ResearchKitOnFHIR

ResearchKitOnFHIR is a framework that allows you to use FHIR Questionnaires with ResearchKit to create healthcare surveys on iOS based on the HL7 Structured Data Capture Implementation Guide

For more information, please refer to the API documentation.

Features

• Converts FHIR Questionnaires into ResearchKit tasks
• Serializes results into FHIR QuestionnaireResponses
• Supports survey skip-logic by converting FHIR enableWhen conditions into ResearchKit navigation rules
• Supports answer validation during entry
• Supports contained FHIR ValueSets as answer options

FHIR <-> ResearchKit Conversion

FHIR R4 QuestionnaireItemType	ResearchKit Type	FHIR Response Type
attachment	ORKImageCaptureStep	valueAttachment
boolean	ORKBooleanAnswerFormat	valueBoolean
choice	ORKTextChoice	valueCoding
date	ORKDateAnswerFormat(style: ORKDateAnswerStyle.date)	valueDate
dateTime	ORKDateAnswerFormat(style: ORKDateAnswerStyle.dateAndTime)	valueDateTime
decimal	ORKNumericAnswerFormat.decimalAnswerFormat	valueDecimal
display	ORKInstructionStep	none
group	ORKFormStep	none
integer	ORKNumericAnswerFormat.integerAnswerFormat	valueInteger
quantity	ORKNumericAnswerFormat.decimalAnswerFormat(withUnit: quantityUnit)	valueQuantity
string	ORKTextAnswerFormat	valueString
text	ORKTextAnswerFormat	valueString
time	ORKTimeOfDayAnswerFormat	valueTime

Navigation Rules

The following table describes how the FHIR enableWhen is converted to a ResearchKit ORKSkipStepNavigationRule for each supported type and operator. (The conversion is performed by constructing an ORKResultPredicate from the enableWhen expression and negating it.)

Multiple enableWhen expressions are supported, using the enableBehavior element to determine if any or all of the expressions should be applied. If enableBehavior is not defined, all expressions will be applied.

FHIR R4 QuestionnaireItemType	Supported QuestionnaireItemOperators	ResearchKit ORKResultPredicate
boolean	=, !=	.predicateForBooleanQuestionResult
integer	=, !=, <=, >=	.predicateForNumericQuestionResult
decimal	=, !=, <=, >=	.predicateForNumericQuestionResult
date	>, <	.predicateForDateQuestionResult
coding	=, !=	.predicateForChoiceQuestionResult

Installation

ResearchKitOnFHIR can be installed into your Xcode project using Swift Package Manager.

1. In Xcode 14 and newer (requires Swift 5.7), go to “File” » “Add Packages...”
2. Enter the URL to this GitHub repository, then select the ResearchKitOnFhir package to install.

Usage

The Example directory contains an Xcode project that demonstrates how to create a ResearchKit task from an FHIR Questionnaire and extract the results in the form of an FHIR QuestionnaireResponse.

Converting from FHIR to ResearchKit

1. Instantiate an FHIR Questionnaire from JSON

let data = <FHIR JSON data>
var questionnaire: Questionnaire?
do {
    questionnaire = try JSONDecoder().decode(Questionnaire.self, from: data)
} catch {
    print("Could not decode the FHIR questionnaire": \(error)")
}

2. Create a ResearchKit Navigable Task from the FHIR Questionnaire

var task: ORKNavigableOrderedTask?
do {
    task = try ORKNavigableOrderedTask(questionnaire: questionnaire)
} catch {
    print("Error creating task: \(error)")
}

Now you can present the task as described in the ResearchKit documentation.

Converting ResearchKit Task Results to FHIR QuestionnaireResponse

In your class that implements the ORKTaskViewControllerDelegateProtocol, you can extract an FHIR QuestionnaireResponse from the task's results as shown below.

func taskViewController(
    _ taskViewController: ORKTaskViewController, 
    didFinishWith reason: ORKTaskViewControllerFinishReason, 
    error: Error?
) {
    switch reason {
    case .completed:
        let fhirResponse = taskViewController.result.fhirResponse
        // ...
    }
}

License

This project is licensed under the MIT License. See Licenses for more information.

Contributors

This project is developed as part of the Stanford University projects at Stanford. See CONTRIBUTORS.md for a full list of all ResearchKitOnFHIR contributors.

Notices

ResearchKit is a registered trademark of Apple, Inc. FHIR is a registered trademark of Health Level Seven International.