From OMOP to DDD

ARC I&A June 2025

Mahmoud Abdelrazek & Angharad Green

2025-06-25

Terms

OMOP

The Observational Medical Outcomes Partnership is a public-private partnership that aims to improve the quality of observational research. OMOP provides a standardized data model and common data elements to facilitate the sharing and analysis of healthcare data across different organizations.

OMOP

OMOP’s Common Data Model (CDM) is an open community data standard, designed to standardize the structure and content of observational data and to enable efficient analyses that can produce reliable evidence.

OMOP

Common Data Model

DDD

Defined Daily Dose is a unit of measurement used to quantify the amount of a drug that is typically prescribed for a specific condition. It is often used in pharmacology and healthcare research to standardize the measurement of drug consumption.

DDD

It is defined by the World Health Organization (WHO) and is based on the average maintenance dose of a drug for its main indication in adults. It allows for comparisons of drug usage across different populations and settings.

ATC

Anatomical Therapeutic Chemical is a classification system, the active substances are divided into different groups according to the organ or system on which they act and their therapeutic, pharmacological and chemical properties. Drugs are classified in groups at five different levels

ATC

Problem

D OMOP OMOP ATC ATC OMOP->ATC DDD DDD ATC->DDD

Solution ?

Enter RAMSES

RAMSES

compute_DDDs(ATC_code, ATC_administration, dose, unit, silent = FALSE)

RAMSES

 - ATC_code,
 - ATC_administration,
 - dose,
 - unit

ATC code

G RxNorm: Clinical Drug RxNorm: Clinical Drug RxNorm: Ingredient RxNorm: Ingredient RxNorm: Clinical Drug->RxNorm: Ingredient ATC 5th ATC 5th RxNorm: Ingredient->ATC 5th ATC 4th ATC 4th ATC 5th->ATC 4th ATC 3rd ATC 3rd ATC 4th->ATC 3rd ATC 2nd ATC 2nd ATC 3rd->ATC 2nd ATC 1st ATC 1st ATC 2nd->ATC 1st

ATC code

G RxNorm to ATC OMOP809928 OMOP809928 L01BE01 L01BE01 OMOP809928->L01BE01 L04AX03 L04AX03 OMOP809928->L04AX03 OMOP2603855 OMOP2603855 OMOP2603855->L01BE01 OMOP2603855->L04AX03

Dose

  • Haloperidol 0.5mg
  • Haloperidol 1mg/ml

Dose

amount_value
amount_unit_concept_id

Dose

amount_value
amount_unit_concept_id
numerator_value
numerator_unit_concept_id
denominator_value
denominator_unit_concept_id

drugsatc

  • DuckDB
  • R package
  • ATC to DDD mapping
  • DDD calculation

drugsatc

https://github.com/SAFEHR-data/drugsatc