Engagement on the move from HL7v3 CDA to CDA using HL7 FHIR

Posted by Policyhubadmin on 21 October 2016
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Code4Health Interoperability Community Board are seeking views from the BCS membership community on the following interoperability topic


  •  Engagement on the move from HL7v3 CDA to CDA using HL7 FHIR




In line with recent developments both nationally and internationally, the FHIR methodology is being progressed both in the vendor market and also by localities and geographies.
This approach is also being supported through the collaboration between CCIOs, CIOs, national organisations and industry (InterOpen and TechUK) through the Interoperability Community. 
Consequently, there is a need for us to collectively be clear on our strategic approach and avoid unnecessary burden on localities by implementing multiple approaches for nationally published specifications.
A FHIR-based CDA model can be used to convey documents using the same core structures as those used in the record API retrieval. This will allow the same structure for the metadata, text and structured entries to be used across all future developments, so providing a single format to be implemented against by all suppliers. 
This means that, for example, the definition of a medication will be the same whether it is extracted as part of a record in an API or whether it is used to share information as part of a document for transfer of care.
NHS Digital, has published a number of specifications for document types to support initiatives such as Transfers of Care and Crisis Care planning as well as the existing 111 specifications.  These specifications detail the use of the Clinical Document Architecture (CDA) as implemented in HL7 v3. 
At the same time, a number of developments in the interoperability area have been focussed on the use of FHIR as an alternative to HL7 v3.  The GP Connect programme has begun specifying interfaces which use FHIR to convey record content as both text and structured data.  This construct is analogous to CDA. Health and Social Care Integration specifications have also been published using FHIR.
Feedback has been received from a number of localities and suppliers that these are competing technologies and there are currently requirements to implement a CDA approach (i.e. text and structured documents) both with HL7v3 and FHIR as a sender and also as a receiver.  This leads to an increased burden on both localities and the supplier community.
There are major initiatives are around eDischarge for transfers of care and access to the GP record and also 111.  This will soon expand with the addition of new transfers of care and definition of additional record structure such as community data.  The table below shows the current sender and receiver requirements.
Organisation Type Mode Message Format
GP Sender Record FHIR
GP Sender Document CDA
GP Receiver Record FHIR
GP Receiver Document CDA
Hospital Sender Document CDA
Hospital* Sender Record FHIR
Hospital* Receiver Document CDA
Hospital Receiver Record FHIR

*future requirement
As can be seen from the above, currently both GPs and hospitals must create content in both formats.  In many cases this content will be the same content or the document will be a subset of the information contained in the record.
Current Status
Some implementations of the existing specification for eDischarge in CDA have gone live or are in development by suppliers.  These specifications are based on hospitals sending content to GP practices. 
There are a small number of FHIR implementations worldwide and some in the UK itself however this technology is only just coming to the implementation stage having gained pace quickly.
In addition to the GP Connect work which has already been mentioned, a number of other specifications based in FHIR have been created or are in the process of being created.  The FGM project has created its specification using FHIR, the Social Care Integration programme have recently made the decision to migrate from their HL7 v3 and CDA to a FHIR based solution, the Ambulance to hospital data flow is proposing the use of FHIR as well as the electronic referral service and the digital diagnostic service.
Consequently, now is the time to be clear on the strategic approach going forward and the use of FHIR so that there is consistency and coherence in national specifications published going forwards.
The rationale for this change is to:
1) Update the modelling methodology to the latest representation facilitating wide community participation
2) Begin the process of bringing together differing representations of the same data
3) Reduce the burden of development for both sending and receiving systems in the service
4) Reduce the burden on NHS Digital maintaining multiple formats
However, in defining the strategic approach and move to FHIR, this stakeholder engagement is seeking views on how this move should be managed to continue to support existing programmes of work and local implementations but to enable the work to move forward at pace.
We recognise that localities may have their own bespoke implementations but what we are looking to consult upon is the consistency in approach of nationally published specifications.
1. Do you think that all future national specifications should be published using only the FHIR methodology?
2. For existing nationally published specifications, what do you think the timescales should be to support these in terms of:
a. Updates to the content of specifications (recognising that updates to the specifications will mean suppliers have to invest in continued development of these as oppose to transitioning to the FHIR-based approach).
b. Continued support from system suppliers of existing nationally published specifications?
The responses to these questions will influence the approach taken at a national level.



Consultation closed
Closed on: 
Tuesday, 1 November 2016