Episode Transcript
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Interviewer: Lowering blood pressure below current guidelines can have a big impact on the health of people with high-risk hypertension. I'm talking with Dr. Brandon Bellows and Dr. Natalia Ruiz-Negron, from the College of Pharmacy at University of Utah Health. What is the problem with high blood pressure?
High Blood Pressure
Dr. Bellows: Yeah, so high blood pressure is a major risk factor for cardiovascular diseases, and as blood pressure increases, there's a strong increased risk for having cardiovascular disease events, so things like heart attacks and strokes.
Interviewer: Over the past few years there has been a milestone study that suggests that tweaking that a little bit can have a high impact.
SPRINT Trial
Dr. Bellows: Yes. So in the last, I guess this is about two years ago, the SPRINT study, the systolic blood pressure intervention trial, came out and it was looking at different systolic pressure goals. So historically guidelines have recommended that most adults target a systolic blood pressure of less than 140. So when you get your blood pressure taken, that's the top number. This study was looking at inpatients who were at higher risk for heart attacks and strokes, targeting a lower blood pressure goal of less than 120. And they found that there was a significant reduction in the risk of cardiovascular disease events as well as mortality with the more intensive goal.
Interviewer: They have results from the short-term study that lasted, what, two and a half years?
Dr. Ruiz-Negron: It was meant to be extended out till five years, but because they did see such a favorable outcome, then they stopped it about halfway through.
Interviewer: But what wasn't known is the long-term effects?
Dr. Ruiz-Negron: Yes. That is correct. So that's where kind of modeling studies can come in. Using the short-term effects that we see, we can try and incorporate that into a model that will try to evaluate what that long-term effect may be out till really whatever time frame we want to look at, say 10 years, or in the case of an older adult, the lifetime just because of their age.
Interviewer: When you looked at these longer-term outcomes through your computer modeling, I mean, what were some of the things that you found?
Dr. Bellows: Because of the extrapolating, three to five year data out for a lifetime has a lot of uncertainty around it. We looked at different scenarios of what may happen to patients. Do they continue taking their medication, do they stop taking their medications, and so on. But what we found is regardless of whether or not patients continued to be adherent after the five year period that SPRINT looked at, that intensive blood pressure control, the less than 120 goal, cost more but it increased survival of these patients and it did so at a value that society is generally willing to pay to increase life.
Blood Pressure Medication
Interviewer: So Natalia, help me understand what some of these different scenarios can look like. I mean, what are some of the things that might happen to somebody if they take their medication or if they don't?
Dr. Ruiz-Negron: To give you an example, say after five years this person may stop taking their medication and one of the big things that we say in pharmacy is if we don't take the medication, then you don't achieve the blood pressures. So that's really important, and so if you don't achieve that less than 120 blood pressure, then the benefits of the systolic blood pressure target would go away.
So then during the first five years, the person had really good chances of lowering their risk of experiencing these complications, but then after the five years, because they stopped taking their medications, then that lowered risk would go away. So the lower risk could be just lower risk of experiencing a heart attack or a lower risk of experiencing a stroke event in the long run.
Research Variables
Interviewer: Yeah. I mean, one thing I wanted to mention is that there were incredible number of variables that went into your different models because there's a lot of variability to real life. Right? So I mean, what were some of these other things that were factored into your modeling, and how did you go about figuring out what you should put in there and what you leave out?
Dr. Bellows: Yeah, that is a great question. So we had lots of different variables. So there are lots of things that contribute to cardiovascular disease risk and so we tried to capture the most important ones. So some of them in terms of the population characteristics were derived from the SPRINT trial. So we modeled a population of patients that looked like those in the SPRINT trial. So we got their cholesterol values, their kidney function, their blood pressures, all of that came from SPRINT.
The other thing that we do with modeling is that we grab variables from lots of different sources, so published literature, large med analyses that are synthesis of lots of different randomized controlled trials. So we pulled together all of these variables from one source or another, and what we did is we consulted with physicians who treat patients with hypertension to figure out what are the most important things to include in this model to try and predict their cardiovascular disease risk. And so after doing that, we constructed a model that we felt like it's not completely accurate. It's a simplification of reality, but it covers the major complications and major risk factors that patients might have.
Interviewer: What can we do with this information? Now that you know that it looks like the benefits outweigh the risks, what's next?
Monitoring Blood Pressure
Dr. Ruiz-Negron: That's a great question. So what we can do with this now, now that we know that intensive blood pressure is a cost-effective alternative for a specific subset of patients, we can try to figure out how to best implement it in different settings. So there's outpatient settings that we can try and evaluate. There's also within the hospital systems what something like that might look like. And so those are things that we're trying to work on next. Potentially developing some sort of tool to identify those patients that would benefit the most from this intervention and then kind of moving forward with that tool in order to implement it in these settings so that we can deliver the best care possible.
Dr. Bellows: Other things that we're doing are looking at how do we actually implement this in health care systems as they exist now. Do we need to hire more pharmacists and nurses, or do we need to buy more blood pressure monitoring devices? Do we need to send home blood pressure devices with patients? So we're looking also at the cost effectiveness of implementing this in health care delivery systems, both here locally as well as nationally.
Announcer: Interesting, informative and all in the name of better health. This is The Scope Health Sciences Radio.