Events outside observation period

[solmazeradat]

Events outside observation period

CDM or THEMIS convention?

THEMIS

Table or Field level?

NA

Is this a general convention?

Yes

Summary of issues

• Forum post was raised after THEMIS issue #23 20 closure in 2018.

The old approach: Before the THEMIS issue #23 20, when START_DATE and END_DATE must be between OBSERVATION_PERIOD_START_DATE and OBSERVATION_PERIOD_END_DATE we populated SOURCE_VALUE with the name of source table and CONCEPT_ID populate with concept like ‘HISTORY OF…’. And diagnosis/procedures from patient history was kept in VALUE_AS_STRING and VALUE_AS_CONCEPT_ID fields field DATE contains OBSERBVATION_PERIOD_START_DATE or date when information about patient history diagnosis/procedures was inputted

The new approach: After the THEMIS issue above, according to that events can fall outside of an observation period we may use new approach: keep diagnosis/procedures from patient history in SOURCE_VALUE and CONCEPT_ID fields and use date of diagnosis/procedures from patient history as DATE.

Disadvantage of this approach is that information about data provenance (medical history) would be lost. Advantage is that we keep real dates of diagnosis/procedures of patient medical history.

So questions are:

For the new approach is it important that diagnosis/procedures are patient history? Do we need change the approach from the old to new? Or we may choose approach depending on the percent of records? Or any other way?

Summary of answer

• The ETL rule was suggested https://forums.ohdsi.org/t/patient-medical-history-events-outside-observation-period/6945/4?u=solmaz.eradat

• Use of a sliding case https://forums.ohdsi.org/t/patient-medical-history-events-outside-observation-period/6945/6?u=solmaz.eradat

• Application of the rule to the first observation period

• Link to github issue was mentioned as a final comment in the forum post.

Related links

• https://forums.ohdsi.org/t/patient-medical-history-events-outside-observation-period/6945

Other comments/notes

[clairblacketer]

I will take this one as a writer

[clairblacketer]

Issue # and location

• Themis issue #23

Issue summary

In databases with defined enrollment that is used to define the observation period, it is possible for there to be events observed outside of the observation period. What should be done with these events?

Convention type

Global

CDM table

NA

CDM field

NA

Links to issue discussion

• OHDSI Forums discussion
• CDM Documentation

Provenance of data

General

The ratified convention

Events CAN fall out of observation period but they cannot be used to identify people in a cohort (as the index date).

Date of ratification/published

Oct 2, 2018

Downstream implications

No

Link to DQD check

Yes - plausibleTemporalAfter (page under construction)

Related conventions/further information

This is related to the convention that every person in the CDM has to have at least one observation period.

#Tags observation_period