Abstract
Background:
In 2014, the Eighth Joint National Committee recommended increasing target systolic blood pressure (SBP) from 140 to 150 mm Hg in persons aged ≥ 60 years without diabetes mellitus (DM) or chronic kidney disease (CKD). The evidence from population-based studies supporting the change was sparse. In a race/ethnically diverse prospective cohort, we examined incident stroke risk by SBP level in those aged ≥ 60 years without stroke, DM, or CKD at baseline.
Methods:
In the Northern Manhattan Study, there were 1706 participants aged ≥ 60 years and free of stroke, DM, and CKD at baseline. Incident strokes were identified through annual follow-up and adjudicated by two vascular neurologists. Cox proportional hazard models were used to estimate the multivariable-adjusted hazard ratio (HR) for baseline SBP categories and stroke risk.
Results:
At baseline, mean age was 72±8 years, 37% were male, 25% non-Hispanic white, 26% non-Hispanic black, and 49% Hispanic; 41% were on antihypertensive medication, and 43% had SBP <140 mm Hg, 20% 140-149 mm Hg, and 37% ≥150 mm Hg. With a median follow-up of 13 years, 167 participants developed a stroke. The crude stroke incidence was greater among individuals with SBP ≥150 mm Hg (10.0 per 1000 person-years) and SBP 140-149 (12.2) compared to those with SBP<140 (6.2). After adjustment for age, sex, race-ethnicity and medication use, participants with SBP 140-149 mm Hg had increased risk of stroke (HR, 1.7; 95% CI, 1.2-2.6) compared with those with SBP <140 mm Hg, and the increased risk remained in those without medication use (1.7; 1.0-3.0). Stratified analysis showed that the increased risk was seen in Hispanics (2.4; 1.3-4.7) and non-Hispanic blacks (2.0; 1.0-4.2) but not in non-Hispanic whites (0.8; 0.3-1.8).
Conclusions:
In a prospective diverse cohort, SBP 140-149 mm Hg was associated with an increased stroke risk, compared to those with SBP <140 mm Hg, in individuals aged 60 years or older without DM or CKD, in particular in Hispanics and non-Hispanic blacks. Raising the threshold for hypertension treatment could have a detrimental effect on stroke risk reduction especially among minority populations.