Saturday, March 9, 2013

Selective Publication of Antidepressant Trials and Its Influence on Apparent Efficacy

This paper shows that negative results of trials are often withheld, when the results of drugs are 
completely random compared to placebo this can make the drug appear to be working.

Selective Publication of Antidepressant
Trials and Its Influence on Apparent Efficacy
Erick H. Turner, M.D., Annette M. Matthews, M.D., Eftihia Linardatos, B.S.,
Robert A. Tell, L.C.S.W., and Robert Rosenthal, Ph.D.
From the Departments of Psychiatry
(E.H.T., A.M.M.) and Pharmacology
(E.H.T.), Oregon Health and Science Uni
versity; and the Behavioral Health and
Neurosciences Division, Portland Veter
ans Affairs Medical Center (E.H.T., A.M.M.,
both in Portland, OR; the De
partment of Psychology, Kent State Uni
versity, Kent, OH (E.L.); the Department
of Psychology, University of California–
Riverside, Riverside (R.R.); and Harvard
University, Cambridge, MA (R.R.). Address
reprint requests to Dr. Turner at Portland
VA Medical Center, P3MHDC, 3710 SW
US Veterans Hospital Rd., Portland, OR
97239, or at
N Engl J Med 2008;358:252-60.
Copyright © 2008 Massachusetts Medical Society.
Evidence-based medicine is valuable to the extent that the evidence base is complete
and unbiased. Selective publication of clinical trials — and the outcomes within
those trials — can lead to unrealistic estimates of drug effectiveness and alter the
apparent risk–benefit ratio.
We obtained reviews from the Food and Drug Administration (FDA) for studies of
12 antidepressant agents involving 12,564 patients. We conducted a systematic lit
erature search to identify matching publications. For trials that were reported in the
literature, we compared the published outcomes with the FDA outcomes. We also
compared the effect size derived from the published reports with the effect size de
rived from the entire FDA data set.
Among 74 FDA-registered studies, 31%, accounting for 3449 study participants, were
not published. Whether and how the studies were published were associated with
the study outcome. A total of 37 studies viewed by the FDA as having positive results
were published; 1 study viewed as positive was not published. Studies viewed by the
FDA as having negative or questionable results were, with 3 exceptions, either not
published (22 studies) or published in a way that, in our opinion, conveyed a posi
tive outcome (11 studies). According to the published literature, it appeared that
94% of the trials conducted were positive. By contrast, the FDA analysis showed that
51% were positive. Separate meta-analyses of the FDA and journal data sets showed
that the increase in effect size ranged from 11 to 69% for individual drugs and was
32% overall.
We cannot determine whether the bias observed resulted from a failure to submit
manuscripts on the part of authors and sponsors, from decisions by journal editors
and reviewers not to publish, or both. Selective reporting of clinical trial results may
have adverse consequences for researchers, study participants, health care profes
sionals, and patients

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