Evidence based medicine

Re: Evidence based medicine

Simon Neuhoff — Sun, 02 Oct 2011 22:18:54 GMT

The thing is though that it IS important - now more than ever. It is no mere matter of semantics and idle debate. In a modern, internet based world anyone can "publish" their opinion - their "experiences" and observations - for all the world to see. He who shouts loudest and longest is often construed to be correct. Without systematic assessent of all of this background noise how do we sift through what is correct, useful and useable and what is mere garbage?

As for us "doing well" I find it thoroughly depressing to realise how much of the time vets are forced to rely on anecdote and limited or no evidence. That is the current state of play and we have to deal with it - but it is very far from ideal and we should aim at better.

Re: Evidence based medicine

plantagenet — Sun, 02 Oct 2011 14:10:25 GMT

'it' referring to earlier in the sentence being the term EBM as it is being used today since I (personally, my opinion) think that is detracting from the wonderful, science and experience based advances that medicine and surgery have made in the last few centuries.

What I am trying to say,badly obviously, is that I think that we were doing pretty well and that introducing a name (an apparently a whole spin-off of departments, professors, books etc) I don't think has added a great deal to the progress that was being made anyway.

What worries me most is arrogance - the arrogance to think that scientist should not be looking at all the available evidence, experience included. If that's what EBM is then fine, but did it need a name?

Anyway this is not a place fora one : one spat, so I'll say no more, the whole thing smacks of defining the wheel rather than using it.

Jenner's biography enticed me into science at the age of 8, I recommend that too.

Re: Evidence based medicine

Niall Taylor — Sun, 02 Oct 2011 12:54:00 GMT

[quote user="plantagenet"]I personally do not think [EBM] has added a great deal to the advancement that medicine has made over the last couple of centuries - wonderful, incredible and lifesaving advances.[/quote]

That is simply incredibly wrong - you need to find out a bit more about both the state of what passed for 'medicine' 200 years ago and also the scientific process itself, particularly how it has improved and refined itself during those crucial two centuries (the Medicines act of 1858, in many ways was when modern medicine started to emerge).

The opening chapter of the book 'Trick of Treatment' by Simon Singh and Edzard Ernst has some excellent information on this period in science and medicine.

Niall

Re: Evidence based medicine

plantagenet — Sun, 02 Oct 2011 11:32:33 GMT

[quote user="Niall Taylor"] "experience" and "anecdote" have been shown to be completely, and occasionally lethally, wrong.[/quote]

So, sadly, have clinical trials - how many drugs are withdrawn each year when they have been through the whole procedure only to be picked up on the experience of a few people dropping dead.

[quote user="Niall Taylor"] Experience on its own just is not enough.[/quote]

Yes of course, although arguably, sufficient experience in the right conditions may well be.

I think this is just playing with words - we all want to do/use stuff that really works. Sometimes we have to make a bloody good guess because the whole picture is not clear. Sometimes there is more than one answer.

My objection to the term EBM is how it is used - usually as a put down to other collegues. I personally do not think it has added a great deal to the advancement that medicine has made over the last couple of centuries - wonderful, incredible and lifesaving advances.

I am also disquieted by political inteference in the design and direction of some experiments, the manipulation and suppression of data to give the required answer and the antipathy to anecdote when it highlights the false conclusions.

Re: Evidence based medicine

Niall Taylor — Sun, 02 Oct 2011 10:37:56 GMT

[quote user="plantagenet"]

[quote user="Niall Taylor"]The whole premise which started this thread is wrong really. [/quote]

Sorry, the whole premise of the thread was to re stir a debate which I find fascinating by being deliberately prevocative.[/quote]

Your purpose may have been to stir debate but the premise that you started with was your contention that a medical trial being stopped before completion would somehow offend "evidence based medicine types".

[quote user="plantagenet"] As such I don't think EBM is anything new - it seems like common sense in which an observation is followed up by further analysis. It does also seem to be a bit of a buzz word with which to snipe at one's collegues for any number of reasons. I think mankind has been using this system since our ancestors first noticed a funny little spark that occurred when he hit 2 stones together, followed it up by repeating the experiment, showing it to his friends and eventually harnessing the result in a simple, predictable form.[/quote]

I don't actually like the term "Evidence Based Medicine" as the definition of "evidence" is so broad that it invites misunderstanding, whether genuine of disingenuous . I prefer the term "Science Based Medicine" and if I had to give a definition of what this term means for me it would be that it is an antidote to "common sense" and what we think we see in the world at large. Anecdotes are indeed a form of evidence and they are useful as a starting point for real investigation but, in and of themselves they are inherently extremely unreliable. What we think we see is very often not what actually happens. Yes, in some cases anecdotes have played an important part, but in far more cases, including the examples I gave above "experience" and "anecdote" have been shown to be completely, and occasionally lethally, wrong.

As humans we are hard-wired by evolution to see and react strongly to patterns, real or imaginary. The neolithic human wandering around the rift valley wouldn't have lasted long if he had stopped to consider all possibilities, including cognitive errors, when hearing a twig snapping behind him. The ones who just thought "Lion!!!" and leaped up the nearest Baobab without thinking were the ones that survived. In those conditions it is far better to be wrong 100 times in order to survive once. With modern medicine that no longer applies and we need science to help us read round our natural tendency to add 2 + 2 and get 5. Experience on its own just is not enough.

The book "Why People Believe in Weird Things" by Michael Shermer is an excellent read on this subject.

Niall

Re: Evidence based medicine

Tim Cheyne — Sun, 02 Oct 2011 05:05:54 GMT

[quote user="mariette asselbergs"]

One bad experience makes you very careful, and rightly so, but us oldies learned never to use morphine in cats didn't we?

[/quote]

I agree; Tinct.opii cough linctus could have a quite startling effect on a cat but I vaguely recall that some recent trials have shown no difference between the effect of morphine in cats and dogs. Difficult!

Tim.

Re: Evidence based medicine

Anthony Todd — Sun, 02 Oct 2011 01:01:09 GMT

[quote user="mariette asselbergs"]but us oldies learned never to use morphine in cats didn't we?[/quote]

You're right, but the interesting thing is, and I 'm not trying to prolong the thread, but it's my argument in reverse in that usually, or perhaps always, ExBM changes a good thing into a no-no or a be-careul but this is one of the few where a no-no became a goody.

Haven't got my old texts with me but the Vet Codex etc. would be a start, some will remember, all soda bic and digitalis leaf.....

Who changed morphine in cats from a no-no to a yes-yes, when, why, based on what etc.

Re: Evidence based medicine

plantagenet — Sat, 01 Oct 2011 18:26:16 GMT

[quote user="Niall Taylor"]The whole premise which started this thread is wrong really. [/quote]

Sorry, the whole premise of the thread was to re stir a debate which I find fascinating by being deliberately prevocative.

Thank you everyone for the fascinating debate which followed.

I still suspect - although I do not know any of the clinicians involved, that the decision to end the trial was probably taken on unproven observation which, no doubt was swiftly followed by backup analysis of the data.

As such I don't think EBM is anything new - it seems like common sense in which an observation is followed up by further analysis. It does also seem to be a bit of a buzz word with which to snipe at one's collegues for any number of reasons. I think mankind has been using this system since our ancestors first noticed a funny little spark that occurred when he hit 2 stones together, followed it up by repeating the experiment, showing it to his friends and eventually harnessing the result in a simple, predictable form.

Re: Evidence based medicine

Anthony Todd — Sat, 01 Oct 2011 04:16:04 GMT

[quote user="Niall Taylor"]did the B-vitamin stop the diarrhoea[/quote]

And the rest of the post sums it up well for me except that I think I've been trying to overemphasise the value of the negative side of ExBM so, to take the quote above, if the animal GOT diarrhoea 48 hours after a new drug I would wonder, if it happened again I would post on vetsurgeon.org.

If a few other posters agreed then the VMD or the Suspected Adverse Reactions Scheme would be prompted to act, the manufacturer would put a caution in the datasheet and/or do a trial on 8 beagles and say it's fine, and it would suddenly become EvBM but, I wager, a lot of us would use the said "new drug" with some caution despite there being no trial, placebo controlled etc. etc.

But without EvBM nothing would have happened. If Aureole hadn't been such a well-known stallion there would have been many more stallions with swinging dongles around the place.

Last post.

Re: Evidence based medicine

Niall Taylor — Fri, 30 Sep 2011 17:46:08 GMT

[quote user="plantagenet"]Is this not a case of - no need the 'evidence', lets go by the experience of what we see before our eyes?

... presumably the EBM purists would be having kittens at such slight regard for clinical trials.[/quote]

The whole premise which started this thread is wrong really. Evidence based medicine is not just about clinical trials, there are a whole load of other ways of deciding whether or not a drug works depending on the strength of the observed effect - look up "number needed to treat" which gives you an idea.

We tend to think of the double blinded randomised placebo controlled trial as the be all and end all but it isn't. AFAIK no one has ever done such a thing for the use of insulin to treat DM or the use of defibrillation in the case of cardiac arrest, to do so would be murderously inappropriate. In these cases there is no need - if you treat 100 people with DM using insulin and 90%+ get better than that's a no brainer, if you treat 100 cardiac arrest victims with defibrillation and 20 of them survive compared with 100 with cardiac arrest who are not given defibrillation and none survive, also a no brainer. Same with Thalidomide - the slew of anecdotes in the early 60s was so enormous that its use was stopped pending investigation - again, no DBPCT required once the anecdotes and case histories were properly correlated.

It's only when you are at the margins of statistical significance that the DBPCT comes into its own, eg when homeopaths claim that magic sugar pills can 'cure a cold', when obviously a cold will cure itself anyway so you do the trial and you find that the difference between magic sugar pills and non-magic sugar pills is negligible. In the trial which the OP mentioned it sounds like the effect observed was so powerful that the researchers had all the evidence they needed before the trial was due to end and considered it unethical to continue. That is evidence based medicine, it is pragmatic and practical.

So called experience based medicine is fair enough on an individual basis where the treatment won't do any harm, we all do it every day I'm sure. But we need to remember that Experience Based Medicine also brought us phrenology, blood letting, trepanning and homeopathy. Also when experience based medicine is in direct contradiction of the science such as with homeopathy so "experience" is all you've got, then the problem there is it encourages the belief that experience is all that counts and there is no need for science. Then you're on dangerous ground, that's when people (and animals) start to get hurt..

"Experience based medicine" is fine so long as you remember exactly what it tells you - the animal I just gave a B-vitamin injection to did indeed stop having diarrhoea 48 hours later, there is no doubt about that, no one is calling anyone a liar, or saying they're deluded, no one is demeaning the story. The big BUT though is "did the B-vitamin stop the diarrhoea" - that is a leap of faith too far.

Niall

Re: Evidence based medicine

Anthony Todd — Fri, 30 Sep 2011 17:37:43 GMT

[quote user="Simon Neuhoff"]Anthony there is a Suspected Adverse Reactions Scheme in place for exactly the situation you describe.[/quote]

Hooray, a formalised Experience Based Medicine but it is retrospective and relies on one or more experiences!

BTW, look up ACP in Wikipedia and see where and when all the contraindications were published.

I wish vetsurgeon.org had been around in the 70s or before......

Re: Evidence based medicine

Simon Neuhoff — Fri, 30 Sep 2011 17:29:56 GMT

Anthony there is a Suspected Adverse Reactions Scheme in place for exactly the situation you describe. If it gets reported it will get published - and investigated.

Re: Evidence based medicine

Anthony Todd — Fri, 30 Sep 2011 17:24:42 GMT

[quote user="Thomas Johnson"]Did you make your decision not to use acepromazine on boxers from one incident, from several incidents, or from discussions with other vets following your one incident? If just based on one incident, how did you know that all boxers were more sensitive to acepromazine rather than just the one you had given it to?[/quote]

AFAIK I rang around; that was all you could do then and my colleagues, from memory, said, either thanks for the tip or "yeah, it's happened to me"

Think I did what another has said and reduced the dose and warned boxer owners of extreme reactions.

My point is though that, without Experience based medicine we might have had lots more unhappy events, so it is important.

It will not always be publicised with a controlled trial etc. and should not, just because of that, be at the bottom of the pile.

Total silence on megestral or is there a controlled trial I am unaware of??

Re: Evidence based medicine

mariette asselbergs — Fri, 30 Sep 2011 15:50:30 GMT

I think that next to the pyramid for weight of evidence (based on its quality), there should be another for the effect of the treatment. By which I mean this: a few anecdotes about very bad or dangerous effects (think thalidomide) should weigh heavy as "evidence", but to evidence-base a possibly mildly supportive treatment like glucosamine which is a very widespread lucrative product in both human and vet medicine, you would like to see a proper large scale study, double blind randomized etc. Unfortunately in this case, megastudies all seem to find no evidence for its effect. One bad experience makes you very careful, and rightly so, but us oldies learned never to use morphine in cats didn't we?

Re: Evidence based medicine

Simon Neuhoff — Fri, 30 Sep 2011 10:20:09 GMT

[quote user="Anthony Todd"]

[quote user="David Mills"]The endpoint of experience is dangerous dogma.[/quote]

Well bless you too David.

Pray tell me your experience with ACP in boxers, ACP in stallions, Propoclear as an I/v anaesthetic, 'cos as far as I know until 1996, there ain't no description of

[quote user="David Mills"] a causative mechanism or a placebo-controlled trial elucidated by scientific experiment/trial [/quote]

yet vets just knew of the dangers.

And what's the feelings in the forum regarding continuous megestrol acetate and sugar metabolism in the cat these days, don't think there's been one of your causative mechanism or a placebo-controlled trial elucidated by scientific experiment/trial in that case either so I guess I'll just medicate on, shall I?

I would modify your last sentence to "the end point of INexperience is dangerous"

[/quote]

We use a low dose ACP regime for most premeds including Boxers - we adjust the dose according to age, health, temperament and breed.

You don't need experience to read a data sheet or a textbook.

As for relying on other vet's opinions - it really depends on the vet! Like everyone, vets believe all sorts of things - some based on facts, some based on their interpretation of their observations, and as far as I can telll, some made up!

Re: Evidence based medicine

Camilla Edwards — Fri, 30 Sep 2011 08:42:57 GMT

I'm not sure what all the discussion is about here. It seems to be a evidence vs opinion. But in EBVM all evidence, including opinion/experience counts, it is just weighted by how reliable it is. The pyramid shows the stronger evidence at the top and weaker evidence at the bottom.

This pyramid is the same as the one used in handbook of ebvm Peter Cockcroft, Mark Holmes. The ideas/editorials/Opinions can be anything from internet derived information and non-veterinary expertise all the way up to diploma holder opinion.

Re: Evidence based medicine

Anthony Todd — Fri, 30 Sep 2011 04:05:07 GMT

[quote user="David Mills"]The endpoint of experience is dangerous dogma.[/quote]

Well bless you too David.

Pray tell me your experience with ACP in boxers, ACP in stallions, Propoclear as an I/v anaesthetic, 'cos as far as I know until 1996, there ain't no description of

[quote user="David Mills"] a causative mechanism or a placebo-controlled trial elucidated by scientific experiment/trial [/quote]

yet vets just knew of the dangers.

I would modify your last sentence to "the end point of INexperience is dangerous"

Re: Evidence based medicine

Anthony Todd — Fri, 30 Sep 2011 03:51:53 GMT

[quote user="Thomas Johnson"]Did you make your decision not to use acepromazine on boxers from one incident[/quote]

I was certainly very careful with dose rates after that but, and at last someone is realising the crux of the matter, I discussed it with others and sure, they had all had similar incidents but it wan't until 1996, remember, that it was common, ie published knowledge.

I, surmise, this was stimulated by those bottom of the pile anecdotes, so suddenly what had been known, in isolation, by many became legitimate and Evidence based.

Now, of course, it's different. Anecdotes are out there on day one and more and more so [see Propoclear] which is why I say Experience based medicine, although a collection of anecdotes, is very important and certainly should be higher up the pile than some say.

I just wonder how quickly thalidomide would have been withdrawn if internet forums had been around then and anecdotes had been elevated to the correct position in the Evidence hierarchy??

Re: Evidence based medicine

David Mills — Thu, 29 Sep 2011 17:49:16 GMT

I think it's pretty clear that Mr Todd doesn't understand evidence based medicine, bless him.

Or argument, in this case. No one denies that initial empirical observation is the red light that often prompts further, controlled research. And in the case of pharms, unless every drug ever licensed is to be tested on every breed at all dose ranges, then this will continue to be the case. Or even new diseases - BSE is a recent example. But to then say that these entail that this silly-ly titled 'Experience based medicine' is what people should put most of their faith is dangerous poppycock - anecdotal evidence has a place but without a causative mechanism or a placebo-controlled trial elucidated by scientific experiment/trial then it remains guesswork akin to quackery - whether you like it or not most vet medicine is already based on scientific evidence of infinite more reliability than the sum of everyone on this forum multiplied by whichever number you conjure up. The endpoint of experience is dangerous dogma.

Re: Evidence based medicine

Bob Russell — Thu, 29 Sep 2011 17:46:46 GMT

I find ACP is a good as part of a premed but at low end dose. Never had a problem in Boxers. I started using it because my boss at the time said it was OK and experience since has suggested this is the case.

I find the whole evidence/experience argument a bit of a murky one. I would love everything I do to be evidence based but there is no NICE for pets. Until someone sets that up and pays for it I will use the evidence available and my experience to do the best job I can. An example - evidence suggests that Advocate kills ear mites but my experience tells me that ear mites don't know this so happily continue to live and breed!

It would be great to have one body deciding (accurately) what is best practice but it is not going to happen. I do CPD, I watch how my referral vets use medication. I listen to colleagues and watch advice given on here, I then put that into practice.

Some seem to be getting hot under the collar about the argument but the reality is that we have to function in an imperfect world.

Re: Evidence based medicine

Thomas Johnson — Thu, 29 Sep 2011 12:24:50 GMT

[quote user="Anthony Todd"]

No, anecdotes are certainly not at the bottom of the pile in Experience Based Medicine and certainly are not at the bottom of my pile when I wanted to sedate a boxer subsequent to my unfortunate "anecdote".

[/quote]

Did you make your decision not to use acepromazine on boxers from one incident, from several incidents, or from discussions with other vets following your one incident? If just based on one incident, how did you know that all boxers were more sensitive to acepromazine rather than just the one you had given it to?

Re: Evidence based medicine

Anonymous — Thu, 29 Sep 2011 07:43:04 GMT

[quote user="Anthony Todd"]

And a good current example is the many anecdotes about the pain on injection of Propoclear, I'll bet not too many of us waited for a study about that!!

[/quote]

I might be side-tracking from the main thread here, but should I not be using ACP in boxers? I do use it (albeit at a lower dose than in most other dogs) and find it usually very effective - is there a risk to this? Should I stop and use e.g. medetomidine instead?

I used Propoclear for 3 years before it was withdrawn from the market and was never aware of pain on injection (slowly through an intravenous cannula) - either I'm terribly unobservant or this 'pain on injection' wasn't all that obvious in the population of pets I was using it in?

Re: Evidence based medicine

Anthony Todd — Thu, 29 Sep 2011 02:32:41 GMT

[quote user="Simon Neuhoff"]There is clearly a world of difference betwen the indvidual and limited experiences[/quote]

Oh sure, but in 1986 or so there wasn't any "multiple reports" were there; that's the point and the penis problem with ACe came after the incident AFAIK so we have to rely on anecdotal experience, as we did recently with Propoclear, no

assessment of carefully controlled clinical trials and a literature search through "pubmed, cab extracts etc"

'cos there ain't none, it was a new anecdote and disregard them at your, or your stallion's peril.

[quote user="Simon Neuhoff"]EBM DOES have a place for anecdotal evidence - it is at the bottom of the pile [/quote]

I doubt if my telling the collapsed boxer's owner that what had just occurred was at the bottom of the pile and was just an anecdote anyway, would have helped much, neither would the patronising "study pubmed and vinmed and be a competent vet" have made Aureole's vet feel that much better!!

I also doubt whether too many trials were done on many boxers just to see whether ACP made them faint, and not too many stallion owners would be happy risking their stallion's crown jewels in the name of Evidence based medicine....

And a good current example is the many anecdotes about the pain on injection of Propoclear, I'll bet not too many of us waited for a study about that!!

But that assumes, therefore, that few of us are competent, thoughtful and experienced practitioners??

Re: Evidence based medicine

Richard Carter — Wed, 28 Sep 2011 18:47:08 GMT

So I hope using the latest EBM none of us is selling any chondroitin /glucosamine as it has been proved to be placebo effect.

Its just that I know when I have forgotten to take mine and apparently so do quite a few clients - by the way this is being said as a previous non-believer. The NSAIDS were making my kidneys hurt.

Re: Evidence based medicine

J G Wray — Wed, 28 Sep 2011 16:56:22 GMT

Evidence based medicine is here to stay. We'd all better get used to it and familiarise ourselves with how it affects our clinical practice. Unfortunately, it has already become cliched and is easily satirised and therefore easily pigeon holed as a fashion.

EBM has flaws, in my view, notably in terms of implementation where limiting factors beyond the purest decision making in respect of the clinical issues may override the use of the optimum EBM approach.

Devotees of EBM may choose to widen the scope of their remit to include compliance, legal and financial constraints, but they shouldn't. In doing so they dilute the concept and invite further huffing and puffing.

As an aside, VDS still defends clients in Court using a justificatinof the action of the vet being what is generally accepted as best practice. The definitive move to use of EBM will come when they (VDS) start to use EBM in Court, not at the behest of well meaning academics.

JGW