About Chronic Condition Data Warehouse

The Centers for Medicare & Medicaid Services (CMS) launched the Chronic Condition Data Warehouse (CCW), a research database, in response to the Medicare Modernization Act of 2003 (MMA). Section 723 of the MMA outlined a plan to improve the quality of care and reduce the cost of care for chronically ill Medicare beneficiaries.

The Beneficiary Link

The CCW data are linked by a unique, unidentifiable beneficiary key, which allows researchers to analyze information across the continuum of care.

The CCW is designed to:

  • Follow beneficiaries across multiple care settings
  • Identify areas for improving quality of care provided to chronically ill Medicare beneficiaries
  • Identify ways to reduce program spending
  • Make current Medicare, Medicaid, Assessment and Part D data more readily available to researchers for all types of studies, populations, and rare events
  • Provide thorough documentation so researchers understand the common keys, relationships between claims types, and how to use data accurately

Data Availability

CCW contains the following 100% Medicare files for years 1999 - 2010:

  • Fee-for-service institutional and non-institutional claims
  • Enrollment/eligibility
  • Assessment data

100% Medicaid files for years 1999 - 2008

100% Part D prescription drug event data for years 2006 - 2009

  • Plan characteristics
  • Pharmacy characteristics
  • Prescriber characteristics

CCW data files may be requested for any of the predefined chronic condition cohorts, or users may request a customized cohort(s) specific to research focus areas.