Systolic Blood Pressure Reduction and CVD Risk

Study Questions:

What is association of mean achieved systolic blood pressure (SBP) levels with the risk of cardiovascular disease (CVD) and all-cause mortality in adults with hypertension treated with antihypertensive therapy?

Methods:

Authors used MEDLINE and EMBASE from inception to December 15, 2015, and manual searches. Studies included clinical trials with random allocation to an antihypertensive medication, control, or treatment target. Studies had to have reported a difference in mean achieved SBP of 5 mm Hg or more between comparison groups. Network meta-analysis was used to obtain pooled randomized results comparing the association of each 5–mm Hg SBP category with clinical outcomes after adjusting for baseline risk. Primary outcomes were CVD and all-cause mortality.

Results:

Forty-two trials, including 144,220 patients, met eligibility criteria. In general, there were linear associations between mean achieved SBP and risk of CVD and mortality, with the lowest risk at 120-124 mm Hg. Randomized groups with a mean achieved SBP of 120-124 mm Hg had a hazard ratio (HR) for major CVD of 0.71 (95% confidence interval [CI], 0.60-0.83) compared with randomized groups with a mean achieved SBP of 130-134 mm Hg, an HR of 0.58 (95% CI, 0.48-0.72) compared with those with a mean achieved SBP of 140-144 mm Hg, an HR of 0.46 (95% CI, 0.34-0.63) compared with those with a mean achieved SBP of 150-154 mm Hg, and an HR of 0.36 (95% CI, 0.26-0.51) compared with those with a mean achieved SBP of 160 mm Hg or more. Likewise, randomized groups with a mean achieved SBP of 120-124 mm Hg had an HR for all-cause mortality of 0.73 (95% CI, 0.58-0.93) compared with randomized groups with a mean achieved SBP of 130-134 mm Hg, an HR of 0.59 (95% CI, 0.45-0.77) compared with those with a mean achieved SBP of 140-144 mm Hg, an HR of 0.51 (95% CI, 0.36-0.71) compared with those with a mean achieved SBP of 150-154 mm Hg, and an HR of 0.47 (95% CI, 0.32-0.67) compared with those with a mean achieved SBP of 160 mm Hg or more.

Conclusions:

This systematic review and meta-analysis suggests that reducing SBP to levels below currently recommended targets significantly reduces the risk of CVD and all-cause mortality. These findings support more intensive control of SBP among adults with hypertension.

Perspective:

Because of conflicting evidence, there is little consensus among experts and particularly trialists regarding the most appropriate target BP in patients with hypertension without or with diabetes, chronic kidney disease, and the elderly. This review provides support for the ‘lower is better’ hypothesis in all cohorts with hypertension. The additional magnitude of reduction in CVD and mortality using the lower target compared to achieved BP of <140 mm Hg and higher is about 50%, and using lifestyle intervention supplemented by generic antihypertensive drugs should not be costly to achieve. It is important to note that the achieved BP of 120-124 mm Hg in a clinical trial approximates home BP and <130 mm Hg in the office.


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