Health Innovation Program DRG Categories

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Patients discharged to a SNF from an inpatient stay experience high readmission rates. Because these patients have varying causes for the inpatient stay, they inevitably have different readmission rates. The HIP Diagnosis-Related Group (DRG) Categories Tool groups patients into DRG clusters based on joint likelihood of readmission and discharge to a SNF.

The DRG Categories include:

  • Medical-AODA
  • Medical-Complicated*
  • Medical-ENT
  • Medical-Mental
  • Medical-Uncomplicated*
  • Pregnancy/Newborn-Complicated
  • Pregnancy/Newborn-Uncomplicated
  • Stent
  • Surgery Musculoskeletal-Low Aftcare
  • Surgery Musculoskeletal-Mid to High Aftcare*
  • Surgery Other-Uncomplicated
  • Surgery-Complicated*
  • Unknown

*These four categories represent the bulk of Medicare admissions.

Who should use this toolkit?

This toolkit is intended for healthcare administrators, policymakers and researchers interested in readmission risk by patient type after discharge.

What does this toolkit contain?

An Excel worksheet contains the mappings from MS-DRGs to corresponding categories. The worksheet includes MS-DRG number and name together with the category it belongs to. It also contains historical mapping starting with MS-DRG designations from 2008 and is updated to reflect changes in DRG numbering through MS-DRG version 36. More information on MS-DRGs can be found here:

How should these tools be used?

This tool can be used to categorize patients during inpatient stay based on their DRG.

To allow you to easily use the tool within your organization, it is provided as a separate file in Microsoft Excel that you can download from the HIPxChange site.

Development of this toolkit

The use of individual DRGs can be limited in many settings as the number of patients in any given DRG may be either quite small or even zero. In addition, there are so many DRGs that even if the numbers are adequate, reports and operational workflows created using individual DRGs can be overwhelming.

To address this gap, we developed the DRG Categories Tool to create a manageable number of DRG categories but still retains some interpretability in terms of individual clinical service lines (e.g. medical vs. surgical) and case complexity (e.g. complicated vs. uncomplicated). Using data from a 100% sample of 2012-2013 Medicare claims from the state of Wisconsin, MS-DRGs for version 36 and earlier were manually grouped by the joint likelihood of readmission and discharge to SNF, or into other relevant categories (e.g., rehabilitation). This DRG mapping to HIP DRG categories can be downloaded at

This mapping will be updated on an occasional basis to account for new or expired DRGs. The mapping retains expired DRGs for working with historical data.

This project was supported by the University of Wisconsin School of Medicine and Public Health’s Health Innovation Program (HIP), the Wisconsin Partnership Program, and the Community-Academic Partnerships core of the University of Wisconsin Institute for Clinical and Translational Research (UW ICTR), grant 9 U54 TR000021 from the National Center for Advancing Translational Sciences (previously grant 1 UL1 RR025011 from the National Center for Research Resources). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or other funders.

The HIP DRG Categories Tool was developed by researchers and clinicians (Principal Investigator: Maureen Smith) at the University of Wisconsin-Madison Health Innovation Program.

Please send questions, comments and suggestions to

Toolkit citation

We suggest using the following citation for this toolkit: Health Innovation Program DRG Categories Tool. Health Innovation Program. Madison, WI; 2018. Available at


About the Developer

The Health Innovation Program DRG Categories was built by staff at the Health Innovation Program at the University of Wisconsin – Madison School of Medicine & Public Health. The mission of the Health Innovation Program is to transform healthcare delivery and population health across the state and nation through health systems research that partners University of Wisconsin faculty with healthcare and community organizations.