OHDSI Home | Forums | Wiki | Github

How to set treatment pathways in ATLAS

Hi~
I am testing treatment pathways in ATLAS.
I would like to set a case where the patient with a diagnosis of epilepsy has only one drug at first, but I do not know what to do with the ATLAS.
Tell me how to set ‘prescribed only one medication instead of several drugs’ in ATLAS

Hi @soyoung_YI

I suppose you want to look on the patients who got mono-therapy for epilepsy.
I think you need to include the patients with
any occurrence of the drug of interest
AND
exact zero occurrence of concept set of “all anti-epileptical drugs except the drug of interest”

@Dymshyts:

That’s correct. If you have one drug you are studying, you can say “and not any of these drugs”. But you cannot say “All patients with just one drug out of the following list”, as far as I know. Can you?

I think ‘Add Group’ can help. Among patients with a diagnosis of epilepsy chose those who have AT MOST1 exposure
of drug A, B , C etc.

No,
I mean for each drug to create a separate concept set.

You can also try this:

Concept Set: The ingredients of interest

Cohort Entry Criteria: First exposure of ‘ingredients of interest’
Cohort Exit Criteria: Drug Era using ‘ingredients of interest’ with specified gap days
Censoring Events: Drug Era using ‘ingredients of interest’ having exactly 2 distinct drug eras of ‘ingredients of interest’ starting all days before and 0 days after event index.

The bolded part is the key: it says that you kick the person out of the cohort as soon as you see 2 distinct drug eras (2 different drug era concept IDs). The nice thing about this is that instead of finding only people that have exactly one ingredient, you let people into the cohort who might have multiple future-ingredients, but take them out as soon as they have a second.

Some limitations: 1) you have to work at the ingredient-level from the drug-era table because all the drug_concept_ids there are at the ingredient level. There’s no notion of ‘augmentation’ in this definition: if a new drug appears, from ‘ingredients of interest’ we assume that’s not mono anymore, so you have to carefully consider the ‘ingredients of interest’ wouldn’t be those that might be used in combination with each other.

For your reference:
http://www.ohdsi.org/web/atlas/#/cohortdefinition/1729524

t