To allow researchers to explore the data in the Clinical Research Data Warehouse (CRDW) prior to making a data request, the CRI operates a cohort discovery tool called BSD Leaf.

Leaf is a powerful self-service tool which provides UChicago investigators a user-friendly interface for querying de-identified electronic health record (EHR) data sourced from the UChicago Medicine (UCM) patient population. Leaf interacts directly with a regularly refreshed subset of data, derived from the EHR and encoded in the OMOP Common Data Model (CDM), and gives users the ability to build and explore cohorts in real time. Simple drag-and-drop functionality lets users quickly build an ad hoc query of the EHR, execute the query, and provide a breakdown of the cohort it discovered.

The primary use case for Leaf is cohort discovery. For example:

  • The data in Leaf (including demographics, encounters, procedures, diagnoses, labs, medications) can help investigators answer a variety of preparatory-to-research questions about the patient population.
  • Leaf is a useful tool to help an investigator determine if there are enough patients within the hospital system who have a given set of conditions matching the recruitment criteria for a trial.
  • It can also help with planning and designing an existing study or submitting a grant proposal.

These results can inform data requests for de-identified or IRB-approved identified data, as well as helping researchers to formulate hypotheses and identify potential cohorts for research studies and clinical trials.




Q: What are the uses of BSD Leaf?

A: BSD Leaf can assist researchers in creating new research hypotheses, identifying potential cohorts for clinical trials, and reducing the time spent on study feasibility and subject recruitment. It is also a way for potential CRDW users to become familiar with the data elements we have available.

Q: What credentials do I need to access BSD Leaf?

A: You can access the BSD Leaf system here with your BSD login credentials.

You must be on a secure University network to access BSD Leaf. If you are working off campus, please log into the University’s VPN. Please note BSD Leaf is only available to UChicago affiliates with valid BSD account credentials at this time.  Inclusion of Pritzker and UCM affiliates is expected in future releases.

Q: How do I use BSD Leaf to perform a query?

A: Detailed instructions for using BSD Leaf are available in our User Guide.

Q: Can I export de-identified data from BSD Leaf?

A: The interface does not currently support direct exporting of de-identified data. If your cohort discovery results are promising and you would like a full data extract, please follow the process for placing a CRDW data request.

How can I get technical help with BSD Leaf?

A:  If assistance is needed, please submit a ticket with the CRI.