Background: There is clinical trial evidence that lowering systolic blood pressure (SBP) to < 120 mm Hg is beneficial, and this has influenced the latest American guideline on hypertension. We therefore used network meta-analysis to study the association between SBP and cardiovascular outcomes.
Methods: We searched for randomized controlled trials targeting different blood pressure levels that reported cardiovascular events. The mean achieved SBP in each trial was classified into 5 groups (110-119, 120-129, 130-139, 140-149, and 150-159 mm Hg). The primary variables of cardiovascular mortality, stroke, and myocardial infarction were assessed using frequentist and Bayesian approaches.
Results: Fourteen trials with altogether 44,015 patients were included. Stroke and major adverse cardiovascular events were reduced when lowering SBP to 120-129 mm Hg compared with 130-139 mm Hg (odds ratio [OR] 0.83, 95% confidence interval [CI] 0.69-0.99 and OR 0.84, 95% CI 0.73-0.96), 140-149 mm Hg (OR 0.73, 95% CI 0.55-0.97 and OR 0.74, 95% CI 0.60-0.90), and 150-159 mm Hg (OR 0.43, 95% CI 0.26-0.71 and OR 0.41, 95% CI 0.30-0.57), respectively. More intensive control to < 120 mm Hg further reduced stroke (OR 0.58, 95% CI 0.38-0.87; OR 0.51, 95% CI 0.32-0.81; and OR 0.30, 95% CI 0.16-0.56). In contrast, SBP ≥ 150 mm Hg increased myocardial infarction and cardiovascular mortality compared with 120-129 mm Hg (OR 1.73, 95% CI 1.06-2.82 and OR 2.18, 95% CI 1.32-3.59) and 130-139 mm Hg (OR 1.53, 95% CI 1.01-2.32 and OR 1.71, 95% CI 1.11-2.61). No significant relationship between SBP and all-cause mortality was found.
Conclusions: SBP < 130 mm Hg is associated with a lower risk of stroke and major adverse cardiovascular events. Further lowering to < 120 mm Hg can be considered to reduce stroke risk if the therapy is tolerated. Long-term SBP should not exceed 150 mm Hg because of the increased risk of myocardial infarction and cardiac deaths.
Copyright © 2018 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.