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Leaf is a cohort discovery tool deployed by the Institute for Translational Medicine (ITM) at University of Chicago, RUSH University Medical Center, and Loyola University Medical Center. The ITM is funded through the Clinical and Translational Science Awards (CTSA) Program from the National Institutes of Health National Center for Advancing Translational Sciences. Leaf was created at the University of Washington’s Institute of Translational Health Sciences.  More information about the background and creation of Leaf can be found in this JAMIA article

Leaf is a self-service web application that allows cohort discovery from clinical data from single or multiple institutions. Cohort discovery involves finding patient populations using inclusion criteria such as demographics, medical conditions, and procedures. Leaf removes barriers between clinical data and end-users by making it easy to design and run queries that define cohorts. Data loaded onto Leaf are from de-identified Electronic Health Records and include demographics, vital status, encounters, diagnoses, and procedures.  Data are organized according to PCORnet common data model specifications. Leaf can be used as preparatory-to-research to determine if there are enough patients that qualify for a study to prepare an IRB protocol or grant proposal.



Leaf is available to all persons at RUSH who have completed IRB training and have access to the RUSH Research Portal.  Users do not need an approved IRB protocol to access Leaf.

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