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Wednesday, July 27, 2011

[AlternativeAnswers] Medical consensus reversals

 


Do not lose this citation it will help you save your sanity and maybe even
your license to practice. I always explain that I practice Advanced
Medicine, which is why generally my second opinion consultations on any case I see
differs extensively from the opinion my patients have received elsewhere
before seeing me.

This is a highly respected AMA based medical journal, Archives Of Internal
Medicine, admitting too much of what is done today is just plain wrong!
They admit that what you were taught in med school, namely that 1/2 of what
they taught you in your 4 years at school is wrong, but they do not know
which 1/2 is right. This discrepancy goes on every 4 years or so and pretty
soon most of what you are doing is not up to date, or is worthless, or is
harming patients.

This is vital for you to know that you can quote this prestigious journal
that is telling the truth and wrong things go on they figure probably for
ten years!

Garry F. Gordon MD,DO,MD(H)
President, Gordon Research Institute
www.gordonresearch.com

http://retractionwatch.wordpress.com/2011/07/11/so-how-often-does-medical-co
nsensus-turn-out-to-be-wrong/#more-3192

So how often does medical consensus turn out to be wrong?

In a quote that has become part of medical school orientations everywhere,
David Sackett, often referred to as the "father of evidence-based medicine,
" once famously said:
Half of what you'll learn in medical school will be shown to be either dead
wrong or out of date within five years of your graduation; the trouble is
that nobody can tell you which half–so the most important thing to learn is
how to learn on your own.

Sackett, we are fairly sure, was making an intentionally wild estimate
when he said "half." [See note about these strikethroughs at bottom of post.]
A fascinating study out today in the Archives of Internal Medicine gives a
clue as to the real figure.

The authors of the study, from Northwestern and the University of Chicago,
looked at a year's worth of studies in the New England Journal of Medicine
(NEJM) that "made some claim with respect to a medical practice." There
were 124 such studies, and 16 — that's 13 percent, or about one in 8 —
constituted reversals. As the authors note:
Reversals included medical therapies (prednisone use among preschool-aged
children with viral wheezing, tight glycemic control in intensive care unit
patients, and the routine use of statins in hemodialysis patients),
invasive procedures (endoscopic vein harvesting for coronary artery bypass graft
surgery and percutaneous coronary intervention for chronic total artery
occlusions and atherosclerotic renal artery disease), and screening tests. In
several cases, current guidelines were contradicted by the study in
question, as indicated in the third column of the eFigure.

The results mean that a good chunk of current medical practice is likely
to be reversed over time. And although that doesn't mean all of those
original papers should be retracted, you can see our obvious interest in this.

We asked study co-author Vinay Prasad, by email, to elaborate on the
findings. First, what made the team decide to do this analysis:
For a long time, we were interested by what we believe to be a pervasive
problem in modern medicine. Namely, the spread of new technologies and
therapies without clear evidence that they work, which are later (and often
after considerable delay) followed by contradictions, which, in turn, after yet
another delay, is followed by changes in practice and reimbursement.

One might contend that if the cardinal principle of medicine is 'first do
no harm'– reversal violates this. First, there is harm to the patients who
underwent the therapy during the years it fell in favor, and second, the
harm to future patients until there is a change in practice. And lastly,
there are the diffuse harms, such as loss of trust in the medical system. The
USPSTF's change of mammography for 40 year old women had painful
repercussions, and was based in large part on the Lancet reversal in 2006.

Prasad noted that there had been an earlier study in JAMA of
contradictions in medical research by John Ioannidis, whose work on the shoddy state of
clinical evidence has been getting more attention lately:
Ioannidis shows that among highly cited research 16% of findings are later
contradicted. There were two limits to Ioannidis paper, however, despite
its merits. The first is that high citation papers may overrepresent
controversy, as controversial topics draw further citations and discussion.
Although, to be fair, this is likely a limit to our paper.

The second reason is that we were specifically interested in what
percentage of standard of care is ultimately mistaken, which is different than what
percent of high citation papers are later contradicted. The former
represents what doctors actually do, while high citation papers may not
necessarily reflect clinical practice.

Naturally, we wondered whether the results could be generalized to
journals other than the NEJM:
There are reasons to believe we are over and underrepresenting reversal.
So the answer is we don't know.

Overrepresent: The NEJM probably gets more reversals than other journals
because good reversals are large randomized trials, which are highly coveted
by high impact journals (Lancet, NEJM, JAMA). So reversal may not be the
same for other journals, particularly lesser ones.

Underrepresent: However, on the other hand, for all the possible testable
questions (that arise from current clinical practice) only a fraction are
being tested at any given time. The bulk of NEJM is evaluating new therapies
(72%, in our paper) as opposed to established ones. There are likely more
reversals out there. Further work is warranted, and we have some ideas on
how to extend our analysis.

So how long do these kinds of reversals typically take?

So, no one has looked at how long practices survive before they are '
reversed.' But, I would argue that it has changed over the years, and
accelerated since the [Cardiac Arrhythmia Suppression Trial] CAST trial in the early
1990s. Reversal probably happens faster now (though still pretty slow). The
Nesiritide study in this week's NEJM has a nice editorial by Eric Topol,
who talks about a 'lost decade,' i.e. how long nesiritide was used before
being contradicted. But, examples like routine use of the pulmonary artery
catheter (one of the early reversals) took decades before a solid reversal
(ESCAPE trial in 2005).
And do these reversals have an impact? If so, how long do they tend to
take to change practice?

Yes they have an impact, but only after considerable delay. One person has
studied how long after 'reversal' before the medical community accepts
the contradiction. John Ioannidis published a paper called Persistence of
Contradicted Claims in the Literature. In this paper, Ioannidis looked at
claims that had been disproven in the medical literature, he found for one
notable example that, "a decade had passed from the contradiction of its
effectiveness, [before ] counterarguments were uncommon." My guess is a decade is
about right.

Prasad concluded:
We want to stress the implications of reversal. Reversal implies harm
which is multifaceted and enduring.

That squares with a recent report that retractions are linked to patient
harm. It doesn't mean doctors who use evidence that is later shown to be
wrong have bad intentions. (In fact, as long as they're using evidence, they'
re ahead of some physicians.) But it does provide yet another reason to
read the Archives of Internal Medicine's "Less Is More" series, which is
where this study appeared. It's some of the most consistently skeptical and
evidence-based stuff we see anywhere.

Of course, half of it may be wrong within four years…

Correction, 11:45 p.m. Eastern, 7/11/11: Eagle-eyed Retraction Watch
reader Dan Fagin noted that our back-of-the-envelope calculations trying to link
this to Sackett's "half" of all studies being proven wrong within four
years were, well, wrong. As he pointed out, we can't multiply 13 percent x 4
years and get 52 percent, because the universe of studies has also
quadrupled over those four years. Apologies for the error, which is solely our
fault and not that of the authors of this important Archives paper.

[Non-text portions of this message have been removed]

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