MEDEST

Publication bias is a bias with regard to what is likely to be published, among what is available to be published. One problematic and much-discussed bias is the tendency of researchers, editors, and pharmaceutical companies to handle the reporting of experimental results that are positive (i.e. showing a significant finding) differently from results that are negative (i.e. supporting the null hypothesis) or inconclusive, leading to a misleading bias in the overall published literature.(1)

When we choose a therapeutic strategy or include some particular treatment in our clinical protocols, based on the existing literature, reviews and meta-analysis, we are, most of the times, mislead!

Publication bias affect all the fields of clinical medicine.

• Half of the studies are buried
• Negative data have twice the chance to be buried than positive ones!(2, 4, 5)

Publication bias became more evident with the introduction and widespread adoption of the use of systematic review and meta-analytic methods to summarize research. If the sample of studies retrieved for review is biased, then the validity of the results of a meta-analytic review, no matter how systematic and thorough in other respects, is threatened. There are now several tools available with which meta-analysts can assess the potential magnitude of bias caused by selective publication. When potential bias can
effectively be ruled out, or shown not to threaten the results and conclusions of a meta-analysis, the validity and robustness of these results and conclusions are strengthened.(3)

The “file drawer” effect also consists in the researchers  who do not wish to release negative results, because it may reflect badly on future grant applications, or they are aware of the mistakes that they made in procedure and have no wish to have their mistakes dissected by their peers.
All of us have to be aware of of “publication bias” and “file drawer” impact  on meta-analysis and literature reviews when we make our choices in everyday clinical life.

Is mandatory a widespread shared database, where to follow all the clinical trials have ever been started, in their development, no matter what are their final findings.

• Free Online Meducation (#FOAMed) and free sharing of knowledge, is the only future I can figure out to improve patients outcome against all the possible misleading “bias”.

• Globalizing the informations about actual and future knowledge, is the key to achieve a real worldwide medical awareness.

Is important to understand that hiding any information about clinical research is a mere fraud on patients health!

References:

1.    Song, F.; Parekh, S.; Hooper, L.; Loke, Y. K.; Ryder, J.; Sutton, A. J.; Hing, C.; Kwok, C. S. et al. (2010). “Dissemination and publication of research findings: An updated review of related biases”. Health technology assessment (Winchester, England)

2.    Ben Goldacre “What doctors don’t know about the drugs they prescribe” http://www.ted.com/talk/ben_goldacre_what_doctors_don_t_know_about_the_drugs_they_prescribe.html

3.    Hannah R. Rothstein (Editor), Alexander J. Sutton (Editor), Michael Borenstein (Editor) Publication Bias in Meta-Analysis: Prevention, Assessment and Adjustments. October 2005

4.    Easterbrook PJ, Berlin JA, Gopalan R, Matthews DR. Publication bias in clinical research. Lancet. 1991 Apr 13;337(8746):867-72.

5.    K. Dickersin, S. Chan,T.C. Chalmersx, H.S. Sacks, H. Smith Jr. Publication bias and clinical trials. Controlled Clinical Trials Volume 8, Issue 4, December 1987, Pages 343–353

Must read:

•    Frequency and reasons for outcome reporting bias in clinical trials interviews with trialists BMJ 2011;342:c7153, http://www.bmj.com/content/342/bmj.c7153

Tag:emergency medicine, ethic