Okay, so hospital readmissions are bad and we should prevent them. A good first step is understanding what diagnoses are most often related to readmissions. An Agency for Healthcare Research & Quality Statistical Brief gives us 2011 data, broken down by payer type. (Stat. Brief) In 2011 there were 3.3 million all-cause readmissions within thirty days after a hospital discharge. These readmissions cost $41.3 billion but it is important to remember that not all these readmissions are inappropriate or avoidable. Some are actually planned, for example, for follow-up procedures. And the all-cause readmission measure means many of the subsequent readmissions were for problems unrelated to the original admission. For Medicare, the largest admission diagnoses followed by a readmission were congestive heart failure, 135,000 readmissions; septicemia, 92,000 readmissions; and pneumonia, 88,000 readmissions. These readmissions represented $4.3 billion in hospital costs and over 17% of all Medicare readmissions. For Medicaid, adult readmissions followed mood disorders, 41,600, most commonly, followed by schizophrenia, 35,800, and diabetes 23,700 readmissions. These represented 15% of all Medicaid readmissions. For privately insured people the highest admission followed by readmission was maintenance chemotherapy at 25,500, almost none of which are likely avoidable; mood disorders, 19,600, and complications of surgical or medical care, 18,000 readmissions, most of which we suspect were avoidable. These three diagnoses accounted for only about 10% of all commercial readmissions. The high number of mental illness related readmissions in Medicaid and private insurance are likely signs of poor outpatient care, especially a failure to ensure that a medication regiment is appropriate and adhered to. For uninsured patients, the diagnoses are similar to those in Medicaid, with mood disorders first at 12,200; alcoholism at 8,800 and diabetes at 7,400, with these being about 18% of all uninsured patient readmissions. This data, which hospitals and payers should already have access to, should help target readmission prevention efforts.