MTV, sundhedstjenesteforskning og klinisk praksis

ging evidence from a systematic review of the early trials. It was
abandoned when the review was updated (14) to take account of
evidence which had accumulated from subsequent trials (15).
Improving the reporting of controlled trials
Up-to-date systematic reviews of the results of other relevant trials
are also essential for adequate reporting of controlled trials. As
recommended by the CONSORT Group (16), data from a new
trial should be interpreted “in the light of the totality of the
available evidence”. The public and others will continue to be misled
if researchers attend to the control of biases and imprecision
within studies, but then ignore the need to attend to biases and imprecision
in setting the results of a particular study in context.
An analysis of all 26 reports of controlled trials published in the
May 1997 issues of the Annals of Internal Medicine, the British Medical
Journal, JAMA, the Lancet and the New England Journal of
Medicine (17) revealed that in only 2 reports (both published in the
Lancet) had the evidence generated by the new study been presented
in the context of updated systematic reviews of other relevant
studies. Many of the other reports, including some that claimed
(without evidence) to be the first trial addressing a particular question,
contained citations to previous trials. But it was not clear
whether these represented every similar trial, or how they had been
identified, or why they had been included. In other words, in terms
of the notion of a population of relevant studies, the cited reports
were non-random numerators without defined denominators.
In his presidential address to the 54th meeting of the British Association
for the Advancement of Science in Montreal in 1884, Lord
Rayleigh, Professor of Physics at the University of Cambridge in
England, said this:
“If, as is sometimes supposed, science consisted in nothing but the laborious
accumulation of facts, it would soon come to a standstill, crushed, as it were,
under its own weight. The suggestion of a new idea, or the detection of a law,
supersedes much that has previously been a burden on the memory, and by
introducing order and coherence facilitates the retention of the remainder in
an available form… Two processes are thus at work side by side, the reception
of new material and the digestion and assimilation of the old; and as
both are essential we may spare ourselves the discussion of their relative importance.
One remark, however, should be made. The work which deserves,
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