Site selection — data extraction strategies
TRANSFORMATION
Following receipt of survey data, we worked with site staff to assess their ability to participate in one of three EHR data extraction strategies. These strategies were designed, in part, based on our experience with the HARMONY Outcomes EHR study [To address the fact that only a minority of sites in this study had the requisite characteristics and resources to create a datamart, we designed a flexible, multimodal approach that enabled participation by sites with limited IT resources and/or technical capabilities while simultaneously leveraging site-level data that already exists in a query-able format (Fig. 
Network ConsortiumThe Network Consortium strategy was offered to sites that were current participants in the Patient-Centered Clinical Research Network (PCORnet®) distributed research network who maintained an associated datamart. Sites choosing this option had already conducted the foundational work of mapping their EHR data to a common data model (CDM) and had made their data available in a query-able format. The CDM used for this study was a simplified version of the PCORnet Common Data Model [Map-to-CDM (Common Data Model)Sites that were not part of an existing Network Consortium but who wished to build a de novo research datamart to support the project objectives were offered the Map-to-CDM option. This option was offered to sites that previously participated in PCORnet or currently participate in another distributed research network. Although building a datamart entails substantial technical effort, this option was attractive to sites that might leverage the datamart for future research studies or that prefer to respond to a research query rather than create and share a full data extract as was required for the third strategy.Central TransformationThe Central Transformation strategy was created to support the inclusion of sites with more limited IT resources who were not part of a distributed research network or Network Consortium. Through this strategy, sites generated standardized reports for different EHR data domains (e.g., demographics, diagnoses, labs) for VESALIUS-CV trial patients who consented to participate in this study, which were then transferred to the coordinating center and transformed into a research datamart. Working with sites to obtain an extract of participant data may be less efficient than leveraging an existing research datamart, but shifting some technical work to a central team may expand both the types of participating sites (enhanced generalizability) and the number of patients included (statistical power).Data extraction strategies were chosen in collaboration with site staff based on survey responses. Key qualifications for the Map-to-CDM or Network Consortium strategy included:
Existence of an EHR platform at the enrolling site used for clinical care purposes, including inpatient hospitalizations;Access to an enterprise data warehouse or clinical data repository that stores structured data from their EHR system;Stated capability to extract EHR data from a data warehouse or repository according to standard specifications;Pre-existing institutional processes and policies for using EHR data for clinical research; andDemonstrated interest from the site-based clinical trial team and engagement of health system IT and analytical personnel at that siteData flow by data extraction strategyThe project goal was to engage a total of 8–10 US sites, with representation across all 3 data collection strategies. Of the 54 US study sites, we determined that 18 had either insufficient data or did not have an EHR system. Of those who sent a feasibility survey (Flow diagram for VESALIUS-CV EHR study site participation