From the NHS Information Centre in regard to Hospital Episode Statistics Inpatient datasets - received within the last week:
"It has recently come to our attention that the method of linkage used between inpatient episodes and critical care periods from the critical care minimum data set may have caused some confusion as we did not fully explain how these records were linked.
This email is to inform you of the data structure that exists within your current extract and of changes we intend to make to future extracts you may order.
Currently we are using a one-to-many link which means that in cases where there is more than one critical care period for a given episode we repeat the episode data in the table so that each critical care period has its own episode. In 2009/10 there are around 18,000 episodes with multiple critical care periods that will be repeated in this way, across the whole HES dataset.
HES episode Critical care period
A (Repeated) A2
A (Repeated) A3
C (Repeated) C2
D (Repeated) D2
In future we will provide critical care data as a separate table to avoid repetition of episode data. If you require your data to only contain each episode once you will need to remove the repeated episode data using EPIKEY to indicate repeated data.
If you have any questions or queries on this matter, please contact us at AHES@ic.nhs.uk"