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What has shaped evidence-based medicine?

Dr. Gord Guyatt, one of the founders of the evidence-based medicine movement, provides an overview of the forces and factors that stimulated the birth of evidence based medicine and have influenced its development.

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Dr. Jamie Meuser:  You're listening to "Clinically Speaking," a podcast that explores the past, present and future of evidence based medicine in primary care, brought to you by the Center for Effective Practice. I'm Jamie Meuser, a family physician practicing home palliative care in Toronto.

Christine Papoushek:  I'm Christine Papoushek, a pharmacist practicing at a family health team in Toronto.

It only made sense for us to start this pursuit to unpack evidence based medicine with one of its earliest and most effective champions, Dr. Gord Guyatt.

Dr. Meuser:  While at McMaster University, Gord spearheaded the initial idea of evidence based medicine and further developed this concept with Landmark Publications and the "Journal of the American Medical Association."

His series of more than 34 articles, collected into to the "Users' Guide to the Medical Literature," has provided the basis of EBM curricula in medical schools and residency programs nationally and internationally.

Today, EBM continues to be a method for appraising applying evidence, but also a movement that characterizes how we understand optimal approaches to medical practice in the modern age.

Christine:  Gord's contribution to the profession cannot be overstated. We are grateful that he could take time to speak with us today. He candidly shares his perspective on the early days of EBM, the motivation behind it, the surprising wins, and the unforeseen shortcomings of the approach.

We delve into how EBM has evolved since the challenges of bringing EBM into everyday practice, the hijacking by the pharmaceutical industry and the hopes that have been realized. He also shares his visions for the opportunities that lie ahead for EBM. Stick around.

Dr. Meuser:  Gord, just as a bit of background, you've got a long history, a substantial reservoir of expertise and a clear passion for evidence based medicine. You were there, I think it's safe to say, at the very beginning of the time when applying evidence to the clinical decision making we undertake as physicians became much more important, almost de rigueur.

Can you give us a bit of an idea, Gord, what was envisioned and what was intended when you conceived the idea of evidence based medicine as a touchstone of how we practice?

Dr. Gord Guyatt:  I still remember being at the Toronto Western Hospital as a second year resident in internal medicine and being told about how one should read the literature. The advice was, read the introduction and the discussion because of the accurate perception that one wouldn't be able to understand the methods and results.

A vision that Dave Sackett, who is my mentor, began with was, "Clinicians should be able to understand the methods and results, and so be able to distinguish what was trustworthy from what was less trustworthy."

At the start, there were a lot of practices that people were doing for which the evidence was not very satisfactory. In fact, the evidence might be that they were doing more harm than good and lots of other things that people weren't doing for which there was good evidence.

Clinicians should be able to look at the original medical literature, be able to understand what was there and distinguish what was useful from what was not useful. It's evolved quite a bit since that, but I would say that that was the original vision at the start.

Christine:  Gord, in your opinion, what hopes were realized, or what were some of the lasting effects on the medical profession and community more broadly?

Dr. Guyatt:  The big hope is that the medical community in general and associated communities, anywhere from pharmacists to nurses to occupational and physiotherapists, have adopted the vision of the requirements of an evidence based approach that is a critical look at the available evidence should inform clinical decision making.

As a result in North America, certainly, and increasingly in other parts of the world as well, both undergraduate and residency education in medicine, in nursing, and in other affiliated health professionals, the teaching of the concepts of evidence based medicine is seen as a core competency.

The licensing and accreditation of medical programs requires them to demonstrate that they are teaching their trainees these activities.

For people already out in practice, there's this general acceptance to that approach should be used. Many, many, many textbooks are called "Evidence Based Cardiology," "Evidence Based Anesthesia," "Evidence Based Pediatrics," and so on.

Analysis has become a selling point to say, "The practices that we are promulgating or encouraging are, in fact, based on evidence." Then in the electronic medical textbooks that have become extremely popular and, in fact, displaced old medical text, such as "UpToDate" and "DynaMed" sell themselves and, I think, try to be evidence based resources as well.

It's basically been accepted over a period of about 25 years as a fundamental of medical practice.

Christine:  In the 25 years, since and reflecting back on the original impetus behind the approach, can you tell me, have there been any unforeseen outcomes or unintended consequences?

Dr. Guyatt:  Well, it's actually ended up as something quite different, in at least two ways. One thing was that if you look at what we wrote at the beginning, the notion of values and preferences and value and preference sensitive decisions was really not there at all.

It only emerged over the first five years of the evolution of EBM, which it's been exciting to be involved in these 25 years or more now because it does keep evolving. What we realized after a while was that evidence never actually tells you what to do. The reason is that so many of our alternative decisions, the alternatives have both upsides and downsides.

Often those ups and downsides are relatively closely balanced. One paradigmatic situation we often use is atrial fibrillation.

Depending on how you feel about the burden of anticoagulation, and how you feel about the bleeding risks with anticoagulants versus the stroke prevention, two individuals in exactly the same situation based on the same evidence, one might very well say yes, anticoagulation is right for me, and another might say no.

There are many, many, many decisions within medical practice that are value and preference sensitive in this way. We've come to say an ironic principle of evidence based medicine is evidence never tells you what to do. There's always evidence in the context that patient values and preferences.

That's been one major shift from the beginning. The other major shift is the realization that clinicians do not have the time to actually read the medical literature in the way we might have envisioned it first. In fact, to really do it properly takes training, that the basics of knowing about what evidence based practice is about, will not take you there.

As a result, we have much more of the focus on pre appraised resources, systematic reviews, more and more guidelines, and presentation evidence summaries. In keeping now, this is a frontier area, decision aids for the practice encounter where both the patient and the clinician have the evidence summarized for them.

Those two things, the importance of values and preferences and the awareness that clinicians are not going to be doing the typical appraisal of the original literature themselves. They need to appreciate the fundamental principles, but then they need high quality clinical practice guidelines to help them achieve evidence based practice.

Dr. Meuser:  Someone we talked to recently talked about the shift from evidence based medicine being a individual skill that clinicians would exercise, usually through clinical appraisal of articles.

It's evolved from being that, as you said, to being more of an exercise of using a trusted source that has packaged evidence in particular ways. Clinical practice guidelines are probably the very best example. I think that's what you're talking about.

Dr. Guyatt:  That's exactly right. Clinicians still have to be able to understand the output of those.

Dr. Meuser:  In our day, there might be two or three different packages of evidence around a particular topic. Sometimes, in fact, quite often, coming to different conclusions or providing different recommendations for what the right next thing to do with patients would be. Which means that the evidence is not neutral.

It's malleable. It's manipulable. Is that a good thing by and large, would you say so?

Dr. Guyatt:  Great point. Clinicians, they do need to be able to identify a trustworthy guideline. There are some guidelines that are trustworthy and some that are less trustworthy. Guidelines based on well done systematic reviews are much more trustworthy than those that are not so based.

The clinicians, they need to be able to look at the outputs. What we would hope is less the evidence is malleable in that well done systematic reviews would come to more or less similar evidence summaries.

However, the inference is that one makes from that may differ and that goes back again to the underlying values and preferences. For instance, American medical practice is different in many ways from Canadian and definitely Europeans. The Americans put, I would say, a much higher value on small and uncertain benefits from highly costly therapies.

Canadians and Europeans, particularly Canadians, to some extent less, Europeans, in many countries even less so, so that same evidence summary in different environments because of different values and preferences lead to different decisions.

What the clinicians needs to be able to do is identify good evidence summary, understand that evidence summary, and help their patients with value and preference sensitive decision.

What follows is that there are many situations in which with the same evidence the patient presents the same way, but the right decision differs between patients depending on their values and preferences. That mandates shared decision making and shared decision making unequivocally is a challenge.

First of all, the clinician has to be able to present it in a way that the patient will be able to understand. They have to have the time to do this in what is for just about everybody a very time constrained practice. How we can make this as efficient as possible is still a big challenge.

For quite a while, there have been decision needs available, which are essentially information from patients and that can be helpful, but it doesn't really facilitate the shared decision making that we think is crucial or it only facilitates it to a limited extent.

Much more and more now we are experimenting with electronic accounts, or decision made designed to be looked at simultaneous and worked to together and understand together.

We think that that has the potential to revolutionize the process of shared decision making, whether it will or not remains to be seen. We've got a long way to go in terms of making the process of shared decision making efficient enough that it actually becomes a standard part of medical practice for most clinicians.

Dr. Meuser:  You probably have heard, as I have, part or more cynical colleagues make the assertion that evidence based medicine to some extent has been hijacked. Hijacked by commercial interests who have a stake in persuading decision makers that their way of approaching a clinical problem that is in the interests of their product should be followed. Do you think there's anything to that?

Dr. Guyatt:  Absolutely, yes. It is certainly the goal of those who are making money within medicine whether they be for diagnostic procedures or for drugs or for devices. It is the smart people in those areas and there is a lot of them, have recognized that using the language, concepts, and presentations of evidence based medicine is a great way to sell your product.

It's their job to present the evidence in such a way. Often, they somewhat distorted way, but nevertheless done in a way that looks convincing to persuade the practitioners and the patients to use their products. No question that goes on and characterizing it as a hijacking of evidence based medicine is quite appropriate.

The big push back then is encouraging physicians not to follow the guidance from their local pharmaceutical representative, but rather look to unbiased, high quality trustworthy guidelines.

Dr. Meuser:  You've talked a fair bit about engagement of patients in clinical decision making and use of evidence that is aimed simultaneously at the clinician and the patient. Are there any other ways that you see evidence based medicine evolving over the next few years?

Dr. Guyatt:  Conflict of interest is still a problem. The optimal production and dissemination of the evidence summaries in ways that are attractive and compelling to clinicians. The uniform application of well done systematic reviews to provide the information for the guideline.

All of that can be improved, but a lot of organizations are doing pretty well now. What we need to do is just raise the bar for everybody who's producing guidelines so that clinicians, when they go through a guideline, can feel comfortable that it is trustworthy.

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Dr. Meuser:  Gord, you've been really generous and helpful. Thank you again.

Dr. Guyatt:  You're very welcome. It's been a pleasure for me to talk to you.

Christine:  Thank you for listening to this episode of Clinically Speaking. It was produced and edited by Pippi Scott Meuser at the Center for Effective Practice.

Dr. Meuser:  Special thanks to our guests this episode Gord Guyatt for taking time out of his busy schedule to talk with us. If you like what you heard today, we encourage you to share with your friends and colleagues. Your support goes a long way.

Christine:  Don't forget to subscribe on iTunes, our website, or wherever else you get your podcasts.


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