Melanie Cole, MS (Host): Welcome to Better Edge, a Northwestern Medicine podcast for physicians. I'm Melanie Cole. And today, we're highlighting PREVENT, the American Heart Association's new cardiovascular disease risk calculator. Joining me is Dr. Sadiya Khan. She's the Magerstadt Professor of Cardiovascular Epidemiology and an Associate Professor of Medicine in Cardiology and Preventive Medicine at Northwestern Medicine, and she was the lead author of the study on the PREVENT calculator.

Dr. Khan, welcome back. Thank you so much for joining us. I'd like you to tell us right at the outset, what is the new Prevent risk calculator? What is that?

Dr Sadiya Khan: Thank you for having me. This is really exciting because the American Heart Association's new PREVENT calculator is the update for more than 10 years after the last calculator was released to be able to estimate what your patient's risk for developing heart disease, and it includes heart attack, stroke, or heart failure, over the next 10 or 30 years will be.

Melanie Cole, MS: Okay. So, this is an important clinical tool and I think it's important for consumers as well because it's something they can take, yes?

Dr Sadiya Khan: Absolutely. The reason this is so important is it helps to start the conversation about what can you do to reduce your risk of heart disease. And in order to really be able to understand what the potential options are that are best for each patient, we have to first understand what that patient's risk is. And this is really the backbone of clinical cardiovascular prevention, understand what somebody's risk is so we can then better tailor and personalize what our recommendations are to prevent heart disease for them.

Melanie Cole, MS: I love this. As an exercise physiologist, our evaluations, you know, I started long before you and 35 years ago, so we didn't have anything but a piece of paper and our questions. And I think that this is fantastic, because it gives a clearer view, it's a comprehensive assessment. Tell us your involvement in the study.

Dr Sadiya Khan: So, I led the working group that developed and validated these new equations, and we had a lot of robust discussion around what risk prediction tools can we use? What are the risk factors that are important? What time horizon should we be using? And how do we build upon the current framework that the pooled cohort equations, which were developed in 2013 by our very own Don Lloyd-Jones here at Northwestern Medicine, were already doing?

Melanie Cole, MS: Well then, tell us a little bit more about your methodology. Tell us how you used that data in the risk calculator, how that was collected, and were there any specific challenges or considerations in developing and validating this risk calculator that you want to mention?

Dr Sadiya Khan: Every risk prediction equation is only as good as the data sources that go into it. And one of the things that we really wanted to focus on was having a large, diverse, and representative sample to derive the equations from. Now, what I mean by that is that we wanted to make sure that we were inclusive, had contemporary data, and really represented the patients that we're seeing and that we would be applying this tool to.

So, what we did was we looked at both research cohort data sets, as well as electronic health record data sets, and were able to pull together over 25 data sets that included more than 3 million people to be able to develop these equations, and then actually validated it in a separate 3 million people to be able to have confidence in the rigor and reproducibility of our results.

Melanie Cole, MS: Tell us about the most significant findings of the study and particularly in relation to the accuracy and reliability of the cardiovascular disease risk calculator. How do these findings contribute to our understanding of disease risk and how does an individual's PREVENT heart score help physicians and other healthcare clinicians to provide good, sound advice and tackle this problem?

Dr Sadiya Khan: That was really an important part of the study, was to be able to see how well did the tool that we had developed discriminate. So, we used a statistic called the C statistic, as well as how precise was it looking at the calibration, or based on what we predicted the risk would be, was that what we actually observed in our data sets? And both of those statistics were really important to be able to give us a sense of how well the tool was doing. Now, the C statistic for cardiovascular disease for the overall equations was 0.79. And if you think about that number, 0.5 is as good as the flip of a coin for that number, and 1 is perfect. So, 0.79 is actually quite good to excellent. In terms of the calibration, we look at a slope of how well does what we predict match up to what we observed. And our slope was 1.03. And if you think about the observed versus predicted as a slope, one would be a perfect slope. So, we had a really good discrimination and calibration in terms of accuracy and precision. Now, that means that gives confidence to clinicians and we hope to our patients that this tool is doing a good job estimating the probability of developing heart disease.

Now, this tool, like with all tools that are giving you an estimate or probability, is not a crystal ball into the future but is a probability. But it gives us a starting point to be able to say this is our best estimate of what the chances of developing heart and one of the things we did in the calculator was provide two time horizons, 10 years, so in the near future, but also 30 years, thinking long term. And especially, Melanie, given your background as an exercise physiologist, we know the critical importance of health behaviors, physical activity and diet in really that long-term prevention that's going to be so important by having that framework there to help people, especially younger adults, and the tool is available for use starting at age 30, which is another update compared with prior risk tools, to start to engage people earlier in life in the preventive measures that we know to be effective at preventing heart disease.

Melanie Cole, MS: Dr. Khan, you and I have spoken before about diversity and cardiovascular risk and underserved populations. Are there specific populations or patient groups for whom this calculator is particularly relevant? And if so, and tying in the first podcast that we did together, how do you foresee awareness for diverse populations to take this calculator or to discuss it with their clinicians?

Dr Sadiya Khan: That was really an important part of our discussion. We have a growing appreciation and understanding of the important role of social determinants of health in cardiovascular risk. We know that where you live so intimately affects your health and access to healthcare, and is highly associated with your risk for heart disease. So, we wanted to include that, and we actually created an additional model that includes ZIP code-based social deprivation index. And so, a clinician or provider can enter the ZIP code in this tool and be able to personalize risk based on where someone lives. We thought this was really important, because we know that while we're assessing risk factors and including risk factors, there are multiple other factors that contribute to someone's health, well-being, and risk for heart disease.

Melanie Cole, MS: So then, how does it align with the existing cardiovascular disease prevention guidelines and what role do you see it? I mean, this is exciting for you, and I'm really happy that you did something like this. It could have a huge role in shaping future guidelines. Tell us a little bit about how it does align with what we've got going now, and then considering future guidelines, anything you would change? User-friendly? Any aspect? Accessibility? What would you change as it continues to move forward in the field?

Dr Sadiya Khan: This is a really important point. The new calculator is very exciting to have available to be able to have access for our patients as clinicians. We want to be able to do our best at estimating risk for heart disease. Within the current framework of the guidelines for primary prevention, for high blood pressure, for blood cholesterol, the goal is to match preventive measures with an individual's risk. So, I think it can plug right in. From the context of having specific guidelines recommend this calculator over the pooled cohort equations, which is our current standard, or other risk tools, we do have to sit tight and wait for that. We know that process is beginning now, and we expect it to really come up in the next few years, but we await the committee's recommendations for that.

Melanie Cole, MS: Well, I look forward to using it and recommending it for my patients, and I certainly hope that it is something, and I foresee that it will be, that clinicians all over the world can use for all of their populations. Now, as we get ready to wrap up, what do you believe, Dr. Khan, is the most impactful aspect of this research? How do you hope that it will shape the landscape of disease prevention and possibly raise awareness?

Dr Sadiya Khan: I think that's the most important thing. We have really come a long way in terms of available therapies that are in our armamentarium for prevention of cardiovascular disease. There have been significant advances in the past decade, and now we need to get them to our patients. And we need to figure out who are the right patients for the right therapies.

Our understanding of cardiovascular disease risk has also evolved over this time frame. And I think we have a lot of work to do in terms of optimizing prevention, but I'm very optimistic. We have the right tools, we have the right therapies, and we need to get it to our patients.

Melanie Cole, MS: Well done, Dr. Khan. Thank you so much for joining us and for creating and helping to create something that could change the landscape of cardiovascular disease prevention and awareness. So, thank you again for joining us and telling us about the study. To refer your patient and for more information, please visit our website at breakthroughsforphysicians.nm.org/cardiovascular to get connected with one of our providers. That concludes this episode of Better Edge, a Northwestern Medicine podcast for physicians. I'm Melanie Cole. Thanks so much for joining us today.