[The relation between publication bias and clinical trials funding]

Publication bias describes the distortion of data in scientific journals resulting from the fact that studies with significant and positive results are more likely to be published than studies with negative or insignificant results. In studies funded by pharmaceutical companies publication bias has a considerable impact. It has been shown that more than half of the studies that are conducted as part of the drug approval process will remain unpublished. In addition, multiple publications of the same results, the selective use of data and the withholding of data relating to adverse drug reactions were also demonstrated. It is unclear, however, whether the probability of publication of studies funded by pharmaceutical companies is different from those not funded by pharmaceutical companies. Also, data vary as to the correlation between the type of funding of clinical studies and the length of time to publication. For the benefit of patients, everyone involved in clinical studies ought to take responsibility and facilitate access to all data.