Distribution of National Institutes of Health Stroke Scale in the Cincinnati/Northern Kentucky Stroke Study

Abstract

Little is known about the distribution of National Institutes of Health Stroke Scale (NIHSS) scores from patients with ischemic stroke sampled from population-based studies. We describe the distribution of NIHSS in ischemic stroke cases from the Cincinnati/Northern Kentucky Stroke Study. Within a biracial population of 1.3 million, all strokes among area residents in 2005 were ascertained by screening discharge records at local hospitals and outpatient clinics. A sampling scheme was developed to ascertain additional cases presenting to physician offices and nursing homes, not identified through the other sources. All confirmed ischemic stroke cases underwent chart abstraction, and a retrospective NIHSS (rNIHSS) score (range, 0-42) was generated on the basis of initial physician examination findings. There were 2233 ischemic stroke cases identified during the 12-month study. The overall median rNIHSS score was 3 (interquartile range, 1-7). Median rNIHSS score was 3, 7, and 1, respectively, for stroke cases ascertained through the admitted, in-hospital, and out-of-hospital sources. Median rNIHSS was significantly higher in subjects ≥80 years compared with younger cases (4 versus 3). More than half of all ischemic stroke cases have mild symptom severity on initial presentation (ie, rNIHSS≤3). Monitoring trends in NIHSS represents a legitimate target for population-based surveillance efforts.