I suggest evidence trumps theory if we have valid evidence.  Theories
are helpful for discovery but can lead us astray if are unable to
recognize the flaw in a seemingly sound argument.

In theory a drug to reduce PVCs would reduce mortality when PVCs are
associated with increased mortality.  But in practice the evidence found
the same drugs reduced PVCs but increased riskier types of arrythmias.
In retrospect the theory could be modified to account for this.  But not
everyone would recognize the flaw until the evidence made it clear.

One problem in describing the process and results comes from the degree
of scrutiny.  Evidence can "pass the test" when using specific
checklists yet still have serious (event fatal) flaws.   For many of us
using checklists we don't seek these additional flaws unless triggered.
Seeing results that do not feel right (face validity) triggers
additional scrutiny.   Therefore some CAM research may get additional
scrutiny.

I would guess if we made up a study report with 2 variations (positive
results or negative results) but kept the methodology the same and
shared this report with EBMers (whatever that means because we haven't
defined the term) we would get different results in methodologic
scrutiny based on the results.  If a seemingly well-done study found
cigarette smoking reduced the risk of lung cancer would be assume it
must be wrong and put extra effort into finding flaws?

If an herb reduced symptoms in 1 trial and a homeopathic preparation
(diluted to infinity) reduced symptoms in 1 trial and these trials has
the same methodology except for the formulation tested would the trials
get the same degree of scrutiny?


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-----Original Message-----
From: Evidence based health (EBH)
[mailto:[log in to unmask]] On Behalf Of Djulbegovic,
Benjamin
Sent: Monday, January 05, 2009 1:30 PM
To: [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