ENGAGE-HF Firebase

Firebase cloud hosting infrastructure for the ENGAGE-HF project.

Behavior

The base functionality of the ENGAGE-HF Firebase Functions revolve around three parts:

• recommending medication changes to patients based on existing medication, vitals and symptom scores
• calculating symptom scores from questionnaire responses of patients
• generating Health Summary PDFs containing recommendations, vitals and symptom scores

Health Summary Generation

Health Summary PDFs contain four sections:

• Medications & Recommendations
• Vital Summary containing only the most important vitals
• Symptom Score Report including a speedometer displaying the current score in relation to the previous one and a baseline, a table with the most recent symptom score results and a small personal summary
• Detailed Vitals Page with graphs displaying body weight, heart rate and blood pressure measurements and important key figures

Recommendation Algorithms

ENGAGE-HF uses four different algorithms to recommend medication changes based on existing medication, vitals and symptom scores. Each recommendation algorithm corresponds to a medication class (Beta blockers, MRA, SGLT2i) or a group of medication classes (RASI including ACEI, ARB and ARNI).

• Note 1: This codebase contains five different recommender types, including one for diuretics. The diurectics recommender simply recommends staying on the existing medication and assumes that medication to already be at the personal target dose.
• Note 2: The algorithms are only expected to be run with one medication per class, not multiple different medications in one class.

ENGAGE-HF utilizes four algorithms to recommend medication adjustments based on a patient's current medications, vital signs, and symptom scores. Each algorithm is tailored to a specific medication class — Beta-blockers, MRAs, and SGLT2 inhibitors — or a combination of classes, such as RASI (including ACEIs, ARBs, and ARNIs).

Notes:

• The codebase includes an additional recommender for diuretics, making a total of five recommenders. The diuretics recommender simply advises maintaining the current medication, assuming it is already at the patient’s personal target dose.
• The algorithms are designed to handle one medication per class, not multiple medications within the same class.

Beta Blockers

Depending on contraindications entered on the Web Dashboard, a different medication is listed in the following order:

• Carvedilol
• Metoprolol Succinate
• Bisoprolol

RASI

MRA

Depending on contraindications entered on the Web Dashboard, a different medication is listed in the following order:

• Spironolactone
• Eplerenone

SGLT2i

Depending on contraindications entered on the Web Dashboard, a different medication is listed in the following order:

• Empagliflozin
• Dapagliflozin
• Sotagliflozin

Contraindications

Contraindications are handled using FHIR AllergyIntolerance resources found in the users/$userId$/allergyIntolerances collections. In the code property, we use RxNorm codes as described in functions/src/tests/resources/contraindications.csv for the different medications. Depending on the type and criticality properties, we identify each allergy as one of the following:

• Severe Allergy (for type allergy and criticality high)
• Allergy (for type allergy and criticality not high)
• Intolerance (for type intolerance)
• Financial (for non-standard type financial)

In the file, we also describe how each of these cases relate to which medications are taken out of the recommendable options.

Symptom Score Calculation

The Kansas City Cardiomyopathy Questionnaire-12 (KCCQ-12) score assesses a patient’s physical limitations, symptom frequency, quality of life, and social limitations. Scores are normalized to a 0-100 scale, where higher values indicate better health status. ENGAGE-HF further adds one additional question about dizziness to the questionnaire used in the application.

Physical Limitations

Questions 1a, 1b, and 1c assess physical limitations. Responses are scored from 1 to 6, where:

• 1 indicates severe limitations.
• 5 indicates minimal limitations.
• 6 indicates "Does not apply" (excluded from scoring).

The Physical Limitations score is the average of the applicable responses, normalized to a 0-100 scale. If fewer than two responses are valid, the score cannot be calculated.

Symptom Frequency

Questions 2, 3, 4, and 5 evaluate symptom frequency, with responses scored from:

• 1 to 4 for Questions 2 and 5.
• 1 to 7 for Questions 3 and 4.

Each response is normalized to a 0-100 scale. The Symptom Frequency score is the average of these normalized values.

Quality of Life

Questions 6 and 7 measure quality of life, with responses scored from 1 to 4, where lower scores indicate worse quality of life. These scores are normalized to a 0-100 scale, and their average forms the Quality of Life score.

Social Limitations

Questions 8a, 8b, and 8c address social limitations, scored similarly to the Physical Limitations questions (1 to 6 scale, excluding "Does not apply"). The Social Limitations score is the average of the applicable responses, normalized to 0-100, provided at least two valid responses are available.

Clinical Summary & Overall

The Clinical Summary Score is the average of the Physical Limitations and Symptom Frequency scores, whereas the Overall Total Score is calculated as the average of all four above-mentioned domain scores.

Dizziness

In addition to the KCCQ-12 questions, ENGAGE-HF uses question 9 to ask the patient about dizziness. Its responses are encoded as integers between 1 and 5.

Data Scheme

This document describes how data is stored in Firestore for the Engage-HF app.

Custom Types

The following section describes custom types defined for this system to be later used

LocalizedText

A LocalizedText object shall be used whenever text requires localization or may require in the future. The object may either simply be a single string (in the case of localizations not being available yet) or a dictionary with string keys and string values. If LocalizedText is represented by a string-string dictionary, the keys represent language-codes following the ISO 639-1 (or if necessary ISO 639-2) standard and the respective text in the given language as value.

Some localizations may require to include regions as well (e.g. Australian/British/American English), so the clients should be aware of this and prioritize the language code with the correct region (en-us) over the general code (en), if it is present.

A LocalizedText object cannot be used in FHIR-conforming types due to its incompatibility with the standard. FHIR types commonly contain text in one language only to be specified using the language property.

Example

{
	"en":"Welcome to the Engage-HF app!",
	"de":"Willkommen in der Engage-HF App!",
	"es":"¡Bienvenido a la aplicación Engage-HF!"
}

invitations/$invitationId$

When a user joins Engage-HF, we first create an invitation code on demand of an operator of the web dashboard.

For patients, upon entering the invitation code using an anonymous login, the userId is set. After successful registration, the user object will be fully created and the invitation is removed from this collection.

For SSO users (e.g. clinicians,owners), upon the first login using SSO, the related invitation is fetched, the user object will be fully created and the invitation is removed from this collection.

Property	Type	Values	Comments
code	string	e.g. 'PAULPAUL'	An 8-digit invitation code or SSO email address.
userId	optional string	-	The userId associated with the invitation. This is set when an anonymous user has entered an invitation code, but has not used a proper account to log in yet.
auth	optional Auth	Authentication information to be set when redeeming invitation. Will no longer be set once invitation has been redeemed.
auth>displayName	optional string	Display name for the user.
auth>email	optional string	E-Mail address of the user.
auth>phoneNumber	optional string	Phone number of the user.
auth>photoURL	optional string	URL for a photo of the user.
user	optional User	See users/$userId$ for full specification. Will no longer be set once invitation has been redeemed.

medications

In this section, we describe information regarding all the medications to be specified in the Engage-HF context. These medications may be used by a clinician for medication requests to a patient (users/$userId$/medicationRequests) or contra-indications (users/$userId$/allergyIntolerances). The medications are generated from functions/data/medicationCodes.json file containing medications (incl. respective RxNorm SCD type codes) grouped by medication classes.

medications/$medicationId$

Based on FHIR Medication, the following properties may be used, while additional properties are ignored by the Engage-HF system.

Property	Type	Values	Comments
id	string	-	Resource: Logical id of this artifact
code	FHIRCodeableConcept	-	FHIRCodeableConcept containing an RxNorm code of the IN/MIN type, a display name and the RxNorm system url.
extension	list of Extension	-	See /medications/$medicationId$/extension for possible values

Based on the Extension format specified in FHIR, a medication may contain a list of these following extension properties. Each property will need to get a url assigned to fit the FHIR data format.

Property	Type	Values	Comments
medicationClass	string	-	A medicationClassId referring to a medicationClass specified in /medicationClasses/$medicationClassId$. One medication object may contain multiple medicationClass extension properties.
minimumDailyDose	SimpleQuantity	-	Unit: mg/day. Occurs exactly once. Multi-ingredient tablets contain an array of double rather than a double.
targetDailyDose	SimpleQuantity	-	Unit: mg/day. Occurs exactly once. Multi-ingredient tablets contain an array of double rather than a double.

medications/$medicationId$/drugs/$drugId$

Property	Type	Values	Comments
id	string	-	Resource: Logical id of this artifact
code	FHIRCodeableConcept	-	FHIRCodeableConcept containing an RxNorm code of the SCD type, a display name and the RxNorm system url.
ingredient	list of Ingredient	-	Use references to medications and strength for quantity information.
ingredient[x]>itemCodeableConcept	FHIRCodeableConcept	-	FHIRCodeableConcept containing an RxNorm code of the IN type, a display name and the RxNorm system url.
ingredient[x]>strength	Ratio	-	Uses "mg" as numerator unit, no denominator unit and denominator value is always 1.

medicationClasses/$medicationClassId$

Property	Type	Values	Comments
id	string	-	-
name	LocalizedText	-	A name for a given medicationClass to be displayed to a user.
videoPath	string	e.g. "/videoSectionId/1/videos/2"	The path to retrieve the respective video from Firestore.

organizations/$organizationId$

Property	Type	Values	Comments
name	string	e.g. "Stanford University"	-
contactName	string	e.g. "Alex Sandhu, MD"	-
phoneNumber	string	e.g. "(650) 493-5000"	-
emailAddress	string	e.g. "dothfteam@stanford.edu"	-
ssoProviderId	string	-	The providerId as used for single sign-on.

questionnaires

In this section, we describe all the information stored for questionnaires.

questionnaires/$questionnaireId$

Based on FHIR Questionnaire, the following properties may be used, while additional properties are ignored by the Engage-HF system.

Property	Type	Values	Comments
id	string	-	Resource: Logical id of this artifact
meta	Meta	-	Resource: Metadata about the resource
identifier	list of Identifier	-	Business identifier for this questionnaire. There may be multiple questionnaire objects in this list, with differing id and language properties, but a common business identifier.
title	string	-	Human-friendly title of the questionnaire.
date	Date	-	last modified date
version	string	-	Business version of the questionnaire.
language	optional string	e.g. "en"	Following IETF BCP-47 / FHIR ValueSet languages
item	list of BackboneElement	-	items as defined in FHIR Questionnaire
item[x]>linkId	string	-	Unique id for item in questionnaire
item[x]>definition	optional uri	-	Details for the item
item[x]>prefix	optional string	e.g. "1(a)", "2.5.3"	Prefix of the item that isn't actually part of the name but may still be displayed.
item[x]>text	string	-	Primary text for the item
item[x]>type	code	e.g. "group", "display", "boolean", "decimal", "integer", "date", etc	See QuestionnaireItemType for available values.

You can find an example KCCQ-12 questionnaire in functions/data/questionnaires.json.

users/$userId$

In this section, we describe all user-related data to be stored. The security rules shall be set up in a way to only allow for a patient to access its own information and a clinician to access all patients' information (or even more restrictive, if needed).

Property	Type	Values	Comments
type	string	e.g. "admin", "owners", "clinician", "patient"	The type of the user.
dateOfEnrollment	Date	-	The date when the invitation code was used to create this user.
dateOfBirth	optional Date	-	The date when the user was born.
genderIdentity	optional string	"female","male","transgender","nonBinary","preferNotToState"	The gender identity chosen when a patient redeemed the invitation.
organization	optional string	-	The id of the organization a clinician, patient or owner is associated with.
invitationCode	string	-	The invitationCode to be used when logging in to the app for the first time.
language	optional string	e.g. "en"	Following IETF BCP-47 / FHIR ValueSet languages.
receivesAppointmentReminders	optional boolean	true, false	Decides whether to send out appointment reminders one day before each appointment.
receivesInactivityReminders	optional boolean	true, false	Decides whether to send updates about inactivity.
receivesMedicationUpdates	optional boolean	true, false	Decides whether to send updates about current medication changes.
receivesQuestionnaireReminders	optional boolean	true, false	Decides whether to send reminders about filling out their questionnaire every 14 days.
receivesRecommendationUpdates	optional boolean	true, false	Decides whether to send updates about recommended medication changes.
receivesVitalsReminders	optional boolean	true, false	Decides whether to send reminders about measuring vitals.
receivesWeightAlerts	optional boolean	true, false	Decides whether to send out alerts when drastic weight changes are observed.
timeZone	string	e.g. "America/Los_Angeles"	The value needs to correspond to an identifier from TZDB. It must not be an offset to UTC/GMT, since that wouldn't work well with daylight-savings (even if there is no daylight-savings time at that location). Also, don't use common abbreviations like PST, PDT, CEST, etc (they may be ambiguous, e.g. CST). If the timeZone is unknown, then "America/Los_Angeles" should be used.

users/$userId$/devices/$deviceId$

This data is required to send push notifications over the Firebase Cloud Messaging System.

Property	Type	Values	Comments
modifiedDate	Date	-	This date is updated whenever the token is sent to the server, even if it is not replaced by a different token. It simply reflects the last date we can definitely confirm the token was active. Idea: We may ignore some devices, if the token has not been updated for a long time, since the app has not been opened for a long time.
notificationToken	string	-	The FCM token as received from Firebase in the app.
platform	optional string	e.g. "iOS", "Android"	This information is important as context for the osVersion, appVersion and appBuild properties.
osVersion	optional string	e.g. "17.5.1"	The version of the OS. Depending on the OS, they may have different formats to be specified separately.
appVersion	optional string	e.g. "1.0.1"	The version of the app as it is specified on the App/Play Store.
appBuild	optional string	e.g. "56"	The build version of the app as defined by the CI pipeline releasing the app.
language	optional string	e.g. "en"	Following IETF BCP-47 / FHIR ValueSet languages

Push notifications over APNS / FCM only contain text in a single language. For this, the device's language property shall be prioritized, falling back on the user's language property and using US-English if both are not present.

Adding a new device or modifying information of an existing one

A device can only be identified by its notification token. When updating a device's information, we therefore check if the notification token already exists in Firestore. If it already exists, we update all other existing fields' values - otherwise, we create a new device.

A device may receive a different notification token at any time though. Therefore, we might create a new device, even though that device already exists in the table with a different (now inactive) notification token. Therefore, every time we send out a new notification and receive the information that a token is no longer active, we need to remove the device from this table.

users/$userId$/allergyIntolerances/$allergyIntoleranceId$

Only users with a patient role assigned have values in this collection.

Based on FHIR AllergyIntolerance, the following properties may be used, while additional properties are ignored by the Engage-HF system.

Property	Type	Values	Comments
id	string	-	Resource: Logical id of this artifact
type	optional allergyIntoleranceType	e.g. "allergy", "intolerance"	In addition to the FHIR defined value set, we also use "financial" - these values shall not be exposed to EHR systems.
code	CodableContent	e.g. {"coding":[{"system":"https://hl7.org/fhir/R4B/valueset-allergyintolerance-code.html","code":"293963004","display":"Cardioselective beta-blocker allergy"}],"text":"Cardioselective beta-blocker allergy"}	Uses either AllergyIntoleranceCode, medicationId as used in /medications/$medicationId$ and/or medicationId as used in /medicationClasses/$medicationClassId$.
patient	string	-	userId as used in /users/$userId$ and related collections.

We use RxNorm codes to identify contraindications using the following rules:

Class	Medication	If allergy, not eligible for	If allergy with reaction type angioedema not eligible for	If intolerance not eligible for	If intolerance default to	If financial, not eligible for
BB	Metoprolol succinate ER	BB	BB	Metoprolol	Carvedilol	BB
BB	Carvedilol	BB	BB	Carvedilol	Metoprolol succinate	BB
BB	Carvedilol phosphate ER	BB	BB	Carvedilol	Metoprolol succinate	BB
BB	Bisoprolol	BB	BB	Bisoprolol	Carvedilol	BB
SGLT	Dapagliflozin	SGLT	SGLT	Dapagliflozin	Empagliflozin	SGLT
SGLT	Empagliflozin	SGLT	SGLT	Empagliflozin	Dapagliflozin	SGLT
SGLT	Sotagliflozin	SGLT	SGLT	Sotagliflozin	Empagliflozin	SGLT
SGLT	Bexagliflozin	SGLT	SGLT	Bexagliflozin	Empagliflozin	SGLT
SGLT	Canagliflozin	SGLT	SGLT	Canagliflozin	Empagliflozin	SGLT
SGLT	Ertugliflozin	SGLT	SGLT	Ertugliflozin	Empagliflozin	SGLT
MRA	Spironolactone	MRA	MRA	Spironolactone	Eplerenone	MRA
MRA	Eplerenone	MRA	MRA	Eplerenone	Spironolactone	MRA
ACE	Quinapril	ACEI	ACEI/ARB/ARNI	ACEI	Valsartan/ARNI	ACEI/ARB/ARNI
ACE	Perindopril	ACEI	ACEI/ARB/ARNI	ACEI	Valsartan/ARNI	ACEI/ARB/ARNI
ACE	Ramipril	ACEI	ACEI/ARB/ARNI	ACEI	Valsartan/ARNI	ACEI/ARB/ARNI
ACE	Benazepril	ACEI	ACEI/ARB/ARNI	ACEI	Valsartan/ARNI	ACEI/ARB/ARNI
ACE	Captopril	ACEI	ACEI/ARB/ARNI	ACEI	Valsartan/ARNI	ACEI/ARB/ARNI
ACE	Enalapril	ACEI	ACEI/ARB/ARNI	ACEI	Valsartan/ARNI	ACEI/ARB/ARNI
ACE	Lisinopril	ACEI	ACEI/ARB/ARNI	ACEI	Valsartan/ARNI	ACEI/ARB/ARNI
ACE	Fosinopril	ACEI	ACEI/ARB/ARNI	ACEI	Valsartan/ARNI	ACEI/ARB/ARNI
ACE	Trandolapril	ACEI	ACEI/ARB/ARNI	ACEI	Valsartan/ARNI	ACEI/ARB/ARNI
ACE	Moexepril	ACEI	ACEI/ARB/ARNI	ACEI	Valsartan/ARNI	ACEI/ARB/ARNI
ARB	Losartan	ARB/ARNI	ACEI/ARB/ARNI	ARB/ARNI	Lisinopril	ACEI/ARB/ARNI
ARB	Valsartan	ARB/ARNI	ACEI/ARB/ARNI	ARB/ARNI	Lisinopril	ACEI/ARB/ARNI
ARB	Candesartan	ARB/ARNI	ACEI/ARB/ARNI	ARB/ARNI	Lisinopril	ACEI/ARB/ARNI
ARB	Irbesartan	ARB/ARNI	ACEI/ARB/ARNI	ARB/ARNI	Lisinopril	ACEI/ARB/ARNI
ARB	Telmisartan	ARB/ARNI	ACEI/ARB/ARNI	ARB/ARNI	Lisinopril	ACEI/ARB/ARNI
ARB	Olmesartan	ARB/ARNI	ACEI/ARB/ARNI	ARB/ARNI	Lisinopril	ACEI/ARB/ARNI
ARB	Azilsartan	ARB/ARNI	ACEI/ARB/ARNI	ARB/ARNI	Lisinopril	ACEI/ARB/ARNI
ARB	Eprosartan	ARB/ARNI	ACEI/ARB/ARNI	ARB/ARNI	Lisinopril	ACEI/ARB/ARNI
ARNI	Sacubitril-Valsartan	ARB/ARNI	ACEI/ARB/ARNI	ARNI	Valsartan	ARNI
Diuretic	Furosemide	-	-	-	-	-
Diuretic	Bumetanide	-	-	-	-	-
Diuretic	Torsemide	-	-	-	-	-
Diuretic	Ethacrynic Acid	-	-	-	-	-

users/$userId$/appointments

Only users with a patient role assigned have values in this collection. There is currently no easy way to check for appointments relevant to one clinician - if it happens to be a requirement in the future, we may need to restructure this.

Based on FHIR Appointment, the following properties may be used, while additional properties are ignored by the Engage-HF system.

Property	Type	Values	Comments
status	AppointmentStatus	e.g. "booked"	-
created	Date
start	Instant	-	-
end	Instant	-	-
comment	optional string	-	May not be shown to the patient.
patientInstruction	optional string	-	May be shown to the patient.
participant	list of CodeableConcept	-	Must contain at least one element.
participant[x]>actor	Reference(User)	e.g. users/123	The Firestore path to the patient.
participant[x]>status	ParticipationStatus	e.g. accepted, declined, tentative, needs-action	-

users/$userId$/medicationRequests/$medicationRequestId$

Only users with a patient role assigned have values in this collection.

Based on FHIR MedicationRequest, the following properties may be used, while additional properties are ignored by the Engage-HF system. Clients may ignore this list and simply query for users/$userId$/medicationRecommendations and retrieve the relevant requests from the recommendations.

Property	Type	Values	Comments
id	string	-	Resource: Logical id of this artifact
medication	Reference(Medication) or CodeableConcept	-	CodeableConcept containing one of the codes from /medications/$medicationId$
dosageInstruction	Dosage	-	-

The dosageInstruction property may contain values with the following properties:

Property	Type	Values	Comments
id	string	-	Resource: Logical id of this artifact
text	optional string	-	Free text dosage instructions
additionalInstruction	list of CodableConcept	information like "with meals", "may cause drowsiness", etc	Supplemental instruction or warnings to the patient
patientInstruction	optional string	-	Patient or consumer oriented instructions
timing	optional Timing	-	When medication should be administered
doseAndRate	list of Element	-	Amount of medication administered
doseAndRate>type	optional DoseRateType	e.g. "calculated", "ordered"
doseAndRate>dose	optional SimpleQuantity	-	Unit is always "tablet". Value is usually 0.5, 1 or 2.
maxDosePerPeriod	optional Ratio	-	Upper limit on medication per unit of time
maxDosePerAdministration	optional SimpleQuantity	-	Upper limit on medication per administration
maxDosePerLifetime	optional SimpleQuantity	-	Upper limit on medication per unit of time

There may be up to three intakes per day (morning, mid-day and evening) with either 0.5, 1 or 2 tablets. The dosages should always be grouped by medication, i.e. there should not be multiple medication elements concerning the same medication but different dosage instructions. Instead, one medication element shall be used for that medication with multiple dosage instructions.

users/$userId$/medicationRecommendations/$medicationRecommendationId$

Only users with a patient role assigned have values in this collection.

These are the output values of the recommendation algorithms. Depending on the type, the recommendations should be displayed with different icons and texts.

Property	Type	Values	Comments
currentMedication	optional Reference(FHIRMedicationRequest)	e.g. {"reference":"users/123/medicationRequest/2"}	Reference to the existing medication request, if applicable.
recommendedMedication	optional Reference(FHIRMedication)	e.g. {"reference":"medications/2"}	Reference to the recommended medication, if applicable. This should always direct to a medication, not a drug.
displayInformation	DisplayInformation	-	The information necessary for the client to display the medication recommendation.

Medication Recommendation Type

Type	Icon	Current Medication	Recommended Medication	Comments
targetDoseReached	Green Checkmark	exists	undefined	The target dose has been reached.
personalTargetDoseReached	Green Checkmark	exists	undefined	The personal target dose has been reached, meaning that vitals signal that we should not increase the dose (yet).
improvementAvailable	Yellow Up Arrow	exists	undefined	The patient should uptitrate.
morePatientObservationsRequired	Yellow	maybe	maybe (mutually exclusive to current medication)	There are not enough patient observations to recommend anything. They should probably do some blood pressure measuring.
moreLabObservationsRequired	Yellow	maybe	maybe (mutually exclusive to current medication)	More lab observations are required to recommend anything. The patient should probably schedule an appointment with a clinician.
notStarted	Gray Up Arrow	undefined	exists	Medication has not been started, but is eligible for initiation.
noActionRequired	Gray	undefined	exists	The recommended medication is not eligible, but should still be shown to the user as an option without recommending it to them.

Diuretics, if currently present as medication request, will be shown as a recommendation with personalTargetDoseReached, so that the logic on the client becomes easier.

DisplayInformation

Property	Type	Values	Comments
title	LocalizedText	e.g. "Carvedilol"	The name of the medication (not the tablet), e.g. coming from medications/1998.
subtitle	LocalizedText	e.g. "Beta Blockers"	The medication class name, e.g. coming from medicationClasses/0.
description	LocalizedText	e.g. "Personal target dose reached. No action required."	The explanation of the recommendation, displayed along with a summary of the medication.
type	Medication Recommendation Type	e.g. "personalTargetDoseReached"	See Medication Recommendation Type for more information.
videoPath	optional string	e.g. videoSections/1/videos/3	This is the video to show when the recommendation is tapped. The clients may want to hide the icon to get to the video when this value is not present.
dosageInformation	DosageInformation	See Dosage Information	A description of the current, minimum, and target doses for a given medication.
When the patient is not yet taking the medication, its currentSchedule will be an empty list.

The DosageInformation property contains the following information:

Property	Type	Values	Comments
currentSchedule	list of DoseSchedule	e.g. [25mg twice daily, 10mg daily]	A list tracking how many times per day the patient currently takes each tablet.
minimumSchedule	list of DoseSchedule	e.g. [6.25mg daily]	A list tracking how many times per day the patient would take each tablet on a minimal dose.
targetSchedule	list of DoseSchedule	e.g. [6.25mg daily]	A list tracking how many times per day the patient would take each tablet on a maximal dose.
unit	string	e.g. "mg"	The unit by which the ingredients in the medications are measured, as found in medications/$medicationId$/drugs/$drugId$.

The DoseSchedule object describes the number of tablets taken per day for a single medication as described in medications/$medicationId$/drugs/$drugId$. For example, taking two 5mg tablets in the morning and one 15mg tablet in the afternoon would result in two schedules: 5mg twice daily, and 15mg daily. Compound (multi-ingredient) tablets have multiple quantities per tablet, and will be displayed as e.g. 24/26mg twice daily. DoseSchedule has the following properties:

Property	Type	Values	Comments
frequency	number	e.g. 1, 2, or 0.5	The number of tablets per day (as described by medicationRequests/$medicationRequestId$/dosageInstruction).
quantity	list of number	e.g. [24, 26] or [6.25]	The amount of each active ingredient per tablet.

Observations

Only users with a patient role assigned have values in these collections.

We are storing different observations grouped by their type, e.g. we use /users/$userId$/bodyWeightObservations/$observationId$ for body weight observations and /users/$userId$/bloodPressureObservations/$observationId$ for blood pressure observations. The different collections are all listed below and they follow the specification of a FHIR observation as defined here with more strict specification following in the respective subsections.

Based on FHIR Observation, the following properties may be used, while additional properties are ignored by the Engage-HF system.

Property	Type	Values	Comments
id	string	-	Resource: Logical id of this artifact
status	ObservationStatus	e.g. "final"	This value is most likely "final" in every case.
code	Code	e.g. {"system":"http://loinc.org","code":"55423-8","display":"Number of steps"}	Use one of the codes mentioned below.
value	optional Quantity	e.g. {"code":"mm[Hg]","system":"http://unitsofmeasure.org","unit":"mmHg","value":120}	Use one of the units listed below.
component	list of components	-	Instead of containing a single value property, some observations are composed of multiple components (e.g. a blood pressure observation contains a diastolic and systolic component).
component[x]>code	Code	e.g. {"system":"http://loinc.org","code":"55423-8","display":"Number of steps"}	Use one of the codes mentioned below.
component[x]>value	optional Quantity	e.g. {"code":"mm[Hg]","system":"http://unitsofmeasure.org","unit":"mmHg","value":120}	Use one of the units listed below.
effective	Period with Date objects or Date	-	Use Date for instant observation and periods for longer observations (e.g. more than 1 minute).

users/$userId$/bloodPressureObservations/$observationId$

Blood pressure observations contain the following code and no value.

code>system	code>code	code>display
"https://loinc.org"	"85354-9"	"Blood pressure panel with all children optional"

Further, blood pressure observations have two components.

code>system	code>code	code>display	value>system	value>value	value>code	value>unit
"http://loinc.org"	"8462-4"	"Diastolic blood pressure"	"http://unitsofmeasure.org"	double	"mm[Hg]"	"mmHg"
"http://loinc.org"	"8480-6"	"Systolic blood pressure"	"http://unitsofmeasure.org"	double	"mm[Hg]"	"mmHg"

users/$userId$/bodyWeightObservations/$observationId$

Body weight observations contain the following code and value.

code>system	code>code	code>display	value>system	value>value	value>code	value>unit
"http://loinc.org"	"29463-7"	"Body weight"	double	"http://unitsofmeasure.org"	"kg" or "[lb_av]"	"kg" or "lbs"

users/$userId$/creatinineObservations/$observationId$

Creatinine observations contain the following code and value.

code>system	code>code	code>display	value>system	value>value	value>code	value>unit
"http://loinc.org"	"2160-0"	"Creatinine [Mass/volume] in Serum or Plasma"	double	"http://unitsofmeasure.org"	"mg/dL"	"mg/dL"

users/$userId$/dryBodyWeightObservations/$observationId$

Dry body weight observations contain the following code and value.

code>system	code>code	code>display	value>system	value>value	value>code	value>unit
"http://loinc.org"	"29463-7"	"Body weight"	double	"http://unitsofmeasure.org"	"kg"	"kg"

users/$userId$/eGfrObservations/$observationId$

Dry body weight observations contain the following code and value.

code>system	code>code	code>display	value>system	value>value	value>code	value>unit
"http://loinc.org"	"98979-8"	"Glomerular filtration rate/1.73 sq M.predicted [Volume Rate/Area] in Serum, Plasma or Blood by Creatinine-based formula (CKD-EPI 2021)"	double	"http://unitsofmeasure.org"	"mL/min/{1.73_m2}"	"mL/min/1.73_m2"

users/$userId$/heartRateObservations/$observationId$

Heart rate observations contain the following code and value.

code>system	code>code	code>display	value>system	value>value	value>code	value>unit
"http://loinc.org"	"8867-4"	"Heart rate"	double	"http://unitsofmeasure.org"	"/min"	"beats/minute"

users/$userId$/potassiumObservations/$observationId$

Potassium observations contain the following code and value.

code>system	code>code	code>display	value>system	value>value	value>code	value>unit
"http://loinc.org"	"6298-4"	"Potassium [Moles/volume] in Blood"	double	"http://unitsofmeasure.org"	"meq/L"	"mEq/L"

users/$userId$/messages/$messageId$

All users are technically allowed to have values in this collection, although the requirements only contain patient-directed messages for now.

This data is used to display messages to a user (patient or clinician). For patients messages are describing recent changes in their respective data from clinicians (e.g. updated medication requests) or calls-to-action to the patient. Currently, there are no messages planned for the clinician, but they may be added in the future.

Property	Type	Values	Comments
dueDate	optional Date	-	The due date of the message to be shown in-app.
completionDate	optional Date	-	Specifies when a message has been completed. TBD: Messages containing a completionDate may either be hidden on user's devices or be shown crossed out.
type	optional string	e.g. "questionnaireReminder"	Some messages are sent out on a regular basis, where only the most recent message is really relevant for the patient (e.g. a reminder for a questionnaire). With this property, we can easily find existing messages of the same type and replace them with a new one, if necessary.
title	LocalizedText	e.g. "Watch Welcome Video in Education Page."	May be localized.
description	optional LocalizedText	e.g. "The video shows how you will be able to use this app."	May be localized.
action	optional string	e.g. "videoSections/1/videos/0"	See "Message types".
isDismissible	boolean	true,false	Whether or not the message is dismissible by the user or is solely controlled by the server.

Message types

The following list describes all different types a message could have. Expiration of messages should only be handled by the server, except for triggering the dismissMessage Firebase function call that adds a completion date when the message is dismissible and has been dismissed by the user. A client doesn't need to know about the type property, since we would otherwise need to check whether a new message type is supported by a client. It may also sort out message types unknown for the client's version.

Type	Trigger	Expiration	Action
MedicationChange	Server: /users/$userId$/medicationRequests changed for a given user. Maximum 1 per day.	Tap	videoSections/$videoSectionId$/videos/$videoId$
WeightGain	Server: New body weight observation received with 3 lbs increase over prior week's median. Do not trigger again for 7 days.	Tap	medications
MedicationUptitration	Server: /users/$userId$/medicationRecommendations changed.	Tap	medications
Welcome	Server: When creating new user.	Tap	videoSections/$videoSectionId$/videos/$videoId$
Vitals	Server: Daily at certain time (respect timezone!)	When receiving blood pressure and weight observations on the server from current day.	observations
SymptomQuestionnaire	Server: Every 14 days.	After questionnaire responses received on server.	questionnaires/$questionnaireId$
PreAppointment	Server: Day (24h) before appointment.	After appointment time or when it is cancelled.	healthSummary

users/$userId$/questionnaireResponses/$questionnaireResponseId$

Only users with a patient role assigned have values in this collection.

Based on FHIR QuestionnaireResponse, the following properties may be used, while additional properties are ignored by the Engage-HF system.

Property	Type	Values	Comments
id	string	-	Resource: Logical id of this artifact
questionnaire	string	-	canonical representation of the questionnaire, i.e. t
author	string	-	The patient's userId
authored	Date	-	The date the answers were gathered.
status	QuestionnaireResponseStatus	-	Will most likely always be completed.
item	list of Item	-	-
item[x]>linkId	string	-	Pointer to specific item from questionnaire
item[x]>definition	optional uri	-	details for item
item[x]>text	optional string	-	Name for group or question text
item[x]>answer	list of Answer	-	response(s) to the question
item[x]>answer[y]>value	any	-	Value depending on the type of question in the survey, e.g. boolean, integer, date, string, etc

users/$userId$/symptomScores/$symptomScoreId$

Only users with a patient role assigned have values in this collection.

Whenever a new questionnaire response is uploaded to Firestore, we calculate the score and keep the results here for easy retrieval later on. We also do not compute the score anywhere but simply refer to the scores listed in this collection.

Property	Type	Values	Comments
questionnaireResponseId	optional string	-	questionnaireResponseId as used in users/$userId$/questionnaireResponses/$questionnaireResponseId$ to be able to verify score calculations afterwards. It should be ignored by all clients.
date	Date	-	must be equivalent to the date specified in the linked questionnaire response.
overallScore	number	must be between 0 and 100	-
physicalLimitsScore	number	must be between 0 and 100	-
specificSymptomsScore	number	must be between 0 and 100	-
socialLimitsScore	number	must be between 0 and 100	-
qualityOfLifeScore	number	must be between 0 and 100	-
dizzinessScore	number	must be between 0 and 100	-

videoSections/$videoSectionId$

In this section, we describe all data related to educational videos to be shown in the Engage-HF mobile apps. The videos are grouped into different categories to be displayed as sections in the mobile apps.

Property	Type	Values	Comments
title	LocalizedText	e.g. "ENGAGE-HF Application"	May be localized.
description	LocalizedText	e.g. "Helpful videos on the ENGAGE-HF mobile application."	May be localized. Are there different videos / videoSections for each platform?
orderIndex	integer	e.g. 1	Since Firestore collections aren't necessarily ordered, we have this property to order the elements by on the clients. The list is supposed to be ordered ascending by orderIndex.

videoSections/$videoSectionId$/videos/$videoId$

Property	Type	Values	Comments
title	LocalizedText	e.g. "Beta Blockers for Heart Failure"	May be localized.
youtubeId	LocalizedText	e.g. "XfgcXkq61k0"	Contains the video id from YouTube.
orderIndex	integer	e.g. 1	Since Firestore collections aren't necessarily ordered, we have this property to order the elements by on the clients. The list is supposed to be ordered ascending by orderIndex.

Embed links for YouTube: https://youtube.com/embed/${youtubeId}. Short links for YouTube: https://youtu.be/${youtubeId}. Watch links for YouTube: https://youtube.com/watch?v=${youtubeId}.

Functions

checkInvitationCode

Use checkInvitationCode to check if an invitation code is still available and connect the currently (anonymously) authenticated userId with the invitation.

• Note: Currently, due to an issue with Firebase Authentication, the user is already enrolled after calling this function with a full user account and an invitation code may be used infinitely often. This should not be the case in the production system.

Security

Any authenticated user may use this function, but it should only occur before that user has linked credentials or the user object has been created.

Input

Property	Type	Values	Comments
invitationCode	string	-	The invitation code provided to the user by the organization. It needs to be between 6-12 characters long and only use uppercase latin characters and arabic digits.

Output

None.

createInvitation

Use createInvitation to create invitations to be sent out to new patients, clinicians or owners.

Security

An admin may create invitations for any user, an owner or clinician may only create invitations within their own organization and below or equal their own rank (i.e. clinicians cannot create owners, owners cannot create admins). Patients may not call this function.

Input

Property	Type	Values	Comments
auth	object	-	Authentication information about the user to be invited.
auth>displayName	optional string	-	A display name to use for the user.
auth>email	optional string	-	An email address to use for the user. This is non-optional for invitations for owners and clinicians, since this email address is used as the invitation code for SSO.
auth>phoneNumber	optional string	-	A phone number to use for the user.
auth>photoURL	optional string	-	A photo URL to use for the user.
user	object	-	A prepared user object to use for the enrollment of the user when using the invitation. It may contain the same properties as in the users collection, except for dateOfEnrollment and invitationCode.

Output

Property	Type	Values	Comments
id	string	-	The Firestore document id of the created invitation.

customSeed

Use customSeed to seed Firestore with your own custom data with little effort. It may also be used to create users, which is not possible with the client SDK or to circumvent security rules temporarily before running tests, etc.

Security

This function may only be called by admins. On emulators, this function can easily be triggered without authentication using an HTTP POST request.

Input

Property	Type	Values	Comments
firestore	optional object	-	Custom data to seed firestore with. It needs to be nested at least two levels deep with the first level defining the collection (e.g. videoSections/0/videos) and the second defining the document id (e.g. 1).
users	optional object	-	Custom user creation using authentication information, user data (dateOfBirth, etc) and user collections (e.g. appointments, bodyWeightObservations, etc).
users[x]>auth	object	-	User authentication information for login after the user has been created.
users[x]>auth>uid	optional string	-	The user id to use when creating the user. When omitted, an id will be autogenerated.
users[x]>auth>email	string	-	The email address to log into the user after it has been created.
users[x]>auth>password	string	-	The password to log into the user after it has been created.
users[x]>user	optional object	-	The user object that will be placed at users/$userId$. This may be useful, when the userId is not specified, since the seeding function will make use of the auto-generated id.
users[x]>collections	optional object	-	Similar to the firestore property, this content will be placed at the given path prefixed by users/$userId$/.

Output

None.

defaultSeed

Use defaultSeed to seed Firestore with some default data. Depending on input, it may create users, invitations, static data (including videoSections, medications, etc) and/or fill existing user's collections.

Security

This function may only be called by admins. On emulators, this function can easily be triggered without authentication using an HTTP POST request.

Input

Property	Type	Values	Comments
date	string	-	An ISO 8601 formatted string of the date to seed data relative to. May be omitted, which will generate data relative to now.
only	list of string	e.g. ["users","invitations"]	Allows to limit seeding data to the provided collections.
onlyUserCollections	list of string	e.g. ["appointments","bodyWeightObservations"]	Allows to limit the creation of user collections for the created users to the provided collections.
staticData	object	-	Allows to seed static data without calling updateStaticData separately. If not provided, static data will not be updated.
userData	list of object	-	Allows to seed user collections to existing users.
userData[x]>userId	string	-	The userId for the user to create seeding data for.
userData[x]>only	list of string	-	The user collections to create seeding data for. If not provided, all available collections will be seeded.

Output

None.

dismissMessage

Use dismissMessage to dismiss messages that are marked with isDismissible equals true. Using this function on non-dismissible functions results in an error. Clients may call this function either on deletion of the user (by displaying an x-mark tapped by the user to specifically remove this message) or on perform of the message (i.e. on tap of the message, if the action could successfully be decoded and performed).

Security

Admins may dismiss messages for any user, otherwise users may only dismiss their own messages.

Input

Property	Type	Values	Comments
userId	optional string	-	The userId of the user whose message you are dismissing. May be omitted for users dismissing their own messages.
messageId	string	-	The id of the message to dismiss. This message needs to have isDismissible set to true.
didPerformAction	optional boolean	-	Whether the message action has actually been performed. Depending on this value, the server may decide to actually dismiss the message or not.

Output

None.

exportHealthSummary

exportHealthSummary creates a health summary PDF and returns its data.

Security

This function may be called by admins (for any patient), owners/clinicians (for patients of the same organization), or patients (for themselves).

Input

Property	Type	Values	Comments
userId	string	-	The patient's user id. Needs to be specified, even if a patient is requesting the health summary for themselves.
language	optional string	e.g. 'en-US'	See LocalizedText for specification.
weightUnit	optional string	e.g. '[lb_av]'	A loinc code for the weight unit to be used during generation of the health summary PDF

Output

Property	Type	Values	Comments
content	string	-	Base64-encoded string of the PDF data.

registerDevice

Use registerDevice to register different client devices for receival of push notifications. Call this function on each fresh start of the app or whenever the push notification token (or any of the remaining data, including language/region settings) may have changed.

Security

Any user can register devices for their own account. In the foreseeable future, the function is only relevant for patients though.

Input

If a notification token could not be generated on the device (e.g. due to missing permissions), simply do not call this function rather than creating a device without token. For the remaining inputs, please provide all values that are available.

Property	Type	Values	Comments
notificationToken	string	-	The notification token to be used for sending push notifications. This may either be an APNS token for iOS devices or a FCM registration token for Android.
platform	string	'iOS' or 'Android'	The platform of the device.
osVersion	optional string	'15.4.3'	The OS version of the device using semantic versioning separated by dots. Minor and patch version may be omitted.
appVersion	optional string	'1.0.1'	The app version as shown in the App Store or Play Store using semantic versioning. Minor and patch version may be omitted.
appBuild	optional string	'43'	The app build version as used internally to identify individual builds within the same marketing version (i.e. the one shown in App Store / Play Store).
language	optional string	'en-US'	The language and region setting as specified for LocalizedText.
timeZone	optional string	e.g. "America/Los_Angeles"	The value needs to correspond to an identifier from TZDB. It must not be an offset to UTC/GMT, since that wouldn't work well with daylight-savings (even if there is no daylight-savings time at that location). Also, don't use common abbreviations like PST, PDT, CEST, etc (they may be ambiguous, e.g. CST). If the timeZone is unknown, then "America/Los_Angeles" should be used.

Output

None.

unregisterDevice

Use unregisterDevice to remove a notification token associated to a user account. This will only remove it from the authenticated user.

Security

Any user can unregister devices for their own account. In the foreseeable future, the function is only relevant for patients though.

Input

If a notification token could not be generated on the device (e.g. due to missing permissions), simply do not call this function rather than creating a device without token. For the remaining inputs, please provide all values that are available.

Property	Type	Values	Comments
notificationToken	string	-	The notification token to be used for sending push notifications. This may either be an APNS token for iOS devices or a FCM registration token for Android.
platform	string	'iOS' or 'Android'	The platform of the device.

Output

None.

updateStaticData

Use updateStaticData to update statically present data in Firestore. This function may either be called when the configuration of the static data has changed or when dynamically generated content needs an update (e.g. medication data is generated based on the RxNorm API).

Security

This function may only be called by admins. On emulators, this function can easily be triggered without authentication using an HTTP POST request.

Input

Property	Type	Values	Comments
only	optional list of string	e.g. ["videoSections","medications"]	The static components to update. If omitted, all components will be updated.
cachingStrategy	optional string	e.g. "expectCache"	Depending on this property static data may simply be updated in Firestore based on cached data or completely generated from scratch and not relying on cached information.

Output

None.

Indexes

To perform certain queries, ENGAGE-HF requires indexes on different properties. The following indexes need to be created:

Type	Reference	Properties	Usage
Composite	collection:users	organization:asc,type:asc,name:asc	Querying users on the Web dashboard
Composite	collection:invitations	user.organization:asc,user.type:asc,name:asc	Querying invitations on the Web dashboard
Single	group:appointments	start:asc	Querying appointments across all users (for appointment messages)
Single	group:devices	notificationToken:asc	Querying devices across all users (for deleting existing notification tokens assigned to other users)

Usage

To use Firebase functions for your own project or to emulate them for client applications, this section will help to give an overview of the different packages in use and how to install, build, test and launch them.

This repository contains two separate packages.

• The package located in functions/models contains model types including decoding/encoding functions and useful extensions that are shared between the Firebase functions and the web dashboard. This package is released via the npm registry and can be accessed as @stanfordbdhg/engagehf-models.
• The package located in functions contains the Firebase functions and services that are called from these functions. This package has a local dependency on the package in functions/models. Therefore, the functions package does not work (e.g. for linting, building, etc) without building the models package first.

To make this structure simpler to use, we provide different scripts as part of the package.json file in the root directory of this repository. The file ensures execution order between the two packages. We only document the scripts located in this file, since they cover the most common use cases, feel free to have a look at the individual package.json files of the respective packages to get a deeper understanding and more package-focused operations.

Command	Purpose
npm run install	Installs dependencies (incl. dev dependencies) for both packages.
npm run clean	Cleans existing build artifacts for both packages.
npm run build	Builds both packages. If you have added or removed files in one of the packages, make sure to clean before using this command.
npm run lint	Lints both packages. Make sure to build before using this command. You may want to append :fix to fix existing issues automatically or :strict to make sure the command does not succeed with existing warnings or errors.
npm run prepare	Combines cleaning, installing and building both packages.
npm run test:ci	Tests the Firebase functions with emulators running and with test coverage collection active.
npm run serve:seeded	Starts up the relevant emulators for ENGAGE-HF and seeds them. Make sure to build the project first before executing this command.

For using the emulators for client applications, it is probably easiest to call npm run prepare whenever files could have changed (e.g. when changing branch or pulling new changes) and then calling npm run serve:seeded to start up the emulators in a seeded state. Both of these commands are performed in the root directory of this repository.

Resources

• See resources/algorithms for diagrams describing the different algorithms for medication recommendations.
• For definitions relevant for the setup of static data, including questionnaires, medication classes, medications and videoSections, have a look at functions/data.

Security

A user usually has one of these roles assigned (some combinations are technically allowed, but may be ignored, e.g. owner+clinician).

Role	Scope	Rights	Source of Truth
Admin	Everything	R/W	User type is admin.
Owner	In organization	R/W of users, R/W of organization	User type is owner.
Clinician	In organization	R/W of users	User type is clinician.
Patient	Own data	R/W of users/$userId$ incl patient-specific collections	User type is patient.
User	Own data	R/W of users/$userId$	auth has same userId

For more detail, please consult the Firestore rules defined in firestore.rules.