I find the issue of date limitations on evidence provocative. Surely
if a large trial or SR/MA is good quality and definitive, then continued
study is substantively unethical if you accept that the "ethicity" of trials
is determined by prior levels of uncertainty regarding the outcome
(equipoise). For instance
* Is continued investigation into the effect of corticosteriods on
neonatal mortality in preterm births justified? Perhaps to establish dosing
or long-term effects, but to actually determine effectiveness?
* Or continued investigation into the use of thrombolysis post-AMI?
Perhaps to test new thrombolytics against old, or to test effectiveness in
subgroups, but to actually determine the effectiveness thrombolysis?
If trials or SR/MAs become seminal, then the date of publication is
surely of minimal concern, unless the therapy is superceded by new and more
cost-effective treatments. Of course this does raise the issue of how long a
paper should be regarded as seminal?
Andrew Jull
Clinical Nurse Consultant
Auckland Hospital
NEW ZEALAND
NB from June 01, 2001, my email address will change to [log in to unmask]
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