New routes (and de-standardization of old SNOMED routes)

[Alexdavv (Alexander Davydov)]

@Christian_Reich

The SNOMED routes are built on the philosophy of how something can move from one body compartment to another

I think we make the same mistake in @tburkard proposal. Nasal transmucosal and topical are not just the routes of administration but an attempt to follow the same approach to reflect not only how the drug is applied, but also how the doctor believes the drug is actually spread and act. Given the SNOMED experience and this attempt to improve it, we already know that there’s no good way to do that in the parent-child hierarchical model. Because it just works differently for different drugs, in different dosas, in different patient’s states, etc - @zhuk has good examples listed here.

Even though we make these decisions once and reflect them in the hierarchical model, at the end of the day, only ETLs that have it distinguished and clearly defined in their source data can map to it. But they’re still not happy, because we’ve made an exclusion for “nasal” and split it into two, but haven’t done it for others that could be relevant also (like injections that lead to a local effect only, or vaginal topical applications, or inhaled systemic drugs, etc.).

Those ETLs that only have general “nasal” in the data will not be able to map at all, because there’s no way they’ll be looking up the ingredients and their mechanism of action, PK/PD parameters. So we either add a more general concept “nasal” to be an alternative top dog, or map to 0. The same is true for “injections”, especially derived from the claims, and other cases.

@funaesthesia

Therefore, transmucosal/nasal could be systemic in some cases and local in others. This holds true for a lot of the mappings. By providing the expected site of action, we could increase granularity and make ETL processes easier

This is what we do in the new approach. But the list of exceptions is arbitrary. And by adding more, the hierarchy itself becomes too complex (SNOMED) or broken (at least for those who don’t follow the general rule).

@funaesthesia

I think in a clinical context, one has to detach the route from the expected site of action/the physician’s intention where the drug should interact.

Exactly. I think this is the only option that can solve the whole problem:

1. Only record a site where the drug was applied. Doctor’s intents, expectations on drug distribution, PK/PD parameters go out from the site concepts.
2. Get rid of a big hierarchy because it only works for those who follow the rules. This way we don’t make the statements like inhalation always and only leads to a local effect.
3. Allow the general concepts like “injections”, and “systemic”, but don’t put them in a hierarchy of things.
4. Allow researchers to make their analytical decisions based on the site of application but considering dose form, ingredient, actual dose, and whatever else is needed.