To determine if a stay should be excluded, identify the index hospitalization and the FIRST readmission (if there is one). If the FIRST readmission was planned for, drop the index.
So, for example 2:
Stay 1. Index hospitalization with unplanned readmission (stay 2): Include as index.
Stay 2. Index hospitalization with planned readmission (stay 3): Drop as index.
Stay 3. Index hospitalization with planned readmission (stay 4): Drop as index.
Stay 4. Index hospitalization with no readmission: Include as index.
Stay 1 is the index. Stay 2 is the first readmission to assess, but because it does not meet criteria for a “planned hospital stay,” stay 1 is not excluded.
HEDIS 2015