Interoperability

Interoperability of healthcare information

Interoperability in healthcare needs to be both effective and sustainable, and two current trends are key enablers for achieving this goal. The first is the ongoing evolution towards maturity of XML-based interoperability standards. The second is growing recognition that standards need to be not only available and adoptable, but also harmonized across all the major standards providers. This is especially true in a sector such as healthcare that combines inherently complex information with an increasingly international market for information systems suppliers.

Standards maturity

Healthcare as a sector was quicker than most to see the necessity of sharing information, and the benefits of open standards for connecting different information systems. Research-based standards for terminology and clinical datasets have developed alongside messaging standards such as HL7v2 and v3.

Being early in the field is a good thing in one way; however, there are also drawbacks. Like other early developers of XML-based standards for complex interactions, HL7v3 messaging in XML had to solve the whole problem of system-to-system interaction within the OSI “level seven” (hence the name HL7 — Health Level Seven). As a result, HL7v3 messaging as it is today provides healthcare-specific solutions to problems that by now are well supported by generic standards (such as Web Services). This increases the difficulty for newcomers, since even without all its provision for message transport etc, HL7v3 is inevitably — just from the sheer complexity of health-related information — a complex set of standards.

HL7 has looked both inward to tried-and-trusted concepts, and outward to new technology developments, in finding ways forward that transcend this problem.

Traditional concept: the clinical note or letter

The first of these innovations is the HL7 Clinical Document Architecture (CDA). This goes back to the roots of XML as a format for shared documents that need to pass between different systems; and also to long-established practice in healthcare, where documents such as clinical notes, referral letters etc have proved their usefulness over many years.

CDA documents all have the same structure: a header containing administrative information such as the identity of the patient and the healthcare practitioner(s) involved; narrative text that conveys the clinical content to a human reader; and data entries that back up the narrative with an appropriate level of clinical coding. The resulting documents are readable for a human healthcare practitioner on any system that can render the very straightforward CDA narrative text. They can also contain clinical coding to support more advanced functionality such as decision support. There is an introduction to CDA with references for further reading on the HL7 UK website, www.hl7.org.uk

New technology: Service Oriented Architecture (SOA)

SOA quickly became part of the IT mainstream because of the benefits it offers for enterprise-wide integration of information and business processes. For HL7 the emergence of SOA was a major challenge. Some felt it was irrelevant, some saw it as a threat to a valuable body of work… however, there were also some that saw it as a challenge to be met with energy and dedication, an opportunity to bring HL7v3 to a new level of maturity and capability.

From its beginnings as an informal interest group, the Healthcare Services Specification Project (HSSP) has grown into a very active and fruitful joint venture between HL7 and the Object Management Group (OMG) Healthcare Domain Task Force (HDTF). You can find further information about HSSP, including its first clutch of formally published standards, at http://hssp.wikispaces.com

Convergence and future-proofing

These developments have encouraged HL7 to move away from a messaging-only world view into a more sustainable vision. At the HL7 annual plenary meeting in September this year, an apparently minor technical decision was made that is in fact a major step forward towards long-term sustainability of HL7 standards.

In future, HL7v3 healthcare-specific message payloads, including CDA documents, will be fully and cleanly separated from the HL7-specific messaging infrastructure.

This is not only essential for bringing HL7v3 information payloads into SOA-style enterprise integration, but also prepares the way for HL7v3 clinical information payloads to move freely and safely across many different system architectures and platforms, present and future.

Harmonization

Issues of sustainability and future-proofing also lie behind the second major trend, towards harmonization and collaboration between the major players in healthcare interoperability standards. The overall enterprise of standards development for healthcare interoperability is too big and difficult, and the market for information systems too international, to sustain competing standards frameworks.

After lots of hard work behind the scenes on all sides, there is now a formal agreement in place between ISO, CEN and HL7 to collaborate rather than compete in future standards development. All concerned are now beginning to work through the practical consequences in terms of workload and process as draft standards begin to flow in both directions for mutual review.

All this will take a little while to work through into published standards, and longer to work through into adoption by national programmes and other influential projects. Nevertheless this apparently distant process has real potential to make information systems much easier to procure and deploy — and after all, that is one of the very few good reasons to spend time and effort developing and implementing interoperability standards.