Western Health Information Collaborative (WHIC)
Western Canada Chronic Disease
Management Infostructure Initiative
Phase 2: Data Standards and HL7 Messaging
CDM Data Standards – Appendix A Coding Systems
FINAL 06/29/2005 1:30 PM
Prepared by
Western Health Information Collaborative
June 29, 2005 - Version 7.1
Western Canada Chronic Disease Management Infostructure Initiative
Phase 2: Data Standards and HL7 Messaging
CDM Data Standards – Appendix A Coding Systems
Page i
TABLE OF CONTENTS
1. Introduction ............................................................................................................................... 1
2. Coding Systems......................................................................................................................... 3
2.1. Brief Description of the Coding Systems ........................................................................ 3
2.1.1. LOINC ............................................................................................................... 3
2.1.2. ICD-10-CA ......................................................................................................... 4
2.1.3. DSM-IV.............................................................................................................. 4
2.1.4. CCI
............................................................................................................... 4
2.1.5. ATC / DDD ........................................................................................................ 5
2.1.6. SNOMED CT ..................................................................................................... 5
2.2. Process for Selection of Coding Systems ........................................................................ 6
2.3. Specific CDM Coding Considerations and Explanations................................................ 7
2.3.1. LOINC Code Selection....................................................................................... 7
2.3.2. Specific Coding Systems .................................................................................... 7
2.3.3. “x LOINC” Codes .............................................................................................. 8
2.3.4. Type Code Sets and Value Code Sets ................................................................ 8
2.3.5. Object Identifiers (OIDs).................................................................................... 8
2.3.6. Symbols in Code Tables ..................................................................................... 9
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Phase 2: Data Standards and HL7 Messaging
CDM Data Standards – Appendix A Coding Systems
1.
Page 1
INTRODUCTION
The primary purpose of the Western Canada Chronic Disease Management (CDM)
Infostructure Initiative is to develop chronic disease management data standards and
information interchange messages, and to support the implementation of this
infostructure within the four participating western provinces (British Columbia, Alberta,
Saskatchewan, and Manitoba).
The CDM Data Standards have been prepared to describe in clinical terms the scope,
content and details of the CDM Data Standards developed for the Western Canada CDM
Infostructure Initiative. This document is intended primarily for a clinical / business
audience1. The CDM Data Standards have been organized as follows:
•
CDM Data Standards – Introduction
This document provides background information on the Western Canada CDM
Infostructure Initiative, provides an overview of the Phase 2 Data Standards and HL7
Messaging project, describes the Chronic Disease Model, and provides an overview
of the record and clinical data elements.
•
Appendix A – Coding Systems
Includes an overview of the coding systems considered for the CDM Data Standards,
describes the criteria and process for selection, and identifies special considerations and
explanations for the selected code systems.
•
Appendix B – Record Level Data
The record level data or structural data elements are generic data elements that are
‘fixed’ and are provided regardless of the type of chronic disease. This appendix
provides the data definition, and identifies the data type and valid values for each of
the data elements.
1
For more technical documentation on the CDM HL7 Message Specifications, please refer to the CDM
HL7 Message Specifications – Implementation Guide.
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CDM Data Standards – Appendix A Coding Systems
•
Page 2
Appendix C – Clinical Data
Clinical data elements are specific data elements that pertain to chronic diseases.
These data elements provide clinical information to assist clinicians in managing
individuals with chronic diseases. This appendix provides the data definition, and
identifies the data type (type code, type code value, type code name) and code table
for each of the data elements.
•
Appendix D – Detail Data
The detailed data attributes give additional specifics on the clinical data elements.
The attributes describe the characteristics or details to be captured on person history,
physical exams, lab tests, medications, procedures, etc. This appendix provides the
data definition, and identifies the data type and valid values for each of the data
elements.
•
Appendix E – Code Tables
This appendix provides the details for the defined code sets that will be used for the
CDM data elements (e.g. Code table name, source, codes, descriptions, print names,
etc.).
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Western Canada Chronic Disease Management Infostructure Initiative
Phase 2: Data Standards and HL7 Messaging
CDM Data Standards – Appendix A Coding Systems
2.
CODING SYSTEMS
Several coding systems were examined to determine their appropriateness for the CDM Data
Standards and subsequently the HL7 Message Specifications. This section provides an overview
of the coding systems, and describes the process and rationale used in their selection.
2.1. Brief Description of the Coding Systems
Six coding systems were identified, with five being selected for the project. These were:
•
LOINC (Logical Observation Identifiers, Names and Codes)
•
ICD-10-CA (International Classification of Diseases, Canadian)
•
DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition)
•
CCI (Canadian Classification of Interventions)
•
ATC / DDD (Anatomical Therapeutic Chemical Classification System with Defined
Daily Doses)
•
SNOMED CT (SNOMED Clinical Terms)
A brief description of each coding system follows.
2.1.1. LOINC2
The purpose of the LOINC database is to facilitate the exchange and pooling of results, such as
blood hemoglobin, serum potassium, or vital signs, for clinical care, outcomes management, and
research. Currently, most laboratories and other diagnostic services use HL7 to send their results
electronically from their reporting systems to their care systems. However, most laboratories and
other diagnostic care services identify tests in these messages by means of their internal and
idiosyncratic code values. Thus, the care system cannot fully "understand" and properly file the
results they receive unless they either adopt the producer's laboratory codes (which is impossible
if they receive results from multiple sources), or invest in the work to map each result producer's
code system to their internal code system. LOINC codes are universal identifiers for laboratory
and other clinical observations. Therefore, the adoption of LOINC codes facilitates correctly
identifying, reporting, exchanging and storing lab results and clinical observations.
2
http://www.regenstrief.org/loinc/. Accessed 18 May 2005
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CDM Data Standards – Appendix A Coding Systems
The laboratory portion of the LOINC database contains the usual categories of chemistry,
hematology, serology, microbiology (including parasitology and virology), and toxicology; as
well as categories for drugs and the cell counts reported on a complete blood count or a
cerebrospinal fluid cell count. Antibiotic susceptibilities are a separate category. The clinical
portion of the LOINC database includes entries for vital signs, hemodynamics, intake / output,
EKG, obstetric ultrasound, cardiac echo, urologic imaging, gastroendoscopic procedures,
pulmonary ventilator management, selected survey instruments, and other clinical observations.
2.1.2. ICD-10-CA3
The International Statistical Classification of Diseases and Related Health Problems, 10th
Revision (ICD-10) is an international standard for reporting clinical diagnoses developed by the
World Health Organization. ICD-10-CA is an enhanced version of ICD-10 developed by the
Canadian Institute for Health Information (CIHI) for morbidity classification in Canada.
ICD-10-CA classifies diseases, injuries and causes of death, as well as external causes of injury
and poisoning. The classification has 23 chapters with alpha-numeric categories and
subcategories. Unlike ICD-9, ICD-10-CA applies beyond acute hospital care. ICD-10-CA also
includes conditions and situations that are not diseases but represent risk factors to health, such
as occupational and environmental factors, lifestyle and psycho-social circumstances.
2.1.3. DSM-IV4
Psychiatric diagnoses are categorized by the Diagnostic and Statistical Manual of Mental
Disorders, Fourth Edition. This manual is published by the American Psychiatric Association
and covers all mental health disorders for both children and adults. It also lists known causes of
these disorders, statistics in terms of gender, age at onset, and prognosis as well as some research
concerning the optimal treatment approaches.
2.1.4. CCI5
The Canadian Classification of Health Interventions (CCI) is the new national standard for
classifying health care procedures. CCI is the companion classification system to ICD-10-CA.
CCI replaces the Canadian Classification of Diagnostic, Therapeutic and Surgical Procedures
3
http://secure.cihi.ca/cihiweb/dispPage.jsp?cw_page=codingclass_icd10_e. Accessed 17 May 2005.
4
http://allpsych.com/disorders/dsm.html. Accessed 08 June 2005.
5
http://secure.cihi.ca/cihiweb/dispPage.jsp?cw_page=codingclass_cci_e. Accessed 17 May 2005
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Western Canada Chronic Disease Management Infostructure Initiative
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CDM Data Standards – Appendix A Coding Systems
(CCP) and the intervention portion of ICD-9-CM in Canada. CCI classifies a broad range of
interventions, such as:
•
Therapeutic interventions including inpatient and day surgeries, surgical and nonsurgical;
•
Diagnostic interventions including diagnostic imaging, tests, measurements, biopsies and
explorations;
•
Cognitive, psychosocial and sensory therapeutic interventions;
•
Other health care interventions such as assistance with activities of daily living,
environmental assessments, and counseling; and
•
Therapeutic interventions strengthening the immune system.
CCI specifies more precisely than ever before what interventions and services health
professionals provide. It has been designed to be service provider and service-setting neutral and
can be used comprehensively throughout the health system.
2.1.5. ATC / DDD6
The ATC / DDD system classifies therapeutic drugs. The purpose of the ATC / DDD system is
to serve as a tool for drug utilization research in order to improve quality of drug use.
In the ATC classification system, the drugs are divided into different groups according to the
organ or system on which they act and their chemical, pharmacological and therapeutic
properties. Drugs are classified into five different levels. Drug consumption statistics
(international and other levels) can be presented for each of these five levels.
2.1.6. SNOMED CT7
SNOMED Clinical Terms (SNOMED CT) is a dynamic, scientifically validated clinical health
care terminology and infrastructure that makes health care knowledge more usable and
accessible. The SNOMED CT Core terminology provides a common language that enables a
consistent way of capturing, sharing and aggregating health data across specialties and sites of
care. Among the applications for SNOMED CT are electronic medical records, ICU monitoring,
clinical decision support, medical research studies, clinical trials, computerized physician order
entry, disease surveillance, image indexing and consumer health information services.
6
7
http://www.who.int/classifications/atcddd/en/. Accessed 17 May 2005
http://www.snomed.org/snomedct/. Accessed 17 May 2005
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The SNOMED CT Core terminology contains over 364,400 health care concepts with unique
meanings and formal logic-based definitions organized into hierarchies. As of January 2005, the
fully populated table with unique descriptions for each concept contains more than 984,000
descriptions. Approximately 1.45 million semantic relationships exist to enable reliability and
consistency of data retrieval.
2.2. Process for Selection of Coding Systems
The CDM Project Team reviewed the applicable coding systems and considered several criteria
in selecting the systems most appropriate for the CDM data standards and HL7 message
specifications. The selection criteria included:
1. Canadian health system context: appropriateness of the coding system for use in the
Canadian health care system, with a specific focus on chronic disease management
(CDM).
2. Availability of coding system: availability and use of the coding system in the
Canadian health care system, with a specific focus on chronic disease management.
3. Affordability: costs to obtain licenses for the coding system with an emphasis on
minimizing the costs to CDM providers in the health care system.
4. Ease of implementation: relatively easy to implement the coding system within the
CDM project timelines.
5. Fit with HL7 model: alignment of the coding system with the HL7 model developed
for CDM.
6. Appropriate granularity: the level of detail available in the coding system and its
appropriateness in meeting the CDM data requirements.
7. Comprehensiveness: the completeness of the coding system in capturing the CDM
data requirements.
Using the above criteria, the following table shows the CDM data grouping, the HL7 data
groupings, the selected coding system and the key criteria for the coding system selection.
In general the criteria were met by all the pertinent coding systems with the exception of
SNOMED CT. The major concerns identified with SNOMED CT were the cost of licenses and
the current lack of implementations within Canada. The CDM project is aware that SNOMED is
currently under review by Canada Health Infoway (CHI) and is seriously being considered as its’
coding standard. If / when SNOMED becomes officially endorsed by Infoway, the CDM data
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Western Canada Chronic Disease Management Infostructure Initiative
Phase 2: Data Standards and HL7 Messaging
CDM Data Standards – Appendix A Coding Systems
standards may need to be revised to allow for the adoption of SNOMED as an additional code
set.
CDM Data Groupings
Person Demographics
Alert Indicators
Characteristics Relevant to the
Condition
Co-morbidities / Complications
HL7 Data Groupings
•
•
•
Record Level Data
Exam / Observations
Exam / Observations
Coding System
•
•
•
•
•
Other Medical Problems
ICD-10-CA
LOINC
All
All
•
ICD-10-CA
DSM-IV
LOINC
All
All
All
•
LOINC
All
•
•
CCI
LOINC
All
All
•
ATC / DDD
All
•
LOINC
All
•
•
•
Markers of Disease Progression
•
•
Interventions - Procedures
•
Interventions - Medications
•
Screening for Further
Complications
2.3.
Lab Results / Plans / Goals
Diagnostic Images
Procedure
Medications and
Immunizations
•
Lab Results / Plans / Goals
•
Exam / Observations
HL7
LOINC
LOINC
Supporting
Criteria
All
All
All
Specific CDM Coding Considerations and Explanations
2.3.1. LOINC Code Selection
The Regenstrief Institute provides a Windows-based mapping utility called the Regenstrief
LOINC Mapping Assistant (RELMA®) to facilitate searches through the LOINC database and to
assist in mapping local LOINC codes. For this project, clinical terminology identified by the
stakeholders, was mapped to the most appropriate LOINC code using specific key words and
RELMA. A common problem with LOINC codes is that two distinct codes may apply to very
similar concepts, especially for clinical observations. In these situations, the “best matched”
LOINC code has been selected and alternate LOINC codes documented where deemed
appropriate.
2.3.2. Specific Coding Systems
While specific coding systems are being used for the CDM data standards and HL7 message
specifications, it is not necessary for the source system to use these coding systems in their
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applications. For example, ICD-10-CA is used in the CDM data and HL7 message specifications.
However, a jurisdiction is not required to use ICD-10-CA in its application and could use ICD-9
CM to store data, and translate to ICD-10-CA codes when exchanging information with other
applications via the HL7 message specifications.
2.3.3. “x LOINC” Codes
For some CDM data elements, specific LOINC codes do not exist. In these cases the CDM
project team developed “x LOINC” codes which will be submitted as proposed codes to the
Regenstrief Institute, the organization responsible for maintaining the LOINC database and the
supporting documentation.
2.3.4. Type Code Sets and Value Code Sets
Two types of code sets are used. To classify a specific type of data element, LOINC codes are
used as they are universal identifiers for laboratory and other clinical observations. As well
LOINC codes directly relate to terminology used in HL7 data models. HL7 groups data as
observations, examinations, diagnoses, results, referrals and imaging. In the CDM Infostructure
Initiative the HL7 data groupings are shown on the data element spreadsheet as part of the row
headings; e.g., Exam / Observations. To classify a specific data element within a type of data, a
further classification using a value code is given. For example, LOINC has a type code for
diagnosis—primary. All primary diagnoses are coded using this type code. However, to give
information on the specific kind of diagnosis requires another classification system. In the
Western Canada CDM Infostructure Initiative, the classification system used for diagnosis is
either ICD-10-CA or in the case of psychiatric diagnoses, DSM-IV.
2.3.5. Object Identifiers (OIDs)
OIDs refer to an ISO Standard for uniquely qualifying all identifiers globally. In HL7 v3, all
identifiers are defined by the II (Instance Identifier) datatype. This includes all identifiers for
each CDM data element such as lab result identifiers, care plan identifiers, prescriptions
identifiers, dispense record identifiers, etc. These identifiers use a combination of a mandatory
OID root with an optional alpha-numeric extension to convey globally unique identifiers. The
OID provides the namespace for the identifier, corresponding with who issued the identifier and
what type of identifier it is.
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The CDM HL7 message specifications require the following types of identifiers:
•
Common identifiers: common identifiers are used across all applications such as the
person identifier (e.g., provincial health number) and provider identifier (e.g.,
provider identifier given by professional affiliation).
•
Application-specific identifiers: application-specific identifiers are created for
records produced by clinical applications; e.g., procedure, observation, and care plan
identifiers.
Common identifiers must be registered with HL7. All applications use the same OID for the
same concept. For example, there will be one and only one OID used for the BC provincial
health number. This would be used for all v3 specifications across all v3 standards.
Application-specific identifiers need to be issued by the application that creates the item. This
means that every application has to register for its own OID. Within its own OID structure, the
application will need to create a sub-id for each type of identifier it produces. The set of
application-specific identifiers in the CDM HL7 message specifications include procedure
identifier, medication / vaccine prescription or dispense identifier, observation identifier,
diagnostic image identifier, referral identifier, and care plan identifier.
In addition to identifiers, OIDs are used to identify coding systems for code sets (e.g., ICD-10CA, CCI, gender codes) and HL7 artifacts (e.g., interaction ids, message ids, etc.). A full
explanation of OIDS is included in the CDM HL7 Message Specifications – Implementation
Guide.
2.3.6. Symbols in Code Tables
•
Use of **. The valid codes for a field that contain ** indicate that all applicable values
or valid codes within that code set would be accepted. For example, “E10**” for diabetes
means that all codes within that range for diabetes would be accepted.
•
Use of ^^. The CCI Code Structure is hierarchical. Each distinct code has up to nine
different elements, with the first five being mandatory [CCI Base (Mandatory)] as
follows:
CCI Base (Mandatory)
Position 1 – Section
Position 2-3 – Group
Position 4-5 – Intervention
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Where the concept is defined only to a certain position (i.e., up to position 5), all
subsequent details [i.e., positions beyond position 5; referred to as CCI Qualifiers
(Optional)] that are not being indicated are displayed as ^^. The CCI Qualifiers
(Optional) follow:
CCI Qualifiers (Optional)
Position 6-7 – Technique or Reason
Position 8-9 – Device or Method
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