Primary care represents a complex clinical activity which does
not presently have a commonly accepted clinical vocabulary and
classification scheme. In order to adequately support the
multiple dimensions of primary care (including patient care
support, relevant research, and teaching activities), we endorse
the concept, development, and evaluation of a standardized
nomenclature or vocabulary for primary care.
A serious problem exists with the capture of structured
information in primary care for optimal health care delivery
(primarily for patient care and secondarily for epidemiologic and
research purposes). There is a need to develop consensus
international standards for clinical vocabulary and
classification in primary care.
Our vision is for primary health care providers to record data
about patients easily and accurately at the point of care, in
such a manner that clinically relevant information is available
for the primary purpose of supporting the care of individual
patients. Additionally, this information should be comparable
with information collected elsewhere in the world.
Standards Statements and Critical
The following characteristics are viewed as essential for a
primary care clinical vocabulary. (No rank order is implied.)
Must support and enhance the best patient-centered care.
- Is clinically relevant to primary care (and primary
- Supports the uncertainty inherent in primary care.
- Deals with the temporal evolution of clinical problems.
- Is able to deal with clinically relevant nuances.
- Is able to deal with pertinent negative terms.
- Must have a rich vocabulary.
- Is unambiguous, nonredundant, and appropriate.
- Supports synonyms and homonyms.
- Supports qualifiers and modifiers of clinical terms.
- Supports mapping to other code sets to facilitate all aspects of clinical practice and administration.
- Supports the documentation needed for education and training.
- Must allow easy data collection.
- Permits seamless and effortless data collection.
- Permits reliable and valid data input and output.
- Must have a sound architectural infrastructure.
- Is broadly available.
- Is sufficiently flexible to deal with multiple levels of granularity (detail).
- Can deal with hierarchical and multiaxial structures.
- Can be used internationally.
- Has adequate structure for maintenance and updates, including version control.
- Can be extended in a disciplined way.
- Is multilingual.
- Is multicultural.
- Must allow consistent use in all possible primary care
- Can be used in all primary health care delivery settings.
- Supports work flow in primary care settings.
- Must support aggregation and analysis of data.
- Supports clinical protocol and guideline implementation.
- Is suitable for research.
- Is suitable for decision support.
- Supports patient-focused outcome measures, including functional status and quality.
Strengths and Weaknesses of Examined
The overwhelming consensus of conference participants was that
the development of clinical vocabularies is a process in
progress. At this time, it would be premature, misleading, and
destructive to recommend any one vocabulary over another. In
time, the best qualities of each system may merge to form one
system that best meets the needs of primary care. The eventual
standard will be either a suite of vocabularies or a blending of
the uniquenesses and strengths of existing vocabularies into a
The participants recommended that primary care practitioners map
and aggressively use all of the examined vocabularies at the
point of service, while researchers use standardized methods to
examine and evaluate the vocabularies. Such studies could
identify gaps and strengths, which could be communicated among
those developing vocabularies. The outcome of such efforts could
be a cooperative development, using the strengths of all existing
systems. It is in this spirit that the following identified
strengths and weaknesses are listed.
ICPC (International Classification of
- Widely available.
- Reasonably good for epidemiologic research.
- Developed specifically for primary care.
- Has been used for "on the fly" coding.
- Supports concepts of comorbidity well.
- Supports concept of episode of care.
- Does not deal well with evolution of disease or disease
- Moderate synonym list; limits level of granularity.
- Does not map broadly to other codes.
- Does not fully support the coding necessary for clinical
patient care or administrative needs.
- Initially written by a general practitioner for general
- Used extensively in practice within the United Kingdom.
- Endorsed by U.K. Clinical Professions in 1994.
- Broad clinical coverage across disciplines.
- Mapping and tool facilities available.
- Implemented by multiple vendors.
- Uncertainty about version 3.1 integrity and version
- Evaluation not complete.
- Available only in English.
SNOMED (Systematized Nomenclature of Human and Veterinary
- Multiaxial and hierarchical.
- Has both breadth and depth.
- Underlying knowledge representation.
- Significant momentum in the United States.
- Too broad.
- Too granular for routine primary care.
- No syntax for combining terms.
- Efficient use in primary care setting not yet demonstrated on
a large scale.
- Not originally developed with primary care in
UMLS (Unified Medical Language System)
UMLS is not a coding system. It is too large and complex for
direct use for primary care coding. It does, however, allow
health professionals and researchers to integrate data from
different sources. The question is: Can UMLS be used as the link
to connect the coding systems proposed for primary care?
- Huge resources behind development of the system.
- Metathesaurus with substantial breadth and potential to
represent the broad range of concepts in primary care.
- Nonmedical words in the specialist lexicon that may be useful
in primary care.
- Includes substantial portions of SNOMED.
- Not specific to primary care.
- No specific primary care sources in current vocabularies,
although this is to be remedied.
- Not truly international at present.
- Many exceptions identified in current version.
Early in the deliberations, it became evident that participants
varied in their understanding and use of terms such as
nomenclature, vocabulary, classification, and coding. A glossary
of terms is necessary.
Primary Care Focus
We agreed that the main purpose of a clinical vocabulary for
primary care is to support patient care at the point of service.
Everything else—administration, epidemiology, and
data—while essential, remains secondary.
To facilitate the development of vocabularies, an overall process
should be designed and implemented. It should include but not be
- Clearly defining goals.
- Developing and adopting a standardized evaluation
- Studies of vocabularies already in use in primary
Recommendations for Future Actions and
The following recommendations for action and direction are far
from complete. However, carrying them out would result in a good
beginning in moving toward international standards in primary
- Link the three coding systems discussed (ICPC, Read,
and SNOMED) in the National Library of Medicine's UMLS.
- Encourage and help developers and users of the four schemes
work with each other toward strategies that focus on cooperative
development of coding and classification systems.
- An adequate infrastructure for primary care informatics,
including centers for primary care coding, should be established
and funded in each country.
- Develop and adopt a glossary of primary care informatics,
including a definition and scope of use of the term "clinical
- Organize and conduct a followup conference to continue the
begun at this conference. Request further funding to support a
future and expanded conference from all sources, especially the
Agency for Health Care Policy Research (AHCPR).
- Identify or develop and adopt standard processes and
methodologies to evaluate clinical vocabularies.
- Develop a problem list for each vocabulary that can be used
working toward an international standard.
- Explore the concept and development of a minimum data set for
ambulatory primary care.
- Investigate methods and processes for developing the new
to be added to a vocabulary for primary care.
- Establish a process to update current vocabularies and
- Seek national and international support.
- Develop a list of strategic national and international organizations to educate about the need for standards for clinical vocabulary in primary care informatics.
- Request review and endorsement of the conference proceedings by these key organizations.
- Seek endorsement and agreement from key organizations and agencies.
- Request funding from key organizations for centers for primary care informatics, with special emphasis on developing clinical vocabularies.
- Share conference outcomes.
- Publish and disseminate the conference proceedings as soon as possible.
- Submit proceedings to the AMIA Board of Directors for information, approval, and endorsement.
- Make presentations and publish articles about the process and content of the conference. Specifically, make presentations at upcoming AMIA conferences.
- Identify other interested agencies and organizations for possible distribution and/or inclusion in existing databases.
- Build support, linkages, and liaison with other groups.
- Work with the American Academy of Family Physicians (AAFP) technical panel for endorsement and action.
- Propose, develop, and/or conduct coding seminars or courses for AAFP, the Society of Teachers of Family Medicine (STFM), private practitioners, and other primary care groups to increase their interest in or knowledge of coding.
- Develop a strategy for liaison with private practitioners and user groups for recommendations that would match their needs and systems.
- Continue support for the participants and conference process.
- Continue to frame the issue of moving closer to international standards by continuously clarifying the purpose statement, goal definition, etc.
- Explore multidisciplinary involvement and consensus, especially an effort to include the entire scope of primary care.
- Continue regular communication among conference participants so members can keep working as a group, thus having greater influence with established organizations.
- Share the conference process methodology and encourage use of the process to gain consensus at the local, regional, and national levels.
- Develop and/or define a research and education agenda in primary care informatics.
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