Study: Not all published trial data is complete
Published journal articles of clinical trial results may not give the complete picture of adverse events and other areas, according to a recent study. In addition, only about half of the studies registered to ClinicalTrials.gov were further published in journals.
The US Food and Drug Administration Amendments Act requires that certain clinical trials and research studies involving human subjects be registered on ClinicalTrials.gov, and results published on the website and/or in scientific journals within a year of completion.
To determine the rate of publication and completeness of randomized controlled drug trials, the study authors searched ClinicalTrials.gov for completed drug studies. Of the 600 trials selected, 50% did not have a published journal article. The researchers also found that, of the 202 studies that had a corresponding journal article, reporting was more complete on ClinicalTrials.gov than in published articles in the areas of adverse events (73% vs. 45%, respectively), serious adverse events (99% vs. 63%), efficacy (79% vs. 69%), and flow of participants (64% vs. 48%). Further, the authors found that the median time of study completion to registry publication was 19 months, and journal publication 21 months.1
"Our results are important for authors because they point out inconsistencies in reporting and highlight the need for more rigorous adherence to reporting guidelines to ensure that all critical information is provided in study reports," the study authors write in the journal PLOS Medicine. "For patients and their clinicians, our results outline the importance of registries to improve transparency in clinical research by making information about clinical trials, including results, publicly available, which is the basis for well-informed decision-making about patients' health."1
The authors also state the importance of the study for highlighting publication bias and time-lag bias. "Further, our results highlight the need to assess trial results systematically from both ClinicalTrials.gov and the published article when available," they write. "Based on our results, searching ClinicalTrials.gov is necessary for all published and unpublished trials to obtain more complete data and to identify inconsistencies or discrepancies between the publicly posted results and the publication."1
To improve the completeness of trial result reporting, the authors suggest the use of templates for standardized reporting in journals, or broader mandatory registration of results.1
- Riveros C, Dechartres A, et al. (2013) Timing and Completeness of Trial Results Posted at ClinicalTrials.gov and Published in Journals. PLoS Med 10(12): e1001566. doi:10.1371/journal.pmed.1001566