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.
Accessing Leaf
Persons can only access Leaf within the institution’s firewalls, i.e., using computers at Rush, or using virtual desktop instances.
- To access leaf, user will need to open a web browser and go to the following link: https://myapps.rush.edu
- Login with your Rush AD credential
- Once you approve the multifactor authentication on your mobile, you will be in myapps
- Click on 'MY APPS' on the top menu
- Click 'Leaf' app in the list
- Click 'Open Citrix Workspace Launcher' to download it and will open a connection session for https://leaf.rush.edu
-
What is Leaf?
Leaf is a cohort discovery tool that originated at the University of Washington and now has been deployed at University of Chicago, Rush University Medical Center, and Loyola University Medical Center by the Institute for Translational Medicine (ITM). It can provide patient counts given specified conditions and events. It is open-source, and was developed using funds from the National Center for Advancing Translational Sciences (NCATS).
-
Who has access to Leaf?
Persons at University of Chicago, Rush University Medical Center, and Loyola University Medical Center who have completed Institutional Review Board (IRB) training can access Leaf using their institution’s sign-on credentials. Persons can only access Leaf within their institution’s firewalls, i.e., using computers at their institutions, or using virtual desktop instances.
-
What data are available in Leaf?
The Leaf instance you have access to is connected to de-identified data from the University of Chicago, Rush University Medical Center, and Loyola University Medical Center. De-identification was performed using the Safe Harbor Method as specified by the Health Insurance Portability and Accountability act of 1996 (HIPAA) Privacy Rule. Data domains that can be queried are demographics, vital status, encounters, diagnoses, and procedures. These data are organized according to PCORnet specifications.
-
How often are data refreshed in Leaf?
Data are refreshed once every six months. Initial data load onto Leaf was from January 2016 to December 2022.
-
How do I get a query started using Leaf?
Use the concept tree on the left-hand side of the application, and drag concepts to boxes on the right-hand side of the application. You can search the concept tree using the search bar above it.
-
What can patient counts inform?
Patient counts given specified conditions and events can help with ascertaining clinical trial feasibility (e.g., how many patients with diabetes mellitus between the ages of 18 and 65 are there?), and can be used for basic epidemiologic studies (e.g., what is the prevalence of diabetes mellitus between 2016 and 2022?).
-
I have my counts but want more granular data. Who do I contact about getting more data?
Fill out a Form 118 with the Rush IRB. Once your project is approved by the IRB, make a data request through Clinical Research Analytics. You can leave the account chargeback fields blank.
-
Who do I contact with other questions regarding Leaf?
You can email us at leaf_support@rush.edu.