Background & Purpose: Current recommendations do not specifically address the optimal blood pressure (BP) cut-off for secondary stroke prevention in patients with previous cerebrovascular events. We conducted a systematic review and meta-regression analysis on the association of BP reduction with recurrent stroke and cardiovascular events using data from randomized-controlled clinical trials (RCTs) of secondary stroke prevention.
Methods: For all reported events during each eligible study period we calculated the corresponding risk ratios (RRs) to express the comparison of event occurrence risk between patients randomized to antihypertensive treatment and those randomized to placebo. Based on the reported BP values, we performed univariate meta-regression analyses according to achieved BP values under the random-effects model (Method of Moments) for those outcome events reported in ≥10 total subgroups of included RCTs.
Results: In pairwise meta-analyses of 14 RCTs comprising 42,736 patients antihypertensive treatment lowered the risk for recurrent stroke (RR=0.73, 95%CI: 0.62-0.87, p<0.001), disabling or fatal stroke (RR=0.71, 95%CI: 0.59-0.85, p<0.001) and cardiovascular death (RR=0.85, 95%CI: 0.75-0.96, p=0.010). In meta-regression analyses systolic BP reduction was linearly related to lower risk of recurrent stroke (p=0.049; Figure A), myocardial infarction (p=0.024), death from any cause (p=0.001) and cardiovascular death (p<0.001). Similarly, diastolic BP reduction was linearly related to a lower risk of recurrent stroke (p=0.026; Figure B) and all-cause mortality (p=0.009). Funnel plot inspection and Egger’s statistical test revealed no evidence of publication bias.
Conclusion: The extent of BP reduction is linearly associated with the magnitude of risk reduction in recurrent cerebro- and cardio-vascular events. Strict and aggressive BP control appears to be essential for effective secondary stroke prevention.