On 2/18/2012 12:34 AM, Anoop Balachandran wrote:
>
> So if the RCT that is answering your specific question is not well
> done (poor methodology/bias), can we fall back to basic science? Can
> basic science stand alone as evidence if the quality of RCT is
> questionable?
>
It is always a matter of judgement. We know that very often open studies
give the same results as randomized control trials, so a poorly
randomized or blinded study - or even a few case reports- is still
better than nothing. The lower the quality of the trial, the more you
will weight pathophysiological reasoning. Of course, when no experience
is available, a supposition based on basic science seems still better
than just throwing a coin....
But remember that you use basic science since the beginning, to
understand the problem, to ask the clinical question(s), to judge the
results, to adapt them to your patient. You never get out of it.
Evidence-based medicine, after all, is based on basic science, and its
most relevant papers are narrative reviews ;-)
> An example: I am thinking RCT's of homeopathy, but which completely
> goes against any basic science.
>
Again, it is a matter of applying basic science. The pre-test
probability of homeopathy being more effective than placebo on any
condition is so low, that only a very, very small P value could
reasonably override it, so any RCT vs placebo are probably meaningless,
whatever their results.
But remember that when it was invented,in the 18th century, homeopathy
was objectively much better than contemporary medicine based on baths,
bloodletting and enemas.AndiIt is still at least as effective as placebo
(which is often more effective than no treatment), and as for lack of
side effects, it is hard to beat. So, in conditions where the
effectiveness of the available treatments is low and their side effects
are high, homeopathy (be it classical, clinical, complex, or isopathic)
could score better than available treatment even in a RCT.
The problem then would be the ethics of using a placebo (homeopathy) ,
rather than cognitive psichotherapy.. In those conditions, a RCT
comparing homeopathy vs. cognitive psychotherapy wouldn't go at all
against basic science!
(for a recent discussion on cognitive psychotherapy and placebo, see
Papakostas and Christodoulou, European Psychiatric Review, 2010;3:13-15)
regards,
Piersante Sestini
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