In Switzerland, a new definition of the case was introduced in 2012. If a patient is readmitted within 18 days in the same hospital for the same major diagnostic category (MDC) or a complication, corresponding cases are merged. This definition was introduced for reimbursement purposes (SwissDRGs) to avoid splitting bills to benefit from several packages per case. But this new definition does not reflect the medical decision to close a hospitalization, searching the best balance between a discharge as soon as possible and the risk of further readmission. If stays are merged, early readmissions occurring during the first 18 days would be missed. Thus, in terms of performance (low length of stay or cost and readmission rate), it is crucial to restore the stays in their original and real form. Another issue is the lack of continuity when measuring performances before and since 2012.
The Swiss medical records provide the dates of interruptions, as well as the dates of procedures and the reason of the readmissions. To ensure the continuity of the temporal comparisons, actual stays are re-built to identify each hospital stay separately. Each procedure is allocated to its corresponding re-built stay, whereas diagnoses are allocated to every stay. Grouped cases caused by a complication are considered as potentially avoidable. The SQLape user can identify those cases with their stay identifier followed by its rank (e.g. 19222110_1, 19222110_2, 19222110_3 if there were two interruptions).
Length of stay of each part of merged stays is computed separately, with a value of zero if the first stay had same admission and discharge dates. Costs are allocated to each part of merged stays, proportionally to the lengths of their stays.