ValueSet - pressure injury classification system to support exchange of wound management information

[robeastwood-agency]

Prerequisites

• I have searched open and closed issues to make sure it isn't already requested or reported
• I have written a descriptive issue title

The feature

Value set(s) to representing pressure injury classification is needed to support exchange of wound management information (see GitHub #119) between healthcare providers, and between healthcare providers and the My Health Record system.

The values are to cover the concepts in the Pressure Injury Classification System (PICS), and are expected to be drawn from SNOMED CT as the preferred national solution for clinical terminology.

The value set(s) will be referenced directly in FHIR and CDA specifications that support the exchange of wound management information in forthcoming aged care specifications, and is intended to be considered for inclusion in other continuity of care specifications such as Discharge Summary, Referral or care planning.

The usage scenario is the electronic exchange of current, valid, pressure injury information documented as part of an assessment by a healthcare provider.

Concept definitions

A pressure injury (PI), is a type of wound that has localised damage to the skin and/or underlying tissue as a result of pressure or pressure in combination with shear, usually occurring over a bony prominence but may also be related to a medical device or other objects¹.

PICS concepts as endorsed by Pan Pacific Pressure Injury Alliance (PPPIA):

Concept	Meaning
Pressure Injury Stage 1	Non-blanchable erythema (intact skin with non-blanchable redness of a localised area usually over bony prominences)
Pressure Injury Stage 2	Partial thickness skin loss (of dermis presenting as a shallow open ulcer with a red/pink wound bed, without slough; May also present as an intact or open/ruptured serum-filled blister)
Pressure Injury Stage 3	Full thickness tissue loss (subcutaneous fat may be visible, but bone, tendon or muscle are not exposed.)
Pressure Injury Stage 4	Full thickness tissue loss with exposed bone, tendon or muscle (Slough or eschar may be present on some parts of the wound bed)
Unstageable Pressure Injury depth unknown	Full thickness tissue loss in which the ulcer base is covered by slough (yellow, tan, gray, green or brown) and/or eschar (tan, brown or black) in the wound bed. Until enough slough and/or eschar is removed to expose the base of the wound, the true depth, and therefore category/stage, cannot be determined.
Deep Tissue Pressure Injury depth unknown	Purple or maroon localised area of discoloured intact skin or bloodfilled blister due to damage of underlying soft tissue from pressure and/or shear

What it actually enables people to do

Provide a publicly accessible FHIR representation of the internationally agreed set of values in a governed manner that is reusable in an Australian context.

How awesome would it be?

Pretty awesome - a small but significant step into the representation of broader concepts, to support exchange of wound management clinical concepts.

The Australian Commission on Safety and Quality in Health Care have declared PI as a leading hospital acquired complication and is specifically called out in the National Safety and Quality Health Service (NSQHS) Standard: Comprehensive Care Standard, 2020. The 3 related actions require that healthcare organisations establish systems and processes for pressure injury prevention and wound management that are consistent with best-practice guidelines. This includes the documentation of the level of tissue loss using an agreed international classification system.

An international collaboration between the European Pressure Ulcer Advisory Panel (EPUAP), the US National Pressure Injury Advisory Panel (NPIAP) and the Pan Pacific Pressure Injury Alliance (PPPIA) resulted in the publication of the Prevention and Treatment of Pressure Ulcers/Injuries: Clinical Practice Guideline The International Guideline (3rd edition 2019), which includes the recommended PI classification system.

Additional context

1. Wound management information is not currently implemented in the MHR system or explicitly supported in existing Agency specifications, the closest material in nature is that of Problem/Diagnosis (i.e. Condition) but no grading, staging, or assessment elements are supported.

Some materials commenting on clinical terms for interest - not directly related to the value set definition.

1. The terminology of pressure injury or pressure ulcer is the subject on ongoing international discussion and debate. The term pressure ulcer is widely used in Europe, however South-East Asia, Australia and New Zealand the term pressure injury has been adopted. The Prevention and Treatment of Pressure Ulcers/Injuries: Clinical Practice Guideline The International Guideline uses the term pressure injury and Australian documentation is predominantly in alignment but there are pockets yet to transition. (Note that the term 'ulcer' is technically defined as a 'break in the skin' and 2 of the PICS choices are associated with intact skin.)
2. The United States Health Information Knowledgebase has a number of related data element definitions that use the same classification system:
   • Status of Stage 3, 4, or unstageable pressure ulcer on admission
   • Most advanced stage of pressure ulcer or sDTI reported, v1.1
   • Status of Stage 3, 4, or unstageable pressure ulcer on admission, v1.2
3. PICS is:
   • developed by an international collaboration
   • recommended by the Pan Pacific Pressure Injury Alliance (PPPIA), as the authority recognised by Australian healthcare providers
   • used pervasively in Australian healthcare settings as an indication of the severity of pressure injuries
4. PI classification is based on the visual and palpatory identification of tissues including skin, subcutaneous fat, bone, muscle, tendon and ligament. Therefore, detailed anatomical knowledge of these structures is essential to accurate classification¹.

Footnotes

1. European Pressure Ulcer Advisory Panel, National Pressure Injury Advisory Panel and Pan Pacific Pressure Injury Alliance. Prevention and Treatment of Pressure Ulcers/Injuries: Clinical Practice Guideline The International Guideline. Emily Haesler (Ed.). EPUAP/NPIAP/PPPIA: 3rd edition 2019 ↩ ↩²

[robeastwood-agency]

Analysis of available terminologies

LOINC

LOINC contains on the an answer list in this space. See below, this represents the answers to the question of what is the pressure injury staging (LL5203-6):

Answer	Answer ID
Stage 1 Pressure Injury: Non-blanchable erythema of intact skin	LA29668-3
Stage 2 Pressure Injury: Partial-thickness skin loss with exposed dermis	LA29669-1
Stage 3 Pressure Injury: Full-thickness skin loss	LA29670-9
Stage 4 Pressure Injury: Full-thickness skin and tissue loss	LA29671-7
Unstageable Pressure Injury: Obscured full-thickness skin and tissue loss	LA29672-5
Deep Tissue Pressure Injury: Persistent non-blanchable deep red, maroon or purple discoloration	LA29673-3

Analysis:

• the concepts in the answer list are equivalent to the PPPIA promoted concepts

Conclusion: Notwithstanding that the concepts are analogous to the PPPIA promoted concepts, SNOMED-CT remains as the preference in Australia to represent clinical concepts. Therefore, these LOINC codes are not recommended for use in this value set. No requirement nor benefit is identified at this time for a concept map with these LOINC codes. However, should a future need be raised, it would be straight forwards to add one/more later.

Wound Grade Concepts code system

Wound Grade Concepts code system is implemented in the HL7 International Wound Assessment FHIR Implementation Guide, with the PI-specific constrained National Pressure Ulcer Advisory Panel Pressure Injury Classification System value set.

The implementation guide notes that this use of concepts is temporary and will be replaced by 'Solor Extension' SNOMED CT terms when available.

Analysis:

• the concepts in the National Pressure Ulcer Advisory Panel Pressure Injury Classification System value set are equivalent to the PPPIA promoted concepts

Conclusion: There is no identified value in adopting or mapping to this terminology in an Australian context.

The International Classification of Diseases (ICD)

The ICD is hosted by the World Health Organization (WHO), used worldwide, and is promoted as the "global standard for diagnostic health information". The WHO have released the ICD-11 version as of Jan 2021.

The following codes are available within ICD-10 (International):

Code	Description	Suitability
L89.0	Stage I decubitus ulcer and pressure area	Not fully equivalent to the preferred concept of pressure injury
L89.1	Stage II decubitus ulcer	Not fully equivalent to the preferred concept of pressure injury
L89.2	Stage III decubitus ulcer	Not fully equivalent to the preferred concept of pressure injury
L89.3	Stage IV decubitus ulcer	Not fully equivalent to the preferred concept of pressure injury
L89.9	Decubitus ulcer and pressure area, unspecified	Not fully equivalent to the preferred concept of pressure injury

The following codes are available within ICD-10-AM (Australian Modification), sourced from the Prevention and Treatment of Pressure Ulcers/Injuries: Clinical Practice Guideline The International Guideline.

Code	Description	Suitability
L89.0	Pressure injury, stage I	Equivalent and suitable for the preferred concept of pressure injury
L89.1	Pressure injury, stage II	Equivalent and suitable for the preferred concept of pressure injury
L89.2	Pressure injury, stage III	Equivalent and suitable for the preferred concept of pressure injury
L89.3	Pressure injury, stage IV	Equivalent and suitable for the preferred concept of pressure injury
L89.4	Pressure injury, unstageable, so stated	Equivalent and suitable for the preferred concept of pressure injury
L89.5	Suspected deep tissue injury, depth unknown, so stated	Equivalent and suitable for the preferred concept of pressure injury

The following codes are available within ICD-11:

Code	Description	Inclusion
EH90.0	Pressure ulceration grade 1	pressure injury stage 1
EH90.1	Pressure ulceration grade 2	pressure injury stage 2
EH90.2	Pressure ulceration grade 3	pressure injury stage 3
EH90.3	Pressure ulceration grade 4	pressure injury stage 4
EH90.4	Suspected deep pressure-induced tissue damage, depth unknown
EH90.5	Pressure ulceration, ungradable	pressure injury with depth unknown
EH90.Z	Pressure ulcer of unspecified grade	pressure injury

Analysis:

• ICD-10-AM coding is used throughout Australia to classify episodes of admitted patient care across hospital services. ICD-11 has not yet been implemented.
• In the 2020 ADHA presentation "Terminologies and classifications: SNOMED CT-AU and ICD-10-AM use in Australia", ICD is described as a classification system, rather than a clinical terminology (such as SNOMED-CT). As such it supports the specific use case of secondary analysis of data, such as statistical aggregating and reporting (rather than supporting direct clinical care as does SNOMED-CT).
• its stated scope is specifically for classifying episodes of admitted patient care - this is much more narrow that the intended application of the PICS, where it would be in use in residential aged care facilities and even home-based care

Conclusion: given its scope, ICD (in any flavour) is not recommended for use as the basis of the PICS. However, given the widespread use in Australian hospital reporting, it is recommended to develop concept maps to the ICD-10-AM equivalents.

SNOMED CT

SNOMED-CT is the most comprehensive multilingual health terminology in the world, with the primary purpose of directly supporting clinical data entry in a patient record. It is the preferred national solution for clinical terminology, endorsed by the Australian Health Ministers’ Advisory Council (AHMAC).

The following codes are currently available (as at October 2021) in SNOMED CT to support grading of pressure ulcers:

Code	Preferred term	Suitability
421076008	Pressure ulcer stage 1 (disorder)	Not fully equivalent to the preferred concept of pressure injury
420324007	Pressure ulcer stage 2 (disorder)	Not fully equivalent to the preferred concept of pressure injury
421927004	Pressure ulcer stage 3 (disorder)	Not fully equivalent to the preferred concept of pressure injury
420597008	Pressure ulcer stage 4 (disorder)	Not fully equivalent to the preferred concept of pressure injury
421594008	Nonstageable pressure ulcer (disorder)	Not fully equivalent to the preferred concept of pressure injury
723071003	Pressure injury of deep tissue (disorder)	Not fully equivalent to the preferred concept of pressure injury

These above concepts that are not fully equivalent will be replaced with Pressure Injury concepts for the January 2022 release. The SNOMED CT concepts for Pressure Injury will provide the concepts for mapping to the six Pan Pacific Pressure Injury Alliance (PPPIA) Pressure Injury concepts.

Analysis:

• in widespread usage across the Australian healthcare system
• there is no known reference set supporting these concepts
• SNOMED-CT will provide support (in Jan 2022) for the above requirements, to directly support the stated usage scenarios, these are suitable for adoption.

Conclusion: clear front-runner to base the PICS terminology on SNOMED-CT. If and when concept maps are needed, SNOMED-CT would be the front-runner to be used as the ConceptMap source.

(updated following review comments below)

[robeastwood-agency]

Solution recommendations

To support the above scenarios, it is recommended to develop:

1. A ValueSet for pressure injury classification system composed of only PICS relevant concepts and composed of only SNOMED CT codes using the codes redeveloped in the international space; no other concepts to be included. This value set is to support the usage scenarios.
2. A ValueSet in ICD-10-AM that is the equivalent set of concepts to the SNOMED CT pressure injury classification system ValueSet to support mapping between SNOMED CT and ICD-10-AM.
3. Two ConceptMaps to go between the 2 new value sets:
   • from the new Pressure Injury Classification System ValueSet to the new ICD-10-AM ValueSet; and the reverse
   • from the new ICD-10-AM ValueSet to the new Pressure Injury Classification System ValueSet

(updated following peer review comments below)

[robeastwood-agency]

Following first pass peer review of the solution recommendations, updates have been made to the analysis and proposal sections.

[dtr-agency]

I agree with and endorse:

• use of SNOMED CT as the source terminology on the basis that SNOMED CT as a terminology is capable of representing this content and it is the Agency's policy to adopt where possible.
  • a single value set composed of 6 concepts (assumed to require development in SNOMED CT) that match exactly the PICS concepts as defined by Pan Pacific Pressure Injury Alliance (PPPIA): Pressure Injury Stage 1, Pressure Injury Stage 2, Pressure Injury Stage 3, Pressure Injury Stage 4, Unstageable Pressure Injury depth unknown, Deep Tissue Pressure Injury depth unknown.
  • the full set of 6 PICS concepts are relevant to the usage scenario and are equivalent to the current requirements and other materials for aged care specifications
• The exclusion of concepts that describe incomplete or abnormal data (e.g. 'unknown') from the value set. The handling of this information is not precluded from the support but should be handled by the data structure rather than the wireformat noting that some means of addressing 'no pressure injuries' and other assertions of no relevant finding will be required for support in exchanging would management information such content is not to form part of a set of terminology to define the staging of an identified wound.
• concept maps from that SNOMED CT to ICD-10 and endorse the action that if no existing ICD-10 value set is suitable for the terminology work to author such a value set to support the concept maps.

Recommend:

• value set design and concept map design to move forward asap with the compose described as a natural language english expression with the exception of the ICD-10 value set.
• value set design and concept map design are to define: title, name, uri, description, compose

Updated above comments based on revised solution recommendations.

[StephenC-ADHA]

@StephenC-ADHA Comments - consolidated by @robeastwood-agency

Comment 1

There are SNOMED CT concepts for Pressure Ulcers:
421076008 | Pressure ulcer stage 1 (disorder)|
420324007 | Pressure ulcer stage 2 (disorder)|
421927004 | Pressure ulcer stage 3 (disorder)|
420597008 | Pressure ulcer stage 4 (disorder)|
421594008 | Nonstageable pressure ulcer (disorder)|
723071003 | Pressure injury of deep tissue (disorder)|
However, these concepts will be replaced with Pressure Injury concepts for the January 2022 release
The SNOMED CT concepts for Pressure Injury will provide the concepts for mapping to the six Pan Pacific Pressure Injury Alliance (PPPIA) Pressure Injury concepts

Comment 2

Thank you Rob, for the comprehensive work.
I agree with and endorse:

• The adoption of Pan Pacific Pressure Injury Alliance (PPPIA) concepts for describing pressure injuries
• The creation of concept map that map semantically equivalent SNOMED CT concepts to the PPPIA pressure injury concepts (The LOINIC question code can still be used, and the answer codes can be replaced with SNOMED CT codes. Note that there will be new SNOMED CT codes on pressure injury to be released by SNOMED International in January 2022)
• Where possible, mapping of PPPIA pressure injury concepts to ICD 10-AM/ICD 11-AM codes
• "exclusions" (e.g. no known, unknown) concepts to be supported by data structure

Re this Solution Recommendation:
"the 2 options of 'unstageable pressure injury' and 'deep tissue pressure injury' are both used when one of the classification grades cannot be applied (ie grades 1-4) as the PI has not yet developed to a state where it can be graded; and respective detail in the code descriptions from the clinical guidelines is sufficient for an informed assessor to choose."

Stage 1 to Stage 4 of the PPPIA concepts are ordinal in nature, indicating progressive seriousness in morphological and pathological changes/damage to the skin and related structures.

Unstageable Pressure Injury: Obscured full-thickness skin and tissue loss
Deep Tissue Pressure Injury: Persistent non-blanchable deep red, maroon or purple discoloration

The developer of these concepts (unstageable; deep tissue) may not have found a way to rank the morphological and pathological injuries described in these two concepts to adequately differentiate them from the Stage 4 injury (Pressure Injury: Full-thickness skin and tissue loss); and hence did not assign rankings to these two concepts
But the concept definitions provide sufficient clarity to allow for morphological and pathological (non-ordinal) staging by clinical users

Suggest remove this statement

Comment 3

Hi Rob,
Thanks for the changes.
One quick question on LOINC codes -
In the LOINC section, the conclusion states that:
"Notwithstanding that the concepts are analogous to the PPPIA promoted concepts, SNOMED-CT remains as the preference in Australia to represent clinical concepts. Therefore, these LOINC codes are not recommended for use in this value set. No requirement nor benefit is identified at this time for a concept map with these LOINC codes. However, should a future need be raised, it would be straight forwards to add one/more later."

This recommendation does not seem to exclude the use of this LOINC code LL5203-6:
"on the question of what is the pressure injury staging (the question of what is the pressure injury staging (LL5203-6))"
If that is correct, can the LL5203-6 LOINC code can still be used?

For example:
Observation.code
The code value can be: LL5203-6
Observation.value[x]:valuecodeableConcept
SNOMED CT codes for pressure injury stages can be used when released in January 2022

It will be useful to include additional clarification.

Response to comment 3 (@robeastwood-agency):
The use of LOINC for Observation.code is certainly not ruled out by the above designs and actually these terminology artefacts would remain ignorant/agnostic to what is used outside of the binding. My understanding is also that LOINC is likely the preferred choice for the 'question' as you state.

[LB-Agency]

I support the use of SNOMED CT for this content. As noted by Stephen, there is work being done by SNOMED International to remodel applicable concepts, so would suggest using the new content once it's been released. It will be interesting to see what terms and modelling are chosen.

For Australian use, there appears to be some inconsistent use of pressure injury classification values. I've not seen the full guidelines due to it not being freely available but the "Prevention and Treatment of Pressure Ulcers/Injuries:
Quick Reference Guide" recommend PIs are classified and notes three main systems for use: International NPUAP/EPUAP Pressure Ulcer Classification System (2009, 2014), WHO ICD-11 (2018), and NPUAP Classification System (April 2016).

I didn't see any concepts defined directly by PPPIA other than their collaborative work in the Quick Reference Guide. The concept definitions provided in the introduction of this issue seem to most closely align with the NPUAP Classification System (April 2016). If there is a direct source, can you please provide? Thanks.

The 2020 NSQHS Standards Fact Sheet - Preventing pressure injuries and wound management, includes the recommendation to "Stage the pressure injury using the National Pressure Ulcer Advisory Panel (NPUAP) / European Pressure Ulcer Advisory Panel (EPUAP) 2014 Pressure Injury Classification System". This appears to be reflected in the guidelines by state health departments. I checked a few: NSW, WA, VIC. This system is also supported by Wounds Australia. In contrast, RCH staging guidelines reflect NPUAP Classification System (April 2016). I haven't see evidence to suggest Australia has moved to the NPUAP Classification System (April 2016) like it appears the US have done.

[robeastwood-agency]

ValueSet Design

1. A ValueSet for pressure injury classification system composed of only PICS concepts from SNOMED CT

ValueSet element	Suggested value
title	Pressure Injury Classification
canonical url	https://healthterminologies.gov.au/fhir/ValueSet/pressure-injury-classification-1
version	1.0.0
description	The Pressure Injury Classification value set includes values that may be used to represent the severity of a pressure injury.
compose	system: "http://snomed.info/sct"; the SNOMED CT concepts that are equivalent to the PICS concepts as endorsed by Pan Pacific Pressure Injury Alliance (PPPIA): Pressure Injury Stage 1, Pressure Injury Stage 2, Pressure Injury Stage 3, Pressure Injury Stage 4, Unstageable Pressure Injury depth unknown, Deep Tissue Pressure Injury depth unknown

Associated FHIR Terminology Request: FTR-1282

2. A ValueSet for pressure injury classification system composed of only PICS concepts from ICD-10-AM

ValueSet element	Suggested value
title	ICD-10-AM Pressure Injury Classification
canonical url	https://healthterminologies.gov.au/fhir/ValueSet/icd10am-pressure-injury-classification-1
version	1.0.0
description	The ICD-10-AM Pressure Injury Classification value set includes values that may be used to represent the severity of a pressure injury.
compose	The ICD-10-AM concepts that are equivalent to the PICS concepts as endorsed by Pan Pacific Pressure Injury Alliance (PPPIA): Pressure Injury Stage 1, Pressure Injury Stage 2, Pressure Injury Stage 3, Pressure Injury Stage 4, Unstageable Pressure Injury depth unknown, Deep Tissue Pressure Injury depth unknown

Associated FHIR Terminology Request: FTR-1287

3. Two ConceptMaps to go between the 2 new value sets

These will be progressed via internal terminology tasks as per the BAU publication schedule; this GitHub issue will be kept up to date as the designs mature. This content has been included here as an indication of the initial direction of this content; review and analysis by a terminology analyst when authoring is necessary.

The two concept maps:

• from the new SNOMED CT Pressure Injury Classification ValueSet to the new ICD-10-AM Pressure Injury Classification ValueSet: the equivalent between each target and source concept is expected to be equivalent or equal.
• from the new ICD-10-AM Pressure Injury Classification ValueSet to the new SNOMED CT Pressure Injury Classification ValueSet: the equivalent between each target and source concept is expected to be equivalent or equal.

Associated FHIR Terminology Requests: FTR-1292 and FTR-1297

[robeastwood-agency]

Status

Terminology designs in peer review

[dtr-agency]

Endorse the value set and concept map designs to go into the FTR pending terminology analyst approval.

[StephenC-ADHA]

Also endorse the value set and concept map design for progression to FTR