Stream: EBMonFHIR
Topic: What is the difference between useContext and subject
Yunwei Wang (Jan 14 2021 at 03:57):
I am a little bit confused
Bryn Rhodes (Jan 14 2021 at 04:49):
Subject is declaring the scope that the artifact is written in, and there are only a handful of them, and they are declared (and understood) by the information model. Like Patient, Location, Organization, they're like Compartments.
Bryn Rhodes (Jan 14 2021 at 04:50):
UseContext is for describing structured criteria that describe when, where, why, and for whom an artifact is appropriate.
Bryn Rhodes (Jan 14 2021 at 04:52):
In a decision support rule, for example, the subject is Patient, which means the logic is written from the perspective of a patient, so if the logic accesses MedicationRequests, it's understood that it's only MedicationRequests for the patient in context.
Bryn Rhodes (Jan 14 2021 at 04:53):
The use context for that same decision support rule might say the rule is appropriate for use in an inpatient setting, for patients with a substance misuse disorder, and by a pain management specialist.
Brian Alper (Jan 14 2021 at 11:14):
Bryn's replies refer to other FHIR resources in the Clinical Reasoning space, but Yunwei is asking about EvidenceReport Resource.
The useContext element is inherited from ancestors so is, as Bryn suggests, available for describing structured criteria that describe the situations in which the artifact is intended to be used.
The subject element in an EvidenceReport is a compound element containing any number of characteristics. Unlike a decision rule (where the subject is often a singular concept to represent the target of application), the subject of an EvidenceReport is for a structured definition of what the evidence report is about. If you were to create a report of the effect of dexamethasone on symptoms in people with COVID-19 reported in a research study in a journal publication, the subject could include 4 characteristics: the intervention = dexamethasone, the outcome = symptoms, the population = COVID-19, and the Citation = the citation for the journal article.
Yunwei Wang (Jan 14 2021 at 15:39):
Thank you @Bryn Rhodes and @Brian Alper Yes my question is about EvidenceReport in EBM. I feel there is an overlap between useContext and subject. In your example, the people with COVID-19 could be either "which the artifact is intended to be used" or "what the artifact is about".
Also in current R5 preview, there is no search parameter defined for subject.
Brian Alper (Jan 15 2021 at 11:46):
You can use EvidenceReport.useContext to express the concept of condition=COVID-19 if you are supporting a system that recognizes a 'context for use' for application (accessing) this EvidenceReport related to COVID-19.
You can use EvidenceReport.subject to express the concept of condition=COVID-19 if you are specifying the focus of the report (the subject matter, what the report is about) included COVID-19.
You can use EvidenceReport.section to express the concept of condition=COVID-19 if you want this concept to be part of the content of the report.
You can potentially have a situation in which all 3 of these concepts apply. The different elements (useContext, subject, section) allow you the precisely specify these related but not equal concepts.
Adding search parameters for subject is an excellent suggestion. Let's follow up after the Connectathon to review how we do this.
Last updated: Apr 12 2022 at 19:14 UTC
