Computable Care Guidelines, published by IHE QRPH Technical Committee. This guide is not an authorized publication; it is the continuous build for version 1.0.0-current built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/IHE/QRPH.CCG/ and changes regularly. See the Directory of published versions

Actors

Actors, Transactions, and Content Modules

The digital health ecosystem of CCG actors and transactions is designed to satisfy four use cases:

1. UC-1 (Green): A person who is a guideline author uses a digital health tool (which plays the role of a Guideline Publisher) to retrieve and edit an existing CCG or to create a brand-new CCG (L3)¹ artifact. Maybe she digitally signs the artifact (at the top level, or every recommendation). She then publishes the CCG (L3) artifact to a Guideline Repository.

2. UC-2 (Yellow): A digital health solution that executes CCGs (e.g., a Guideline Engine) refreshes its local cache of CCGs from a Guideline Repository.

3. UC-3 (Red): A person who is a care provider leverages her digital health solution (e.g., an EMR) to associate a patient with one or more CCG-supported, evidence-based care programs.

4. UC-4 (Blue): A person who is a care provider has an ambulatory encounter with a patient who is enrolled in one or more CCG-supported care plans. During the encounter, she leverages her digital health solution (e.g., EMR, playing the role of a Guideline Performer) to invoke processing by a Guideline Engine actor to concurrently execute the relevant CCGs. She acts upon the recommendations to provide person-centric, guideline-adherent care.

The actors that participate in operationalizing the four color-coded use cases are pictorially illustrated by Figure 13.

To operationalize use cases 1, 2 and 4, four new IHE actors are defined in this profile:

• Guideline Publisher: an actor that may find and retrieve an existing CCG from a Guideline Repository and can publish a CCG to a Guideline Repository.

• Guideline Repository: an actor that can receive and catalog a submitted CCG and can respond to searches / requests for CCGs and return relevant lists / artifacts to a requester.

• Guideline Performer: an actor that can directly or indirectly interact with a human user, construct appropriate encounter-specific artifacts (e.g., a bundle containing relevant contextual and person-centric content), manage the iterative invocation of $apply operations that will concurrently process one or more relevant CCGs, and appropriately process the transaction responses.

• Guideline Engine: an actor that can ingest a submitted bundle of relevant contextual and person-centric content and execute the processing logic needed to return the appropriate response(s) indicating what care actions are recommended.

Use case 3 is operationalized by two existing IHE actors defined in the IHE Dynamic Care Planning (DCP) Profile¹ published by IHE’s Patient Care Coordination (PCC) technical committee:

• Care Plan Contributor: an actor that can search for and retrieve an existing Care Plan and can submit an updated Care Plan to a Care Plan Service.

• Care Plan Service: an actor that acts as a repository of Care Plans and which can respond to requests from Care Plan Contributors.

The conformance-testable behaviors of the Care Plan Contributor and Care Plan Service actors are described in the IHE PCC Dynamic Care Planning Profile and a description of these behaviors is not replicated here.

The new CCG actors and their transactions are listed in Table 1 and further described in the following subsections.

Table 1: CCG Actors and Transactions

Actor	Transaction	Initiator or Responder	Optionality	Reference
Guideline Publisher	Search for Guidelines [QRPH-61]	Initiator	O
	Retrieve Guideline [QRPH-62]	Initiator	O
	Publish Guideline [QRPH-63]	Initiator	R Note 1
Guideline Repository	Search for Guidelines [QRPH-61]	Responder	R
	Retrieve Guideline [QRPH-62]	Responder	R
Guideline Performer	Apply Guideline [QRPH-64]	Initiator	R Note 2
Guideline Engine	Search for Guidelines [QRPH-61]	Initiator	R
	Retrieve Guideline [QRPH-62]	Initiator	R Note 3
	Apply Guideline [QRPH-64]	Responder	R Note 2

Note 1: there are options for digitally signed CCGs (see below).

Note 2: a Guideline Performer that is grouped with its own internal Guideline Engine need not support transaction [QRPH-64] as an originator nor as a responder; it will be conformance tested as a single grouped entity (see below). Otherwise [QRPH-64] support is required by both actors.

Note 3: a Guideline Engine that supports the Trusted CCG Option will evaluate CCGs returned by transaction QRPH-62 to ensure the artifacts are signed by trusted parties and that they have not been tampered with (see below).

Guideline Publisher

A Guideline Publisher is a digital health solution that may be used to create or to edit CCG artifacts. Such solutions may be human-usable authoring tools or batch-processing tools that convert other artifacts (e.g., spreadsheets, DMN models, BPMN models, etc.) into CCG-conformant artifacts. The internal processes by which this is done are out of scope for this IHE Profile.

Normatively, a Guideline Publisher:

1. MAY be able to submit a query to a Guideline Repository using Search for Guideline [QRPH-61] [as originator]; and

2. MAY be able to submit a query to a Guideline Repository using Retrieve Guideline [QRPH-62] [as originator]; and

3. SHALL be able to submit a well-formed CCG payload to a Guideline Repository using Publish Guideline [QRPH-63] [as originator];

   1. The well-formed CCG payload submitted using transaction [QRPH-63] MAY adhere to the stipulations of the Digitally Signed Folder Option.

   2. The well-formed CCG payload submitted using transaction QRPH-63 MAY adhere to the stipulations of the Digitally Signed CARD Option.

The content specifications in Volume 3 of the IHE CCG Profile define a base set of normative requirements for a well-formed CCG artifact. One or more alternate content definitions may be documented in Volume 4. A Guideline Publisher SHALL declare the content model option to which it adheres.

Guideline Repository

A Guideline Repository is a digital health solution that catalogs submitted CCG artifacts and responds to queries for these artifacts. Such repositories typically operate as online services in front of a database management system (DBMS). Except for the normative behaviors noted below, the internal processes of the repository are out of scope for this IHE Profile.

Normatively, a Guideline Repository:

1. SHALL be able to appropriately respond to a well-formed transaction Search for Guideline [QRPH-61] [as responder]; and

2. SHALL be able to appropriately respond to a well-formed transaction Retrieve Guideline [QRPH-62] [as responder]; and

3. SHALL be able to appropriately respond to the submission of a well-formed CCG payload by a Guideline Publisher using Publish Guideline [QRPH-63] [as responder]; and

   1. If the well-formed CCG payload adheres to the stipulations of the Digitally Signed Folder Option – the Guideline Repository SHALL appropriately evaluate the payload and process it accordingly; and

   2. If the well-formed CCG payload adheres to the stipulations of the Digitally Signed CARD Option – the Guideline Repository SHALL appropriately evaluate the payload and process it accordingly.

The content specifications in Volume 3 of the IHE CCG Profile define a base set of normative requirements for a well-formed CCG artifact. One or more alternate content definitions may be documented in Volume 4. A Guideline Repository SHALL declare the content model option to which it adheres.

Guideline Performer

A Guideline Performer is a digital health solution that helps operationalize a guideline-based (CCG-supported) care workflow. Examples of such a solution include electronic medical records (EMR) products, consumer-facing or provider-facing digital health apps, or even SMS-based chat services leveraging digital public infrastructure platforms such as UNICEF’s RapidPro². Typically (but not always), these solutions are able to connect to health information exchange (HIE) infrastructure. Often, the Guideline Performer can leverage the HIE to obtain up-to-date health information about the subject of care and to update the HIE with the results of the care encounter, once it is completed.

As a practical matter, it is anticipated that a Guideline Performer will often be grouped with a Care Plan Contributor, and potentially also with a Care Plan Service. Such an actor grouping will enable a digital health solution to associate one or more CCGs with a subject of care as well as to leverage the relevant CCGs in supporting guideline-based care workflows.

Some Guideline Performer Actors will be grouped with a Guideline Engine as part of a single holistic solution. In other configurations, the Guideline Performer will call the “engine” as an external service. Except for the normative behaviors noted below, the internal processes of the Guideline Performer are out of scope for this IHE Profile.

During a care encounter, the Guideline Performer:

1. SHALL establish the relevant care context, including the uniquely identified care subject, the care provider and care location (if applicable), and the initial version of the care subject’s person-centric health data;

2. SHALL iteratively loop until there are zero CCG-informed recommendations that remain to be actioned. In this loop, it is expected the following processes will be executed:

   1. User inputs will be captured to operationalize each relevant CCG CARD recommendation or to log the reason code for not operationalizing the recommendation;

   2. The relevant care context data will be updated to reflect the user inputs from step 2.1;

   3. The relevant care context data will be leveraged by a Guideline Engine, either internally or via an external call using transaction Apply Guideline [QRPH-64] [as originator], to generate and return a set of CCG CARD-based recommendations.

3. SHALL persist the updated care context data, reflective of the activities carried out during the processing of the iterative loop (2), along with appropriate audit log records.

The base content specifications related to care context and related to person-centric health data are defined in Volume 3 of the IHE CCG Profile, as are the calling conventions and data inputs for the Apply Guideline [QRPH-64] transaction and the normative Resulting Data from the processing of the transaction response. One or more alternate content specifications may be documented in Volume 4. A Guideline Performer SHALL declare the content model option to which it adheres.

Guideline Engine

A Guideline Engine is a digital health solution that, based on a supplied input data bundle, evaluates a set of one or more relevant CCGs and returns the care recommendations that are applicable, given the inputs. Guideline Engine Actors must be able to query for, retrieve, and ingest CCGs that have been published to a Guideline Repository. To protect against CCGs being used as an attack surface, a Guideline Engine may support an option to only ingest and operationalize CCGs that have been digitally signed by trusted sources.

For the purposes of this FHIR-based CCG Profile, a Guideline Engine is an actor that correctly executes the HL7™ FHIR® CPG PlanDefinition Apply operation³ as defined by the CPG-on-FHIR Implementation Guide. Guideline Engine solutions may be implemented as an add-on to a FHIR® server or the server may natively operationalize support for this operation. There are many deployment options. For example, an engine might be operationalized by a software development kit (SDK) or it might be a hosted online service operated by a Ministry of Health. As noted above, some Guideline Performer actors may be grouped with a Guideline Engine as part of a single software solution. Except for the normative behaviors noted below, the internal software processes of the Guideline Engine are out of scope for this IHE Profile.

Normatively, a Guideline Engine:

1. SHALL be able to submit a query to a Guideline Repository using Search for Guideline [QRPH-61] [as originator]; and

2. SHALL be able to submit a query to a Guideline Repository using Retrieve Guideline [QRPH-62] [as originator] and ingest the resulting CCG packages, if applicable; and

3. MAY, if the Trusted CCG Option is supported, ensure for digitally signed artifacts returned via transaction [QRPH-62]

   1. The signing authorities are trusted; and

   2. The digital signatures match the relevant hashes on signed content.

4. SHALL support execution of the CPG PlanDefinition Apply operation with the input (“IN”) parameters defined for Apply Guideline [QRPH-64].

5. MAY support execution of the CPG PlanDefinition Apply operation with any other input (“IN”) parameters defined in the operation’s specification.

The base content specifications related to care context and related to person-centric health data are defined in Volume 3 of the IHE CCG Profile, as are the calling conventions and data inputs for the Apply Guideline [QRPH-64] and the normative Resulting Data from the processing of the transaction response. One or more alternate content specifications may be documented in Volume 4. A Guideline Engine SHALL declare the content model option to which it adheres.

Options

Each CCG actor SHALL declare the common content model it supports. All the actors in a CCG ecosystem SHALL support the same common content model option.

The Guideline Publisher and Guideline Repository each MAY support two options for digitally signed CCGs:

1. Digitally Signed Folder

2. Digitally Signed CARD

The Guideline Engine MAY support the Trusted CCG Option.

Table 2: CCG Actor Options

Actor	Option	Optionality
Guideline Publisher	Common Content Model	R
	Digitally Signed Folder	O
	Digitally Signed CARD	O
Guideline Repository	Common Content Model	R
	Digitally Signed Folder	R
	Digitally Signed CARD	R
Guideline Performer	Common Content Model	R
Guideline Engine	Common Content Model	R
	Trusted CCG	O

Common Content Model

Each CCG actor SHALL support at least one of the common content options listed below:

1. Volume 3

2. An alternate common content model defined in Volume 4

3. None

Note: an alternate common content model defined in Volume 4 may alter/augment the content model defined in Volume 3 or it may replace the base model altogether. All of the content models defined by this IHE Profile are peer alternates, including the base model defined in Volume 3.

Digitally Signed Folder

Guideline Publisher Actors supporting this option SHALL include a single digital signature that applies to the entire CCG artifact. For actors supporting the common content model in Volume 3, this signature is applied to the whole “Folder” (note the folders-and-CARDS model described in section Folder-and-CARDs Metaphor).

A Guideline Repository SHALL support both levels of digital signature on the Publish Guidelines transaction: at the Folder level (whole-CCG) and at the CARD level (each artifact). If a digital signature has been included at the Folder level, and if the signature does not match the content hash, an exception will be returned to the submitter and the content will not be persisted to the repository.

Digitally Signed CARD

Guideline Publisher actors supporting this option SHALL also support the Digitally Signed Folder Option. In addition to including a digital signature on the Folder, a digital signature SHALL also be included for each individual knowledge artifact in the CCG. For actors supporting the common content model in Volume 3, this option operationalizes digital signing at the CARD level (note the folders-and-CARDS model described in section Folder-and-CARDs Metaphor).

A Guideline Repository shall support both levels of digital signature on the Publish Guidelines transaction: at the Folder level (whole-CCG) and at the CARD level (each artifact). If the digital signature on any individual knowledge artifact does not match its hash, an exception will be returned to the submitter and none of the submitted content for the offending CCG will be persisted to the repository.

Trusted CCG

A Guideline Engine supporting the Trusted CCG Option SHALL verify that each CCG knowledge artifact is signed by a trusted entity and that the digital signature on every artifact matches the artifact’s hash. If the artifact’s signing certificate is not in the trust list, or if the artifact’s hash does not match its digital signature, then an exception SHALL be raised and every CCG Folder referencing the relevant artifact SHALL be made inactive until the issue is resolved.

For clarity: a Guideline Engine supporting the Trusted CCG Option SHALL flag an unsigned artifact as an exception.

Actor Groupings

Groupings Related to Security and Auditing

To support the trusted execution of transactions within a regulated healthcare domain, all actors in this specification are implicitly grouped with IHE’s Secure Application⁴ and Time Client⁵ Actors and the Authorization Client⁶ Actor.

Optional Groupings Related to Care Context and Person-Centric Data

The Guideline Performer SHALL be able to construct the [QRPH-64] data payload and process the transaction result to create the Resulting Data, based on the common content option to which the actor claims adherence. To support these requirements, the Guideline Performer MAY be grouped with IHE’s Care Services Selective Consumer⁷, Patient Demographics Consumer⁸, and Content Creator (IPS)⁹ Actors, and support IPS-related transaction processing behaviors described in the ITI Sharing IPS (sIPS) Profile¹⁰.

Implications of Digital Health Solutions Composed of Multiple Grouped Actors

As noted in the Actors, Transactions, and Content Modules section, a single digital health solution may choose to incorporate the functionality of multiple actors. Where this is the case, the solution will not be conformance-tested against transactions internal to its operation, but rather only against those transactions that it executes with external actors.

A short set of particularly likely actor groupings is discussed in the following sections.

Guideline Performer | Care Plan Contributor | Care Plan Service

An electronic medical records (EMR) solution is likely to be capable of creating or updating a person-centric care plan for a subject. A digital health solution that is claiming conformance as a Guideline Performer will be able to claim conformance as a grouped Care Plan Contributor and Care Plan Service if it can demonstrate that it is able to achieve State-C and State-D as defined in the Use Cases section of this profile (Figures 7 and 8).

Guideline Performer | Guideline Engine

Some digital health solutions may leverage software development kit (SDK) or add-on products to operationalize CCG-processing capabilities as part of their native functionality. A digital health solution that is claiming conformance as a Guideline Performer will be able to claim conformance as a grouped Guideline Engine if it can demonstrate that it is able to correctly achieve State-E from a known starting point of State-D and State-B (as illustrated by Figure 8 in the Use Cases section of this profile).

Security Considerations

All person-centric health information is a potential target for hackers. In recent years, the security of multiple hospital information systems, across many countries, has been compromised¹¹. CCGs however, represent a particularly nefarious potential attack surface:

• Because their purpose is to inform the course of patient care, bad actors who can alter the recommendations in a CCG can potentially impact the care pathways of entire populations, or of targeted subpopulations.

• Where CCG adherence is a component of provider payment schemes, “spoofing” the CCG’s reportable indicators and/or its audit trails could be a potential instrument of financial fraud.

Important mitigations against CCG tampering are the Digitally Signed Folder, Digitally Signed CARD and Trusted CCG Options (see detailed descriptions in the Options section). These mitigations rely on the ability to establish a digital certificate chain of trust.¹² Public Key Infrastructure (PKI) is an effective tool for operationalizing such a chain of trust, but establishing and maintaining a PKI is nontrivial. The granularity of signing at the CARD level (each recommendation) vs. at the Folder level (entire CCG) can support initiatives that encourage organizations to be evolving recommendations as new evidence emerges. The US CDC’s “living guidelines”¹³ initiative, for example, would be well served by digital signatures at the CARD level.

Implementation architectures may also be employed to afford a credible degree of protection. Some jurisdictions have deployed clinical decision support engines as hosted services. With such an approach, the security practices of the host would defend the integrity of both the CCGs and their processing engine.

Another important security aspect relates to CCG Engines’ audit records. It should be expected that such records could be of medico-legal importance. In a malpractice case, for example, such audit records are a potential source of evidence. To be trusted, these records should be demonstrably faithful and tamper-proof. Of note – detailed audit logs are also a useful instrument of conformance-testing. Since passing conformance tests may be a requirement of market entry – this also augers for the importance of credible audit logging.

Footnotes