In message <[log in to unmask]>, Guthrie, Dr Bruce
<[log in to unmask]> writes
>
>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.
>
That is, I think (paradoxically) impossible. The practice of EBM
requires the acquisition of new skills and attitudes, and it is is
hardly likely that we could take one group of clinicians and ensure they
are all practising EBM in order to compare with another who are not.
Some in the intervention group would not practice EBM, and some in the
control group would take it up of their own accord.
I think that evaluation of the benefits of EBM needs to look largely at
process (did EBM practitioners ask more questions and use more
interventions based on current best evidence than those who did not?),
and should also look at the professional and social aspects (are EBMers
more satisfied with their work than non-EBMers?!) as well as at other
important matters such as their behaviour during consultations (do they
explicitly address more context-specific questions than other
clinicians, do they clarify and explain the options to their patients in
order to involve them in decision-making?)
The practice of EBM is a complex intervention and cannot be investigated
by purely quantitative methods. There is a nice paper by Campbell et al
(Framework for design and evaluation of complex interventions to improve
health. BMJ 2000;321:694-6) which discusses the investigation of complex
interventions, including the necessity of using proxy measures as
outcomes (e.g. HbA1C rather than mortality in diabetics) and to
incorporate qualitative research.
http://bmj.com/cgi/content/full/321/7262/694
EBM is more complex than most and certainly needs the use of qualitative
methods to investigate the effect (for example) of EBM workshops on
participants. We have had informal feedback that attendance at the
Durham workshops raised the self-confidence and assertiveness of
participants, who were then able to have a discernable effect on
decision making in their organisations when they returned post workshop.
This could be investigated by interviews, by participant observation
studies, and so on.
These ideas then lead back to the discussion on epistemology - while the
*material* of EBM is positivist for the most part (RCTs and other
analytic studies - although questions do occur that require qualitative
research to answer them), the incorporation of EBM into practice, and
its consequences for clinicians and patients, are socially constructed,
and hence need constructivist, interpretivist approaches to understand
them.
That is not to belittle the need to obtain evidence that it improves
health outcomes, but we must understand that in complex situations the
positivist approach becomes much more difficult to apply.
Toby
--
Toby Lipman
General practitioner, Newcastle upon Tyne
Northern and Yorkshire research training fellow
Tel 0191-2811060 (home), 0191-2437000 (surgery)
Northern and Yorkshire Evidence-Based Practice Workshops
http://www.eb-practice.fsnet.co.uk/
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