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Public Journal Club: SPRINT Blood Pressure Study Joins the Race | Brian Secemsky MD

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Background:

Hypertension is one of the most common conditions diagnosed and managed by primary care physicians around the world. Managing hypertension matters, as is it is often cited as one of the leading risk factors for cardiovascular events and death. Given the high prevalence and unhealthy effects of hypertension on our populace, expert professional committees have been scratching their heads as to how best to manage this condition.

In 2013, JAMA independently published guidelines for the management of hypertension based on the Eighth Joint National Committee (JNC-8), which called for looser BP parameters than those recommended in previous iterations. Compelling observational studies, however, demonstrate a progressive increase in cardiovascular events with increasing blood pressure. Recognizing the hypothesis-generating value of these observational studies in conjunction with a dearth of high-quality studies indicating otherwise have motivated clinical researchers to continue the search for ideal target BP goals.   Thus, the Systolic Blood Pressure Intervention Trial (SPRINT).

 

The Study:

SPRINT randomly assigned 9361 participants >50 years old with an initial SBP 130-180 and an increased risk for cardiovascular events to a target SBP of <120 (intervention group) or a target SBP of < 140 (control group). Notably CKD patients were included in this trial, and diabetics were excluded. The primary outcome of interest was composite outcome of MI, ACS, stroke, CHF or death from cardiovascular causes.

The study was planned for a 2-year recruitment period and a 6-year follow-up period; however the trial was stopped early by its data and safety monitoring board after a median of 3.26 years of follow-up due to overwhelming benefits seen in the intervention group. The numbers needed to treat (NNT) to prevent a primary outcome event during the trial was 61. That is to say that for every 61 participants treated to an SBP goal of <120, 1 participant avoided a CV event. Medication and BP-related side effects, including syncope, hypotension, acute kidney injury, and metabolic abnormalities were significantly higher in the intervention group.

 

Why This Matters:

This is a huge study, and will be wrestled by the research community and fretted by primary care clinicians for some time to come. The JNC-8 raised the systolic blood-pressure goals to less than 150 mm Hg for people 60 years of age or older without diabetes or CKD just 2 years ago. This high-quality, randomized control trial suggests doing quite the opposite in their studied population. And if we take this study to the trenches of real life, a NNT of 61 to prevent CV events in a population containing millions of hypertensive patients is quite compelling in a population health perspective.

 

Take Home Point:

Despite the impressive results, we should be cognizant of some of the lesser-discussed findings of this study: serious adverse affects were seen in the intervention group and most participants in this group needed a mean of 2.8 BP meds to keep their blood pressure at goal. Given the high likelihood of additional costs, side effects, med interactions, and increased resources needed to maintain more conservative BP goals in our patient population, it is important to into account the preference of the individual, discuss the risks/benefits of polypharmacy, and more eagerly promote healthy diets such as the DASH and Mediterranean Diet when thinking about our current practice.

That said, the race surely isn’t over when it comes to best practices of blood pressure control, and one must keep an open mind as future studies on hypertension support or refute the remarkable findings seen in SPRINT.

 

See here for the SPRINT study published online in NEJM this week.

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Brian Secemsky, M.D.

Medical writing for patients, students
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