Purpose: This study explored the differences of associating patterns of blood pressure (BP) according to the different stroke outcomes and investigated their changes by the elapsed time after stroke onset.
Methods: Patients who arrived within 48 h of stroke onset were consecutively identified between 2008 and 2014 in retrospective manner. Of them, all measured systolic BP (SBP) during hospitalization were summarized into mean values at acute (first 3 days) and subacute stage (afterward to 10 days) per person. Stroke outcomes were poor outcome (modified Rankin Scale > 2) at discharge and time to composite event of stroke, myocardial infarction and death for 1 y follow-up period.
The adjusted odds ratios (AOR) for poor outcome were interpolated through whole range of mean of SBP (SBPmean) in separate to acute and subacute stage using restricted cubic spline technique (RCS) added to logistic regression models with predetermined covariates. The interpolation of hazards for composite event by SBPmean in acute and subacute stage were analyzed using RCS added to Cox proportional hazard models.
Results: This study enrolled 3723 subjects (mean age, 66.7 ± 13.2 years-old and median baseline NIHSS score, 3). SBPmean in acute and subacute stage were 134.3 ± 15.9 and 135.6 ± 14.8 mmHg.
AORs for poor outcome showed linear trends through SBPmeanin both stages, however, there was significant increases of risk at higher values of SBPmean in acute stage not in subacute stage (Figure 1). For 1 y of observation, SBPmean in both acute and subacute stage demonstrated U-shaped associations with hazards for composite event (Figure 2). There were significant higher hazard levels below 120 mmHg of SBPmean in subacute stage.
Conclusion: In ischemic stroke, association patterns of BP are measured differently depending on stroke outcome. And prompt ranges of BP would be changed by the elapsed time after onset.