Meta-analysis: Lowering systolic BP confers reduced risk for CVD, CHD, stroke, HF, death

A new meta-analysis published in The Lancet came to the same conclusion as the SPRINT trial: the lower the systolic BP, the less the risk for CV events.

Researchers analyzed 123 studies with 613,815 participants from 1966 to Nov. 9, 2015, the date SPRINT was published.

All studies were randomized controlled trials of BP-lowering treatment with at least 1,000 patient-years of follow-up, some comparing therapies to each other, some comparing a therapy to placebo and some comparing BP targets.

Kazem Rahimi, DM, FRCP, from the George Institute for Global Health, University of Oxford, England, and colleagues analyzed summary-level data on outcomes, including major CVD events, CHD, stroke, HF, renal failure and all-cause mortality, and pooled estimates by using inverse variance weighted fixed-effects meta-analyses.

Relative risk reductions occurred in a similar magnitude as the BP reduction achieved, regardless of an individual’s BP at the start of the study, Rahimi and colleagues wrote.

For every 10 mm Hg reduction in systolic BP, there was a significant reduction in risk for major CVD events (RR = 0.8; 95% CI, 0.77-0.83), CHD (RR = 0.83; 95% CI, 0.78-0.88), stroke (RR = 0.73; 95% CI, 0.68-0.77), HF (RR = 0.72; 95% CI, 0.67-0.78) and all-cause mortality (RR = 0.87; 95% CI, 0.84-0.91), according to the researchers, who did not find a significant effect on renal failure (RR = 0.95; 95% CI, 0.84-1.07).

Millions of lives saved?

“Our findings clearly show that treating [BP] to a lower level than currently recommended could greatly reduce the incidence of [CVD] and potentially save millions of lives if the treatment was widely implemented,” Rahimi said in a press release. “The results provide strong support for reducing systolic [BP] to less than 130 mm Hg, and [BP]-lowering drugs should be offered to all patients at high risk of having [MI] or stroke, whatever their reason for being at risk.”

Most guidelines currently recommend treating patients to a systolic BP target of less than 140 mm Hg, with some suggesting less stringent targets in older individuals.

Proportional risk reductions in major CVD did not differ by baseline disease except for diabetes and chronic kidney disease, for which the risk reductions associated with lower BP were smaller, the researchers wrote.

Rahimi and colleagues also compared five drug classes to each other. They determined that beta-blockers were inferior to the other four for prevention of major CVD events, stroke and renal failure; calcium channel blockers were superior to the other four for prevention of stroke but inferior to the other four for prevention of HF; and diuretics were superior to the other four for prevention of HF.

“The broad consistency of the proportional effects of [BP] lowering on [CV] outcomes across various baseline [BP] levels and several disease categories will challenge the current guidelines on [BP] and will support the case to shift their focus from rigid [BP] targets to risk-based targets, even when starting systolic [BP] is lower than 130 mm Hg,” Rahimi and colleagues wrote.

Guidelines should change

In a related editorial, Stéphane Laurent, MD, PhD, FESC, and Pierre Boutouyrie, MD, PhD, both from European Georges Pompidou Hospital and University Paris Descartes, Paris, wrote that there is enough evidence for guidelines to be changed to focus on risk-based targets.

“Since data are accumulating against the J-shaped relationship, and because energetic lowering of [BP] seems safe and beneficial to patients, there is no reason not to apply it to high-risk patients,” they wrote. “The prevalence of uncontrolled hypertension is elevated worldwide, particularly in patients with hypertension who are at high risk of [CV] complications.” – by Erik Swain

Disclosure: Rahimi and another researcher report receiving research grants from Servier. Boutouyrie reports receiving grants and personal fees from Servier. Laurent reports no relevant financial disclosures.