Background: Switching of outcomes in trials is a well-known problem in clinical research. It has been observed that clinical trial reports are often not identical with the protocol or registry entry of the study, especially with regard to the reporting of the outcomes. This problem leads to a lack of transparency in clinical research and misinformation.

Objectives:The objective is to assess the quality of register entries in the German Clinical Trials Register (DRKS) with regard to completeness and comprehensiveness, compared with the information in the publication.

Methods: Interventional trials which were registered in the DRKS (completed for >1 year, conducted in Germany) have been identified. A 10%-sample was drawn and analysed to see whether results have been posted in DRKS. After that we compared the information given in the register with the information provided in the journal publication. Interesting parameters to be compared are outcomes, inclusion and exclusion criteria.

Results: 55 out of 124 trials posted results in different formats (link to publications, uploaded reports, etc.). The evaluation of the data is currently in progress and the results will be published once they are available (but at the latest at the Summit).

Conclusions:Modifying data is a serious problem in medical research. It is advisable to ask the study investigator to publish all the data and make sure that they make amendments in the publication or study entries if any changes are required.