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# How to calculate Quantity and effective_drug_dose?

(Soyoung Yi) #1

Hello,
I ask about the ‘quantity’ and ‘effective_drug_dose’ columns in the drug_exposure table.
For example, If a doctor prescribes a patient to " tylenol 650mg, 2tablet, 3times, , 7days"

• quantity : 3
• days : 7
• effective_drug_dose : 1300

then, for example, if a doctor prescribes a patient to “tylenol 650mg, 2tablet, once every 2weaks, 56days”

• quantity : ?
• days : ?
• effective_drug_dose : ??

(Rae Woong Park) #2

That columns were removed in CDM V5.2.
Rae

(Christian Reich) #3

Tylenol 650 mg tablets, 2 tablets 3 times a day, 7 days:

• quantity: 42
• days_supply: 7
• sig: “2 tablets 3 times a day”

Tylenol 650 mg tablets, 2 tablets once every 2 weeks, 56 days:

• quantity: 8
• days_supply: 56
• sig: “2 tablets once every 2 weeks”

As @rwpark said, no effective_dose anymore. When you calculate the DOSE_ERA, you will get for the first example dose_value=3900 (that’s actually overdosing the patient), and for the second dose_value=92.857.

#4

@Christian_Reich

Now we have no more “dose_unit_concept_id” info as well.
You calculated “quantity” using “packing unit” such as tab, cap, amp.

so, how can we calculate “quantity” using “volume unit” such as IU, ml, mg … ?

Are there any guidelines to ETL “converted quantity” using “only packing unit” ??

or I like to find ways how we can figure out whether drug is prescribed by “packing unit” or “volume unit”.

Thank you.

(Christian Reich) #5

Yeah, this will be written up in the new CDM documentation we are working on. But here is the short shrift:

• If it is a solid formulation, quantity means those units
• if it is a liquid formulation, quantity means the value. The unit is defined in DRUG_STRENGTH for each ingredient. If for example you got mg there you have to put the value in mg.
• If you don’t have a formulation then quantity makes no sense. If you want to record the strength (e.g. Acetaminophen 500 mg) then find that Clinical Drug Comp. If there isn’t one, let us know.

(Christian Reich) #6

The last bullet point is not quite correct, as @Alexdavv pointed out offline. It should be:

• If you don’t have a formulation, but you are recording a strength incorporated into a drug product (eg. Acetaminphen 500 mg) then use Clinical Drug Comp.
• If you don’t have a standard formulation, but a compounded drug, or if the drug dispensation is through standard forumlations (e.g. chemotherapy) the drug_concept_id should refer to an Ingredient, and then dose is defined as quantity (amount or value) in combination with the amount_unit_id in the DRUG_STRENGTH table for that Ingredient.

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