Abstract WP158: Previous Encounter Blood Pressure Variability Associates with Admission Stroke Severity

Background: Stroke severity, measured by the National Institutes of Health Stroke Scale (NIHSS), is a critical aspect of acute ischemic stroke (AIS) assessment and subsequent outcomes. As AIS treatments and outcomes are time sensitive, there is a need to identify early warning signs to anticipate severe stroke before onset. We examine the association between previous-encounter systolic blood pressure variability (BPV) with first 24-hour NIHSS severity during AIS. Methods: Data for patients admitted with first-ever AIS between May 2016 and August 2025 were retrieved from the Registry of Neurological Endpoint Assessment among patients with Ischemic and Hemorrhagic Stroke (REINAH), including the mean first 24-hour NIHSS scores. Blood pressure measurements, discharge dispositions, admission severity (expected/urgent/emergency), days before stroke onset, and active prescription for outpatient antihypertensive medication were retrieved from the most recent previous encounter. Moderate/Severe stroke was defined as NIHSS > 15. Coefficient of Variation (CV; 100*standard deviation/mean) was used to measure systolic BPV, assessed in quartiles. Logistic regression models were fit to assess associations with moderate/severe stroke. Results: The patient cohort comprised 9359 patients with previous hospital encounter (median age: 72 [62-81]), including 5092 (54.4%) female and 5141 (54.9%) White, 2406 (25.7%) Black, 1308 (14.0%) Hispanic, 420 (4.5%) Asian, and 84 (0.9%) Other/unknown patients. In total 938 (10.0%) patients exhibited moderate/severe stroke. Previous encounter admission occurred 179 [39-555] days before AIS admission, with patients exhibiting a median CV of 11.69 [8.97-14.71]. Patients with moderate/severe stroke on admission showed significantly higher previous-encounter BPV (12.27 [9.80-15.20] vs 11.59 [8.89-14.64]; p<0.001). Multivariable modelling showed higher odds of moderate/severe stroke for patients in the 2 nd (1.38 [1.15-1.66]), 3 rd (1.47 [1.22-1.76]) and 4 th BPV quartile (1.20 [1.27-1.82]; vs 1 st quartile) (Figure 1). Discussion: Patients with moderate/severe stroke on the admission NIHSS exhibited higher BPV during previous hospital encounters.