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Maintenance and Support of the Chronic Conditions Warehouse (CCW) for Comparative Effectiveness Research (CER)

Supporting expanded data infrastructure enhancements to the Chronic Conditions Data Warehouse to facilitate patient-centered outcomes research.
  • Centers for Medicare and Medicaid Services (CMS)
Start Date
  • FY 2012: 07/11/2012
  • FY 2013: 09/30/2013


  • Linking Clinical and Other Data for Research
  • Use of Enhanced Publically-Funded Data Systems for Research


STATUS: Completed Project


The CMS Chronic Conditions Data Warehouse (CCW) provides researchers with Medicare and Medicaid beneficiary, claims, and assessment data linked by a unique beneficiary key, permitting researchers to analyze data across the continuum of care. Previously, CMS had received American Recovery and Reinvestment Act (ARRA) funding to make enhancements to the CCW to support comparative effective research (CER). Although the ARRA funding supported the expansion of the CCW infrastructure, the one-time ARRA investment resulted in an increase to the cost of continued maintenance, licensing, and support for the CCW that could not be fully covered by the CMS appropriated budget.


In Fiscal Year 2012 CMS was awarded OS-PCORTF funding to continue maintenance and licensing for the CER enhancements made to the CCW undertaken with ARRA funding. In FY2013, OS-PCORTF funding was extended to provide access, continued maintenance, and renewal of licensing. Access for researchers focused on supporting approximately 20 approved researchers conducting patient-centered outcomes research (PCOR) projects via the CCW Virtual Research Data Center (VDRC). The VDRC enables researchers to access CCW data and perform their own analysis and manipulation of CMS data virtually via a secure mechanism, enabling access timelier to data in a more efficient and cost-effective manner. VDRC operations and maintenance included such activities as creating SAS dataset files, exploring new data files, renewing and tracking equipment maintenance, and updating data dictionaries.


  • Over the course of the two consecutive rounds of funding, two sets of activities were accomplished that focused on maintaining and developing the CCW.

    • The first set involved renewing licenses, and other maintenance agreements to support the infrastructure enhancements.
    • The second set was the development of 19 ‘seats’ in the VRDC for research which often required additional analytic space to accommodate large volumes of data, such as multiple years or large cohorts. These 19 ‘seats’ were approved for the researchers of 15 approved studies. Support for researchers using the VDRC seats was provided.




  • In October 2016, the project team published a journal article in the International Journal of Radiation Oncology titled, “Geographic Disparity in the Use of Hypofractionated Radiation Therapy among Elderly Women Undergoing Breast Conservation for Invasive Breast Cancer.” The article can be found here:

  • The project team published a journal article in September 2016 in the American Heart Journal titled, “Readmission after Inpatient Percutaneous Coronary Intervention in the Medicare Population from 2000 to 2012.” The article can be found here:

  • In July 2016, the project team published a journal article in the Annals of Thoracic Surgery titled, “Trends in Patient Characteristics and Outcomes of Coronary Artery Bypass Grafting in the 2000 to 2012 Medicare Population.” The article can be found here:

  • The project team published a journal article in July 2016 in the Annals of the American Thoracic Society titled, “Effect of Transplant Center Volume on Cost and Readmissions in Medicare Lung Transplant Recipients.” The article can be found here: 



Below is a list of ASPE-funded PCORTF projects that are related to this project

Improving the Mortality Data Infrastructure for Patient-Centered Outcomes – Comprised of all U.S. mortality events since 1979, the National Death Index (NDI) database allows researchers to match entries in the NDI to those participating in longitudinal clinical and epidemiologic studies to determine both fact and cause of death. A significant challenge with the NDI has been the lag between the date of death and the availability of the record for matching purposes. The CDC’s National Center for Health Statistics (NCHS) worked to improve the infrastructure to support more timely and complete mortality data collection through more timely delivery of state death records (e.g., cause of death) to the National Death Index (NDI) database and through linking NDI records with nationally collected hospital datasets to obtain a more complete picture of patient care.

Expanding Data Collection for the National Program of Cancer Registries (NPCR) for Comparative Effectiveness Research (CER) – Enhanced data collection and data linkages between central cancer registries and other health related datasets can provide researchers with essential real-world and population-based data for CER. This project built upon previous funding provided to central cancer registries operated by 10 states—part of the National Program of Cancer Registries (NPCR)—to collect detailed treatment and outcomes data from electronic data sources. The PCORTF funding extended longitudinal data collection for a subset of cancer patients in these 10 states, enabling patient-level CER of cancer outcomes, and to improve the tools and timeliness of cancer reporting to the Centers for Disease Control.