Racial Differences in the Impact of Elevated Systolic Blood Pressure on Stroke Risk

Arch Intern Med. 12/10/2012

Background  Between the ages 45 and 65 years, incident stroke is 2 to 3 times more common in blacks than in whites, a difference not explained by traditional stroke risk factors.

Methods  Stroke risk was assessed in 27 748 black and white participants recruited between 2003 and 2007, who were followed up through 2011, in the REasons for Geographic And Racial Differences in Stroke (REGARDS) study. Racial differences in the impact of systolic blood pressure (SBP) was assessed using proportional hazards models. Racial differences in stroke risk were assessed in strata defined by age (<65 years, 65-74 years, and ≥75 years) and SBP (<120 mm Hg, 120-139 mm Hg, and 140-159 mm Hg).

Results  Over 4.5 years of follow-up, 715 incident strokes occurred. A 10–mm Hg difference in SBP was associated with an 8% (95% CI, 0%-16%) increase in stroke risk for whites, but a 24% (95% CI, 14%-35%) increase for blacks (Pvalue for interaction, .02). For participants aged 45 to 64 years (where disparities are greatest), the black to white hazard ratio was 0.87 (95% CI, 0.48-1.57) for normotensive participants, 1.38 (95% CI, 0.94-2.02) for those with prehypertension, and 2.38 (95% CI, 1.19-4.72) for those with stage 1 hypertension. Read More