According to a study of a 5% sample of all Medicare fee-for-service beneficiaries with continuous Part A and B coverage:

• Beneficiaries with 10 or more chronic conditions were over 6 times more likely to be readmitted to a hospital within 30 days of discharge, than beneficiaries with 1 to 4 chronic conditions • Beneficiaries with 10 or more chronic conditions comprised only 8.9% of all Medicare beneficiaries and 31.0% of all hospitalizations, but they were responsible for 50.2% of all readmissions • The 31.8% of beneficiaries with 5 to 9 chronic conditions (55.5% of all hospitalizations) had the second highest odds ratio (2.5) for readmissions, and were responsible for 45% of all readmissions Source: "Medicare beneficiaries most likely to be readmitted," Journal of Hospital Medicine, abstract only, August 28, 2013, http://onlinelibrary.wiley.com/doi/10.1002/jhm.2074/abstract