SPRINT: Caution on Aggressive BP Reduction in Certain Groups

September 07, 2017

BARCELONA, SPAIN — Patients with a systolic blood pressure of 160 mm Hg or above who are at otherwise low general cardiovascular risk may be better off aiming for a target of below 140 mm Hg rather than below 120 mm Hg, a new analysis of the SPRINT trial suggests[1].

"The key message from our analysis is that a universal blood-pressure target may not be appropriate for all and that for some with baseline systolic pressure of 160 mm Hg or more, the harms of aggressive treatment might outweigh the benefits," said SPRINT investigator Dr Tzung-Dau Wang (National Taiwan University Hospital, Taipei City, Taiwan).

Presenting the new data at the European Society of Cardiology (ESC) 2017 Congress, Dr Wang added: "Although these results need further verification, it's worth considering that a universal target of 120 mm Hg might not be best for everyone."

"Our results suggest that there is an intricate interaction between each individual's baseline blood pressure, their inherent cardiovascular risk, and their degree of blood-pressure reduction," he said. "We have to consider all three of these elements in managing hypertensive patients."

Main results of the landmark SPRINT trial, funded by the US National Institutes Health, were published in the New England Journal of Medicine in 2015. They showed that in the total population of 9361 patients with a systolic blood pressure of 130 mm Hg or higher, those randomized to intensive treatment, which targeted a systolic pressure of less than 120 mm Hg, had significantly lower rates of fatal and nonfatal major cardiovascular events and death from any cause than standard treatment with a target of less than 140 mm Hg.

The current post hoc analysis focused on various subgroups of patients with different baseline systolic blood pressures and cardiovascular risks.

The results suggest that those with very high baseline systolic blood pressure but otherwise at low cardiovascular risk appear to have a worse outcome with intensive blood-pressure lowering than with standard treatment.

In the group with a baseline systolic pressure of ≥160 mm Hg and a lower 10-year Framingham risk score (≤31.3%, median), intensive treatment resulted in an approximate threefold increased risk of death from any cause.

"Although these results must be seen as hypothesis-generating because they come from a post hoc analysis, it seems prudent to recommend targeting a systolic blood pressure of less than 140 mm Hg rather than less than 120 mm Hg in patients with stage 2 hypertension and a 10-year Framingham risk score of ≤30%," Wang concluded.

In the whole population of the study, intensive blood-pressure lowering to a target below 120 mm Hg was associated with a 25% relative risk reduction in the primary outcome, a composite of MI, non-MI ACS, stroke, acute decompensated HF, and CV death (HR 0.75, 95% CI 0.63–0.89). There were also significant reductions in noncardiovascular and all death.

In the subgroup of patients with a baseline systolic BP of ≥160 mm Hg and low Framingham 10-year risk score, there was no benefit on the primary outcome of intensive blood-pressure lowering (HR 0.95, 95% CI 0.37–2.46). But there were two- to threefold increases in noncardiovascular death (HR 2.60, 95% CI 0.81–8.31), and in all cause death (HR 3.12, 95% CI 1.00–9.69).  

"In patients with baseline systolic above 160 mm Hg and at higher cardiovascular risk, intensive blood-pressure lowering is still beneficial—the benefits outweigh the harms," Wang concluded. "But in patients at low cardiovascular risk the harms seem to outweigh the benefits of lowering blood pressure too much. It is obviously a very delicate balance."

Commenting on these latest findings for theheart.org | Medscape Cardiology, Dr Maklim Graham, chair of the Joint European Societies Cardiovascular Prevention Committee, said he thought the results were showing a real effect.

"Any post hoc analysis needs to be tested, but it is intuitive if you start at very high blood pressures and force them down you would expect harm, especially in older people. We all know that there is a large increase in side effects when you are too aggressive in lowering blood pressure in older patients—probably because of postural hypotension."

But Graham says he remains cautious on the overall findings of SPRINT. "None of the other large trials of aggressive blood-pressure lowering have shown such a big benefit of reducing blood pressure to below 120 mm Hg. I don't think people are quite convinced of the more aggressive targets for blood pressure suggested by the SPRINT main results yet. I think they will need to be replicated before they become routine clinical practice."

SPRINT was funded by the National Institutes of Health.  Wang reports no relevant financial relationships.  

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