I believe that unrecognized aspect of the use of EBM therapeutic
summary measures is that they CANNOT alone be used in medical decision
making, and their application cannot involve simple comparison between them
(i.e. measures of benefits and harm). If they are going to be used in
medical decision making EBM therapeutic summary measures should be
integrated within some coherent clinical (decision) model. We showed that
almost all EBM measures and harms can be succesfully integrated within
decision analytic model. Again, from a decision analytical point of view
evidence-based medicine therapeutic summary measures can be expressed as
utilities . The tenets of decision analysis hold that we should choose a
management strategy whose worth or expected value is maximal and not
necessary the one associated with highest utility for any particular
outcome. Consequently, evidence-based medicine therapeutic summary measures
alone cannot be used in medical decision making.
When EBM summary measures are integrated within decision analytic model,
some new interesting relationship to action thresholds (and new principles
in medical decision making) may emerge. The model is particularly suitable
to take into consideration "patient's unique biology" in clinical decision
making. For technical details, I already referred in my previous e-mail to
http://www.moffitt.usf.edu/pubs/ccj/v5n5/article2.html and
http://www.hsc.usf.edu/~bdjulbeg/Programs/BR/br-java.htm. (The MS written
for GPs is still under review).
It is also possible to include patient preferences in our model.
However, to obtain "patient-preference" threshold for action involves at
least 2 standard reference gamble scenarios. Despite user-friendly program
that Iztok Hozo developed, this exercise rarely takes less than 60 minutes
(in medically trained volunteers; have not attempted to try on patients yet.
This is the main reason that we still have not submitted our paper for
publication, despite the fact that we solved the theoretical difficulties).
Consequently, we would be very interested to examine Dr. Strauss' method in
details (and happy to share our model with your group).
Thanks for the opportunity to clarify my earlier messages regarding
NNT and NNH.
ben
Benjamin Djulbegovic, MD
Associate Professor of Medicine
H. Lee Moffitt Cancer Center & Research Institute
at the University of South Florida
Division of Blood and Bone Marrow Transplant
12902 Magnolia Drive
Tampa, FL 33612
e-mail:[log in to unmask]
http://www.hsc.usf.edu/~bdjulbeg/
phone:(813)979-7202
fax:(813)979-3071
> -----Original Message-----
> From: Dave Sackett [SMTP:[log in to unmask]]
> Sent: Wednesday, January 27, 1999 12:51 PM
> To: EBH Discussion Group
> Subject: NNT or NNH
>
> interesting discussion.
>
> when we use this stuff at the bedside, we don't use "raw" NNTs and NNHs,
> and don't make a simple comparison between them. rather, we adjust both
> the NNT and the NNH for the patient's unique biology and then bring in a
> 3rd key element: the patient's values for the alternative states.
>
> sharon straus has led this work and can do it in about 6 minutes
> on our busy service. she's presented this at several meetings and has a
> Ms under review.
>
> cheers
> dls
>
> ..........................................................................
> ..
> Prof David L. Sackett
> Director, NHS R&D Centre for Evidence-Based Medicine
> Consultant in Medicine Editor, Evidence-Based Medicine
> Nuffield Department of Medicine, University of Oxford
> Level 5, John Radcliffe Hospital, Oxford OX3 9DU, England
> Phone: +44-(0)1865-221320 Fax: +44-(0)1865 222901
> Email: [log in to unmask] WWW: http://cebm.jr2.ox.ac.uk
> ..........................................................................
> ..
>
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