Thanks James
I agree with your solution: to simply state what the evidence is --- this will undermine evidence ranking systems (which are tools for someone else to do the thinking for you).
I also agree that target levels endanger common sense --- because they also are tools for someone else to do your thinking for you.
Michael
________________________________
From: James McCormack [mailto:[log in to unmask]]
Sent: Tue 23/10/2007 16:35
To: M Power
Subject: Re: Is there a place for common sense in EBM?
Hi Michael - some good examples of why we need to let the evidence speak for itself.
I think as EBM people we should simply state - based on the available evidence (describe that evidence) "X" increased/decreased "Y" compared to "Z" - or in the case of the osmotic laxatives - there are no adequately designed RCTs showing the effect of these products - in my experience, individuals with a modicum of common sense can figure out how to incorporate the evidence or lack thereof into practice when it is presented in this format.
I would suggest without much tongue in cheek that all the "evidence-based" target levels for things such as blood pressure, cholesterol, diabetes, osteoporosis endanger common sense. We should just be stating that if you take "X" we can reduce your chance of "Y" from roughly A% to B% - if you are interested great, if not great.
Just a couple of thoughts. Thanks.
On 23-Oct-07, at 1:50 AM, Michael Power wrote:
Does EBM-speak endanger common sense?
Example 1.
"Use a 21-guage needle (green) in women who weigh more than 90kg."
This recommendation is appropriate for a brainless robot.
In plain English, the common sense recommendation for a thinking human
would be "Use an adequately long needle if you have to give an
intramuscular injection through a thick layer of adipose tissue."
Example 2.
"We don't know if other osmotic laxatives such as magnesium salts , or
phosphate or sodium citrate enemas are effective."
There is a simple cure for this piece of ignorance: take a dose of epsom
salts and see what happens. Or, submit a grant application for a
doubleblind, placebo controlled RCT.
Example 3.
"Macrogol 3350 26 g daily was significantly more effective than
20 g lactulose daily".
In practice, the dose of a laxative is adjusted to achieve the desired
effect. So, comparing fixed doses of different laxatives provides
information that is more likely to be useful for marketing than for the
patient or practitioner. Most of the evidence on laxatives is at this
level.
If you have any other examples where common sense has been sacrificed to
the form of EBM-speak, please send them to me. I am building a collection.
Thoughts on the aetiology and treatment of hypocommonsentia would also be
welcome.
Michael Power
Clinical Knowledge Author, Guideline Developer and Informatician
Clinical Knowledge Summaries Service www.cks.library.nhs.uk
Sowerby Centre for Health Informatics at Newcastle Ltd www.schin.co.uk
James McCormack, BSc(Pharm), Pharm D
Professor
Faculty of Pharmaceutical Sciences
UBC, Vancouver, Canada
604-603-7898
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