The first EHDEN ‘e-thon’ – confirming the second E in EHDEN: evidence

EHDEN is pleased to be over half-way in its IMI project phase and to be working with such an extensive network of Data Partners (DPs) and Small-to- Medium Enterprises (SMEs) across the European region.

With a strong foundation of 98 DPs and 46 SMEs certified or in the process of certification across 23 countries, EHDEN already has engaged in evidence generation previously through network studies and study-a-thons, for example in response to COVID-19 with our OHDSI colleagues. Another critical aspect is the collaboration across the DPs network, as they complete their mapping to the OMOP common data model (CDM), and support for them to be able to both utilise the OHDSI research framework, from the CDM through standardised analytical tools, themselves on their own data, as well as with others for wider research.

We have created an ‘Evidence Taskforce’ to facilitate a focus on evidence generation through use cases and network studies, as well as expanding our educational activities via ‘e-thons’, or focused evidence generation events to work with newly mapped DPs.

Our first e-thon took place on 21st and 22nd July, remotely of course and via MS Teams. The first DPs to participate, following the completion of their mappings of COVID-19 datasets in collaboration with the COVID-19 ETL Taskforce created for DP Call#2 were:

  • APHM (France, clinical hospital data warehouse/EHR)
  • CC Serbia (Serbia, clinical hospital data warehouse/EHR)
  • FIMIM (Spain, clinical hospital data warehouse/EHR)
  • HIC (UK (Scotland), population based data)
  • UK Biobank (UK, genomic)

EHDEN First E-thon

EHDEN COVID-19 ETL Taskforce members, and colleagues from OHDSI facilitated the two day agenda of educational methods sessions, clinical briefings, group sessions and DP breakouts. The premise was running the R packages from the study published as a special paper in the BMJ on characterising the background incidence rates of adverse events of special interest (AESIs) for COVID-19 vaccines in eight countries1. This would enable DPs to familiarise themselves with running analyses on top of their OMOP mapped datasets, and for EHDEN and OHDSI colleagues to both evaluate the veracity of those mappings, as well as providing educational support to the DPs.

EHDEN First E-thon

The two days were split also by AESI, with deep vein thrombosis (DVT) on day one, and thrombocytopenia on day two, particularly focused on evaluating the incidence rate (number of new outcomes within a defined time-at-risk-/person-time within the population at-risk). Utilising the R packages available on the publication’s GitHub repository, as well as using R shiny applications for the results, and ATLAS, the DPs were taken through the analytical process of conducting these short studies individually and together.

EHDEN First E-thon

A particular aspect helpful to all was the granularity of understanding afforded by this event in exploring the mappings to the OMOP CDM and the specific nuances per DPs dataset, especially as they were so diverse across the four countries represented.

Filip Maljkovic, Core Technology Lead at Heliant Information Systems, Serbia, commented, "What I found most interesting is that we have a lot of data, but without deeper analyses we're never sure what's the quality of it. This deep dive made us aware of all the caveats and problems with our own data, but also how we compare to some other data sources and how no data source is the same in terms of what it covers."

Prof Dani Prieto Alhambra, University of Oxford and EHDEN Research Coordinator suggested, “this first e-thon is the first of many to come, as we see all of our Data Partners complete their mappings, and start to focus on research of their own, and with other researchers,” and he added, “it is very important for EHDEN to support them in doing this, so we can put the mapped data in action to generate evidence at scale across the region.”

We will also follow up with a DPs survey (as we did through the mapping process) to evaluate the e-thon’s impact and usefulness, as well as to inform future events.

The project wants to thank our first DPs for starting the e-thon process together, and we look forward to the many more that will see the widening network transition from the initial mapping work to the OMOP CDM to conducting studies at scale using the OHDSI research framework.


  1. Li X, Ostropolets A, Makadia R, Shoaibi A, Rao G, Sena A G et al. Characterising the background incidence rates of adverse events of special interest for covid-19 vaccines in eight countries: multinational network cohort study BMJ 2021; 373 :n1435 doi:10.1136/bmj.n1435