Main features • References • Installation • Overview • Databases • Data model • Example workflow • Analysis across registers • Tests • Acknowledgements • Future

ctrdata for aggregating and analysing clinical trials

The package ctrdata provides functions for retrieving (downloading), aggregating and analysing clinical trials using information (structured protocol and result data, as well as documents) from public registers. It can be used with the

• EU Clinical Trials Register (“EUCTR”, https://www.clinicaltrialsregister.eu/)
• EU Clinical Trials Information System (“CTIS”, https://euclinicaltrials.eu/, see example)
• ClinicalTrials.gov (“CTGOV2”, see example)
• ISRCTN Registry (https://www.isrctn.com/)

The motivation is to investigate the design and conduct of trials of interest, to describe their trends and availability for patients and to facilitate using their detailed results for research and meta-analyses. ctrdata is a package for the R system, but other systems and tools can use the databases created with this package. This README was reviewed on 2025-06-07 for version 1.22.2.9000.

Main features

• Protocol- and results-related trial information is easily downloaded: Users define a query in a register’s web interface, then copy the URL and enter it into ctrdata which retrieves in one go all trials found. A script can automate copying the query URL from all registers. Personal annotations can be made when downloading trials. Also, trial documents and historic versions as available in registers on trials can be downloaded.

• Downloaded trial information is transformed and stored in a collection of a document-centric database, for fast and offline access. Information from different registers can be accumulated in a single collection. Uses DuckDB, PostgreSQL, RSQLite or MongoDB, via R package nodbi: see section Databases below. Interactively browse through trial structure and data. Easily re-run any previous query in a collection to retrieve and update trial records.

• For analyses, convenience functions in ctrdata implement canonical trial concepts to simplify analyses across registers