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

OBJECTIVE: In this meta-analysis, we sought to evaluate the association between prehypertension and the risk of stroke.

METHODS: 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.

RESULTS: 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).

CONCLUSIONS: 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.