Chronic Condition Data Warehouse (CCW) Data Available

CCW Background | CCW Chronic Conditions | CCW RIF Data Available

CCW Background

Section 723 of the Medicare Prescription Drug, Improvement, and Modernization Act of 2003 required the Secretary of the Department of Health and Human Services (DHHS) to make Medicare data readily available to researchers who are studying chronic illness in the Medicare population. To support this effort, the Office of Research, Development, and Information (ORDI) of the Centers for Medicare & Medicaid Services (CMS) awarded a contract to establish the Chronic Condition Data Warehouse (CCW).

For the years 1999-2004, the CCW is based on the 5% national Medicare sample. Unique to the CCW, any beneficiary that enters the cohort will remain in the cohort from that time forward. From 2005 forward, the CCW will contain information for 100% of the enrolled Medicare beneficiaries.

The CCW data include claims, enrollment, and assessment data and can be linked by beneficiary across years and files. CCW data files can be extracted for a set of 21 predefined chronic health conditions. To read more about the CCW, please see the CCW User Manual.

CCW Chronic Conditions

Researchers may request CCW data for any or all of the 21 predefined chronic conditions as defined by CMS. The chronic disease algorithms include specific criteria for reference time periods (searching one to up to three years), diagnosis and procedure codes, number and type of qualifying claims (i.e., must have 2 Carrier claims during reference time period) and coverage (must have Part A and Part B coverage).

These common chronic disease classifications include the following (see Attachment A of the CCW User Manual for complete definitions):

Acute Myocardial Infarction
Alzheimer's Disease
Alzheimer's Disease, Related Disorders, or Senile Dementia
Atrial Fibrillation
Cataract
Chronic Kidney Disease
Chronic Obstructive Pulmonary Disease
Congestive Heart Failure
Depression
Diabetes
Glaucoma
Hip/Pelvic Fracture
Ischemic Heart Disease
Osteoporosis
Rheumatoid arthritis/ Osteoarthritis (RA/OA)
Stroke / Transient Ischemic Attack
Breast Cancer
Colorectal Cancer
Prostate Cancer
Lung Cancer
Endometrial Cancer

For more information about the number of beneficiaries found in the CCW data files by chronic condition, please see the CCW Summary Statistics website.

CCW Research Identifiable Files (RIFs):

The CCW data are considered RIFs, which contain person-specific data on Medicare providers, beneficiaries, and recipients including individual identifiers that would permit the identity of a beneficiary or physician to be deduced (e.g., date of birth, age, race, sex, residence information).

Data with beneficiary or physician identifiers are subject to the Privacy Act, Freedom of Information Act and other Federal government rules and regulations. As such, the information is confidential and is to be used only for reasons compatible with the purpose(s) for which the data are collected.

CMS employs strict security measures to safeguard individual privacy. CMS data release policies seek to ensure that files containing physician and/or beneficiary identifiers are used only when necessary and in accordance with disclosure provisions of the Privacy Act.

Researchers need to submit to CMS a data request packet. If CMS approves the release of the data, researchers need to pay the cost incurred in the processing of data.

For more information about the difference between the CCW RIFs and the CMS RIFs, please see the Technical Note titled "Differences in how the Medicare 5% Files are Generated".

Last Modified October 16, 2008