Relationship of Day-by-Day Blood Pressure Variability and Admission Stroke Severity in Acute Ischemic Stroke

Abstract

Objectives: Research on the association between stroke severity and day-by-day blood pressure variability (BPV) in acute ischemic stroke (AIS) is rare as the majority focus on the blood pressure (BP) or the short-term BPV. Our study aims to explore the exact roles of daily BPV through the 7-day commencement on stroke severity in AIS. Methods: The study included 633 patients with AIS, defining AIS as the time from the beginning of symptom up to 7 days with recording BP twice a day as well as calculating the daily BPV, and then matching them to the stroke severity. The logistic regression models were used to evaluate associations between stroke severity and day-by-day BPV. We used the smooth curve fitting to identify whether there was a nonlinear association. In addition, the subgroup analyses were performed using the logistic regression. Results: According to the modified National Institutes of Health Stroke Scale score, 301 (47.5%) patients were allocated to the mild stroke group and 332 (52.5%) to the moderate-to-severe stroke group. In terms of stroke categories, we found no significant difference between BP at admission or mean BP. However, the moderate-to-severe stroke group exhibited higher daily BPV. The multiple logistic regression analysis indicated that day-by-day BPV was positively correlated to stroke severity [odds ratio (OR)=1.05, 95% CI:1.01–1.1, P=0.03 for SBP-SD; OR=1.08, 95% CI:1.01–1.15, P=0.03 for SBP-CV; OR=1.04, 95% CI:1.01–1.07, P=0.015 for SBP-SV). Conclusions: High day-by-day BPV in AIS was associated with more severe stroke independent of BP levels.