There was a time when I admired the adoption of CDA in the U.S. as a part of their impressive "Meaningful Use" initiative. I have worked first hand with CDA documents from various EMR systems in the U.S. and have seen many successful Health Information Exchanges launch in the U.S. based on CCDA XDS repositories.
Despite the flurry of CDA activity south of the border, I see serious obstacles to adoption of CDA here in Ontario:
- The strongest case for CDA in Ontario is the abundance of CDA support and tooling in the U.S. What's important to recognize, however, is that CDA encodes country-specific data types like postal codes and units of measure that are different between the U.S. and Canada. So even if we wanted to take advantage of American CDA tools here in Canada, we would first need to modify those tools to use Canadian data types before we could use them up here. The cost of this will in many cases be prohibitive.
- The next case for CDA in Ontario is how naturally it would support continuity of care scenarios like eReferral, eConsult, hospital discharge, admission, etc. The problem with this is that Ontario EMR vendors have already achieved OntarioMD 4.1 certification that requires supporting the import and export of patient data in the OntarioMD "Core Data Set" data format. In hindsight, it's clear that Ontario should never have invented its own proprietary EMR data exchange format. But now that we have it, the EMR vendors are going to prefer that we build on that capability rather than trying to add support for a completely new CDA format.
- Lastly, many people I speak with about CDA are quick to point out that despite all the HIEs and EMR support developed in the U.S., it has not even come close to living up to its promise there. In fact, the EMR backlash against CDA has prompted the formation of an industry association called the CommonWell Health Aliance that is promoting FHIR as the way forward for health data interoperability. Every technical person I've spoken with who's seen both the CDA and FHIR specs has emphatically preferred FHIR. Support for FHIR is snowballing everywhere.
So it now feels like we're in an awkward in-between time for EMR interoperability in Ontario. Support for CDA is waning, but the FHIR spec is still only half-baked. It will be years before the FHIR is released as a normative standard.
I will be watching how EMR interoperability unfolds south of the border with interest. Momentum will either end up falling with CDA or FHIR, and it will be in Ontario's long-term best interest to follow whichever interoperability standard wins in the gigantic market to our south.