Presence of baseline prehypertension and risk of incident stroke: a meta-analysis

Abstract

Objective: To qualitatively and quantitatively assess the association of prehypertension with incident stroke through a meta-analysis of prospective cohort studies.

Methods: We searched Medline, Embase, the Cochrane Library, and bibliographies of retrieved articles. Prospective cohort studies were included if they reported multivariate-adjusted relative risks (RRs) and corresponding 95%confidence intervals (CI) of stroke with respect to baseline prehypertension.

Results: Twelve studies with 518,520 participants were included. Prehypertension was associated with risk of stroke (RR 1.55, 95% CI 1.35-1.79; p < 0.001). Seven studies further distinguished a low prehypertensive population (systolic blood pressure [SBP] 120-129 mm Hg or diastolic blood pressure [DBP] 80-84 mm Hg) and a high prehypertensive population (SBP 130-139 mm Hg or DBP 85-89 mm Hg). Among persons with lower-range prehypertension, stroke risk was not significantly increased (RR 1.22, 0.95-1.57). However, for persons with higher values within the prehypertensive range, stroke risk was substantially increased (RR 1.79, 95% CI 1.49-2.16).

Conclusions: Prehypertension is associated with a higher risk of incident stroke. This risk is largely driven by higher values within the prehypertensive range and is especially relevant in nonelderly persons. Randomized trials to evaluate the efficacy of blood pressure reduction in persons with this designation are warranted.

Figure 1. Study selection

Figure 2. Prehypertension and stroke risk

Association of prehypertension (systolic blood pressure 120–139 mm Hg or diastolic blood pressure 80–89 mm Hg) and stroke risk in prospective cohort studies. CI = confidence interval; IV = inverse variance.

Figure 3. Low and high range of prehypertension vs stroke risk

Association of prehypertension subsets, low range of prehypertension (systolic blood pressure [SBP] 120–129 mm Hg or diastolic blood pressure [DBP] 80–84 mm Hg), and high range of prehypertension (SBP 130–139 mm Hg or DBP 85–89 mm Hg) and stroke risk in prospective cohort studies. CI = confidence interval; IV = inverse variance.

Figure 4. Subgroup analyses according to patient characteristics

Influence of other patient characteristics on relation between prehyptertension and stroke risk in prospective cohort studies. CI = confidence interval; RR = relative risk.