| OHDSI Home | Forums | Wiki | Github |
Hi all,
We are mapping to the Drug Exposure table and have the following question. When mapping to a specific standard RxNorm Extension where the name indicates the quantity, will this attribute automatically be captured or do we need to specify it?
For example, say we are mapping to drug_concept_id 21151336 (infliximab 100 MG [Remsima]). Would the quantity field automatically be populated with ´100´, or do we add this ourselves?
Many thanks,
Ed
The drug concept (drug name) only shows the strength of the medication, not the quantity. For example, drug_concept_id 21151336 (infliximab 100 MG [Remsima]) indicates the strength of the drug is 100 MG/per syringe. If the patient gets 2 shots, the quantity will be 2, which should be put in the Quantity field.
Thanks for the clarification!
So, just to make sure I understand fully, the strength of the medication will be stored in the drug strength table (not the drug exposure table). And, for a standard concept such as 21151336, there would be a corresponding entry in the derived drug strength table.
But, how would you suggest we go about mapping an example like ´REMSIMA 150mg´? This doesn´t appear to have an obvious standard concept equivalent. So would we map to a higher level term like 937368 infliximab? But then would this have an associated strength?
So, just to make sure I understand fully, the strength of the medication will be stored in the drug strength table (not the drug exposure table).
No. That is not correct. The strength of the medication is stored in concept_id filed in Drug_Exposure table. For example, concept_id 21151336 contains the strength information 100 MG/per bottle or per pre-filled syringe. Of course, you get that information from the concept_name column in the Concept table.
And, for a standard concept such as 21151336, there would be a corresponding entry in the derived drug strength table.
Yes. But please note that Drug_Strength table is a derived table from the Drug_Exposure and vocabulary tables. In another word, if the information does not exist in Drug_Exposure table, it will not be in the Drug_Strength table either.
But, how would you suggest we go about mapping an example like ´REMSIMA 150mg´?
In this case, there is no corresponding concept in the vocabulary that has the strength of 150 mg/per bottle REMSIMA. If you are sure that the drug comes with this strength, the best practice is to to ask @Dymshyts to create a new concept with this strength (150 mg). As a alternative, you can certainly map it to the ingredient level as you suggested that has no strength information.
.
Although it doesn’t change the overall answer, drug_strength is the table where dose of a drug is stored and it’s not a derived table but rather the original vocabulary table that was created specifically for the dose data.
The general rules for populating quantity are:
if you have Quant Clinical/Branded Drug or a Pack, quantity represents the number of units (syringes, bottles, etc.)
if you have a solid Clinical/Branded Drug then quantity represents the number of tablets, capsules, suppositories etc.
Otherwise quantity represent the dose itself. E.g. if you map you source REMSIMA 150mg to an ingredient, then you put 150 in the quantity field.
And another comment: you’re highly welcome to submit your vocabulary to be added to OMOP Vocabularies, but for that you need a vocabulary and not just free-text strings.
OK. @aostropolets is correct. Drug_Strength table is not a derived table. I messed it up with the Dose_Era table.
@aostropolets, thanks for this answer. That is also how I saw the quantity populated when looking at examples. However, the quantity definition in the drug exposure table is different. It says that for some drugs, it should contain the quantity the patient received quoting "Clinical drugs with divisible dose forms (injections) the quantity is the amount of ingredient the patient got. For example, if the injection is 2mg/mL but the patient got 80mL then quantity is reported as 160. Quantified clinical drugs with divisible dose forms (prefilled syringes), the quantity is the amount of ingredient similar to clinical drugs. " My question is: can this definition be changed to what you said. And furthermore, was quantity a required field? It is not any more (I thought it was). @Christian_Reich
We overloaded the field. One of the things to fix in the next version.
We can’t require it, since some data sources don’t have that information. All they have is ingredient. (some of them not even that, but a drug class).
You are right, the text is incorrect. This would go to @clairblacketer, We cannot have a definition that talks about one ingredient, when the concept class allows more than one.
thank you! @Christian_Reich
@clairblacketer please let me know when you plan the change 
I may be able to help if you want to talk. I went through a lot of clinical examples and looked at quantity for my dosing project.