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Prehypertension and the Continuum of Stroke Risk

Prehypertension, especially in the higher range, is associated with incident stroke.

To assess whether so-called prehypertension is associated with incident stroke, researchers conducted a meta-analysis of prospective cohort studies. The analysis included 518,520 participants from 12 studies originating in the U.S., China, Japan, and India. Prehypertension was defined as systolic blood pressure of 120–139 mm Hg or diastolic blood pressure of 80–89 mm Hg. In seven of the studies, prehypertension was further subdivided into a low range (120–129 mm Hg systolic or 80–84 mm Hg diastolic) and a high range (130–139 mm Hg systolic or 85–89 mm Hg diastolic).

Overall, prehypertension was associated with a significantly increased risk for stroke (relative risk, 1.55) that was driven by higher-range prehypertension (RR, 1.79). Lower-range prehypertension was not significantly associated with increased stroke risk. In subgroup analyses by baseline characteristics, the association was not affected by race/ethnicity, stroke endpoint (fatal vs. all stroke), stroke subtype (ischemic vs. hemorrhagic), or follow-up duration (<10 vs. 10 years). The association did not remain significant for people older than 65 and when study quality was only "fair."

The authors conclude that prehypertension, especially in the higher range, is associated with incident stroke.

Comment: Hypertension is associated with stroke on a continuum of risk (Lancet Neurol 2002; 1:149). For example, mild, moderate, and severe hypertension are all associated with stroke risk, with the highest relative risk for stroke among those with the highest blood pressure, and the greatest absolute number of strokes in those with mild or "high-normal" blood pressure, a designation that includes prehypertension. The current findings support the concept of a continuum of risk for stroke with increasing blood pressure, especially among patients with higher-range prehypertension. However, whether lowering blood pressure in the prehypertension range will reduce stroke risk remains uncertain; this hypothesis deserves additional efficacy, safety, and cost-effectiveness testing. Currently, rigorous lifestyle modification is recommended for people with prehypertension. A blood pressure target <130/80 mm Hg has been recommended for those with, for example, diabetes mellitus, chronic renal disease, or carotid artery disease and for those with 10-year Framingham risk scores of 10% (Circulation 2007; 115:2761).

— Philip B. Gorelick, MD, MPH

Dr. Gorelick is the John S. Garvin Professor and Head, Department of Neurology and Rehabilitation, University of Illinois College of Medicine at Chicago.

Published in Journal Watch Neurology October 18, 2011

Citation(s):

Lee M et al. Presence of baseline prehypertension and risk of incident stroke: A meta-analysis. Neurology 2011 Oct 4; 77:1330.

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Reader Remarks:

Review and add to remarks on this article

• What is now considered to be normal blood pressure for a person to be considered healthy?
  Leah D. Amir, 21 Oct 2011 11:12 AM EST
  Specialty: Cardiovascular Disease
  Given that the low range is within what some consider "normal" blood pressure, what is recommended now consider to be... [more]
• Evidence of stroke
  Abdullah saeed Al amoudi, Indonesia, 24 Oct 2011 7:25 AM EST
  Specialty: Family Medicine
  If it is not affected by race/ethnicity ,how about genetic ?
• lower pre-hypertension level?
  Hugh R. Dana, M.D., 3 Nov 2011 12:10 PM EST
  Specialty: Internal Medicine
  (1): Are you implying that stroke risk starts to rise above 120/70, which I have read is "ideal", and above... [more]

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