Prehypertension and the risk of stroke: a meta-analysis.

Abstract

In this meta-analysis, we sought to evaluate the association between prehypertension and the risk of stroke. We searched PubMed and EMBASE databases for studies with data on prehypertension and stroke. Two independent reviewers assessed the reports and extracted data. Prospective studies were included if they reported multivariate-adjusted relative risks (RRs) with 95% confidence intervals (CIs) for the associations between stroke and prehypertension or its 2 subranges (low-range prehypertension: 120-129/80-84 mm Hg; high-range prehypertension: 130-139/85-89 mm Hg). We conducted subgroup analyses according to blood pressure ranges, stroke type, endpoint, age, sex, ethnicity, and study characteristics. Pooled data included the results of 762,393 participants from 19 prospective cohort studies. Prehypertension increased the risk of stroke (RR 1.66; 95% CI 1.51-1.81) compared with optimal blood pressure (<120/80 mm Hg). In the secondary outcome analyses, even low-range prehypertension increased the risk of stroke (RR 1.44; 95% CI 1.27-1.63), and the risk was greater for high-range prehypertension (RR 1.95; 95% CI 1.73-2.21). The RR was higher with high-range than with low-range prehypertension (p < 0.001). There were no significant differences in any of the subgroup analyses (all p > 0.05). After adjusting for multiple cardiovascular risk factors, prehypertension is associated with stroke morbidity. Although the increased risk is largely driven by high-range prehypertension, the risk is also increased in people with low-range prehypertension.