PITAC Draft Recommendation on ICD-10/SNOMED (4/13/04)(1) “A specific study should reassess the cost-benefit of the planned conversion of diagnosis andprocedure coding requirements for Federal programs from the International Classification ofDiseases, Ninth Revision, Clinical Modification (ICD-9-CM) to ICD-10-CM, compared to thepotential alternative of moving directly to reporting diagnoses and procedures coded for clinicalpurposes in the Systematized Nomenclature of Medicine, Clinical Terms (SNOMED CT). Thismight provide incentives for standardized EHR implementations.”

Response to the Draft Recommendation:
The recommendation above refers to the use of SNOMED CT as an “alternative” to ICD-9-CM
or ICD-10-CM.1 This has generated much concern, particularly among those who create and use
the ICD classification system. As representatives from AHIMA and other organizations havecorrectly stated, there will always be a need for classification systems, and ICD has to its credit
world wide acceptance and use. The US will continue to be required to submit cause of death
information to the WHO based on the base ICD-10 codes. Beyond that, however, the various
national clinical modifications are not directly comparable.
SNOMED CT on the other hand consists, at its most basic level, of formal definitions linked bydescription logic into relationships. It is not primarily a classification of diseases or procedures,
although it can be used to be used to map to other classifications and potentially to generate its
own aggregations.2 In addition, the diagnostic content coverage of SNOMED CT significantly
exceeds that of ICD-9-CM3 and, it appears, ICD-10.
There is a long history of discussion regarding the vision of an interconnected group of nonoverlapping classification systems, resting on top of a single, ontologically sound, detailedreference terminology. This paradigm was perhaps most clearly described by the three
Terminology Summit conferences in the early 1990s. It is in just the last two years, however,that there has been a significant quickening of steps in this direction, including:•••1

the designation of the NLM as the lead government agency in creating mappings of theICDs to the UMLS (previously this lead role belonged to NCHS)
the purchase by the United States of a national site license to SNOMED CT, making it
available for widespread use, andthe specification of SNOMED CT as the preferred terminology for a majority of the CHI
domains, including the standard for clinical diagnoses and problem lists4

We assume it is implicit in the PITAC proposal that SNOMED CT is also being proposed as an alternative to ICD10-PCS for procedures codes for inpatients.
2
The intermediate “hierarchy” content implicitly aggregates content below it, although no formal study has yet been
done to evaluate the appropriateness and consistency of such internal aggregations.
3
Chute et al. Content Coverage.
4Although these standards are being mandated only for use within the government, CHI standards are intended toinfluence standards adoption in the private sector as well. As most electronic record systems that have problems
lists now base them on the ICDs, the CHI recommendations appear to suggest continuation of the ICDs for financial•••the recent progress made by CAP on the explicit task of mapping SNOMED to the ICDs
the current initiative within HL7 to develop a standardized data structure for the use ofterminologies within electronic health records that is based upon a foundation allowing
for inter-terminology mappings
the inclusion among the technical requirements enumerated at the first NHII conference,
the requirement not only for standardized terminologies, but also for mappings between
them.

It may be that the time to pause and take a practical look at the “long term” vision is “now.”
There are two key questions.
The first key question is, can data collected in SNOMED CT terms, be automatically5 translated
into ICD-9-CM or ICD-10-CM? If so, is it as simple as “flipping a switch” to do this, or is it
more complicated: is specialized user interface software needed? Are there characteristics of theICDs (e.g. the fact they only roll up one way; the use of “excludes”, “includes,” “not elsewhereclassified”) that make this difficult, or indeed, impossible. It should be possible to come up withan explicit, technical, agreed-up answer to this question since it is a factual question and given
the current state of terminology science and the existence of expertise in the mechanics of how
these coding systems work. This would require the work of a group of experts versed in themechanics of the terminologies.
The second key question has to do with whether the ICDs are needed at all. This alternative
should not be discarded without consideration. A brief look at the evolution of the ICD clinicalmodifications themselves may be required. Though first introduced in 1972, a significant change
took place in 1983 when, with the introduction of DRGs, ICD-9-CM codes began to be used forreimbursement. This not only led to the proliferation of ICD-9-CM codes in financial andadministrative (and, indeed, clinical) systems, but also led to the subtle transformation of thecodes, through the on-going update process. The ICD-9-CM codes have evolved to reflect, inaddition to clinical description, reimbursement considerations. This has led to the perception
among some physicians that the coding system has not enough to do with clinical description andmuch to do with financial priorities. A question arises: if freed from the current widespreadrequirements for the ICDs for reimbursement, is it the ICDs per se that are required or would
another classification – perhaps a roll-up within SNOMED itself rather than into another coding
system, suffice?6 This seems closest to PITAC’s Draft Recommendation #1, as presently stated.
However, it appears that this could entail profound changes to the reimbursement system and is
intimately tied to question of the nation’s long-term approach to paying for health care for its
citizens
uses but encounrages the implementation of new SNOMED-based problem lists. This would be a duplicative(problem lists could no longer drive reimbursement), and likely, confusing.
5
Study of total effort should be considered. It may be that it is not possible for cross-correlation to take place withno human intervention whatsoever; but it may be that software to offer assistance in the process could be used toassist coders, billing professionals, as well as direct care providers with an overall savings of effort and whilebringing the capture of standardized information closer to the physician and patient.
6Indeed, in principle, it may be possible to use aggregation logics to derive DRGs directly from SNOMED codes.
Hopefully the additional granularity already in SNOMED would avoid the post facto hairsplitting of codes which
has made managing ICD-9 periodic updates so difficult.

The NCVHS report and the AHIMA and RAND studies on ICD-10 assumed the main option
under consideration was the proposed move from ICD-9-CM to ICD-10-CM/PCS. However, it
may no longer be appropriate to consider this as the only option. Indeed, if either of the above
approaches is deemed desirable and achievable, it becomes clear that implementing ICD-10CM/PCS in the traditional manner, while at the same time encouraging the adoption ofSNOMED-CT for clinical applications, could be, of the three, the most duplicative, expensive,and cumbersome of approaches. Indeed, it can be expected that stakeholders in all health caresectors would need to make such major investments in moving to ICD-10-CM/PCS thatsimultaneous adoption of SNOMED-CT may be seriously hindered, under-budgeted, perhaps
even derailed.
To not consider these two options (A and B below) at this time – this critical juncture – may be
to sell short the possibility of rapid progress toward higher quality, more clinically useful, andmore cost-effective healthcare for a generation of Americans.
Alternative Approaches:•••

Approach A (SNOMED Æ ICD): Appoint a “blue ribbon” panel of experts in themechanics of the ICD-10s and SNOMED to address the technical question of whether
ICD-10-CM/PCS codes can be generated automatically from SNOMED terms, which
could, if implemented, allow stakeholders to focus on implementing SNOMED while
retaining ICD-based functionality
Approach B (SNOMED ONLY): Consider whether the ICD line of classifications
should continue to be used for reimbursement (plus its myriad post hoc uses), or ifinstead it might be replaced by a simpler system of handling reimbursement (perhapsusing SNOMED structures to group cases), while the full SNOMED terminology
emerges as the principal foundation for clinical communication (the PITACrecommendation), orApproach C (SNOMED + ICD): Proceed with the current NCVHS proposal to replace
ICD-9-CM with ICD-10-CM/PCS, while simultaneously encouraging (e.g. bymechanisms like CHI) the adoption of SNOMED-CT for clinical uses (the default path).

If Approach C is pursued without consideration of Approaches A and/or B, some time will besaved in moving to ICD-10-CM/PCS. But forging ahead with so many unanswered – but
answerable – questions regarding the potential interoperability of ICD-10 and SNOMED risks
the potential waste of resources, diminished speed of adoption of SNOMED-CT, and continuingdebate. Perhaps we need to take some time out to look at the alternatives.