Question: Medication Checking in a FHIR eco-system

Aug 16, 2013

Question:

I am MS student and I am doing my thesis in FHIR. My task is to make current system reactive that is it should generate alert if two drugs can cause reaction, when taken together.

Can you please guide me that in this problem where FHIR will be used.

Answer:

This is actually a missing piece in FHIR at the moment. If you look here, you’ll see a hole for it:

Decision Support 2.5.3Still to be done.

On the other hand, the framework is laid down, though there’s still some missing pieces.

Firstly, let’s start with the context. I’m going to assume that you have an EHR System (EHR) that is maintaining a patients records, including managing their medications, and you have an expert system (XPERT) that is able to provide medication interaction knowedge.

The EHR system maintain patient records. Firstly, with regard to the patient, there’s the question of what medications they are on. This turns out to be a pretty complicated thing to figure out. There’s 4 relevent kinds of resource in FHIR:

  • MedicationPrescription - the medications a patient has been instructed to take. Or at least, to get their hands on in case they decide they need to take it
  • MedicationDispense - a record from a pharmacy that they actually gave the medication to the patient (or the agent or whatever)

Neither of those means the patient is or has taken the medication at all

  • MedicationAdministration - a record from a healthcare provider that they actually injected the medication, or watched the patient ingest it (and not throw it up?) or rubbed it on or whatever
  • MedicationStatement - a statement that the patient is actually ‘taking’ a medication - or did take it - or feels as though they should claim that they take it, or something.

Tracking a patient’s actual medictions is hard. But let’s assume that between these sets of resources, and an active system with enthusiastic data entry people, we can get a good grip on what the patient is believed to be taking.

In addition to these medication resources, there’s some other resources that might be of interest to the decision:

  • DiagnosticReport / Observations - to get a handle on the patient’s GFR rates for calculating medication kinetics
  • CarePlan - a statement of the intended goals for this patient (perhaps the drug interaction is known and tolerated? - but this is advanced usage)

So the EHR system needs to share these with the XPERT system, and then ask the XPERT system for an opinion, and the XPERT system needs to return it’s opinion to the EHR.

Getting a decision

At this point, the EHR needs to query the XPERT system. There’s many ways that this can be done. Here’s some choices:

  • The EHR can bundle up everything it has on the patient (or everything that might be relevant) and submit it to the xpert system with a query asking for the decision
  • expose the patient record to the xpert system (using the FHIR API), and then post a query to the xpert system
  • expose the patient record to the xpert system (using the FHIR API), post the query in the same place, and wait for the xpert system to see it (by subscribing to changes)

Then the EHR system gets the response back.

Query/Response

Now - what’s the query, exactly, and what’s the response?

That’s work that hasn’t been done yet, I’m afraid. But HL7 is actively working on these kind of decisions, so I expect we’ll see this clarified fairly soon. If it’s your thesis subject…. you need to get involved in HL7 (pharmacy work group) and push it along, perhaps by providing a sample implementation for people to evaluate.