From: Pam Barclay [pbarclay@mhcc.state.md.us] Sent: Friday, September 12, 2008 4:43 PM To: Robert Murray Cc: Theressa Lee; Dianne Feeney Subject: Followup on Readmission Analysis Bob The methodology used for the Commission's data on readmissions used the following approach: Readmissions to the same acute care hospital were determined by matching claims based on the hospital unique identifier. Readmissions to other acute care hospitals were determined by matching individuals based on their birth date, gender, county, zip-code, and MDC. Delmarva analyzed the readmissions using the HSCRC / DC inpatient data. At the time the analysis was performed, it was done as a QIO special project. Therefore, Delmarva was permitted to use the QIO data (in this case, Medicare inpatient claims for DC and MD) as well. They applied the same logic to the Medicare claims to verify that the readmission logic was correct, since in the Medicare data, they could in fact track a beneficiary across facilities because a beneficiary's unique Medicare number appears on all claims regardless of the provider. This process of verifying the readmission logic using the Medicare data yielded very few incorrect answers (Delmarva was not able to find the exact analysis-however, they estimate that this procedure results in an incorrect match for a readmission in "less than 1 in every 10,000 cases." I hope this is helpful. Pam