I am confused by this discussion and wonder if two different issues
are being discussed here.
The uncertainty principle, it seems to me, is what should be
operative in
order to determine whether a study should be undertaken at all. Do
we know
if drug A is definitely better than placebo? If we don't know the
answer to
that, then and only then, is a study ethical.
Firstly Jeanne seems to be talking about the determination of
whether a trial protocol is ethical or not. This is governed by the ethical
principle of equipoise, or level of collective uncertainty about the
efficacy/effectiveness of a treatment.
However, once we determine
that we are uncertain and a study is ethical - to allow clinicians
to remove
patients from randomization still seems to be risky to me and I
wonder about
that undermining the study's genuine randomness.
Secondly are not random selection and random allocation being
confused here? The example Jeanne initially used seemed to involve selection
prior to randomisation. I interpret the issue Jeanne is concerned about is
the influence inclusion/exlusion criteria may have on the trial's
generalizability, and this seems to get at the substantive ethics of RCTs
i.e. whether this trial design is addressing a societally desired/needed
issue. The application of inclusion/exclusion criteria gets to the heart of
the purpose of the trial - whether it is explanatory or pragmatic; if
explanatory then stricter inclusion criteria may be appropriate, but it may
be argued that a pragmatic design (i.e. one that is more open in its
inclusion criteria) is what is needed.
But as I say I may be the confused one.
Andrew Jull
Clinical Nurse Consultant
Auckland Hospital
NEW ZEALAND
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