How to transform HealthKit data to FHIR

For this part, we use the Microsoft package HealthKitToFHIR

https://github.com/microsoft/healthkit-to-fhir

This is a usefull package that offer factories to transform HKQuantitySample to FHIR Observation

     let observation = try! ObservationFactory().observation(from: item)
      let patientReference = try! Reference(json: ["reference" : "Patient/\(patientId)"])
      observation.category = try! [CodeableConcept(json: [
          "coding": [
            [
              "system": "http://terminology.hl7.org/CodeSystem/observation-category",
              "code": "activity",
              "display": "Activity"
            ]
          ]
      ])]
      observation.subject = patientReference
      observation.status = .final
      print(observation)
      observation.create(self.fhirServer,callback: { (error) in
          if error != nil {
              completion(error)
          }
      })

Where item is an HKQuantitySample in our case a stepCount type.

The factory does most of the job of converting ‘unit’ and ‘type’ to FHIR codeableConcept and ‘value’ to FHIR valueQuantity.

The reference to the patientId is done manually by casting a json fhir reference.

let patientReference = try! Reference(json: ["reference" : "Patient/\(patientId)"])

Same is done for the category :

      observation.category = try! [CodeableConcept(json: [
          "coding": [
            [
              "system": "http://terminology.hl7.org/CodeSystem/observation-category",
              "code": "activity",
              "display": "Activity"
            ]
          ]
      ])]

At last the observation is created in the fhir repository :

      observation.create(self.fhirServer,callback: { (error) in
          if error != nil {
              completion(error)
          }
      })