Abstract
Background: Lowering systolic blood pressure (SBP) to <120 mmHg has been shown to reduce cardiovascular events and mortality. Whether this should be the treatment SBP goal is controversial. We therefore related cardiovascular outcomes in large clinical trials to the level of SBP attained using network meta-analysis.
Methods: We searched for randomised controlled trials comparing different BP targets up to 1 July 2017. The mean SBP attained in each trial was classified into five groups (110-119, 120-129, 130-139, 140-149 and 150-159 mmHg). The primary outcomes were cardiovascular mortality, stroke, and myocardial infarction, which were analysed using R.
Results: We included 14 trials involving 44015 patients over 50 years old. Major adverse cardiovascular events (MACE) and stroke were significantly reduced when SBP was reduced to 120-129 mmHg compared to 130-139 mmHg (OR 0.84, 95% CI 0.73-0.96 and 0.83, 0.69-0.99), 140-149 mmHg (0.74, 0.60-0.90 and 0.73, 0.55-0.97), and 150-159 mmHg (0.41, 0.30-0.57 and 0.43, 0.26-0.71), respectively. Stroke was further reduced with more intensive control to <120 mmHg (0.58, 0.38-0.87, 0.51, 0.32-0.81, and 0.30, 0.16-0.56, respectively). In contrast, myocardial infarction and cardiovascular mortality increased with SBP of 150 mmHg and over compared to 120-129 mmHg (2.18, 1.32-3.59 and 1.73, 1.06-2.82) and 130-139 mmHg (1.53, 1.01-2.32 and 1.71, 1.11-2.61). The relationship between SBP and all-cause mortality was not significant.
Conclusions: Lowering SBP to <130 mmHg reduces MACE and stroke. More aggressive reduction to <120 mmHg reduces stroke risk further and is therefore an option if the treatment is tolerated. Long-term SBP should not exceed 150 mmHg because of the increased risk of cardiovascular events and mortality. Our network meta-analysis provides the evidence to support the SBP target of <130 mmHg in the 2017 AHA/ACC guideline.
