CRTDL

The Clinical Resource Transfer Definition Language (CRTDL) is a JSON-based format used to define cohorts and data extraction rules for TORCH. It allows users to specify who to extract data for, what data to extract, and how to handle consent and masking.

Key Features of CRTDL

• Cohort Definition: Specify the population of interest using FHIR resources and criteria.
• Data Extraction Rules: Define which FHIR resources and fields to extract.
• Consent Handling: Integrate consent rules to ensure compliance with privacy regulations.

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CRTDL Structure

A CRTDL definition is structured as a JSON object with the following key components:

• inclusion criteria: Defines the population of interest.
• data extraction: Specifies the FHIR resources and fields to extract.

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Cohort Selection

The cohort selection uses the CCDL (Cohort Definition Definition Language) to define the population of interest.

TORCH supports CQL or FHIR Search for the cohort selection execution.

If your FHIR server does not support CQL itself then the FLARE component must be used to extract the cohort based on the cohort definition of the CRTDL.

The cohort evaluation strategy can be set using the TORCH_USE_CQL setting in the enviroment variables.

Torch uses the Consent Key to enforce consent rules during the cohort selection and data extraction process.

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Data Extraction Selection

The data extraction object contains an array defining attributeGroups, which bundle attributes together.

Each group has an identifier for the group called groupReference, a list of attributes to be extracted **attributes ** and a filter object containing not more than one time filter and a list of code filters filters.

Every data extraction must have exactly one attribute group that describes patient attributes.

An attributes to be extracted contains an attribute reference attributeRef and information if the attribute is required must-have e.g.

{
      "attributeRef": "medicationCode",
      "mustHave": true
          
          }

If a must have condition is violated, it will result in a complete stop of the extraction for a patient.

Filters definition have a list of FHIR search parameter operations containing the type supported, name and corresponding parameters. Currrently token and date are supported.

{
    "version": "http://json-schema.org/to-be-done/schema#",
    "display": "",
    "cohortDefinition": {
      "version": "http://to_be_decided.com/draft-1/schema#",
      "display": "",
      "inclusionCriteria": [
        [
            {
              "termCodes": [
                {
                  "code": "424144002",
                  "system": "http://snomed.info/sct",
                  "display": "Gegenwärtiges chronologisches Alter"
                }
              ],
              "context": {
                "code": "Patient",
                "system": "fdpg.mii.cds",
                "version": "1.0.0",
                "display": "Patient"
              },
              "valueFilter": {
                "type": "quantity-comparator",
                "unit": {
                  "code": "a",
                  "display": "a"
                },
                "value": 18,
                "comparator": "gt"
              }
            }
          ],
          [
            {
              "termCodes": [
                {
                  "code": "263495000",
                  "system": "http://snomed.info/sct",
                  "display": "Geschlecht"
                }
              ],
              "context": {
                "code": "Patient",
                "system": "fdpg.mii.cds",
                "version": "1.0.0",
                "display": "Patient"
              },
              "valueFilter": {
                "selectedConcepts": [
                  {
                    "code": "female",
                    "display": "Female",
                    "system": "http://hl7.org/fhir/administrative-gender"
                  }
                ],
                "type": "concept"
              }
            }
          ],
          [
            {
              "termCodes": [
                {
                  "code": "8-918",
                  "system": "http://fhir.de/CodeSystem/bfarm/ops",
                  "version": "2023",
                  "display": "Interdisziplinäre multimodale Schmerztherapie"
                }
              ],
              "context": {
                "code": "Procedure",
                "system": "fdpg.mii.cds",
                "version": "1.0.0",
                "display": "Prozedur"
              }
            }
          ]

      ],
        "dataExtraction": {
          "attributeGroups": [
            {
              "groupReference": "https://www.medizininformatik-initiative.de/fhir/core/modul-labor/StructureDefinition/ObservationLab",
              "attributes": [
                {
                  "attributeRef": "Observation.code",
                  "mustHave": false
                },
                {
                  "attributeRef": "Observation.value",
                  "mustHave": true
                }
              ],
              "filter": [
                {
                  "type": "token",
                  "name": "code",
                  "codes": [
                    {
                      "code": "718-7",
                      "system": "http://loinc.org",
                      "display": "Hemoglobin [Mass/volume] in Blood"
                    },
                    {
                      "code": "33509-1",
                      "system": "http://loinc.org",
                      "display": "Hemoglobin [Mass/volume] in Body fluid"
                    }
                  ]
                },
                {
                  "type": "date",
                  "name": "date",
                  "start": "2021-09-09",
                  "end": "2021-10-09"
                }
              ]
            }
          ]
        }
    }
}