STEP: Lowering Blood Pressure Below 130 mm Hg Shows CV Benefit

August 30, 2021

Another large clinical trial has endorsed the approach of intensive blood pressure lowering, reinforcing the benefits of this approach seen in the previously reported SPRINT trial.

The STEP trial was conducted in China and involved patients over 60 years of age with hypertension. Intensive treatment with a systolic blood pressure target of 110 to <130 mm Hg produced a lower incidence of cardiovascular events than standard treatment with a target of 130 to <150 mm Hg.

The intensive group showed a 26% reduction in cardiovascular events, a 33% reduction in stroke, a 33% reduction in acute coronary syndrome (ACS), and a 73% reduction in acute heart failure.

The intensive group achieved a systolic pressure of 127 mm Hg with an average of 1.9 medications vs 135 mm Hg with an average of 1.5 medications in the standard group.

However, unlike in the SPRINT trial, the lower pressure in the intensive group was achieved without major tolerability issues in the STEP trial, which has been attributed to a healthier population of patients included.    

The STEP trial was presented August 30 at the virtual European Society of Cardiology (ESC) Congress 2021 by Jun Cai, MD, FuWai Hospital, Beijing, China. It was simultaneously published online in the New England Journal of Medicine.

"Several large trials have shown a beneficial effect of intensive blood pressure control on cardiovascular outcomes in older patients, but the appropriate systolic blood pressure target remains unclear," Cai said.

"Our large trial provides important evidence, showing that a reduction in the systolic blood pressure to <130 mm Hg resulted in cardiovascular benefits in older patients with hypertension in China," he stated.

However, noting that the trial was conducted exclusively in Han Chinese individuals, Cai advised caution when generalizing the results to populations that were not included in the trial, including patients with a history of stroke.

Discussant for the trial at the ESC meeting, Bryan Williams, MD, University College London, UK, described STEP as a "terrific study" with "very exciting results" that showed "remarkable similarity" to those from the SPRINT trial.  

"There is no doubt that the intensified treatment dramatically reduced cardiovascular events and was well tolerated, which is an important consideration in older patients. The levels of blood pressure were also achieved with a conventional strategy that we recommend in current guidelines," noted Williams, who was the recent chair of the ESC/European Society of Hypertension guideline task force,.  

But he pointed out that the population involved was relatively low risk, robust and healthy, and not all older patients would be able to achieve the blood pressure levels attained in this study.

"The key message for me from this study is that we can go lower in the older population and we shouldn't deny those patients the opportunity to be considered for lower levels of blood pressure on treatment as that may produce additional benefit as compared to conventional targets," Williams said.

"But the type of patients in this trial were fitter and healthier than the average older patients we see in practice, so doctors will need to adjust the target depending on the individual patient," he added.  

The STEP trial enrolled 8511 Chinese patients with hypertension, aged 60 to 80 years, who were assigned to a systolic blood-pressure target of 110 to <130 mm Hg (intensive treatment) or a target of 130 to <150 mm Hg (standard treatment).

At 1 year of follow-up, the mean systolic blood pressure was 127.5 mm Hg in the intensive-treatment group and 135.3 mm Hg in the standard treatment group.

The primary outcome was a composite of stroke, ACS (acute myocardial infarction and hospitalization for unstable angina), acute decompensated heart failure, coronary revascularization, atrial fibrillation, or death from cardiovascular causes.

During a median follow-up period of 3.34 years, primary outcome events occurred in 3.5% of patients in the intensive treatment group, compared with 4.6% of patients in the standard treatment group (hazard ratio, 0.74; 95% CI, 0.60 - 0.92; P = .007).

The results for most of the individual components of the primary outcome also favored intensive treatment: the hazard ratio for stroke was 0.67 (95% CI, 0.47 - 0.97); ACS 0.67 (95% CI, 0.47 - 0.94); acute decompensated heart failure 0.27 (95% CI, 0.08 - 0.98); coronary revascularization 0.69 (95% CI, 0.40 - 1.18); atrial fibrillation 0.96 (95% CI, 0.55 - 1.68); and death from cardiovascular causes 0.72 (95% CI, 0.39 - 1.32).

The results for safety and renal outcomes did not differ significantly between the two groups, except for the incidence of hypotension, which was higher in the intensive-treatment group (3.4% vs 2.6%), although there was no difference in dizziness, syncope, and fracture.

"Bespoke Medicine"

In his discussion of the trial, Williams noted that the issue of blood pressure targets in older people was challenging because as people age, patient heterogeneity increases dramatically as a consequence of multiple morbidities.  

"While some older patients are biologically young, active in their lifestyle and completely independent, others at the same age can be biologically very old, frail, and dependent on care. And the interpretation of the results of studies like this are strongly dependent on where the patients sit on this multi-morbidity scale."

He pointed out that the population in the STEP trial was relatively low risk, with 75% below 70 years of age. Only 2% had a renal impairment, 6% had cardiovascular disease, and patients with prior stroke were excluded. The mean baseline blood pressure was 146/83 mm Hg. "So we're not talking about lowering an elderly person's blood pressure from a very high level down to a low target."

"This does not diminish the importance of the findings, but it puts them into context on where the patients sit on the scale of heterogeneity."

Williams added: "I think treatment of blood pressure in the older population is a classic example of where we need clinical decision-making on a patient-by-patient basis."  

In a comparison with SPRINT, Williams said the STEP data showed remarkable similarity, with big reductions in major events.

He said there would be suggestions that SPRINT went lower in terms of blood pressure levels, but he noted that SPRINT used a methodology to measure blood pressure which many thought resulted in lower than usual clinic values, and when this is taken into account, "the blood pressure levels achieved in STEP and SPRINT are probably quite similar, as are the outcomes."

What Do Current Guidelines Advise?

Williams explained that in terms of current recommendations for older people, US guidelines advise aiming for a blood pressure of below 130/80 mm Hg with no qualifiers. European guidelines recommend getting below 140/90 mm Hg if possible and then aim to go down to 130 mm Hg if tolerated but do not recommend going lower than 130 mm Hg.

"Perhaps as a consequence of this study, you could say that tailored targets in older patients over 65 years of age would be firstly, to try to get blood pressure below 140/90 mm Hg because many patients can't even achieve that level of control. Then we can aim to go lower down below 130 mm Hg if you can, if patients will tolerate it and accepting that this is most likely to be possible in those who are independent and active with fewer comorbidities like the patients in the STEP study."

Williams added: "It is not going to be easy to get there in everybody. We should just try and get blood pressure as low as we can bearing in mind that tolerability is very important in determining persistence with therapy. This study provides some reassurance to doctors to get blood pressure down in older patients particularly if they are relatively robust."

Also commenting on the STEP results, Diederick Grobbee, MD, University Medical Center, Utrecht, the Netherlands, agreed with Williams.  

"This is important information showing that it is possible to lower blood pressure in older patients safely and it works," he said. "It is about generalizability. This population is clearly a healthy one who tolerated this sort of reduction well. We know that many patients can't do this, and these types of patients were not abundant in this study," he said.

The STEP trial was funded by the Chinese Academy of Medical Sciences. Cai has disclosed no relevant financial relationships. The other authors' disclosures can be found here.

European Society of Cardiology (ESC) Congress 2021. Presented August 30, 2021.

N Engl J Med. Published online August 30, 2021. Abstract  

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