Stream: research
Topic: General questions
Traven (Apr 19 2021 at 09:10):
Hello everybody
We are evaluating how a hospital could handle the data processing of it's internal studies with a CDR that implements FHIR.
An internal study for example is comparing different ways of inserting catheter.
Process (It's only a proof of concept, therefore kept simple):
a) create a study
b) add a patient to the study
c) capture the data
d) close the study
I tried to find the corresponding fhir ressources which led to the following questsions:
1) Is it correct that the study itself can be represented with the ResearchStudy Resource (Step a) ?
2) How do I link a patient or encounter to the study (Step b)
3) Are there typical ressources used to capture the data or are you free to use an observation Ressource, Diagnostic Ressource,... (Step c)
4) Why do I only find the ImagingStudy being linked in several other ressources e.g. the Observation Ressources "part of" value, but not the RessearchStudy?
Thanks in advance for all the help
Greeting Michael
Lloyd McKenzie (Apr 19 2021 at 14:17):
1 - yes
2 - ResearchSubject ties a Patient to a ResearchStudy and tracks their status within the study. Encounter is linked through Patient, though there's also an extension where you can tie resources directly to ResearchStudy if there's a need to distinguish which patient encounters are tied to the study and which aren't
- Data would typically be captured using standard resources.
- Links to ResearchStudy are through an extension - because we don't believe that most systems that support the resources also support tying to ResearchStudy
Traven (Apr 19 2021 at 16:15):
Thanks @Lloyd McKenzie , I think i now got the idea:
A) You have a ResearchSubject Ressource which contains
1) a "study" element, which references a ResearchStudy Ressource
2) a "individual" element, which references a Patient
B) You then create e.g. a Observation Ressource with the researchStudy Extension (https://build.fhir.org/extension-workflow-researchstudy.html)
With those linkage it should be possible to get either all the data for a study or just from a specific patient.
Traven (Apr 21 2021 at 13:15):
Something I don't understand : Why does the ResearchSubject Ressource only reference to One Patient (Cardinality 1:1).
Usually there are several patients taking part in studys? I therefore expected it to be 1:* :thinking:
John Moehrke (Apr 21 2021 at 13:24):
my understanding is that the ResearchSubject resource represents an individual state within a study -- http://hl7.org/fhir/researchsubject.html#statemachine
Not the cohort.
The cohort would be the list of all ResearchSubjects with a .study with the value of the ResearchStudy (id) of interest.
Traven (Apr 21 2021 at 13:34):
Ah okay, meaning if I have a ResearchStudy Ressource "SampleStuy" with Id X and to list all the patient that take part in I would have to
1) List all the Ressource ResearchStubject Ressources that have a .study _id = X
2) Looping through results of 1) and list the Patient Reference in the individual segment
Is this correct or is there an easier way?
John Moehrke (Apr 21 2021 at 13:35):
that is pretty easy
Lloyd McKenzie (Apr 21 2021 at 15:19):
You can do all that with a single query using _include. ResearchSubject represents the linkage for each patient - because each will have different enrollment dates, be part of different arms, have different statuses, etc.
Traven (Apr 21 2021 at 16:11):
thanks @John Moehrke and @Lloyd McKenzie I am still rather new to FHIR so all the advice I can get is very helpful
Traven (Apr 21 2021 at 21:53):
@Lloyd McKenzie May I ask for help again?
I looked up "_include" search and found the following example in the documentation
Example: GET [base]/MedicationRequest?_include=MedicationRequest:patient
Explanation: This search requests all matching MedicationRequests, to include any patient that the medication prescriptions in the result set refer to
So I tried the following search on the test server:
http://hapi.fhir.org/baseR4/MedicationRequest?_include=MedicationRequest:patient=2045294
I expected it to result in a Bundle only containing MeddicationRequest with a patient ressource of id = 2045294.
This did not happen, it lists also MeddicationRequest for different patients.
How can I use the "_inclucde" query to get a Ressource that includes a certain Ressource for a specific value?
Lloyd McKenzie (Apr 21 2021 at 22:25):
_include says "for all matching MedicationRequests you find, also bring back these related resources". The filters on what MedicationRequests should come back are outside the _include. (Key thing to be aware of is that you can't have more than one "=" in a clause.)
What you want is:
http://hapi.fhir.org/baseR4/MedicationRequest?patient=2045294&_include=MedicationRequest:patient
Last updated: Apr 12 2022 at 19:14 UTC
