Master Beneficiary Summary File (MBSF): 27 CCW Chronic Conditions Segment

The Chronic Conditions segment of the Master Beneficiary Summary File (MBSF) flags each Medicare beneficiary for the presence of one of 27 specific chronic conditions.

What does this file include? (variable highlights)

  • Three flags for each chronic condition:
    • First occurrence date
    • Mid year indicator
    • End of year indicator

Special considerations

  • The algorithms used to assign the flags are available from the CCW website.
  • Algorithms requiring a multiple-year look back period are completed without requiring the researcher to order multiple years of data.
  • Algorithms search data from Medicare Fee-For-Service (FFS) claims.
  • The 27 CCW algorithms are being replaced with 30 CCW algorithms starting with CY 2017 data files. See individual variable pages for a description of how the algorithms impact specific variables and the Chronic Conditions File Enhancements white paper for more detailed information.
  • This file is a segment that can be requested in addition to the Master Beneficiary Summary File (MBSF) base file.
  • CCW will no longer produce the 27 CCW Chronic Conditions file after the 2021 calendar year data file.

Availability of this file

CY 1999-2021
See what is in this file