A meta-analysis of large-scale blood pressure lowering trials supports lowering blood pressure to systolic blood pressures (SBP) less than 130 mm Hg and providing treatment to individuals with a history of cardiovascular disease, coronary heart disease, stroke, diabetes, heart failure, and chronic kidney disease.
Because the benefits of blood pressure lowering treatment for cardiovascular disease prevention are well established, researchers sought to determine the extent to which these effects differ by baseline blood pressure, presence of comorbidites, or drug class.
The findings, published in The Lancet, indicate that for every 10 mm Hg reduction in SBP, there was a significant reduced risk of major cardiovascular disease events (relative risk [RR]: 0.80; confidence interval [CI]: 0.77-0.83), coronary heart disease (RR: 0.83; CI: 0.78-0.88), stroke (RR: 0.73; CI: 0.68-0.77), and heart failure (RR: 0.72; CI: 0.6700.78). This reduction led to a 13% decrease in all-cause mortality (RR: 0.87; CI: 0.84-0.91).
Investigators searched MEDLINE between January 1, 1966 and July 7, 2015 for all randomized controlled trials of blood pressure lowering treatment. They categorized eligible studies into 3 groups: random allocation of patients to a blood pressure lowering drug or placebo, random allocation of patients to different blood pressure lowering drugs, and, random allocation of patients to different blood pressure lowering targets. Each study was required to have a minimum of 1000 patient-years of follow-up of each group.
In total, researchers identified 123 trials with 613 815 patients eligible for inclusion in the meta-analysis. In proportion to the magnitude of blood pressure reduction achieved, relative risk reductions were shown in major cardiovascular disease events (P<.0001), stroke (P<.0001), heart failure (P<.0001), and all-cause mortality (P=.014).
Major cardiovascular disease events were reduced by 20%, coronary heart disease by 17%, stroke by 27%, and heart failure by 28%.
“Both of these major findings—the efficacy of blood pressure lowering below 130 mm Hg and the similar proportional effects in high-risk populations—are consistent with and extend the findings of the SPRINT trial,” the researchers noted. “Collectively, these data suggest that revision is urgently needed to recent blood pressure lowering guidelines that have relaxed the blood pressure lowering thresholds.”
In addition, modest differential effects were seen between drug classes. For example, beta blockers seemed inferior in comparison to other drug classes for the prevention of major cardiovascular disease events, stroke, renal failure, and all-cause mortality, while calcium channel blockers seemed superior to other drug classes for stroke prevention. Overall, all of the drug classes demonstrated similar levels of effectiveness.
“The broad consistency of the proportional effects of blood pressure lowering on cardiovascular outcomes across various baseline blood pressure levels and several disease categories will challenge the current guidelines on blood pressure and will support the case to shift their focus from rigid blood pressure targets to risk-based targets, even when starting [SBP] is lower than 130 mm Hg,” researchers wrote.
Instead of focusing on what researchers called “an arbitrary threshold for a single risk factor,” blood pressure management should be tailored to the individual patient and physicians should carefully assess when treatment should begin and identify target goals.
Ettehad D, Emdin, CA, Kiran M, et al. Blood pressure lowering for prevention of cardiovascular disease and death: a systematic review and meta-analysis. Lancet. 2015. http://dx.doi.org/10.1016/S0140-6736(15)01225-8.