Start/end date on treatment object

[mshadbolt]

Further to discussion today at GA4GH meeting after OMOP->phenopackets presentation

I mentioned that we couldn't find a good place to put start/end dates for a specific drug_treatment. It was suggested we use the doseIntervals object to do this. In our case we do not have specific information about the dose, like the individual dose quantity and schedule frequency which are required for this object. We only have the cumulative dose. As such our treatment object would look something like this:

"treatment": {
        "agent": {
          "id": "RxNorm:3390",
          "label": "diethylstilbestrol"
        },
        "route_of_administration": {
          "id": "SNOMED:261665006",
          "label": "Unknown"
        },
        "drug_type": "PRESCRIPTION",
        "cumulative_dose": {
          "unit": {
            "id": "SNOMED:404216004",
            "label": "mg/m2"
          },
          "value": 25.7
        },
       "dose_intervals": [{
         "quantity":
          "unit":
            "id": "SNOMED:261665006"
            "label": "Unknown"
          "value": -99
         "scheduleFrequency":
           "id": "SNOMED:261665006"
           "label": "Unknown"
          "interval":
            "start": "2020-03-15T13:00:00Z"
            "end": "2020-03-25T09:00:00Z"
      }]

This seems a little clunky, but works. Not sure if it would make sense to add some fields on to the base treatment object or change the quantity and schedule_frequency fields to non-required so someone could just specify the known start and end dates for the drug exposure