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Season 1 Episode 2: Foundations of Evidence-Based Practice with Dr. Gordon Guyatt.

Updated: May 30, 2023

Two years after the term first appeared in the medical literature, we were now in an era of evidence based medicine and that shows that the world was somehow ready.

Hey, Brad. Greetings, Matt.

How are you? I’m good, how are you?

I’m nothing to complain about except for all the pandemics.

Man Yeah, it’s pandemic fatigue for sure. Zoom fatigue, pandemic fatigue. My pants aren’t fit and correctly fatigue. Lots of fatigue.

As long as you’ve got your pants on, we’re on zoom, right.

Yeah, right. Yes. Pants are staying on. So we’ve got a really interesting episode here. Dr. Gordon Guyatt. We’re going to be hearing from him not having a science background. I had no idea who Dr. Gordon Guyatt was, but it seems like if I had gone anywhere near clinical nutrition or or anywhere near scientific literature, I would have run into the Grade recommendation system and or even the term evidence based medicine. So how does he sort of fit into the nutrition science of the science community as a whole?

Yeah, sure. So Doctor Guyatt is a very important figure in the field of medicine and particular evidence based medicine because he coined the term and in the interview with him, he’ll kind of go through how the whole field of evidence based medicine kind of came about. Yeah. And so he’s done a lot more than just coined the term. He’s a great teacher and a very serious researcher who is involved in a lot of different projects now for well over 30 years and kind of bringing evidence based principles alive.

And we’ll talk about that. We’ll get into that. And part of the evolution of evidence based medicine is really the the growth or first, the kind of the founding of a group called the Grade Working Group, and then how it’s kind of influenced the methodology around making guideline recommendations, whether it be clinical guideline recommendations or public health guideline recommendations, which, of course, would include nutrition around the world. The Grade Working Group, which he co-chairs with the gentleman by the name of Dr. Holger Schunemann, and they’re both situated at McMaster University in Ontario, Canada.

Their method of doing guidelines has been adopted by over one hundred. And I think now over one hundred and twenty organizations around the world, ranging from the show to the Cochrane Collaboration to the Joanna Briggs Institute, the CDC, the Centers for Disease Control. So a lot of groups, international groups that are well recognized, like GRADE use, GRADE promote, GRADE

wow, that’s really interesting.

It’s a simple system, but there’s a lot of complexity within the system once you kind of get into it. Not the overuse, the word complexity, but it seems to be the word of the day.

I mean, you know, that’s what we had talked about earlier, that ‘s it’s almost it’s almost the theme for the podcast is that there’s a lot of complexity in the science of nutrition. And so how do we approach that complexity in a way that is as objective as we can be and I guess egalitarian as far as information I want to talk a little bit about. So I don’t have a science background, which is easy because I don’t.

But how would you explain the term evidence based medicine to someone like myself who doesn’t have a science background? It seems to be something that he’s really well known for, right?

Yeah. So that’s a great question. It’s been defined by Dr. Guyatt and kind of really the McMaster Group, which was ultimately founded by a gentleman, by the name of Dr. Dave Sackett who founded. And we’ll talk about this in the episode as well, or the episodes, as well. He founded the McMaster Department of Clinical Epidemiology and Biostatistics. So kind of the work of those two gentlemen, as well as many other colleagues in the field when they did find evidence based medicine.

There were three things. One, what is what the evidence says? What did it mean? And in particular, what do systematic reviews of the evidence say on a target, clinical question or public health question two what does your clinical experience tell you? So if you’re a physician or a registered dietitian and you’ve seen twenty patients like this in the. What’s your experience tell you, should you give them the drug, should you give them nutritional intervention, what are the benefits and harms that you’ve observed?

And then three, which is probably at least as important as the best summaries of evidence or the systematic reviews of evidence, is what are the values and preferences of the patient or client in front of you? And or the values and preferences of the general public making recommendations. So it’s really three things. Best summaries of evidence, clinical experience and the values and preferences of either the client or patient in front of you and or members of the public who will bear the actual recommendations.

Wow, that’s really fascinating. It seems like a really great approach. I’m excited to listen to this interview clip. You have known Dr Guyatt for a while, right? You guys have worked together for a number of years. Yeah.

Yeah. I joined this group and I think it was 2009. So a little over 10 years ago. Great. Yeah. So it’s been a privilege.

Yeah. Good. He, he sounds, he sounds like a really singular mind. Someone that has really contributed a lot. And I’m really interested to hear what the two of you talk about.

There’s lots of adjectives we could use, but one that I would throw his way is he’s very much an independent thinker. Very original. Very independent.

Yeah, that’s great. So just for the benefit of our audience, we’re going to be hearing from Dr. Guyatt in more than one podcast episode. But we’re going to hear in this episode that it seems to be more like the foundations of evidence based medicine and a little bit about his background and how he got into the field of medicine, which for me is really fascinating because it sounds like he didn’t go sort of the traditional route.

Yeah, his undergraduate degree was in English. So and then he arrived into medicine without ever having taken a science course in university. So that’s great. It’s a very different story, I think.

Yeah. Yeah. Well, I’m sure that contributes to him being, as you say, a really independent thinker. So great. We hope you guys enjoy this interview clip from Dr. Gordon Guyatt.

Greetings, colleagues and friends, you may have heard of the term evidence based medicine. Well, today’s guest, Dr. Gordon Guyatt, coined the term evidence based medicine in 1991, in a paper published in the Annals of Internal Medicine. Dr. Guyette is a distinguished professor of medicine of Health Research Methodology, formerly clinical epidemiology and biostatistics at McMaster University, and is a clinician scientist or perhaps more aptly, a clinician methodologist. He founded the user’s guides to the medical literature, which are published in JAMA, the Journal of the American Medical Association.

He’s the co-chair of the Grade Working Group, which is an international group that has set standards for assessing the certainty or quality of evidence for systematic reviews. So, Dr. Guyatt, when I first and I can probably refer to you as Gordon or Gord, I’ve been working with you for well over 10 years now, I think. And when I first thought of this podcast, the first person I thought of interviewing was you. You’ve done a lot for me and a lot for my career over the years.

I’ll thank you again for all of your mentorship and guidance along the way. And I’m really excited to kind of just talk to you today about evidence based medicine, about evidence based clinical practice and about more about GRADE and what it is and how it came about and kind of where you are today with it. So you’re currently a distinguished professor of medicine and health research methodology, as I said, at McMaster University. How did you get to where you are today?

Can you tell us a little bit about your path?

So I was an undergraduate student at the University of Toronto taking English and psychology as my joint majors and not thinking of medical school because I hadn’t even in high school not taken a biology course. However, after a couple of years in university, I thought that I would want to do medicine and thought of actually going back and doing some that was then grade 13, doesn’t exist anymore. High school courses to prepare myself for doing university science courses. However, there was one medical school in the country that accepted people without a science background, and that was McMaster Medical School, the only medical school for which I was eligible.

So at a relatively young age. I think of it now, it’s an extremely young age 20, I applied and gained admission to McMaster Medical School. So the first part of the story had no science background at all. When I entered medical school, the only school that would have taken me and McMaster was very new at the time. Not only was it the only school accepting people without a science background, it had this problem based curriculum, no tests or examinations.

Your evaluation was, based on what you said in your small groups, was really extremely different.

Yes, very innovative.

And there’s an irony. So lots of places have moved toward McMaster, while McMaster has become progressively more conservative. But when I finished medical school, of course, the other schools thought this wasn’t real medicine that was being taught. And many of us were nervous. Could we when we put ourselves against medical students from other institutions, how would we fare? So I decided I wanted to do my residency training in Toronto against shoulder to shoulder with lots of people graduating from a prestigious conservative medical school in Toronto.

Hmm. And so I’d done no science in high school, no science in my undergraduate university and in medical school. There was no basics. There were no basic science courses. There are no courses at all. It was all this problem based thing. So I haven’t learned any basic science in medical school. So I went to U. T and started rubbing shoulders with the beauty graduates. And I found I knew as much basic science as they did, and that was because they knew any basic science.

It was because all the basic science they’d done early in their undergraduate and early their medical training, they had forgotten because they never used it at the right time. So anyway, I got through and have never felt any problems as a result of my lack of basic science exposure. So I got through medical school, decided I wanted to do internal medicine, but I quickly found that I wanted to be in an academic environment. I loved the academic environment, but what I loved was teaching.

I knew very quickly. I love to teach in an academic environment. I thought to myself, I’m going to be a clinical teacher. And then I went to had an interview with a guy named Jack Hirsch, who for years was the leading investigator on thrombosis in the world and turned McMaster into a huge, powerful, prestigious, very productive center at Thrombosis Research Institute of Medicine at the time, and called me into his office and said, Gordon, you may like to do education now, education and clinical work, but in ten years you will be bored.

And that would be a big mistake. That would be unfortunate. So as a result of that conversation, I went into what was then the DME program design measurement and evaluation, which was the ClinEpi Program master. The program is now called Health Research Methods, and to my pleasant surprise, I really enjoyed it. And as it went along an equally pleasant surprise was that I was good at it and so I had still been thinking my primary point would be in the Department of Medicine.

But the chair of the department and the team decided that perhaps I belonged with my primary appointment in what was then clinical epidemiology. And I took that up. The first theory of research, I entered into what we would now call health status measurement, which was quite primitive at the time from the current view. And I started working in that area. And as I say, when I started, it seemed like beyond what it was a really special person who did original methodology.

And then I found my pleasant surprise. I had the ideas to do original methodology, so I identified another grad student who actually had a new original conceptualization of measurement because previously it has all been the psychologists and whatever the psychologists were interested in. They were interested in measuring intelligence, they were interested in measuring attitudes. But measuring the effects of interventions was very personal to them. It became obvious to me that a lot of our treatments. Some of our treatments are to prevent bad things like heart attacks or deaths that make people live longer.

But a lot of our treatments are just to make people feel better. And we didn’t have the tools to measure that.

Right. So it’s kind of like the psychometrics in the Clinimetrics. Is that fair to say. So a guy named Alan Feinstein came up with the term Clinimetrix? That would be one way to characterize it. Anyway, we quickly decided that a different framework was necessary and to different measurement properties. So the psychology measurement properties have been reliability and validity. And you needed something more for measuring the effects of treatments and randomized trials. This other grad student had truly changed the foundation by distinguishing between the purpose of an instrument, which was to measure differences between people versus measuring change over time.

And it became clear that these were two fundamental purposes. Nobody had ever clarified this, right? I said this is the guy’s thesis, and it never occurred to him that he now had an idea that could change the whole way we look at measurement. When I said Brad, this could change this change, anyway we wrote it up and it did change how people think of measurement. What followed from that, we needed a concept in the evaluation sense, measuring treatment effects of measuring whether a measurement instrument could pick up change if change occurred, even if it was small.

And we made up a name for that called responsiveness. And then we found that a lot of these measurement instruments measure quality of life, nobody knew how to interpret the results. You change by five points on a zero to 100 scale. Is that a small effect? Is that a big effect? Is it trivial? What is it? Mm hmm. And we didn’t know how to interpret it. So we made up another measurement property and we called it interpretability so that initial work caused fundamental change, resulting in fundamental changes in how we approach measurement.

And one of the streams in my research and subsequent 30 years has been the substantial measurement. What’s happened to my career subsequently is that my core has been issues in evidence based medicine, which the health status measurements under the umbrella encompassed by evidence based medicine. But my primary focus is elsewhere.

And then just to clarify, Gordon, so you talked about interpretability. And so for our audience, the other term terminology that they might recognize it more aptly is minimal, clinically important difference that I know you and Dr. Schunemann then wrote a paper and said maybe we should drop the ‘al’ from minimal clinically important difference and just call it the minimal important difference. And so drop the ‘c’, actually. But yes.

Yeah, sorry. Drop the C. Yes, thank you. And so yeah, that’s kind of a concept that people may be familiar with in the audience. So and then as you referred to earlier, when we say minimal important difference, that helps us get into the thinking about what the size of the effect is. And so really moving the field away from statistical significance and into what the size of the effect is.

So historically, clinicians were not taught to read the medical literature. And I actually remember as an intern being given advice about how to read it, which is don’t bother with the methods and results, just read the introduction and discussion and whatever the author is telling you how to interpret their work. Well, they decided that that was misguided and he wanted to turn it on its head and have people ignore the introduction and discussion of the methods and results and understand his vision of what clinicians should be taught to do.

And this is really where the roots of evidence based principles are: evidence based medicine is kind of taking form with these insights. Is that fair to say?

Absolutely. Absolutely right. So he called it critical appraisal. He started running a critical appraisal courses for clinicians and they were classroom activities. So as a medical resident, it was one of Dave’s Lentees, Brian Haynes. Subsequently, chair of epidemiology for a decade and a very important original contributions to evidence based medicine, and maybe if all this clarifies, said Dave Sackett was one of your mentors and he was the first chair of clinical epidemiology and biostatistics at McMaster University.

So that’s for sure. So I’m a medical resident and I say, oh, I’ll sign up for this critical appraisal course. And at the end I start saying, Oh, I guess I’m able to read the medical literature now. So I started to read methods and results, and I found it impossible that a dozen sessions of critical appraisal got me nowhere. So I said, OK, I’ll put that aside. So then I was thinking about what my career is going to be.

And so I think I already said I love clinical teaching, but Jack Hirsch then told me I would be bored if I was going to be doing that 10 years from now and encouraged me to go into the master’s program. And I then really learned how to read the medical literature. And it was into my second course before I said, hey, this is clicking. I can read the methods and results and understand. And that experience has bearing on the evolution of evidence based medicine subsequently.

So Dave Sackett created critical appraisal and he now gets the idea of such classroom activity and he now gets the idea, bringing critical appraisal to the bedside. So he now starts taking it from a classroom activity into the wards and outpatient clinics and starts talking about using the medical literature to guide your clinical practice. And that’s what we, I and a number of colleagues we’re starting to do. We were starting to take these principles and apply them in our day to day clinical practice and encourage others to do so.

And it felt different. It felt like a day we had entered a different way of thinking of medical practice. Previously, it was what the experts told you without thinking very much about what they were doing. This huge emphasis on physiologic reasoning and fundamentally unquestioning approach and no capacity to read the literature oneself. And we were now going and starting to question why we are using this treatment? What is the evidence is it low quality is it high quality evidence.

It quickly became clear that it fell to us. Still, 30 years later, it still feels that this was something completely different. So I then decided that I would like to run the internal medicine residency program. And I was going to make this new thing. I was going to say this residency program McMaster will be different than it’s going to teach you this new way of practicing medicine. So I wanted to advertise. I thought, well, I can say a new way of practicing medicine, but it needs a name.

And my first idea was to call it scientific medicine, the then chair, that is the guy named John Terrance and subsequently became the Dean UC. He was introducing me to the faculty. And I sent around a document that described what I wanted to do. I wanted to teach this scientific medicine. When I was introduced to the Department of Medicine, there was an outpouring of rage by the basic scientists who I was appropriating. They were the scientists and I was appropriating the term science for my stuff when it was really their stuff.

And I was told by the person sitting beside the chair that about three times John Terrance was about to stand up and say, that’s enough, lay off the guy. But each time I managed to control the situation and got to the end. But in the end I decided this scientific medicine is not going to work. Just it’s a whole furor of antibodies that has elicited. So I decided, OK, I need another name. And my second thought and what we might call it was evidence based medicine.

The discoveries that are made or the changes in the way people think are always building on what’s before, whether you know it or not. I was chosen as chair of the residency program. I’m going to say we’re going to this program to do evidence based medicine that was sent around in 1990 to prospective candidates to come to our program. And in 1991 in a paper of which I was the sole author in American College of Physicians Journal Club, was the time that evidence based medicine first appeared in the literature.

Nobody noticed that, but in 1992, by that time we had a couple of years of the program and we published the paper. That was the flagship announcement of evidence based medicine in the world in JAMA. Fortunately, the huge reason for the success of EBM was one of the JAMA deputy editors. Drummond Rennie, made it his mission to help initially David and me to disseminate evidence based medicine. So we published this paper, Evidence Based Medicine, A New Paradigm for Medical Education and Practice.

So we made this big announcement and this paper had a huge impact.

It had a huge impact.

It had a huge impact. And I remember two years later, I received a newsletter advertising something or other from the American College of Physicians, the American internal medicine organization that started out in this era of evidence based medicine. Two years after the term first appeared in the medical literature, we were now in an era of evidence based medicine and that shows that the world was somehow.

Thanks for listening, if you’d like to hear more episodes of Methodology Matters, a podcast on evidence based nutrition. Please head over to MethodologyMatters,

If you’d like more information on the user’s guides to the medical literature, please visit the Journal of the American Medical Association at that’s

And if you’d like to learn more about Dr. Guyatt and his work, you can find him at or on Wikipedia.

Thanks for tuning in. We’ll see you on the next episode of Methodology Matters.


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