Risk factors

Go lower: new evidence beyond SPRINT supports case for intensive BP control

Further evidence has emerged to support intensive treatment of hypertension, with a study showing a systolic blood-pressure target of 110 – 130 mm Hg results in a lower incidence of cardiovascular events than standard treatment to a target of 130 – 150 mm Hg.

In the Chinese STEP trial, 8,511 patients 60 to 80 years of age with hypertension (systolic blood pressure of 140-190 mm Hg), were randomised to either the intensive target or the standard target with antihypertensive drugs including olmesartan, amlodipine, and hydrochlorothiazide.

The trial was stopped early after a median follow-up of 3.34 years based on a clear cardiovascular benefit in the intensive-treatment group at two consecutive time points.

The study, published in the NEJM, found that throughout follow-up, the mean systolic blood pressure was 126.7 mm Hg in the intensive-treatment group and 135.9 mm Hg in the standard-treatment group.

The primary-outcome events (a composite of stroke, ACS, acute decompensated heart failure, revascularisation, AF or cardiovascular deaths) occurred in 3.5% of patients in the intensive-treatment group versus 4.6% of the standard-treatment group (hazard ratio, 0.74; 95% CI, 0.60 to 0.92; P=0.007).

The results for most secondary outcomes including major adverse cardiac events also favoured intensive treatment.

In safety and renal outcomes, only the incidence of hypotension was significantly higher in the intensive treatment group (p=0.03).

“Our large trial provides important evidence, showing that a reduction in the systolic blood pressure to less than 130 mm Hg resulted in cardiovascular benefits in older patients with hypertension in China,” the investigators said.

They noted that their findings of cardiovascular benefit with intensive treatment were consistent with those of the landmark SPRINT trial. that led US cardiology groups to revise their guidelines.

However they said that such a low systolic blood-pressure target was challenging to reach and can result in higher medication costs and more frequent clinic visits.

“In addition, a significantly increased incidence of kidney injury was observed with a systolic blood-pressure target of less than 120 mm Hg among participants without chronic kidney disease in SPRINT; an increased incidence of kidney injury was not observed with a systolic blood-pressure target of 110 to less than 130 mm Hg in the STEP trial.”

Real world implementation

An editorial in the NEJM by Professor Mark Nelson, noted that only a modest number of medications were needed to reach the targets (1.9 in the intensive-treatment group v 1.5 in the standard-treatment group) which was “crucial for real-world implementation of the findings”.

“Like SPRINT, the STEP trial was stopped early because there was a clear cardiovascular benefit in the intensive-treatment group,” he said.

“Unlike SPRINT, the STEP trial did not show a significant benefit in the intensive-treatment group with respect to death from any cause or death from cardiovascular causes.”

Professor Nelson, from the Menzies Institute for Medical Research at the University of Tasmania, said the STEP trial confirmed that systolic blood-pressure targets below currently accepted levels provide real clinical benefits with relative safety.

Professor Garry Jennings from the Baker Heart and Diabetes Research Institute told the limbic that the STEP trial appeared to confirm SPRINT’s findings – “as do a number of other different kinds of analyses”.

“So I think that the key message for practitioners is that if you can go lower, in this case to 130 or below, then you should provided the patients tolerate it well and they fit these high risk subgroups that these studies were performed in.”

He said it does mean that more people are going to end up on multiple medications but given the availability of combinations and that most are once daily, it was not going to inconvenience patients.

“It is going to have an outcome benefit but there will be some more postural hypotension and other consequences…that seems to be outweighed by the benefits.”

Professor Jennings said we don’t achieve optimal blood pressure targets very well in Australia in the communities of concern.

“And part of that is a problem of not identifying it, and a lot of it is not having people on treatment that are recommended to be on treatment, and then not having people on intensive treatment. And there are patient barriers and there are clinician barriers to that.”

“What this should address at least is the conversations that we have with our patients and also the confidence with which clinicians can make sure they are shooting for optimal blood pressure levels with safety and benefit.”

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