Lower Blood Pressure Target Could Affect MillionsNov 9, 2015
Results from the landmark Systolic Blood Pressure Intervention Trial (SPRINT) shows that a blood pressure target of 120 mmHg, lower than current guidelines, significantly reduces risk for heart failure, heart attacks and death. Implementing these findings into medical guidelines would be expected to affect at least 16.8 million Americans and could greatly reduce the incidence for heart disease in this country. Adam Bress, PharmD, assistant professor of pharmacotherapy at the University of Utah College of Pharmacy, explains who would most likely be affected by guideline changes, and the tough choices that physicians and patients could be faced with. His research was published in the Journal of the American College of Cardiology.
Interviewer: Results from a large clinical trial could have implications for millions with high blood pressure. More about that next, on The Scope.
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Interviewer: I'm talking with Dr. Adam Bress, Assistant Professor of Pharmacotherapy at the University of Utah. High blood pressure or hypertension, that's a big problem in this country, right?
Dr. Bress: Absolutely. Hypertension or high blood pressure affects about 80 million Americans, which is about 1 in 3. Hypertension has been associated with important clinical outcomes such as heart attacks, strokes, and heart failure.
Interviewer: There was a clinical trial that the results were just reported on and these results are really striking. They could possibly have big implications for how hypertension is treated in the future. Could you briefly talk about the results of that trial?
Dr. Bress: So for the last 20 years or so, hypertension has been treated to a target of less than 140 of systolic blood pressure or the top number. SPRINT is a landmark trial that challenges this paradigm and provides high-quality evidence that a [inaudible 00:01:05] of less than 120, so a more intensive target, is superior to the conventional goal of 140 for the prevention of cardiovascular disease events and total mortality. This is in patients without diabetes or stroke.
These findings are very exciting and important because given the large number of Americans with hypertension, they may be applicable to a very large population which means that these findings have the potential to greatly reduce the incidents of cardiovascular disease in the United States.
Interviewer: You've actually taken those results and done some analysis to find out how many people these results could affect.
Dr. Bress: We've analyzed the National Health and Nutritional Survey to quantify the potential impact of the SPRINT findings on the US population. We found that 7.6% of US adults meet the SPRINT eligibility criteria.
Interviewer: People with these characteristics that were enrolled in the trial would be the first ones that would possibly be affected by any results to come out of the SPRINT trial. Is that right?
Dr. Bress: Exactly. The individuals meeting all of the SPRINT criteria are the individuals that clinicians will have the most confidence in that the benefit observed in SPRINT would be seen in those patients. So the general eligibility criteria for the SPRINT trial were age greater than 50 years, systolic blood pressure higher than 130, and you had to be at high risk of cardiovascular disease. Which means you had renal dysfunction, you had a history of coronary artery disease, etc.
Interviewer: What you're saying too, is that any results could affect a broader population as well, right?
Dr. Bress: Exactly, it is likely that clinicians may extrapolate the SPRINT findings to a couple larger groups of patients. For example, this could be a 55 year old with blood pressure in the 140 range that doesn't have any other diseases. This type of patient would not have met the SPRINT eligibility criteria but is likely to have a conversation with a clinician as to what is the most appropriate blood pressure target for that patient.
Getting to a blood pressure of less than 140 requires two anti-hypertensive medications per patient. Getting to a blood pressure of less than 120 requires about three and a half drugs on average per patient. So it is a big decision to get that lower goal, more medications and more exposure to potential side-effects.
Interviewer: Part of your analysis was looking at how many other people might be affected by those decisions. What are some of those findings?
Dr. Bress: We estimated that 45 million US adults are 50 years and older, have a blood pressure over 120, and do not have diabetes or stroke. So these are patients that are likely going to have those conversations with their physicians. They wouldn't specifically have met the criteria for SPRINT but they may derive benefit from a new and more intensive blood pressure goal of less than 120.
This highlights that challenge of translating the evidence into practice because it really highlights this question, "To whom do these results apply?" Is it only to patients that meet the strict inclusion and exclusion criteria? Or does it apply to other patients, lower risk patients, that were not included in SPRINT? That's the big question and the challenging task that clinicians will face when trying to implement or practice evidence based medicine.
Interviewer: People who maybe were considered healthy before now might be considered to have hypertension or high blood pressure.
Dr. Bress: That's right. So it is going to be a very challenging environment for clinicians to treat patients that are otherwise healthy but have blood pressure in the 130 to 140 range. These patients would not have been included in SPRINT. So it is unclear if they would receive the cardiovascular risk reduction that was observed in the SPRINT trial and it will be interesting to see what the forthcoming hypertension guidelines recommend.
Interviewer: I think that's a good point that just because the SPRINT trial had very striking results, we don't know if these are going translate in to medical guidelines.
Dr. Bress: Absolutely, and it is just one trial and it is unclear what the guideline committee will do with the SPRINT trial. It is likely though, that it will impact the guidelines in some way. We're just not sure how and to whom they will recommend this new intensive blood pressure goal of 120.
Announcer: Interesting, informative, and all in the name of better health. This is The Scope Health Sciences Radio.