1 Introduction

The SNOMED CT International General/Family Practice Reasons for encounter and Health issues reference set (hereafter called the GP/FP subset) and the map from the GP/FP subset to the International Classification of Primary Care (ICPC-2) were developed between 2010 and 2013 by the GP/FP subset and ICPC mapping project group. This project ended on December 31, 2013 after field-testing of the products was completed. 

2 Background

In December 2009 a harmonization agreement was finalized between the IHTSDO and WONCA to promote co-operation and collaboration between the two organisations. 
This agreement led to the formation of the International Family Physician/General Practitioner Special Interest Group (IFP/GP SIG) under the auspices of the IHTSDO. The IFP/GP SIG was established to suggest content for the Systematized Nomenclature of Medicine – Clinical Terms (SNOMED CT®) related to general/family practice and to provide quality assurance for SNOMED CT content from the general/family practice perspective. The IHTSDO's existing Primary Care Special Interest Group was converted to the IFP/GP SIG after the agreement was signed. 
The agreement contained a commitment to develop a mapping program, classifying relevant content in SNOMED CT to the International Classification of Primary Care, Version 2 (ICPC-2). Under the terms of the agreement, each task or project in the mapping program was to be managed by a mapping project group, comprised of members from the IFP/GP SIG, the WONCA International Classification Committee (WICC) and the IHTSDO's Mapping Special Interest Group. A project group for this task was established in early 2010 and called the 'International GP/FP subset and ICPC mapping project group'. The release of the map from the SNOMED CT GP/FP subset to ICPC-2, described in this document, fulfils the commitment to classify relevant content from SNOMED CT to ICPC-2. 

2.1 The International Classification of Primary Care, Version 2 (ICPC-2)

ICPC-2 is a classification designed for use in general/family practice around the world. ICPC-2 is developed and maintained by the Wonca International Classification Committee (WICC), representing members from over 20 countries. The copyright of ICPC is owned by Wonca. Version One of the classification was released in 1987 (ICPC-1), with the second version (ICPC-2) in 1998. The map is based on ICPC-2e-v.4.2 May 2012.
ICPC-2 contains approximately 1,300 codes and has a biaxial structure containing chapters and components. The 17 chapters are based on body systems, with additional chapters for psychological and social problems. The seven components are:

1. Symptoms and complaints

2. Diagnostic and preventive procedures

3. Medication, treatment, therapeutic procedures

4. Results

5. Administrative

6. Referrals and other reasons for encounter

7. Diagnoses and diseases.

Components 2 to 6 inclusive are collectively called 'processes of care'. 

3 Release content

3.1 Overview

Note: This document provides release information about the map from the GP/FP subset to ICPC-2. Release information about the GP/FP subset can be found in the July 2017 SNOMED CT to General Practitioner/Family Practitioner (GPFP) Subset Release Notes.

To determine the 'relevant' SNOMED CT content for mapping to ICPC-2, a decision was made to focus on two semantic data types commonly used in general/family practice electronic health records:

• Reasons For Encounter (RFEs)

• Health Issues.

A reason for encounter was defined as:

"An agreed statement of the reason(s) why a person enters the health care system, representing the demand for care by that person. The terms written down and later classified by the provider clarify the reason for encounter and consequently the patient's demand for care without interpreting it in the form of a diagnosis. The reason for encounter should be recognized by the patient as an acceptable description of the demand for care" (WONCA Dictionary of General/Family Practice, 2003). 

A health issue was defined as an:

"issue related to the health of a subject of care, as identified or stated by a specific health care party". This is further defined in the notes as "according to this definition, a health issue can correspond to a health problem, a disease, an illness" (Health Informatics – System of concepts to support continuity of care – Part 1: basic concepts (CEN/ISO FDIS 13940-1)). 

These definitions were used to define the scope of a subset of SNOMED CT concepts that represented terms commonly used to populate these semantic data types. The content of this subset was subsequently mapped (or classified) to ICPC-2. 

3.2 Status of content

The ICPC-2 map is a SNOMED CT module; the original Baseline Release was published following the July 2015 SNOMED CT International Edition Release.

This latest July 2017 Production release of the ICPC-2 map is aligned to the SNOMED CT July 2017 International Edition.

3.3  Changes to the July 2017 release ICPC-2 map

As a result of changes to the July 2017 release of SNOMED CT, the following maps were changed: