Cascade of care

Some diseases, such as HIV, have a complex sequential cascade of care that individuals must navigate. For example, going from testing to diagnosis, receiving medical counseling, taking antiretroviral therapy, and achieving viral suppression. Other life events, such as pregnancy, migration, relationship changes, or diagnostic criteria may trigger different medical interventions.

Health care in EMOD can be applied to individuals, such as through a vaccination campaign, or be sought out by various triggering events including birth, pregnancy, or symptoms. A potential problem created by this structure is that an individual could end up in care multiple times. For example, an individual might have an antenatal care (ANC) visit and, in the same time step, seek health care for AIDS symptoms, both leading to HIV testing and staging.

To avoid this situation, you can configure interventions using the InterventionStatus individual property in the demographics file (see NodeProperties and IndividualProperties for more information). In the demographics file, create as many property values as necessary to describe the care cascade. For example, undiagnosed, positive diagnosis, on therapy, lost to care, etc.

In the campaign file, set up your event coordinator as you typically would, using Target_Demographic, Property_Restrictions_Within_Node, and other available parameters to target the desired individuals. See Targeting interventions to nodes or individuals for more information on targeting interventions and Events and event coordinators for all available event coordinators.

Then, in the intervention itself, you can add any properties that should prevent someone who would otherwise qualify for the intervention from receiving it. For example, someone who has already received a positive diagnosis would be prevented from receiving a diagnostic test if they sought out medical care for symptoms. You can also add the new property that should be assigned to the individual if they receive the intervention.

The following example shows a simplified example with two interventions, a diagnostic event and distribution of medication. The demographics file defines intervention status values for having tested positive and for being on medication.

{
    "Use_Defaults": 1,
    "Events": [{
            "class": "CampaignEvent",
            "Start_Day": 1,
            "Nodeset_Config": {
                "class": "NodeSetAll"
            },
            "Event_Coordinator_Config": {
                "class": "StandardInterventionDistributionEventCoordinator",
                "Target_Demographic": "Everyone",
                "Demographic_Coverage": 1.0,
                "Intervention_Config": {
                    "class": "SimpleDiagnostic",
                    "Disqualifying_Properties": [
                        "InterventionStatus:OnMeds"
                    ],
                    "New_Property_Value": "InterventionStatus:TestPositive",
                    "Base_Sensitivity": 1.0,
                    "Base_Specificity": 1.0,
                    "Cost_To_Consumer": 0,
                    "Days_To_Diagnosis": 5.0,
                    "Dont_Allow_Duplicates": 0,
                    "Event_Or_Config": "Event",
                    "Positive_Diagnosis_Event": "NewInfectionEvent",
                    "Intervention_Name": "Diagnostic_Sample",
                    "Treatment_Fraction": 1.0
                }
            }
        },
        {
            "class": "CampaignEvent",
            "Start_Day": 1,
            "Nodeset_Config": {
                "class": "NodeSetAll"
            },
            "Event_Coordinator_Config": {
                "class": "StandardInterventionDistributionEventCoordinator",
                "Intervention_Config": {
                    "class": "NodeLevelHealthTriggeredIV",
                    "Trigger_Condition_List": [
                        "NewInfectionEvent"
                    ],
                    "Disqualifying_Properties": [
                        "InterventionStatus:OnMeds"
                    ],
                    "New_Property_Value": "InterventionStatus:OnMeds",
                    "Demographic_Coverage": 1.0,
                    "Actual_IndividualIntervention_Config": {
                        "class": "ARTBasic",
                        "Viral_Suppression": 1,
                        "Days_To_Achieve_Viral_Suppression": 1000000
                    }
                }
            }
        }
    ]
}