Decreasing Blood Pressure Trajectories Are Associated with Reduced Stroke Risk: A Group-Based Trajectory Analysis

Abstract

Objective: This study aims to identify the independent and multiple trajectories of systolic blood pressure (SBP) and diastolic blood pressure (DBP), and to explore their associations with the risk of incident stroke.

Methods: This study included 10,420 participants who underwent at least three measurements of blood pressure. Group-based trajectory modeling and group-based multi-trajectory modeling were used to identify the trajectory patterns of blood pressure. Logistic regression models were used to assess the association between the trajectories and the risk of stroke.

Results: During a median 11.07-year follow-up, 788 incident stroke cases were observed. We identified three SBP and DBP trajectory groups respectively, and five multi-trajectory groups. Among the SBP trajectories, compared to the normotensive-stable group, the high normal-slight increase and hypertension-decrease groups had 133% and 179% higher stroke risks when compared to the normotensive-slight decrease group. In DBP trajectories, the high normal-slight decrease and hypertension-decrease groups had 50% and 96% higher risks, respectively. In multi-trajectories of SBP and DBP, compared with participants with normal stable SBP and normal decreased DBP levels, the other four groups had a significantly higher stroke risk; individuals with high initial blood pressure and a decreasing pattern had the highest stroke risk (3.04-fold increase), followed by those with increasing SBP and stable DBP patterns (1.96-fold increase). When further adjusting for baseline blood pressure levels, the stroke risk of the participants with a hypertension-decrease SBP pattern was lower than that in the high normal-slight increase trajectory group; the multi-trajectory group, whose SBP decreased from stage 1 hypertension to high normal while DBP decreased from high normal to normal, showed no significant difference in stroke risk compared to the low-level group.

Conclusion: Participants with persistently high SBP and DBP levels have a higher stroke risk, while a decreasing trend in blood pressure is independently associated with reduced stroke risk regardless of baseline levels. This study emphasizes the importance of controlling blood pressure, especially SBP, for stroke prevention; it offers epidemiological evidence for stroke prevention and control.