Abstract 2593: Pulse and Mean Arterial Pressure as Predictors of Stroke in the REGARDS Study
Background: The definition of hypertension (HTN) is based on systolic blood pressure (SBP) and diastolic blood pressure (DBP). Recently, however, increased attention has been given to pulse pressure (PP) and mean arterial pressure (MAP) as potential risk factors of cardiovascular disease including stroke. We examined the relationship between 4 different blood pressure indices (SBP, DBP, PP, and MAP) and incident stroke.
Methods: Data were derived from the REasons for Geographic And Racial Differences in Stroke (REGARDS) national cohort study of 30,239 black and white participants aged ≥45, enrolled between 2003 and 2007 from the continental United States. A computer-assisted telephone interview obtained demographics, medical history, health behaviors and health status. At 3-4 weeks post interview, an in-home visit was conducted by a trained technician who collected blood pressure, biometrics, and blood and urine samples following standard protocols. SBP and DBP were defined as the average of two measurements obtained after a 5 minute seated rest. PP and MAP were calculated (PP=SBP-DBP and MAP=1/3SBP+2/3DBP). Follow-up by telephone occurred every six months for self or proxy-reported suspected stroke and events were confirmed using expert adjudication. Cox-proportional hazards models examined the association of incident stroke with the different BP measurements with multivariable adjustment for socio-demographic and clinical risk factors including hypertensive medication use.
Results: This analysis included 27,680 men and women ages ≥ 45 (mean age=64.7±9.4 years, 40.4% black, 44.6% male) without prevalent stroke at baseline. A total of 609 strokes over 135,247 person-years of follow-up revealed graded associations between each blood pressure measure (SBP, DBP, PP and MAP) and incident stroke. The hazard ratio (HR) for stroke associated with one standard deviation higher SBP (16.5 mmHg) was 1.21 (95% CI 1.13 - 1.31), DBP (9.7 mmHg) was 1.16 (95% CI 1.07 - 1.24), PP (13.3 mmHg) was 1.15 (95% CI 1.07 - 1.24) and MAP (10.7 mmHg) was 1.21 (95% CI 1.12 - 1.31). Higher levels of SBP remained associated with an increased HR for stroke after additional adjustment for DBP (1.19, 95% CI: 1.09 - 1.30), PP (1.27, 95% CI: 1.11 - 1.46), and MAP (1.15, 95% CI: 0.99 - 1.30). After adjustment for SBP, the other BP indices were not associated with incident stroke.
Conclusions: Although these data show that PP and MAP are positively associated with stroke, only SBP was independently associated with incident stroke after multivariable adjustment including other indices of blood pressure. PP, DBP, and MAP were not associated with incident stroke after adjustment for SBP.
- © 2012 by American Heart Association, Inc.