DRUG_EXPOSURE conventions

[bailey (Charles Bailey)]

Urgh. Forget the denominator then. alternative_unit_concept_id?

We (at least here) call the normalized dose the “dose basis”. So maybe dose_basis_unit_concept_id? Or maybe that’s thinking too focusedly . . .

[Chris_Knoll]

What about ‘rate’? so exposure_rate and exposure_rate_unit? Seems like we’re talking about 2 things possibly happening when a patient is exposed to a drug: they get a dose of something or they are exposed at a rate of something. I found this discussion here, tho it was describing radiation, but the idea might apply to our drug exposure table:
https://www.nucleonica.com/forum/showthread.php?301-Diffrence-between-Dose-and-Exposure-Rate

So, this way, you can have someone exposed to the same mass of a drug as another person, but the rate could be different between them. Maybe we can standardize the units to either by time (to a day) or by weight (to a gram),

[Dymshyts (Dmytry Dymshyts)]

looks like the discussion goes to the relative units only

@Christian_Reich, another example where we have problems is when the substance can be present both in iU and mg.
and conversion is not so easy in this case.

nystatin.mg is predefined as a unit in DRUG_STRENGTH table. In RxNorm there are no any Clinical Drug Components with mg.
bacitracin/ bacitracin zinc.mg is predefined as a unit in DRUG_STRENGTH table. In RxNorm there is just only one Clinical Drug Component with mg - bacitracin zinc 0.5 MG/MG which is used just for one single Clinical Drug - bacitracin zinc 0.5 MG/MG / Polymyxin B Sulfate 10 UNT/MG Topical Powder.
Penicillin G (almost the same case like bacitracin).

And rather important that in general clinical practise these drugs are measured mostly (sometimes always) in iU. The main question: what units should we use for figures which would be inserted to the DRUG_EXPOSURE.quantity field? If source data contain all the quantities in iU should we convert them to mg and basically how?

and it’s not so easy to convert.

@Alexdavv, I know you tried something, can you share?

[Christian_Reich]

dose_basis_unit_concept_id

Not a bad idea.

Seems like we’re talking about 2 things possibly happening when a patient is exposed to a drug: they get a dose of something or they are exposed at a rate of something

Yes, but we already were talking about two things before: Absolute unit based (=dry) dose like in tablets, and divisible dose (=liquid). Now we are talking a third thing: the first derivation thereof. We haven’t made those distinctions canonical, except when we want to calculate daily doses (e.g. for DOSE_ERA records). That’s when we need the complex @Klaus-like logic. This will add to that.

We could try figuring it out. But won’t be easy on the ETLers, because instead of just dumping NDC codes they will have to start getting into the detail.

both in iU and mg

Correct, but I would definitely not open the door for that. In contrast, in the long run we should provide means to convert. The conversation here is about what dose is actually given. Not how it can be differently represented.

And rather important that in general clinical practise these drugs are measured mostly (sometimes always) in iU

That is the idea, @alexdaw. We will fix it.

[MPhilofsky (Melanie Philofsky)]

dose_basis_unit_concept_id

Not a bad idea.

+1 for @bailey’s idea

And this would be the concept_id for the dose_unit_source_value field, correct?

[MPhilofsky (Melanie Philofsky)]

I’ve added a proposal to create a dose_unit_concept_id field for the dose_unit_source_value field here

@Bailey I’ve changed the field name that you proposed to stay in line with naming conventions. Keep the concept_id name the same as the source_value name

@Christian_Reich @clairblacketer Would this be considered a bug fix since the source value didn’t have a corresponding concept id field?