Association of 24-hour blood pressure variability with functional outcome on discharge and midterm outcome in patients with acute ischemic stroke

Objective To elucidate whether 24-hour blood pressure (BP) variability in the acute phase of ischemic stroke is associated with functional outcomes. Methods Case-control study was performed in patients with acute ischemic stroke admitted to our hospital from January 2013 to December 2015. Clinical data and 24-hour continuous BP monitoring data right after admission were recorded, and BP variability profiles were subsequently calculated. Functional outcomes were evaluated with modified Rankin scale (mRS) on discharge and at 6 months after discharge respectively (favorable outcome: mRS scores≤2; poor outcome: mRS scores>2). BP variability profiles were compared with distinctive functional outcomes. Logistic regression models were established to investigate factors contributing to poor outcome on discharge and at 6 months after discharge. Results Of 188 eligible patients, 67 (35.6%) discharged with poor outcome and 95 (50.5%) were reported poor outcome at 6 months follow-up. Patients with poor outcome on discharge had significantly higher 24-hour mean systolic blood pressure (SBP, [149.6±20.0] mmHg vs. [137.6±20.2] mmHg) and SBP standard variation (SBP-SD, [13.4±3.8] mmHg vs. [12.1±3.8] mmHg, P<0.05). After adjusting for crude variables, the increase of 24-hour mean SBP and SBP-SD was independently associated with poor outcome on discharge (OR=1.284,95%CI=1.067-1.544, P=0.008; OR=1.098, 95%CI=1.016-1.188, P=0.019). Patients with poor outcome at 6 month after discharge had significantly higher 24-hour mean SBP ([146.6±20.6] mmHg vs. [137.1±20.2] mmHg, P<0.05). Conclusion Increased 24-hour BP variability after admission is associated with early functional outcome in patients with acute ischemic stroke, but not with midterm outcome. Key words: Blood pressure; Stroke; Prognosis