Interpretation of HICL (hierarchical ingredient code list?)

[cothurn]

I am opening this issue for more information regarding the drugHiclSeqno variable in the medication table. The comments given for drugHiclSeqno in the medication table is "HICL for the drug e.g.: 8255, 6055, 1694, etc." I assume HICL means hierarchical ingredient code list, a list of hierarchical ingredient codes associated with each drug given by First Data Bank (https://reference.pivotrock.net/HealthCareTraining/Drugs/RXC.html).

However:

1. The Format of HIC in the referenced webpage (e.g. H3AD) does not match the format presented in eICU (e.g. 1694).
2. While RxNorm provides an API call that translates HIC to RxCUIs, the API call only returns valid results for selected HICLs recorded in eICU. (For example, 8255 returns no valid RxCUI).
3. For the selected few HICLs that the RxNorm API can translate, the result of the translation does not match the records in eICU. For example, the drugname MORPHINE INJ is associated with drugHiclSeqno 1694 in eICU. The concept associated with HIC 1694, according to RxNorm however, is pilocarpine hydrochloride (RxCUI 235426).

Here is the list of questions I have regarding this variable:

1. Is my assumption that HICL = Hierarchical Ingredient Code List from First Data Bank correct?
2. If so, why is there a discrepancy between the recorded drug names in eICU and RxNorm?
3. My affiliated research institution does not have a subscription to the drug knowledge database offered by First Data Bank. Is there any way that I can gain a rough understanding of the code?

For our current research project, we are trying to group medications into a few (several dozens at max) broad categories. Without a better understanding of the drug classification system, the task is simply impossible.

Any insight regarding the HICL and/or how to better categorize medications is appreciated!

[jraffa]

I'm afraid I don't know HICL well enough to give you any guidance. This sounds like a good question for @obadawi .

[liweihenshuai]

Hi @cothurn, Sorry to bother you. I am trying to use the same information. I wonder if you found a solution to the coding system? I was trying to clean a code list, however, I found the same substances sometimes have very different codes. If you managed to make use of the information at the end?

Best,