Linked Clinical Trials

Crossmark can be used to display the relationships between different publications that report on a common clinical trial. This page describes the steps a publisher needs to take to participate in this new initiative. For background to the project please see this blog post.

Clinical trial numbers should be extracted from the paper by the publisher or supplied by the author on submission.

There are three elements to the metadata that publishers need to deposit to participate in linked clinical trials:

1. The registry in which the clinical trial has been registered (required)

Clinical trials should be registered with one of the WHO-approved national trial registries or with Clinicaltrials.gov. Crossref is maintaining a a list of these approved registries, and has assigned a DOI to each one. This ID should be deposited. The registry ID is used in combination with the trial number to identify trials correctly.

2. The registered clinical trial number (required)

The trial number, including its prefix, e.g. ISRCTN00757750

3. The relationship of the publication to the clinical trial (optional)

This field is optional but encouraged. The three allowed elements are “pre-results”, “results” and “post-results”, indicating which stage of the trial the publication is reporting on.

These fields should be included within the custom metadata section of the Crossmark deposit. When clinical trial metadata is deposited the “Clinical Trials” section of the Crossmark box will automatically appear and be populated.

Sample deposit

<clinicaltrial_data>
<doi>10.5555/12345678</doi>
<ct:program>
<ct:clinical-trial-number registry="10.18810/isrctn" type="results">ISRCTN1234</ct:clinical-trial-number>
<ct:clinical-trial-number registry="10.18810/isrctn" type="results">ISRCTN9999</ct:clinical-trial-number>
</ct:program>
</clinicaltrial_data>