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Warrick is a practicing cardiologist and author with a passion for improving care by helping patients understand their heart health through education. Warrick believes educated patients get the best health care. Discover and understand the latest approaches and technology in heart care and how this might apply to you or someone you love.
Hello and welcome to my consulting room. I’m Dr. Warrick Bishop. Today I’d like to tell you a little bit about one of the chapters in my book that you might find interesting and the chapter I’ve called “The Art of Good Medicine”. In that I talk about how we use evidence base, which is the scientific assessment of how we evaluate treatment and therapy and responses. The evidence base, when we look at a particular subject or area, can sometimes be very complicated during studies. We can match up all sorts of things – age, sex, blood pressure, diabetes – lots of these things are important to match up, but there’s lots of things we can’t match up. So the complexity of these situations will always exist in the studies that we perform. We could, for example, randomise many people to two different arms of an intervention, only to subsequently find out that some people within those two arms… like peanut butter for example and other people… don’t like peanut butter. Some are lefthanded. Some may wear spectacles.
Do those things impact the way we deal with the evidence? Well I’m using, sort of light-hearted examples, but it is possible that those variations of complexity make it very difficult. The other thing with evidence that’s difficult to sort out is that the more we study a group or a population, the greater we are likely to get an answer for the average person. Well, I have to say to you, quite commonly, the people who walk in through my door are not average. They’re either at one end or the other end of the range, and for that very reason they’re seeing me to try and figure out what suits their needs the best. So evidence base gives us a distillation of average, not necessarily the answer for the extremes.
We’ve got to remember when we look at the evidence base in medicine, sometimes the study just hasn’t been done and that’s because it would be unethical. Antibiotics when they were first used were not randomised and that’s because they work so well it would have just been unreasonable not to treat everyone with them. So, if we were to look at the evidence base for the initial use of antibiotics we would find nothing to support they worked.
Yet, there is no question that they clearly work. A trial was written a number of years ago called the parachute trial – for want of a better term – and this trial made that point the parachutes have never had a randomized control trial to demonstrate they work. Yet, we accept that they do. So sometimes in the evidence base the study is just not done.
One of the other things about evidence base that that’s important to consider is that sometimes the study design doesn’t necessarily achieve the goal because it wasn’t an appropriate study designed for the question being asked. A really simple example of that might be using a very low dose of the active agent that just doesn’t do the job.
We also know that the evidence base is historical. It can only be implemented into therapy after years – generally – of observation and study. What happens is that time can erode that evidence base and things like new technologies can suddenly shift the way we look at that information. One of the other things about evidence base is that we sometimes see conflicting data. So, the role of vitamin C, for example, in some studies may look really encouraging in others not very encouraging.