The Chronic Condition Data Warehouse (CCW) is a research database designed to
(1) identify areas for improving the quality of care provided to chronically ill Medicare beneficiaries;
(2) identify ways to reduce program spending; and
(3) make current Medicare data more readily available to researchers studying chronic illness in the Medicare population.
The CCW contains fee-for-service institutional and non-institutional claims, enrollment/eligibility, and assessment data from 1999 forward for a random 5% sample of Medicare beneficiaries (100% for 2005 forward). The data are linked by a unique, unidentifiable beneficiary key, which allows researchers to analyze information across the continuum of care.
Medicare FFS beneficiaries limited to those who (a) have no months of HMO enrollment and (b) have both Part A and Part B for whatever portion of the year that they are covered by FFS Medicare (i.e., they have no months of A-only or B-only coverage).
Beneficiary age group (< 65 and 65+ ) was determined using the age of the individual at the end of the reference year or the individual's age at the time of death.