Re-Visiting Blood Pressure Targets: What Is Low Enough?

Study Questions:

What are the effects of blood pressure reduction on cardiovascular outcomes and death across various baseline blood pressure levels, major comorbidities, and different pharmacological interventions?

Methods:

This was a systematic review and meta-analysis. All randomized controlled trials of blood pressure lowering treatment published between 1966 and 2015 were eligible for inclusion. Eligible studies fell into the following three categories: random allocation of participants to a blood pressure lowering drug or placebo; random allocation of participants to different blood pressure lowering drugs; and random allocation of participants to different blood pressure lowering targets. Data were extracted for major cardiovascular disease events, coronary heart disease, stroke, heart failure, renal failure, and all-cause mortality.

Results:

A total of 123 trials with 613,815 participants were eligible for inclusion in the meta-analysis. Every 10 mm Hg systolic blood pressure reduction significantly reduced the risk of major cardiovascular disease events (relative risk, 0.80; 95% confidence interval, 0.77-0.83), coronary heart disease (0.83, 0.78-0.88), stroke (0.73, 0.68-0.77), heart failure (0.72, 0.67-0.78), and all-cause mortality (0.87, 0.84-0.91). Beta-blockers were less efficacious than other medications for the prevention of major cardiovascular disease events (1.17, 1.11-1.24), stroke (1.24, 1.14-1.35), and renal failure (1.19, 1.05-1.34). Calcium channel blockers were superior to other classes for stroke prevention (0.90, 0.85-0.95), but were inferior to the other classes for heart failure prevention. Diuretics were superior to other classes for heart failure prevention (0.81, 0.75-0.88).

Conclusions:

Blood pressure reduction improves cardiovascular outcomes across blood pressure levels and every 10 mm Hg (to a systolic blood pressure even less than 130 mm Hg) reduction is associated with more favorable cardiovascular outcomes.

Perspective:

This is a valuable meta-analysis that buttresses the findings of the SPRINT trial, challenging current guidelines, which advocate for blood pressure lowering to only 140 mm Hg. The authors summarize the approach to blood pressure lowering well as they write, ‘By showing no evidence for a threshold below which blood pressure lowering ceases to work, the findings call for blood pressure lowering based on an individual’s potential net benefit from treatment rather than treatment of the risk factor to a specific target.’

Keywords: Adrenergic beta-Antagonists, Antihypertensive Agents, Blood Pressure, Calcium Channel Blockers, Comorbidity, Coronary Disease, Diuretics, Heart Failure, Mortality, Renal Insufficiency, Risk Factors, Secondary Prevention, Stroke


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