Research That Changes the World: Rod Jackson Part 1

From Hypertension to Cardiovascular Risk: Rod Jackson’s Big-Data Impact in New Zealand

Adrian, a Butler University Medical Science Bridge Program faculty member, interviews Dr. Rod Jackson, an epidemiologist at the University of Auckland, on the Building Bridges podcast. Jackson describes growing up in rural New Zealand, choosing medicine, and shifting from clinical practice to public health after working with cardiovascular epidemiologist Robert Beaglehole, focusing on prevention such as smoking reduction. He explains how conflicting hypertension definitions led him in the late 1980s to advocate replacing single risk-factor thresholds with multivariable cardiovascular risk assessment, influencing New Zealand guidelines in the 1990s and later integrated cardiovascular risk guidelines. To replace Framingham-based estimates, he helped build a primary-care clinical decision support system that created a linked national cohort exceeding 500,000 people, producing New Zealand “PREDICT” risk equations published in The Lancet (2018) and diabetes-specific equations (2021), incorporating ethnicity and social deprivation to address inequities.

00:00 Welcome and Guest Intro

00:51 Oxford Mentorship Story

02:06 Rod Jackson Bio Highlights

04:25 Early Life and Schooling

06:03 Choosing Medicine and Prevention

08:12 Switch to Epidemiology

10:11 Hypertension Definition Mess

13:41 Risk Based Guidelines Breakthrough

17:12 Building NZ Predict Cohort

21:50 Equity and Social Determinants

23:46 Part One Wrap Up

Cardiovascular disease risk prediction equations published in The Lancet – University of Auckland

Transcript

0:04

Hello, my name's Adrian. I'm one of the faculty members here in the Butler University, doctor of Medical Science Bridge Program. You're listening to the Building Bridges podcast. I'm so excited today because my guest is Dr. Raw Jackson, who's a researcher and an epidemiologist at the University of Auckland in New Zealand. He's also a far away mentor of mine, and I think he has so much to share. About having a successful career and influencing patient care in many ways. So we're gonna jump right in. Professor Jackson, thank you so much for being here.

rod 0:41

Yeah. And, right from the start, everyone calls me Rod, so don't even bother about the professor. That's

0:48

I'll do my best. I cannot make any promises. I will give a little more background that I was lucky enough to meet Rod, met him at the Center for Evidence-Based Medicine in Oxford University more than 10 years ago now when I attended a week long training there and he was my small group facilitator. I did not know that was gonna happen when I signed up for this program. It seems to have happened randomly, but I was thrilled because I already knew who he was ahead of time. I'd been teaching evidence-based medicine with his materials and talking about him in my lectures. And so on the first day when those groups were assigned, I like totally fangirled. I was super excited I was thrilled. And I needed help with. Converting, I think it was like number needed to treat absolute risk reduction to number needed to treat. And doing that formula. And we were kind of talking about like how we don't really love the spin and snout sensitivity and specificity acronyms. This is, so weird, but I asked you to sign the paper. I asked you to like autograph the paper where you were like doing the, the formula for me and I kept it and I showed to all my students. It's on one of my slides. So yeah, that's, that's what your bio is, right? I think I've just given the bio, but that's definitely why I invited you on the podcast. Let me give you the official Rod Jackson. Bio. So Rod completed a medical degree in 1977, his PhD in 1989, fellowship in Public Health in 1990. He's been a professor of epidemiology at the University of Auckland in New Zealand since 99. He has over 40 years of research experience in Cardiometabolic disease epidemiology. Over the past 25 years. He's developed and led big data health cardiometabolic research that generates very large cohort studies. When I say very large, I mean like over 500,000 participants. And even more, you're gonna hear in a couple minutes actually about a web based clinical decision support system. That's based on his research, that supports primary care. And so we're talking. Huge databases and the main focus of the research program has been to develop cardiometabolic risk prediction algorithms to apply them to patient care. And aside from all of that. He's also taught courses in epidemiology, evidence-based medicine for over 30 years. He teaches epidemiology with pictures using the gate tool. That's graphic appraisal tool for epidemiology. You'll hear more about that. He's one of those professors that students really love. They've made like a YouTube video about him. And I think, you know, for any educator listening, if they're. Willing to parody you in a kind way that's, the biggest phrase you're gonna get. He's published over 360 peer reviewed papers. So just, wow. So glad to have you here, rod.

rod 3:46

I'm very happy to be here.

3:49

I have so many questions, but I'm going to just try to start at the beginning because hopefully that's the most talking I'm gonna do. I'd really just like to hear from you, rod. Can you talk to us about how you got where you are today? And I mean, really start at the beginning from your upbringing, which I find really interesting, and then your training to become a leading epidemiologist in New Zealand, having these huge databases at your disposal to generate data and public health. Informing healthcare. So basically what I'm saying is start at the very beginning and tell us everything. Okay.

rod 4:25

Yeah, I grew up, in a small country town and on farms. So we kind of moved backwards and forwards from small town where my father was, a full-time lawyer and we moved to our farm where my father was also a full-time farmer. So we were backwards and forwards And that was back in the, late 1950s and sixties. And my mother had been a teacher, but she also became a full-time mother'cause there were five boys, two sets of twins. I'm an identical twin. And that was a full-time job for my mother. And she was also on the farm, so it was a real mix. And I still remember sometime in my childhood, she was a part-time teacher as well.

5:09

So it must have seemed like sometimes your family had more than 24 hours in a day. Like there were so many duplicate lives happening.

rod 5:18

Yeah. It, I think there was a strong work ethic in, in, in my family. And then all my brothers went to high school in Auckland, the main city in New Zealand. So we ended up boarding at the, at a school in Auckland. Both my parents had originally come from Auckland, the city now of a million plus people. Biggest city in New Zealand. Five, only five and a half million people in New Zealand. So it's quite a small population, in a country the same size as, the United Kingdom or Japan, that's the size of the country. Anyway, was all, was assumed that we would all probably go to university. It was just an assumption it wasn't, really pushed. So I ended up when I was 16 or maybe 17 last year in high school, what am I gonna do? And just happened in my class at school. Everyone either did and it was the top class in one of the top, probably the top school in New Zealand, but I was near the bottom. I wasn't like a top student, but really the choice it was a boys school. It was either medicine, law, engineering, or pure maths. And the only thing among those sort of disciplines that was interesting to me was medicine. And I just thought, you know, there were more opportunities there. And, I'd been told that there were more potential, different opportunities in medicine than in any other professional career. And given I wasn't really sure what I wanted to do. I chose medicine. So I went to medical school and I did okay. I was a B student all the way through, but I was looking forward to practicing medicine, although I was kind of more interested in why people presented the hospital than their diagnosis. So their diagnosis was less important to me than why they had that diagnosis, so, mm-hmm. You know, it's always an interest in prevention. And certainly I, I have a few memories of, when I was doing pediatrics why were most of the kids who came to Clinic? Brown, you know, in, New Zealand is a country, were about 70% of the population is European. And about 20% are either the indigenous Maori population or Pacific Islanders, Polynesian people from the Pacific Islands. It was in the order of 20%. But so many of the faces of the kids. Were Maori or Pacific Island and those kids. And so I was always, you know, why are these kids coming? And then when I did cardiology, I remember doing an attachment. Cardiology, why were all the patients smokers or overweight or whatever. So I was more interested in those things. Then I started practicing medicine and I got an opportunity after three or four years in clinical medicine to spend a year, with an epidemiologist. It was just happened to be this job that no one had taken before. And the staff really who organized our jobs said this, look, how about trying this rod? Yeah. And I thought, I'll give it a go. I've never thought of academia as a career particularly, but I spent a year with a. Epidemiologist and academic epidemiologist. And I never went back to medicine. I'm, it wasn't,'cause I didn't enjoy medicine. But I got sucked in to, medicine and he was a cardiovascular disease epidemiologist. We were very much big picture public health. he was, his name was Robert Beaglehole. I, I mean, it's a name that people in cardiovascular he know a little bit about. He was responsible for, new Zealand's smoke free laws legislation. He was really the major person behind that. So I spent the next 10 years with him trying to prevent people starting smoking. We were very focused on high saturated fat diets and stuff. So it's very much in the preventive. Field. And that was all through the eighties. So in the 1970s, I trained and practiced in medicine, and in the 1980s I retrained and practiced in public health epidemiology, mainly focusing on cardiovascular disease. Did a bit of work on asthma as well, but mainly cardiovascular disease.

9:48

So you're moving into cardiovascular epidemiology, but it can't really be understated that you really helped shape our understanding of not just individual risk factors, but of this concept of a cumulative cardiovascular risk. Will you talk more about how that began, that you really helped give us some of the words that we all use internationally in cardiovascular care.

rod 10:11

I won't go on too much about this, in my first degree in public health, which was a master's of public health, I basically designed a study and I recruited a representative sample of adults in the city of Auckland. was 1600, which seemed like a big number. At that time. We randomly selected people from the electoral roles and the goal was to describe the cardiovascular risk factor status of this population. So we measured all their blood pressures, their lipids, whether they smoked or not. In the mid 1980s, as I was putting all this data together, I had all these blood pressure, let's just start with blood pressure. But it was a similar, I had a similar challenge with lipids as well. I'd measured all that blood pressures described mean blood pressure levels by age and gender and also by ethnicity. And then I wanted to go beyond just description of means and distributions. And so I started looking into what was the definition of hypertension?'cause I thought I could describe the proportion who were hypertensive. I should have known this, but when I looked into the literature, I found multiple definitions of hypertension. And what struck me is it was the international literature and there were definitions of hypertension that could define 5% of my middle aged adult population. My study population as having hypertensive way up to 50% between five and 50%, depending on the definitions. And when I thought back, you know when I first went to medical school in 1972, the definition of hypertension. Was a systolic blood pressure of a hundred plus your age.

Adrian 12:12

No kidding.

rod 12:13

Back in the 1960s, early seventies. Now, by the time I finished medical school, that had changed, it had gone from a hundred plus your age. You know, I'm 71, so, I wouldn't get hypertension until I had a systolic blood pressure of 171. And then by the time I finished med school, it had completely changed to initially 170 on 105 and 160 on a hundred. And then through my first few years in clinical practice, it had come down to 1 50 90 and then 1 40 80. And for people with diabetes, it even got to one 30 you know, 75. So it was a complete mess.

Adrian 12:55

In summary, it was a complete mess.

rod 12:58

Yeah. And I realized, and so in the late 1980s, I realized that it was complete nonsense, that the definition of hypertension was complete. Nonsense. There I was. I was a young epidemiologist with, you know, limited, just recently experienced. And I thought no one in the world knows what hypertension is. It's completely confusing. We need to start again. We need to start again. And I'd been reading Jeffrey Rose, who in the cardiovascular disease field in epidemiology. He was an English epidemiologist. And he was famous in the uk. And also I've been reading about the Framingham I've been reading this work and. Basically what was coming out of both the English this very smart epidemiologist and the fantastic work that was coming outta Framingham was that the focus on cardiovascular risk factors should be a multi-variable approach. It should be, we should not be looking at individual risk factors alone because a systolic blood pressure of say one 40 means something completely different than a man and a woman and a 40-year-old and a 60-year-old and a combined. And so, you know, two people could have an identical blood pressure but a very, very different risk. Of having an event. having a cardiovascular event. And I, this made so much sense to me. This makes sense. So I started talking about it, presenting lectures at, at various conferences and just saying, it's time to get rid of the term hypertension. It's meaningless. We need to replace it by cardiovascular risk. And and I've been talking about that since the late eighties. And in New Zealand, just to cut a long story short in the early nineties, again, we're a small country. Everyone knows everybody. And there was someone in our Ministry of Health who had heard me lecture. And he was. In the process of trying to develop consensus guidelines for a whole lot of medical things, he said, rod, would you develop a guideline for New Zealand on hypertension?

Adrian 15:12

I mean, as one does.

rod 15:14

As one does. And and, um, so I ended up developing the world's first guideline for the management of raised blood pressure. I got rid of hypertension. It was called the management of raised blood pressure, but it didn't use a blood pressure level as the, threshold for treatment. It used cardiovascular risk, which was, I used a multi-variable equation from Framingham, from the US Framingham study. And so basically the. Guts of the whole guideline was measure people's blood pressure, obviously. And lipids and whether they've got diabetes, et cetera, whether they're smokers, put it together in this cardiovascular risk equation and make your treatment decisions largely based on the estimated risk. Because there was increasing evidence coming out that if your risk was say 10% in five years you were able to potentially have that risk by treating blood pressure, lipids and smoking. So you can go from 10% to 5% but if your risk before you treat, was 1%, so 10% goes to 5%, 1% goes to half a percent. So exactly the same treatments would give you. A tenfold greater benefit if you start off at high risk.

Adrian 16:38

Which is like the definition of absolute risk reduction.

rod 16:41

Absolute risk reduction. Yeah. Yeah. Yeah. So that was the nineties and I started with blood pressure. I then infiltrated the heart foundation's lipid guidelines and managed to get the them changed to the same thing. So it was all based on risk. And then in the early two thousands New Zealand developed a holistic guideline. We got rid of hypertension guidelines, lipid guidelines, and we replaced them with a cardiovascular risk guidelines. So everything was what I'd wanted. but we had a problem and our problem was that the Framingham equation, despite being amazingly, it was revolutionary and it was you know, it was unique in the world and it was, I mean it was just amazing work. But it was based on 5,000 middle-aged Americans from the town of Framingham

Adrian 17:36

Who had been recruited in a very particular spot.

rod 17:38

In a particular spot, mainly in the 1970s. They were kind of working class, middle class people. And New Zealand was a multicultural. Country with a much more diverse population. Socioeconomically. And also there'd been radical changes. Major changes in cardiovascular disease that had been plummeting for decades. And so I realized we would have to replace the framing equation with the New Zealand equation.

Adrian 18:09

Yeah, for your population.

rod 18:11

For our population.

Adrian 18:13

Yeah.

rod 18:14

Yeah. And so I established, I decided this in the late. 1990s that we would've to do something about it. And in a nutshell what I decided we needed to do is that we would give as many GPS as possible some software that had the framing equation in it. So that's all we had at the time. And it was in our guidelines. We would use the framing equation would get general practitioners to use the framing equation. But every time they used it, we would get a copy of the data and gradually over time we would, develop, we would get sufficient numbers of patients that we could then turn that data into a cohort study and replace the freemium equation with a New Zealand equation so by 2016 in a country, you know, as I said, which has just over 5 million people, we got over half a million people in our cohort. So we had the largest prospect of cohort study of, in primary care in the world, in one of the smallest countries in the world.

Adrian 19:29

I'm laughing because it kind of sounds so pie in the sky, like, oh, I'll just get data from everyone in the entire country and then I'll make a study. Like if someone proposed that to me, I'd be like, oh, that sounds a little unrealistic. Yeah, that's

rod 19:47

what people told me every New Zealander has a unique health. And, and that unique health number is linked to most interactions with the health sector. So in primary care the GPS had this unique number linked to each of their patients. And if people were hospitalized or died, that same number was linked to that. So we created a cohort in primary care. Again, because New Zealand is relatively small we focused mainly on Auckland the northern part of New Zealand where I was based, and our team were based. But we had access to national data on deaths and hospitalizations. The patient data came from primary care, like the patient characteristics. The outcomes came from hospitalizations and deaths. We were able to electronically link these data. It was quite a big deal. I mean, we had to get grants ma you know, quite major grants to do this work, but it's probably the cheapest large scale cohort that's been developed anywhere in the world because the GPS used it as a clinical tool, but were aware that it would be used also as a research tool. So they used it on a daily basis in clinical practice. But they were aware that we were going to use that data.. And then in 2018 we had the paper with the new equations, New Zealand equations called Predict Equations. They were published in The Lancet. And they became, the new equations in our guidelines. And we subsequently published an equivalent, set of equations for people with diabetes, that was also in The Lancet in 2021. But they're now in the guidelines as well. And, currently New Zealand and Australia use our equations.

Adrian 21:42

It's just really remarkable. It's outstanding and frankly, I'm just grateful. There's so much that you've added to the conversation about cardiovascular health in the entire world. And I wanna point out too, as we're moving away from the background and the equations, like the science of it, and more towards the clinical implications that you were also really thinking about social determinants of health at this time.

rod 22:07

Yeah. I guess we, we also absolutely, we, we, one of the predictors in the equation is social deprivation. So, every New Zealander, even though they won't know it has a social deprivation score that's based on it's an area based score. But it's quite an important predictor of future cardiovascular events. Ethnicity every healthcare record in New Zealand has ethnicity. In there where the indigenous people of New Zealand Maori wanted everyone to be classified by their ethnicity because they felt that was the only way they could start addressing inequity issues, is to have it measured. Right.

Adrian 22:51

And so this is happening in conversation with the different ethnic groups.

rod 22:55

I mean, the whole discussion about ethnicity on health records happened before the study I did, but it's been for 20 or 30 years, Maori have been pushing to have an ethnicity classification in every health record so that they can describe the inequities in health. So in New Zealand, you know, ethnicity is, something that you ask people. What is your ethnicity? And it's in your health records. So yeah, so we have, the work I've done is one very focused on preventing cardiovascular disease, but also reducing inequities between socioeconomic groups and ethnic groups.

Adrian 23:38

I mean, this alone is just such an impressive impact on the world of research and epidemiologic research, certainly. But we haven't even gotten into the clinical application of this long term and how people can carry this forward now, or people listening can carry it forward now.'cause a lot of New Zealand has heard this and we haven't talked about your teaching yet, so this is gonna wrap part one. And I'll ask listeners to transition now to part two so we can hear Rod's thoughts on butter and on teaching as well.