This tutorial and exercise will introduce and walk through the modeling of diseases using the Synthea Module Builder. The session will highlight Synthea (“Synthetic Health”), an open-source software package that generates synthetic patient records. The software models and simulates over 500 clinical concepts, with a growing list of community written modules.

After completing this tutorial, you will be able to:

1. Explore and Modify the Disease Modules
2. Understand the pertinent elements of disease life-cycles to include in modeling for Synthea
3. Understand the concepts of disease modeling within Synthea

Have fun and remember to ask for help if you get stuck!

1. Starting a New Module

We will start the tutorial with a step by step guide on building a new module. We will need to start by navigating to https://synthetichealth.github.io/module-builder/. Choose Examplitis as the initial module. From there,

• Open a new module by clicking on New Module
• Navigate to Module Remarks and title your module My CHF module
• Navigate to + Add State
• Navigate to the State Type drop down menu and choose ConditionOnset
• Open separate window to utilize for SNOMED searches. (Example Site: browser.ihtsotools.org)
• Search for an appropriately broad parent SNOMED code (eg 42343007)
• Add your chosen SNOMED code to the Code section in the State Editor
• Label the SNOMED code by clicking on the Display SNOMED Code place-holder
• Title your ConditionOnset State by clicking on the New_State place-holder and titling it CHF Condition Start
• Navigate to the Initial state
• Within the State Editor for the Initial state, navigate to Transition Type and choose Direct. Choose CHF Condition Start in the Transition To drop down.
• Navigate to and click on + Add State
• Navigate to and click on State Type and choose Encounter
• Choose ambulatory in Encounter Class drop down
• In Separate browser, search for appropriate SNOMED code to label the encounter (Recommend searching for encounter SNOMEDs – e.g. 185347001)
• Navigate to the State Editor and label the encounter CHF Initial Workup Encounter
• Navigate to back to CHF Condition Start and navigate to Transition Type. Choose Direct in the drop-down option. Choose CHF Initial Workup Encounter in the Transition To drop down.

You have now successfully created two states linked together at the initial start of the disease module.

2. Building a Complex CHF Module: Modeling Prevalence Rate

Continue building your module in a similar fashion by adding the following states (click on + add state for each new state):

• State Type = delay. Label this state age delay. Type 50 within state editor, under exact quantity. Choose years in exact unit drop down. Keep Transition Type as Direct.
• State type = Symptom. Label this state CHF symptom onset 1. Under Symptom, type shortness of breath. Under Cause, type Congestive Heart Failure. Keep Transition Type as Direct.
• State type = delay. Label this state chance of CHF. Type 1 under exact quantity. Choose years in exact unit. Choose Distributed as Transition Type. Within Distributed Transition, choose chance of CHF. Weight this with 0.99905. Click on the +/- to add a nested transition option. Choose CHF symptom onset 1. Under weight, type 0.00095
• Navigate to Initial State. Change Transition To to age delay state.
• Navigate to age delay state. Change Transition To to chance of CHF state.
• Navigate to CHF symptom onset 1 state. Change Transition To to CHF Condition Start state.

3. Building a Complex CHF Module: Modeling Encounters & Diagnostic Work-Ups

Keeping with the same model, you should now have a module that has an age delay, a state to prevalence rates, an example symptom of SOB, and the condition onset of CHF. Next, we will model a sample encounter.

• Navigate to + Add State. State type = encounter. Label this state CHF initial workup encounter. Encounter class is ambulatory. Label the Reason as chf. Under codes, choose an appropriate problem based SNOMED code (e.g. 185347001).

• Navigate BACK to the CHF Condition Start encounter. Within Target Encounter, type the EXACT text of the just-added encounter, CHF initial workfup encounter. Under assign to attribute, type the exact text recently added in the Reason section of the encounter, chf.

• Navigate to + Add State. State type = Observation. Label this state BNP lab workup. Under category, choose laboratory. In unit, type pg/mL. Within the nested Codes section, under Code, you will need to insert an appropriate LOINC code. We recommend using an appropriate LOINC browser/search, such as: loinc.org. In this case, choose 42637-9 as an ORDERABLE lab. Under Display, type the exact label of the lab test Natriuretic peptide B. Within the Value section, select Change to Range. Type the LOW range to be 2, and the HIGH range to 100.

• Navigate to + Add State. State type = EncounterEnd. Label this CHF initial workup encounter end. Under NUBC code, search for the appropriate NUBC discharge code. In this case, the patient is discharged home, so choose code 01. Within Transition to, choose End.

You have now completed the initial CHF module modeling. You should have an encounter that begins with an age delay, has a prevalence rate modeled, that leads to symptom progression, the start of CHF, and an initial work-up with a sample laboratory test ordered.

4. Advanced CHF Module Building

The last phase of the tutorial, should there be enough time, is to attempt to re-create the Congestive Heart Failure module on your own. Critical additional elements to pay close attention to include the following:

• Multiple laboratory orders within one section
• Understanding and leveraging hard-coded Vitals (e.g. BUN, Creatinine, etc.)
• Starting Medications. Leveraging RxNorm values (recommend [https://rxnav.nlm.nih.gov/]) Building and leveraging CONDITIONAL Transition Types (see “Maintaining CHF” State)
• Building and leveraging DISTRIBUTED Transition Types (see “Possible CHF Flare” State)
• Understanding an Inpatient clinical workflow (See start of inpatient section, with “acute Inpatient CHF flare” and subsequent sections.