Samson, Vipul, All
I saw this by accident and have not been involved in the main
discussion - so excuse the intron. However, the issue of the relation
between ontologies and health records is close to my heart. There are
papers about it at both KR-MED 2006 and Medinfo 2007, the KRMed paper
due to appear in Applied Ontologies RSN.Both papers are available from
my web site http://www.cs.man.ac.uk/~rector. An expanded and clearer
version of the KR-MED paper will be available as soon as the mills of
the gods grind at AO
Fundamentally, the only interpretation that works is to regard codes
as being "meta" to the ontology. I.e. the individuals in the ontology
are things in the conceptualisation of the world - cases of diabetes,
people, livers, etc. - individual codes represent classes in the
ontology. The entire information structure - HL7 or Archetypes - in
fact, is at a meta-level. It makes sense to talk about a form on a
patient on which the code or value for body-temperature is missing; it
does not make sense to talk about a patient without a body
temperature, even if it is ambient. It makes no sense to talk about
the class of hypertensive patients except those that fall into some
subclass of hypertension, but it makes perfectly good sense to talk
about the code for hypertension but not its subcodes as being a valid
filler for, say, a heading.
We are again in the process of doing such representations for both
OCRe and two commercial collaborations. One thing I feel confident
about from this work is that a single level representation of the
ontology of disorders of patients and the information structures about
them, including codes, does not work. We can often get away with
approximations which ignore the difference for specific applications.
Because our tools for handling multi-layer representations are poor,
we sometimes have to, but the problem is fundamental.
it isn't even a question of what formalism one uses. Medicine involves
* Pathophysiology - what we know about the patient
* Clinical care - what we do to the patient based on our assessments
of the pathophysology of the patient
* The record of that care and those assessments
Decisions often involve all three levels. Our actions may be based on
whether or not a particular piece of information is present in teh
record , our uncertainty about its value , or is value.
As far as SNOMED-CT goes, to a first approximation, the distributed
form can be viewed as being "codes" in this sense and should not be
taken as an "ontology" the codes are individuals representing classes
of patients. The "Ontology" is the underlying "stated form" which we
rarely see. Unfortunately, some of the things people try to do with
SNOMED ignore this point, and the documentation on the issue is
confusing at best.
Regards
Alan
On 7 Apr 2008, at 21:45, Samson Tu wrote:
On Apr 3, 2008, at 7:56 PM, Kashyap, Vipul wrote:
OK, we disagree on this point. I'd just point out that, if you are
interested in working with HL7 RIM or BRIDG, you have a conceptual
mismatch with them.
[VK] I do not view it as a conceptual mismatch as I can get Snomed-
CT the terminology by specifying a transformation on Snomed-CT the
information model.
Perhaps you can elaborate on your idea of SNOMEDCT the information
and what kind of transformations are involved to get SNOMEDCT the
terminology.
If your Acute MI is a subclass of Observation/Problem, then
instances of "Acute MI" class are observations of Acute MI, not
instances of the disease MI. An "observation" does not have
severity, location, and so on. You lose the ability to talk about
properties of the things in the world. An information model refers
to codes not because of implementation concern, but because
component parts of informational entity are also informational
entities, IMHO.
[VK] Would like to separate the issue of incorrect modeling from
the issue of including class analogs of terminological codes into
an information model in general.
As far as severity, location, etc are concerned, these could be
implemented as qualifiers to the observations as proposed in the
Clinical Element Model approach by Stan Huff et. al.
That said, the issue is not that of accuracy in modeling as I used
Acute MI as an example. was proposing an information architecture
where we create a common framework to model and perform inference
on information models and terminologies.
Several years ago, I tried to formulate the Clinical Element Model
as an ontology without any success. I came to see it as a very
flexible data structure for encoding information. If you have better
luck formulating it as an ontology, I'd like to know about it.
Thank you.
Samson
-----------------------
Alan Rector
Professor of Medical Informatics
School of Computer Science
University of Manchester
Manchester M13 9PL, UK
TEL +44 (0) 161 275 6149/6188
FAX +44 (0) 161 275 6204
www.cs.man.ac.uk/mig
www.clinical-esciences.org
www.co-ode.org
