FAST-MAG), the relation between early NIHSS and early ICH volume was assessed with correlation and linear trend analysis, in all patients and separately in; left vs right; IVH-positive vs IVH-negative, hyperacute (≤60min) vs acute (61-120min) imaging; men vs women; and younger (<65y) vs older (≥65y). Results: Among 372 patients with ICH, age was 65y (SD 13), 67% were men, early NIHSS was 16 (IQR 9-25) and initial ICH volume was 14.9 cc (IQR 6.1-36.4). Overall, there was substantial correlation between NIHSS and ICH volume, r=0.77 (p<0.001), and for every 10cc increase in ICH the NIHSS increased by 4.5 points. Correlations remained substantial and similar in all subgroups (Table), but magnitude of NIHSS change with ICH volume alteration varied, including greater NIHSS change with ICH unit volume increase in left than right hemisphere, absence of IVH, earlier (≤60min) than later presentation (61-120min), men than women, and younger than older patients (Table). Conclusion: Early NIHSS deficit severity values correlate strongly with initial ICH hematoma volume. As with ischemic stroke, lesion volume increases produce greater NIHSS changes in the left than right hemisphere, reflecting greater NIHSS sensitivity to left hemisphere function. These findings provide further support for the use of the NIHSS in risk-adjusted mortality measures for intracerebral hemorrhage.