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Implementation Guide for use of SNOMED CT in Allergy and Hypersensitivity Data Records Subtitle Date: Version: Status: Document1 Status: Draft 20141315 0.02 Draft Page 1 of 19 Date <Document Name> Version 0.01 Document1 Status: Draft Page 2 of 19 Date <Document Name> Version 0.01 Amendment History Version Date Editor Kin Wah Fung 0.01 20141201 Bruce Goldberg Jim Campbell Amy Sheide 0.02 20150309 Beverly Knight Kin Wah Fung James Campbell Comments Glossary terms from IHTSDO discussions Draft chapter from Bruce Goldberg Addition of Background, Purpose, Scope, Problem statement, Clinical use case scenarios, proposal for inclusive information model Approvals Version Date Approver Comments YYYYMMDD Future Review Timetable Review date Responsible owner Comments YYYYMMDD Person/group responsible Summary of action (remove or add rows if necessary) © International Health Terminology Standards Development Organisation 2017. All rights reserved. Document1 Status: Draft Page 3 of 19 Date <Document Name> Version 0.01 Table of Contents 1 Introduction ......................................................................................... 6 Background .............................................................................................. 6 Purpose .................................................................................................. 6 The benefits include: ................................................................................................... 6 Benefits for IHTSDO and its Members .............................................................................. 6 Benefits for SNOMED CT Implementers ............................................................................. 7 Benefits for SNOMED CT End-Users, Clinical Researchers, Health Provider Organizations, and Vendors7 Scope ..................................................................................................... 7 Audience ................................................................................................. 8 2 Statement of the problem ........................................................................ 8 3 Clinical use case scenarios........................................................................ 8 Documentation of an allergic reaction to a substance............................................ 8 Drug allergy or intolerance alert to provider ...................................................... 9 Additional scenarios clarifying scope for documentation of allergy/adverse reaction statements .................................................................................................. 9 4 Survey of hypersensitivity information models .............................................. 10 Previous IHTSDO deliberations ...................................................................... 10 4.1.1 Historical perspective ........................................................................................ 10 4.1.2 Organization and features of hypersensitivity content currently in SNOMED CT .................. 12 Survey of reference information models and value sets ......................................... 13 4.2.1 HL7 CCDA model ............................................................................................... 13 4.2.2 HL7 Patient Care revised model ............................................................................ 13 4.2.3 FIHR .............................................................................................................. 13 4.2.4 epSOS ............................................................................................................ 13 4.2.5 openehr ......................................................................................................... 13 Proposal for inclusive information model .......................................................... 13 4.3.1 Propensity class ................................................................................................ 14 4.3.2 Adverse reaction (condition) class ......................................................................... 15 4.3.3 Sensitivity test result class .................................................................................. 15 5 SNOMED CT reference valuesets ............................................................... 16 6 Promoting interoperable EHR communication ............................................... 16 Document1 Status: Draft Page 4 of 19 Date <Document Name> Version 0.01 7 Glossary of Terms ................................................................................ 18 Appendix A First Appendix ........................................................................ 19 A.1 First sub-heading if required ........................................................................ 19 Document1 Status: Draft Page 5 of 19 Date <Document Name> Version 0.01 1 Introduction Background Interoperable deployment of SNOMED CT in support of Electronic Health Record (EHR) hypersensitivity/allergy/adverse sensitivity data is inconsistent and fails to support interoperability across IHTSDO member realms. This arises due to confusion regarding the scope and definition of adverse sensitivity data, uncertainty regarding the reference models for defining relevant data records and inconsistency in guidance for the appropriate value sets from SNOMED CT that should populate those records. This proposal expects to develop an implementation guide which will: extend previous IHTSDO work on definitions of adverse sensitivity events, survey and summarize the relevant interoperability standards, advise the IHTSDO community regarding best practice deployment of allergy data within the EHR and identify the SNOMED CT refsets (value sets) that would constitute best practice for use in electronic health records. Several Standards Development Organizations (SDOs) such as HL7 and epSOS have also provided some material to assist implementers, however without formal or informal collaboration with IHTSDO. There is recognition that some realms have developed their own Drug dictionaries which would be preferred for use in hypersensitivity/allergy/adverse sensitivity data. Purpose This implementation guide is intended to accelerate consistent implementation of vocabulary with an emphasis on the use SNOMED CT within the domain of allergy and adverse reaction. This guide expects to develop an implementation guide which will: extend previous IHTSDO work on definitions of adverse sensitivity events, survey and summarize the relevant interoperability standards, advise the IHTSDO community regarding best practice deployment of allergy data within the EHR and identify the SNOMED CT refsets (value sets) that would constitute best practice for use in electronic health records. The benefits include: Benefits for IHTSDO and its Members Members will have uniform, clear best practices for documenting adverse sensitivity events This work will support how adverse sensitivity information models such as HL7 can incorporate SNOMED CT Provide definitions for the community to clearly understand the terms of allergy, adverse sensitivity, adverse reactions, etc Document1 Status: Draft Page 6 of 19 Date <Document Name> Version 0.01 Cost savings: reduce investment requirements by member vendor community; consolidate NRC costs for SNOMED CT distribution of value sets Benefits for SNOMED CT Implementers Support interoperability within and between realms in a consistent way by providing clear guidance for structuring Adverse sensitivity data as part of a patients Electronic Health Record Enable consistent adoption of SNOMED CT by providing guidance on the representation of adverse sensitivity information with different levels of granularity, with and without the use of post-coordination Benefits for SNOMED CT End-Users, Clinical Researchers, Health Provider Organizations, and Vendors Fill the knowledge gap in the community of practice by providing authoritative guidance and ref sets that can be used consistently for the representation of; o an allergy, pseudoallergy and intolerance o an adverse reaction o the criticality of the allergic condition (ie the potential seriousness of a future reaction) o the severity of a reaction Provide guidance for the aggregation & analysis of reported adverse drug reactions (ADR) and sharing/interoperability of ADR reports Scope The MapSIG and Implementation SIG will supply volunteer effort for preparation and documentation of the implementation guide and refsets. The approach will include identification of the areas of overlap and synergy with work underway at various StandaredHL7,epSOS, and openehr and determine how this work will be coordinated, aligned and disseminated in collaboration with SDOs, national release center representatives and vendors. It is expected the delivery will be as part of IHTSDO regular release cycle. The scope will include phases: Phase 1: Implementation guide including: 1. Statement of the problem and documentation of scope 2. Summary of definitions and reference standard publications 3. Advice for best practice deployment of the binding of information model-todomain ontology in support of adverse sensitivity record data 4. Documentation of refsets/value sets Phase 2: Refset (Value Set) development: 1. Hypersensitivity conditions and dispositions 2. Allergenic substances: drugs, chemicals, foods, animals, environmental agents 3. Sensitivity types 4. Adverse reactions (clinical findings: signs, symptoms and diagnoses) 5. Certainty 6. Criticality 7. Severity Document1 Status: Draft Page 7 of 19 Date <Document Name> Version 0.01 8. Explore the use and approach of the SCT drug hierarchy for drug allergy content (consideration for generic only) Value set publication, maintenance, and governance plan including joint agreement between IHTSDO, HL7 and NRCs Audience The audience of this implementation guide includes but is not limited to IHTSDO and its Members. Specifically this guide is targeted at SNOMED CT Implementers SNOMED CT EndUsers, Clinical Researchers, Health Provider Organizations, and Vendors. 2 Statement of the problem The capture and exchange of hypersensitivity/allergy/adverse sensitivity data varies across EHRs. As an effect, much of this data is not interoperable across electronic systems. Confusion regarding the representation and definition of adverse sensitivity data within the EHR presents challenges to organizations that are trying to implement SNOMED CT for electronic data sharing. Further, this uncertainty limits the use of hypersensitivity/allergy/adverse sensitivity data for clinical decision support and longitudinal patient care records. The capture of allergy data must be clearly defined to support patient safety and a comprehensive health record. 3 Clinical use case scenarios Documentation of an allergic reaction to a substance Scenario: A physician sees a patient in clinic for routine outpatient care. The patient has been receiving care for diabetes and hypertension. Recently the patient was prescribed 25mg hydrochlorothiazide for his blood pressure. He tells the physician that he has been having a lot of itching lately and on examination, the physician notes hives. A review of systems fails to reveal any other causes and the physician concludes that the patient is having an urticarial reaction to hydrochlorothiazide; instructs the patient to stop the thiazide and employ diphenhydramine for relief.. When preparing his encounter summary for the visit, the physician uses the EHR diagnosis list to select his encounter diagnoses. He tries to find “Urticarial reaction to hydrochlorothiazide” but the best he can locate is “89322006|Drug-induced urticaria|”. He employs a feature that the vendor has supplied which allows him to choose a more specific diagnosis. The feature offers a list of drugs causing the hives and he chooses “5487|Hydrochlorothiazide|”. The vendor software creates a diagnosis reference in the EHR data dictionary for the diagnosis “Drug induced urticaria due to hydrochlorothiazide” and creates an extension concept reference with the full definition. The vendor mapping software suggests an ICD-10 diagnosis “L50.0 Y54.5” to report the encounter. The vendor software asks if the physician wishes to make an update to the allergy list. Document1 Status: Draft Page 8 of 19 Date <Document Name> Version 0.01 Drug allergy or intolerance alert to provider Scenario: The clinic nurse calls the patient a week later with test results from his visit. She inquires as to the urticarial and the patient verifies that they have disappeared with discontinuation of the diuretic. Following clinic protocols she accesses the patient EHR and proceeds to make a new entry into the allergy list. The software steps through a series of questions asking: what was the offending agent, what were symptoms or findings resulting from the reaction, what class of reaction occurred, what was the severity and criticality. The nurse answers the questions and an allergy record appears in the list “Hydrochlorothiazide; Allergy; Moderate severity; Moderate criticality; Symptoms-Hives”. Years later the patient is seeing another physician for consultation on treatment of resistant hypertension. The second physician decides that an ACE inhibitor/thiazide medication is appropriate for the patient. When the physician creates an order for “Lisinoprilhydrochlorothiazide 20/25” and commits to the electronic prescription, an alert appears which requires a response by the physician warning him of an allergy history to hydrochlorothiazide which is an ingredient in the drug he is about to order. The physician retracts the order and chooses another antihypertensive. Additional scenarios clarifying scope for documentation of allergy/adverse reaction statements Animal allergy scenario: A physician sees a patient for the first time in clinic for routine outpatient care. The patient tells the physician he has an allergy to cats. Upon further exploration the physician learns the patient develops swollen and itchy eyes when in contact with a cat. The physician documents the allergic propensity and reaction in the EHR ‘allergy list’. Non-drug allergy scenario: A patient reports to their physician that they react violently to eating peanuts with symptoms that include generalized hives, wheezing and hypotension requiring use of epinephrine for resuscitation. The physician records a peanut allergy with anaphylaxis, hives and wheezing as reaction symptoms, records a criticality of high and reaction severity of ‘severe’. No Known Allergies scenario: A nurse is performing an intake examination on a patient that is new to the clinical practice. As part of the clinical interview he inquires about medication allergies. The patient reports that she is not allergic to any medications, foods, chemicals or animals. The nurse opens the ‘hypersensitivity list’ in the EHR and documents ‘No known allergies’ which electronically validates that the nurse inquired of the patient and that the history was confirmed at the date and time recorded. Document1 Status: Draft Page 9 of 19 Date <Document Name> Version 0.01 4 Survey of hypersensitivity information models Previous IHTSDO deliberations 4.1.1 Historical perspective Efforts to revise the allergy-related hierarchies in SNOMED can be traced back to at least 2005 during which time several deficiencies were identified in the modeling of allergies and adverse reactions involving the inconsistent use of the causative agent role and the need to clearly differentiate the propensity to react from the reaction itself in order to better integrate with proposed HL7 models for allergy. Thus allergy (disorder) was replaced by allergic state (disorder) as a child of 420134006 | Propensity to adverse reactions (disorder) and adverse reactions/allergy to various substances, food and drugs were updated in the 2006 release of SNOMED CT. Additional revisions to the SNOMED CT allergy content occurred in 2006 included an attempt to align the terminology with the nomenclature for allergy developed by the WAO/EAAACI in 2001. The most recent update to the allergy terminology was implemented for the July 2013 release of SNOMED CT. This update organized all of the three main allergy classes (conditions, propensities and reactions) which up to this point resided in three unrelated hierarchies under a single “allergy condition” hierarchy. Additionally, the July 2013 release included a more robust concept model for hypersensitivity/allergy conditions, particularly for the allergy propensity class (since named allergic disposition). Text definitions for the major organizing classes were also included for the first time. Revising SNOMED CT to the three class model meant that hypersensitivity data were represented by: Dispositions (propensities) which model the patient state of an “Allergy to x”. <<420134006|Propensity to adverse reactions(finding)| Processes (reactions) Example: “Allergic reaction to x”. <<281647001|adverse reaction (disorder)| Conditions (may be either propensities or reactions) Example: “Allergic rhinitis due to x”. <<473010000|Hypersensitivity condition (disorder)| Abnormal structure was not felt to be relevant to this particular model. An initial “Aspirational” model for allergy/hypersensitivity was constructed using formal ontological principles based on BioTop. Document1 Status: Draft Page 10 of 19 Date <Document Name> Version 0.01 Figure 1 Aspirational Model of hypersensitivity Realizing that such a model would be difficult to implement at least in the short term, several features of this model were able to be represented using the current SNOMED CT description logic and roles (see section IV Features of current implemented model for allergic conditions in SNOMED CT). Document1 Status: Draft Page 11 of 19 Date <Document Name> Version 0.01 Figure 2 Current organization of hypersensitivity conditions in SNOMED CT 4.1.2 Organization and features of hypersensitivity content currently in SNOMED CT Top level terms fully defined by means of pathological process role using the following role values: 472963003|Hypersensitivity process (qualifier value)| o 472964009|Allergic process (qualifier value)| 472965005|Allergic sensitization process(qualifier value)| o 609404002|Pseudoallergic process (qualifier value)| A novel approach was taken to link a causative agent to the allergy disposition for purposes of data retrieval. Since causative agents cause the realization of the disposition (the allergic reaction process) and not the disposition itself (the allergic disposition) we allowed that only processes and not dispositions can have causative agents. For this reason, in the “aspirational” model, a unique property, agent_of_realization was created. In order to approximate this Document1 Status: Draft Page 12 of 19 Date <Document Name> Version 0.01 functionality using current SNOMED CT description logic, causative agent was linked to another process (allergic sensitization) upon which the disposition is dependent using the following role group: Group {255234002|after (linkage concept)|=609327009|allergic sensitization (disorder)|, 246075003|causative agent (linkage concept)|= 105590001|substance (substance)|} From this, an allergic disposition must necessarily follow an allergic sensitization caused by an allergen. Survey of reference information models and value sets 4.2.1 HL7 CCDA model 4.2.2 HL7 Patient Care revised model 4.2.3 FIHR 4.2.4 epSOS 4.2.5 openehr Proposal for inclusive information model After considering reference information models from various standards development organizations and other national or regional sources, an inclusive information model is proposed. This model aligns the essential elements of different information models into a coherent and comprehensive model. Classes and data elements in the inclusive information model can be mapped to individual models for compatibility. The inclusive information model is made up of three classes. The Propensity class is the centerpiece which must be present. A propensity class may be associated with zero-to-many Adverse Reaction classes and zero-to-many Sensitivity Test Result classes. Note that in some information models, propensity and adverse reactions are documented as a single entity. This is unsatisfactory because a propensity may not be associated with a reaction (e.g., allergy diagnosed by sensitivity test alone), or may be associated with more than one reaction (e.g., multiple exposure to a single allergen with different reactions). Moreover, a severe reaction may not necessarily be a severe (or critically important) propensity, and vice versa. The following tables depict the three classes and their data elements. Only data elements specific to the allergy/intolerance use case are shown. Generic data elements such as date, time, patient and provider identifiers are omitted. Document1 Status: Draft Page 13 of 19 Date <Document Name> Version 0.01 4.3.1 Propensity class Table 1. Propensity class Data element Description Notes Substance Represents the specific allergen or other agent/substance to which the patient has an adverse reaction propensity. A substance is a physical material which can mean a drug or biologic, food, chemical agent, plants, animals, plastics etc. Must be present. Primary key to identify a propensity record and to link to the corresponding adverse reaction and sensitivity test result records. Substance type Represents the type of substance related to the propensity e.g. drug, food, environment, vaccine etc. This can usually be inferred from the hierarchy in the terminology used for documenting the substance. May need to be entered separately if the substance falls outside the terminology. Propensity type Indicates whether the propensity is of an allergic nature or an intolerance to a substance. Propensity certainty Indicates whether there is evidence that the propensity has been confirmed. For example, an allergy could be further categorized as: Confirmed - via laboratory testing or witnessed observation or other strong evidence, or Suspected (Unconfirmed) - Patient reported but not further verified by clinical history, diagnostic testing or is uncertain. Propensity criticality Indicates the potential seriousness of the propensity for a future reaction. This represents a clinical judgment about the worst case scenario for a future reaction. It would be based on the severity of past reactions, the dose and route of exposure that produced past reactions, and the lifethreatening or organ system threatening potential of the reaction Document1 Status: Draft Not the same as severity of the reaction, because a severe reaction can be noncritical and vice versa. Page 14 of 19 Date <Document Name> Version 0.01 type. Criticality is an attribute of the propensity, not the reaction(s). Propensity status Indicates the current status of the propensity. For example, an allergy may become ‘Resolved’ after desensitization. 4.3.2 Adverse reaction (condition) class Data element Description Notes Substance Represents the specific allergen or other agent/substance to which the patient has an adverse reaction. Must be present. Primary key to identify an adverse reaction record and to link to the propensity record. Reaction manifestation Indicates the specific adverse reaction that occurred. Example: Rash, Hives A negative entry (e.g., “no adverse reaction observed”) can be used to document an exception to a propensity to a class of substance (e.g., patient has penicillin allergy but can tolerate amoxicillin) Reaction severity How severe the reaction was Exposure type How the exposure occurred. Example: Vaccination, Prescription Administration, Accidental Observation method How the observation was made e.g., patient reported, observed by family member, observed by healthcare professional 4.3.3 Sensitivity test result class Data element Description Notes Substance Represents the specific allergen or other agent/substance being tested. Must be present. Primary key to identify a sensitivity test result record and to link to the propensity record. Sensitivity test performed Document1 Status: Draft Page 15 of 19 Date <Document Name> Version 0.01 Sensitivity test result 5 SNOMED CT reference valuesets This section of the document is not going to contain the ref sets themselves but rather survey the available ref sets that are related to allergy/hypersensitivity that are available from IHTSDO and other organizations. It will also acknowledge that SNOMED CT will not be suggested as the only terminology for allergy information but highlight what parts of SNOMED CT fit into the inclusive information model above. Additionally, this section of the document is going to provide a reference point on where implementers can find the allergy/intolerance ref sets. 6 Promoting interoperable EHR communication This section of the document focuses on how this work applies to interoperable HER communication. It also acknowledges that this is a living document and is going to be revised and added to over time. 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CAUTION: please note that this macro will delete all text that is formatted with the style “guidance” and therefore if you have accidentally used this to format some of the text in your document, then it will be deleted. > Document1 Status: Draft Page 17 of 19 Date <Document Name> Version 0.01 7 Glossary of Terms The following table contains the definition of any terms used within this document. <insert any terms used within the document into the following table. This section should be the last section of the document before any Appendices. If there are no terms requiring definition, then delete this section.> Term Definition Hypersensitivity condition The disposition to develop an allergic or pseudoallergic reaction, the reaction itself or its consequences. Hypersensitivity disposition The disposition to develop an allergic or pseudoallergic reaction Hypersensitivity reaction A pathological process initiated by exposure to a defined stimulus at a dose tolerated by normal persons. It is the realization of the disposition to hypersensitivity. Allergic condition The disposition to develop an allergic reaction, the allergic reaction itself or its consequences Allergic disposition The disposition to develop an allergic reaction Allergic reaction A pathological immune process generally directed towards a foreign antigen, which results in tissue injury, which is usually transient. It is the realization of the allergic disposition. It is most often applied to type I hypersensitivity but other hypersensitivity types especially type IV (e.g. allergic contact dermatitis) may be involved Allergic sensitization A process characterized by a humoral or cell-mediated immune response to a foreign antigen resulting in the production of specific antibodies and/or immune cells which may then lead to an allergic disposition. Pseudoallergic condition The disposition to develop a pseudoallergic reaction, the pseudoallergic reaction itself or its consequences Pseudoallergic disposition The disposition to develop a pseudoallergic reaction Pseudoallergic reaction A pathological nonimmune process generally directed towards a foreign substance, which results in tissue injury, which is usually transient. It is the realization of the pseudoallergic disposition. A variety of mechanisms such as direct histamine release, complement activation, cyclooxygenase activation and bradykinin generation may be involved Document1 Status: Draft Page 18 of 19 Date <Document Name> Version 0.01 Appendix A First Appendix A.1 First sub-heading if required <insert content here> Document1 Status: Draft Page 19 of 19 Date