Stable data are data that remains the same or ‘stable’ over time e.g. birht data.
Since one of the main objectives of Healthdata is to reduce the registration effort, we want to avoid that this stable data has to be entered manually over and over again.

Stable data can be reused in 4 ways:

• At first data collection via HD4DP
• After 1st data collection period via HD4DP
• Across registers
• By recoding registers

At first data collection via HD4DP v1

• Only for registers that used eHealth coded NISS before healthdata (BCFR, BNMDR, IQED, IQECAD) 
• For these registers, a recoding needs to be done by eHealth: from the ‘old’ project-specific key to the healthdata key
• Once this is done, a subset of relevant historical data is uploaded to HD4DP

• In HD4DP v1, when creating a new registration with a NISS present in the historical data, the stable data is automatically enriched

After 1st data collection period via HD4DP

There are 2 options:

Enrichment on NISS

• When creating a new registration for a patient that was already registered in a previous data collection period, the stable data for this patient will be automatically fetched and used to prefill the new registration
• To check which fields are marked as ‘stable’, see www.healthdata.be/dcd 

Csv download & upload

• Some registers (BCFR, BNMDR) prefer to create registrations in bulk with stable data
• Stable data from previous data collection period can be exported cf. article "CSV download and upload for stable data"

Across registers

• Currently only possible via manual csv download and upload  cf. article "CSV download and upload for stable data"
• Will become automatic in Q2 or Q3 release.

Recode registers

• For registers that did not use eHealth coded NISS as patient identifiers, but that wish to link the data collected without healthdata with the data collected with healthdata (longitudinal analysis)
• A subset of relevant historical data is sent to HD4DP
• Centres are asked to complete the registration with the NISS
• Examples: BCFRecode, IQECAD_Recode, IQED_Recode
• Researchers can not validate these data in the ‘standard’ way. This has to a manual job/interaction between DWH team and researcher
• For clarifications to be done for IQED_Recode contact the support team support.healthdata@sciensano.be