Mammography,
I quess the only answer is that if there are so many different results on
this topic that that is just the only answer ! When all the results had been
positiv and within a certain range nobody would have questioned the issue,
but with results on mortality in such a broad range as found for mammography
the answer can only be "we don't know" it may or may not decrease mortality
..............
> -----Ursprüngliche Nachricht-----
> Von: Evidence based health (EBH) is the integration of individual
> knowledge [mailto:[log in to unmask]]Im Auftrag von
> Adrian Roberts
> Gesendet am: Sonntag, 28. Oktober 2001 12:57
> An: [log in to unmask]
> Betreff: The mammography saga: a blow to credibility of EB decision
> making?
>
> Most of us on this conference are advocates of the methods of EBH and are
> involved in teaching about it. How should we deal with such a major
> disagreement between experts, as is currently revealed in the mammography
> debate? Leaving aside the issue of harm and whether or not there is valid
> evidence that surgery is increased in women undergoing mammography, what
> about the main concern, mortality? On the basis of the Swedish studies
> there seemed to be sufficient certainty, just a few years ago, that
> mammography conferred a 25% approx. reduction in mortality. Governments
> were sure enough of the validity of this evidence to initiate highly
> expensive breast screening programmes as national policy. Now we have a
> Cochrane metanalysis of 7 trials involving half a million women suggesting
> no effect on mortality. Inadequacies are now seen in older studies that
> did not appear to invalidate their results at the time.
>
> Or is this all just the unfortunate play of chance? The earlier studies,
> each on 45,000 women, were methodologically OK but just gave the wrong
> results by chance? Will that wash with a sceptical audience at an
> introductory EB Health Care workshop? If the evidence based
> recommendations of "experts" can perform such a dramatic a U-turn on the
> value of mammography, how can we trust the "concrete" evidence on
> cholesterol lowering in secondary prevention of CHD, tight glycaemic and
> BP control in diabetes, or anything else, they might well ask?
>
> EBM claims to provide ordinary doctors with the ability to be able to
> critically appraise evidence; to sort the wheat from the chaff. What hope
> have they of accomplishing this when the professional epidemiologist and
> trialist appear unable to reach agreed and consistent conclusions?
>
> I need to sort out my own confusion on this. How do others make sense of
> this and how would you simply explain it to those learning about EBM?
>
> Adrian Roberts
> General Practitioner
> Constantine
> Cornwall
> UK
>
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