Systolic Blood Pressure Reduction and Risk of Cardiovascular Disease and Mortality: A Systematic Review and Network Meta-analysis.

Importance: Clinical trials have documented that lowering blood pressure reduces cardiovascular disease and premature deaths. However, the optimal target for reduction of systolic blood pressure (SBP) is uncertain. Objective: To assess the association of mean achieved SBP levels with the risk of cardiovascular disease and all-cause mortality in adults with hypertension treated with antihypertensive therapy. Data Sources: MEDLINE and EMBASE were searched from inception to December 15, 2015, supplemented by manual searches of the bibliographies of retrieved articles. Study Selection: Studies included were 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. Data Extraction and Synthesis: Data were extracted from each study independently and in duplicate by at least 2 investigators according to a standardized protocol. 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. Main Outcomes and Measures: Cardiovascular disease and all-cause mortality.
Results: Forty-two trials, including 144 220 patients, met the eligibility criteria. In general, there were linear associations between mean achieved SBP and risk of cardiovascular disease and mortality, with the lowest risk at 120 to 124 mm Hg. Randomized groups with a mean achieved SBP of 120 to 124 mm Hg had a hazard ratio (HR) for major cardiovascular disease of 0.71 (95% CI, 0.60-0.83) compared with randomized groups with a mean achieved SBP of 130 to 134 mm Hg, an HR of 0.58 (95% CI, 0.48-0.72) compared with those with a mean achieved SBP of 140 to 144 mm Hg, an HR of 0.46 (95% CI, 0.34-0.63) compared with those with a mean achieved SBP of 150 to 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 to 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 to 134 mm Hg, an HR of 0.59 (95% CI, 0.45-0.77) compared with those with a mean achieved SBP of 140 to 144 mm Hg, an HR of 0.51 (95% CI, 0.36-0.71) compared with those with a mean achieved SBP of 150 to 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 and Relevance: This study suggests that reducing SBP to levels below currently recommended targets significantly reduces the risk of cardiovascular disease and all-cause mortality. These findings support more intensive control of SBP among adults with hypertension.