Btw, here is our response to John Ioannidis' article you cited...



-----Original Message-----
From: Djulbegovic, Benjamin
Sent: Monday, January 05, 2009 5:07 PM
To: 'Michael Power'; [log in to unmask]
Subject: RE: Fw: Special Issue:Evidence in Evidence-Based Medicine Fw: Social Epistemology - informaworld



Michael,
This really does not "clarify EBM's epistemological stand". Neither to be fair, it cannot. As I am sure you understand it, this is not a trivial issue (and, by the way, has been debated for at least 200-300 years). Indeed, "when should a scientist NOT believe anomalous evidence that seems to contradict established theory"? There is no LOGICAL reason to, in examples I provided, to believe the results of the HRT trial, but not to believe homeopathy trials. Today most people think the answer to this questions can be linked to what Thomas Kuhn labeled as dominant scientific paradigm (or, research program, or research tradition denoted by some other philosphers of science). Acceptance of a particular finding will, however, depend on JUDGMENT, which is always a mixture of subjective and objective factors, but not on inconvertible logical analysis. In the final analysis, this is one of the key reasons why evidence rarely serve as the sole arbiter among competing views.
Whether we agree on this or not (and I am amenable to modify my views in light of new evidence:-), I believe this is a very important discussion to have. Hope others will join the "fray".
Thanks
Ben


-----Original Message-----
From: Evidence based health (EBH) [mailto:[log in to unmask]] On Behalf Of Michael Power
Sent: Monday, January 05, 2009 4:25 PM
To: [log in to unmask]
Subject: Re: Fw: Special Issue:Evidence in Evidence-Based Medicine Fw: Social Epistemology - informaworld

Ben

I think that you are wrong when you say "EBM does not have a consistent stand on the issue", "i.e. whether evidence trumps theory or theory comes prior to evidence".

The issue you raise boils down to "when should a scientist NOT believe anomalous evidence that seems to contradict established theory".

For example, when an RCT of a homeopathic remedy is positive, this contradicts established scientific theory that pure water (the homeopathic remedy) delivered theatrically should have no more effect than a placebo delivered with the same theatricality.

EBM (and science in general) *is* consistently sceptical about anomalous results. John Ioannidis has some great empirical evidence why this should be so for EBM. See his paper "Why most published research findings are false", which is freely available at www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1182327.

The problem of how to interpret the anomalous experimental result has been much debated by philosophers of science. You can find an excellent introduction to the issues here: http://apgaylard.wordpress.com/2008/02/03/expect-the-unexpected, and the two subsequent blog postings. The blog is quite long and detailed, and I won't attempt to summarize it here.

But, there is a clear analogy (which I think I read in the book "Trick or treatment" by Simon Singh and Edzard Ernst), which makes the point in two short sentences:

If my wife calls me at work and says that there is a goat in the garden, I will believe her - I live on a farm, and we do get trespassers in the garden from time to time.

But, if she says that she has seen a unicorn in the garden, I want more corroborating evidence, such as a zoologist's report that the horn on the animal's head hasn't been glued on.

As Colleen Derkatch (Social Epistemology 2008; 22(4): 371-388) might say, arguments about the priority of evidence or theory can be read, metonymically, as expressions of anxiety about goats or unicorns in the garden.

I hope this clarifies EBM's epistemological stand.

Michael



-----Original Message-----
From: Djulbegovic, Benjamin [mailto:[log in to unmask]]
Sent: 05 January 2009 18:30
To: Michael Power; [log in to unmask]
Subject: RE: Fw: Special Issue:Evidence in Evidence-Based Medicine Fw: Social Epistemology - informaworld

In fact, CAM research such as homeopathy RCTs represents one of the great challenges and opportunities for EBM to clarify its epistemological stand. It deals with eternal scientific question which comes first : evidence or theory i.e. whether evidence trumps theory or theory comes prior to evidence. In fact, it has been shown that EBM does not have consistent stand on the issue. On one hand, EBM movement has documented numerous examples when getting our evidence right overturned the prevailing theory of the day (e.g. findings from the RCT that tested the effects of hormone-replacement therapy resulted in a dramatic abandonment of theory claiming that estrogen can help reduce risk of coronary disease despite a score of observational studies i.e. lower quality evidence supporting the estrogen theory). However, results of RCT homeopathy trials were largely dismissed not because of lower quality evidence (many of these trials were high-quality placebo-controlled trials) but because of poorly formulated theory which does not correspond to the contemporary physical and chemical principles (homeopathic drugs are prepared by serial dilutions of remedy, the result of which is that "drug" is diluted beyond the point where there is any likelihood that a single molecule from the original solution is present in the final product). In this case, the lack of credible theory trumped seemingly rigorously obtained observations.

ben

Benjamin Djulbegovic, MD, PhD
Professor of Medicine and Oncology
Co-Director of Clinical Translation Science Institute
Director of Center for Evidence-based Medicine and Health Outcomes Research


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-----Original Message-----
From: Evidence based health (EBH) [mailto:[log in to unmask]] On Behalf Of Michael Power
Sent: Monday, January 05, 2009 10:43 AM
To: [log in to unmask]
Subject: Re: Fw: Special Issue:Evidence in Evidence-Based Medicine Fw: Social Epistemology - informaworld

<snip>

CAM can't be tested by RCTs because "Randomisation and standardisation are
foreign, and often incommensurate, concepts in CAM"

<snip>

I find it fascinating that The British Homeopathic Association (BHA) does not
agree that CAM can't be tested by RCTs. Their website
(www.trusthomeopathy.org) states "There are over 50 randomised controlled
trials demonstrating homeopathy has a positive effect."

Of course, and this is a key difference between CAM and EBM, it does not say
how well these studies were designed, conducted, and analysed. Nor does it
say how many negative trials there are. If you look in the Cochrane Library
you will find 5 systematic reviews of homeopathy for attention
deficit/hyperactivity disorder, asthma, dementia, nocturnal enuresis, influenza,
and induction of labour. The reviews found 29 RCTs, mostly of poor quality,
and none providing evidence strong enough to support the use of homeopathy.

I expect that, when I read the Social Epistemology articles, I will find the
claim that CAM can't be tested for specific conditions because it treats the
patient holistically. So, it is interesting to see that the BHA has found positive
evidence for the following "conditions" (the scare quotes indicate that this is
the term used by the BHA, but that some "conditions" would not be classified
as such by a medical doctor).

Allergic asthma
Anal fissure
Ankle sprain
Attention deficit hyperactivity disorder
Brain injury
Bronchitis
Cardiac insufficiency
Childhood diarrhoea
Childhood fever
Chronic fatigue syndrome
Common cold
Cough
Dry mouth
Fibromyalgia
Gastrointestinal cramps
Hay fever
Headache
HIV infection
Immune function
Infertility (female)
Influenza
Irritable bowel syndrome
Kidney failure
Low back pain
Migraine
Muscle soreness
Obesity
Osteoarthritis
Otitis media
Plantar fasciitis
Post-operative agitation
Post-operative bruising, pain or swelling
Post-operative ileus
Post-partum bleeding
Post-partum lactation problems
Premenstrual syndrome
Pruritis
Radiotherapy-induced dermatitis
Respiratory tract infection
Seborrhoeic dermatitis
Sepsis
Sinusitis
Stomatitis
Tendinopathy
Tracheal secretions
Varicose veins
Vertigo
Viral infection


A pubmed search found a meta-analysis of trials of homeopathy for
postoperative ileus. The abstract does not say how many trials were found,
but it does say that the primary outcome was time to first flatus.

I think I need a breath of fresh air!

Michael