Dr. Guthrie,

I can't help but say "Hear, hear" to your comment

"How about a well designed, large enough RCT of practicing EBM vs not
practicing it, and measure patient outcome?  That's what EBM says is best
evidence."

I also count myself as an advocate for EBM, but hopefully not a wide-eyed
one.  More evidence to 1) test the hypothesis that EBM makes a difference in
patient outcomes from pragmatic studies of its implementation and 2)
quantify the amount of heretofore unexplained variation in patient outcomes
that the practice of EBM removes would be quite helpful to determine its
true role when the next step in its integration into the mainstream of
medicine is being considered.

Otherwise the criticisms of its opponents that EBM adherents rely on
'conceptual pathophysiologic' reasoning to justify the practice of EBM while
criticizing that very same basis of evidence when applied to drug and
surgical therapies is quite valid.

Ken Yew
NH Jacksonville
Department of Family Practice
(904) 777-7963



-----Original Message-----
From: Guthrie, Dr Bruce [mailto:[log in to unmask]]
Sent: Wednesday, January 17, 2001 5:52 AM
To: [log in to unmask]
Subject: Re: Consequences to practitioners of ebm (fwd) (fwd)


Dear Roy,

This is my last contribution to this strand since I don't think it's a
resolvable question, and apologies to those of you who find this
stuff irrelevant.

> The question of the benefits of "practicing EBM" I believe has been
> revisited on this list multiple times.  I guess it all depends on what
> one means by "practicing EBM" and what sort of evidence one seeks.

How about a well designed, large enough RCT of practicing EBM vs
not practicing it, and measure patient outcome?  That's what EBM
says is best evidence.

> I think it's easy to show that practice according to some of the more
> striking results of good clinical research improves outcomes.  The
> example that comes to mind readily to an old sore throat researcher is
> in the 50's RCT's showed that treating streptococcal pharyngitis with
> penicillin reduced suppurative complications.  Streptococcal
> pharyngitis is now almost always treated with antibiotics in the
> developed countries. (We often treat non-specific pharyngitis with
> antibiotics too, but that's another story.)  The suppurative and
> non-suppurative complications of streptococcal pharyngitis are now
> quite rare. That is a good outcome for patients and society.

Hmmm.  I'm not sure that you can jump from that to assuming that
it is antibiotics that have reduced the prevalence of these
complications in the community.  Alternative explanations include
the streptococcus changing its relationship with humanity, either
because it's changed or we have (better fed etc).  The case of TB
suggests it's a mixture - TB treatment matters a great deal if you
get TB, but the decline in UK TB incidence and death was largely
due to other factors.

If you were writing an evidence based guideline on whether
clinicians should practice EBM or not, what level of
recommendation would you give on the basis of this kind of
evidence?

> Ah, but questioning the existence of an external objective reality is
> a very particular kind of belief.  If you really disbelieve in
> objective reality in general, how do you survive the day?  One
> problem with postmodernists' repetitive recitation that there is no
> objective reality, or that reality is socially constructed, is that in
> their everyday lives they act like there is an objective reality.  No
> postmodernist has ever taken Sokal up on his dare: "Anyone who
> believes that the laws of physics are mere social conventions is
> invited to try transgressing those conventions from the window of my
> apartment.  I live on  the twenty-first floor."

The point I was trying to make is that I don't disbelieve in an
"external objective reality in general".  Sometimes I act as if I
believe in it, sometimes I don't.  When considering walking out of
windows, I do believe in it - it's useful.  When considering social
interaction and culture, I sometimes find it helpful to act as if reality
is socially constructed - that's useful too.  It isn't necessary to
commit yourself to a single perspective on the world in all
situations.

> Ah, but you are quickly retreating from the position that "reality is
> socially constructed."  You are now pointing out that perceptions,
> beliefs, and opinions about reality are socially influenced, e.g.,
> that how one perceives one's chest pain may be socially influenced.  I
> obviously agree.  But that isn't what postmodernists are saying.  And
> if that is all they are saying, they are just repeating what most
> people would think is the obvious.

I never took the position that reality is only socially constructed.  I
took the position that it can be helpful to take different perspectives
at different times, and to act as if these different incompatible
beliefs were true at the moment of their use.

To say that perceptions, beliefs and opinions about reality are
socially influenced is to accept a degree of social construction.  It
may be "what most people think is the obvious", but doesn't that
prove my point?  A hard belief in an objective external reality full of
"facts" isn't sustainable in all situations.  Neither is a hard belief in
multiple shifting realities if it leads to an inability to act in the world.

Bruce

PS  Despite the seemingly negative tone of all this, I'd like to
emphasise that I really like EBM.  I did my first medline search as
a house officer/intern in 1988, and was calculating numbers needed
to treat the next year before I'd read anything about EBM.  EBM
gave me an excellent structure for things I already did, and
broadened my thinking in all sorts of other ways.  But it only works
when it's relevant.  When it's not relevant, other ways of thinking
may be better.

Bruce Guthrie,
MRC Training Fellow in Health Services Research,
Department of General Practice,
University of Edinburgh,
20 West Richmond Street,
Edinburgh EH8 9DX
Tel 0131 650 9237
e-mail [log in to unmask]