Chronic Condition Data Warehouse
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.
https://www.ccwdata.org/web/guest/home and related web pages.