Almost a third of clinical trials remain unpublished five years after completion, researchers said, in a finding that may add to pressure on drugmakers to be more open about the outcomes of medical studies.
Of 585 trials registered on a U.S. website to track drug research, as many as 171, or 29 percent, remained unpublished five years after concluding, according to a search of scientific literature databases by researchers led by Christopher Jones at Rowan University in Camden, New Jersey. The study was published today in the medical journal BMJ.
The finding comes as pharmaceutical companies face demands to be more open about their research. BMJ, formerly known as the British Medical Journal, is part of a campaign to push for all trials to be registered and their results published. Doctors and regulators need to know test outcomes to make decisions about treatments, the activists leading the AllTrials.net effort say.
U.S. law requires that many trials involving human participants be registered and their results posted on the largest clinical trial website ClinicalTrials.gov. Non-publication was more common among trials that received industry funding than those that didn't, according to the study.
The AllTrials campaign says that trial results that show a drug doesn't work are much more likely to be hidden, leading to so-called publication bias, in which only favorable outcomes are reported.
The lack of availability of results from trials "contributes to publication bias and also constitutes a failure to honor the ethical contract that is the basis for exposing study participants to the risks inherent in trial participation," the authors said in a statement.
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