by R.G. Wilson, B.Sc., and I.N. Purves, MBBS, MRCGP
"Classification is a key to knowledge and an international
classification makes for comparability between items of new
knowledge arising out of work in new environments." Dr. M.K.
Rajakumar, President of WONCA (World Organization of National
Colleges, Academies and Academic Associations of General
Practitioners/Family Physicians) (1).
Coded nomenclatures enable clinicians to record medical records
in natural language. They are the route to added value from
computerized medical record systems in that they enable
computerized manipulation of data into clinical information.
They also unlock the power of classification in real time via
mappings. Dr. Ian Purves, Director of the Sowerby Unit for
Primary Care Informatics, University of Newcastle,
Newcastle-Upon-Tyne, United Kingdom.
This paper describes a preparatory phase of the American Medical
Informatics Association Family Practice Primary Care Working
Group's Standards in Primary Care Conference in New Orleans in
1995: an attempt to gather information using the Internet as the
primary research tool. The initial phase was carried out from
October to December 1995 and results continue to be gathered at
the Sowerby Unit Web site: http://www.schin.ncl.ac.uk
The survey findings demonstrate the diversity of coding and
nomenclature systems around the world and the variations within
those systems, especially the International Classification of
Primary Care (ICPC). This is partly a reflection of the marked
differences among countries in the provision of health care and
the resulting differences in information requirements. The
consequences for the comparability of statistics derived from
these coding systems are evident.
We employed a snowball sampling method using E-mail. We searched
the GP-UK, Family-L, and Fam-Med LISTSERV®; approximately 70
personal contacts; and the WWW for other possible respondents.
Additionally, all mailshots were prefaced with an introduction
and a request to forward the survey to relevant individuals. This
means we cannot be sure how many individuals eventually saw our
questionnaire, although we estimate that we reached over 2,000
people. The first mailshot was sent four times due to a bug in an
E-mail package, so some individuals received the survey as many
as 14 times. How this may have affected the response rate is not
clear. (However, no one could have claimed to have missed the
message.) A second message was sent as a reminder, along with a
list of the countries from which responses had already been
Overall 30 responses were received from 20 countries. Responses
were heaviest from countries with relatively well developed
primary care/family practice (PC/FP) systems with computers and
therefore more widespread Internet facilities. Countries with the
highest level of computerization in PC/FP, either by number
(United States) or percentage (Iceland), are the most likely to
be attempting to adopt a coherent national approach to
coding—for example, the National Health Service Centre for
Coding and Classification in the United Kingdom or the SNOMED
(Systematized Nomenclature of Human and Veterinary Medicine)
Secretariat in Canada.
The first set of surveys we received included the United States,
Canada, Australia, New Zealand, and the United Kingdom. Responses
from non-English-speakers were somewhat lower, partly because the
LISTSERV® are largely dominated by English-speakers. Other
supplementary explanations exist to explain nonresponse:
- Individuals felt unable to answer because the survey was
pitched at an inappropriate level.
- The information requested was not readily available. Figures
on the percentage of computers in general practice tend to be
based on respondents approximations rather than hard statistical
- The relevant individuals were not contacted by the E-mail
- The initial survey had a short time scale for
Coding and Nomenclature Systems
Figure 1 (9 KB) shows
the coding and nomenclature systems in use. Not
all respondents from the same country gave the same response,
which is evidence of the patchy nature of such information.
More than 90 percent of respondents stated that the 9th Revision
of the International Classification of Diseases (ICD-9) continued
to be used in their country in at least some areas of primary
care. As the coding system used most often, the ICD-9 currently
is the most common denominator and offers the best basis for
comparisons among countries. However, its limitations in terms of
PC/FP are well documented, and it was hoped that its successor,
ICD-10, would be more applicable to the needs of health care.
ICD-10 appears to be superseding ICD-9. Four of the countries
responding already use ICD-10, one uses it in combination with
ICPC, and South Africa and Iceland intend to implement it
The development of coding schemes seems to be centered on three
main systems: SNOMED (Canada), ICPC (The Netherlands), and the
Read Codes (United Kingdom). Each system has its adherents and
detractors, as well as strengths and weaknesses (described
elsewhere in this summary). All of these systems are
undergoing continuing development: The Dutch Thesaurus has been
added to ICPC in the Netherlands, the ICPC
is used in Australia, and SIN-FM is used in Canada. Read Version
3.1 is in the process of being finalized. The development of
coding systems reflects the dynamism of PC/FP in some countries.
Systems that received a mention in the "Other" category were
Veska (Switzerland), TNM (Austria), NANDA (Iceland), CMBS and ATC
(Australia), and PSK (Denmark).
ICPC was the second most popular coding system with survey
respondents, although it is sometimes used in combination or
competition with other systems or add-ons, such as the Dutch
Thesaurus. Read was mentioned only in terms of the United
Kingdom, Eire, and New Zealand, where it was more or less
exclusive. In Australia, 10 classification systems are currently
in use in a practitioner population that has only an estimated 5-
to 20-percent computer usage but hundreds of computer suppliers.
Official Coding Body
The majority of respondents testified that their country has some
form of centralized body for control over coding systems or that
there were moves afoot to set one up. In some cases, there was
confusion about who was to be in control. As one respondent put
it:"Coding is a political issue here and you may well find that
people in the public sector give different answers from those in
the private sector."
Another put it even more bluntly: "I've forwarded the survey to
Dr. X, but don't believe all that he says."
This is testimony to the ongoing controversy in this area.
However, there continues to be recognition that standards are
required. We hope that this conference will lead to an increased
mutual understanding and a healthier dialogue.
The situation in some areas was harmonized. In the Netherlands,
for instance, all clinicians used the ICPC in combination with
the Dutch Thesaurus. Coding is led by the Department of Health in
the United Kingdom, the Netherlands, and some other countries. In
Norway the National Insurance Administration has made use of ICPC
compulsory. As the respondent put it quite neatly: "No ICPC
diagnosis, no pay!"
Figure 2 (7 KB)
demonstrates the percentage of primary care doctors
in each country who use computer systems. When interpreting this
figure, it must be borne in mind that the majority of the
respondents were able only to guess at the level of computer
The most striking feature of the results was the variance
among countries. Generally, usage was either more than 70 percent
or less than 20 percent. The Icelandic respondent predicted that,
under the SAGA 96 initiative to fully computerize Icelandic
primary health care, 95 percent of clinicians would be
computerized by February 1996, and all would be using the same
computer system. The Icelandic respondent also reported: "We are
implementing a new classification tool, including browser, where
primary care providers can use ICPC as an index from subordinate
sets of concepts or terms. This will submit proposals for new
codes/concepts or terms. This will be an on-line feature.
Therefore, you can E-mail your proposal instantly."
A similar level of computerization has been attained in the
United Kingdom. The figure for computer usage in primary care
given by survey respondents ranged from 5 percent to 95 percent.
This range may reflect the problematic definition of
"computerization." As two respondents observed, having a computer
in the office is one thing, but if it is used only for
appointments and accounts—and not for recording clinical
data—the efforts of those working on coding and nomenclature
systems will have been largely in vain.
The level of variance in the number of computer system suppliers
was similarly marked, with Iceland having one and Australia
having hundreds. Again these figures are approximations on the
part of the respondents, but they indicate the different stages
in the computerization process that the different countries have
Although this is a very small-scale and skewed survey, both
survey results and indications from the literature suggest that
the countries from which responses were received tended to have
fairly centralized health care systems. This is not a situation
shared by all countries. Health care provision and the right to
direct its operation and allocate resources are not powers that
are relinquished easily. Health care represents a large part of
the autonomy of devolved regions or states, both financially
politically. This, we would argue, is the model for countries
that have an organic model of health care, have a relatively
unstructured pattern of access to care, or lack gatekeepers (2,3).
A good example of this is Germany, where local PC/FP clinicians
exist but are, to some extent, in competition with each other and
with providers that other countries would regard as secondary
care specialists. In contrast, the countries that are most
advanced in using some form of coding or nomenclature seem to fit
into a mechanistic model of health provision, which relies on the
PC/FP sector to filter those receiving care and refer them to
specialists when necessary. An example is the U.K. National
Health Service. Probably a mechanistic and centrally organized
model of health provision is more likely than the organic model
to lead to attempts to record and classify on a national level,
with resources allocated accordingly.
The survey shows the dearth of information about the state of
coding and nomenclature systems, computer usage, and number of
computer system suppliers in many countries. Also evident is the
diversity in coding and nomenclature systems as countries
modify systems to their own specific health care requirements.
If "comparability between items of new knowledge" is to be
achieved, then agreement is needed on some standards or, perhaps
more likely, standard methods of comparison.
- Lamberts H, Wood M, editors.
Classification of Primary Care. London: Oxford University Press;
- Fry J, Hoarder J. Primary care in an
London: Nuffield Provincial Hospitals Trust; 1994.
- Berma W, de Jong F, Mulder P, editors.
health care. Prepared for the WONCA (World Organization of
National Colleges, Academies and Academic Associations of General
Practitioners/Family Physicians) Congress. NIVEL & Royal
College of Dutch Practitioners; 1993.
Other Works of Interest
Bernstein RM, Hollingsworth GR, Viner G. Evaluation of
controlled medical terminologies for use in primary care
electronic records. Discussion paper prepared for the American
Medical Informatics Association Primary Care Working Group
Conference, 1995 Nov 1; New Orleans.
Board of Directors of the American Medical Informatics
Association. Standards for medical identifiers, codes, and
messages needed to create an efficient computer-stored medical
record. Journal of the American Medical Informatics
Association 1994 Jan/Feb;1(1):1-7.
Campbell K, Das AK, Musen MA. A logical foundation for
representation of clinical data. Journal of the American
Medical Informatics Association 1994;1:218-32.
Côté RA, Rothwell DJ. The Systemized Nomenclature of
Human and Veterinary Medicine: SNOMED International. Canadian
Medical Informatics 1994 Nov/Dec;1(4):47-53.
Lamberts H, Wood M, Hofmans-Okkes I, editors. The International
Classification of Primary Care in the European Community with a
multi-language layer. London: Oxford University Press; 1993.
O'Neil M, Payne C, Read J. Read Codes Version 3: A user led
terminology. Methods of Information in Medicine 1995;34:187-92.
Williams J. Do we need a classification for primary care?
Journal of Informatics in Primary Care 1996
Wood M, Lamberts H, Meijer JS, et al. The conversion between
ICPC and ICD-10: requirements for a family of classification
systems for the next decade. Methods of Information in
Internet Medical Terminology Resources:
GALEN (Generalised Architecture for Languages, Encyclopaedias
and Nomenclatures in Medicine):
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