A retrospective analysis was conducted using a nationally representative 5% sample of Medicare fee-for-service claims data from the U.S. Centers for Medicare and Medicaid Services to identify Medicare beneficiaries 65 years or older who had an acute care episode for an AE-COPD between January 1, 2006, and December 31, 2010 (n = 52,741). 
Medicare fee-for-service claims data