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The vocabularies here are being used to help build our Cochrane vocabulary.
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WHO ATC/DDD |
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Where synonyms or near-synonyms appear in the controlled vocabularies that we will use the following processes to standardize annotations (as much as possible).
- A term in one vocabulary has a synonymous term in the same vocabulary
- A term in one vocabulary has a synonymous term in a different vocabulary
A term in one vocabulary has a synonymous term in the same vocabulary
MedDRA
For some reason, MedDRA has been structured so that every term at the second-lowest level of its hierarchy (PT - Preferred Term) has a synonymous term at it's lowest level (LLT - Lowest Level Term). The LLT member of each of these pairs has been removed from our Cochrane Vocabulary, so there should be no exactly identical terms within MedDRA. If you uncover any examples in the course of annotation or QA, please flag them up for us to resolve. However, there will be many close matches within MedDRA - for example UK and US spellings of a term (oedema, edema etc) are separate terms in MedDRA. We are in the process of resolving this in a way that will merge these MedDRA synonyms.
Interim work-around
- If one of the MedDRA synonyms is linked to a SNOMED term, pick that one
- If a UK spelling exists, please use it.
- If neither of the above exists, just pick any one of a group of MedDRA terms that seem to be synonyms and we will be able to merge your annotation with annotations using one of the other terms.
ATC/WHO
Duplication arising from different formulations of the same drug
WHO-ATC is organized by organ system, so a drug that is used in different formulation for different body systems will have multiple entries in the original WHO vocabulary (e.g. tetracycline formulations for application to the skin have a term that starts with D (dermatologic), those for use in eyes or ears have an S (sensory), in the mouth it's A (alimentary) etc.) We have merged all of these terms into a single Cochrane tetracycline term and merged it with related terms from RxNorm and SNOMED CT - so tetracylcline is now mapped to
SNOMED: 66261008
RxNorm: 10395
ATC: S02AA08,S03AA02,S01AA09,J01AA07,D06AA04,A01AB13
MeSH: D013752
If you come across multiple identical terms for an individual drug, please let us know so that we can resolve the issue.
Duplication in Drug Category arising from different formulations of the same drug
Unfortunately the WHO drug categories are also organized by organ system, and WHO has chosen to give identical labels or labels that appear synonymous to to drug categories in different (organ system) parts of their vocabulary. So the parent terms for Tetracycline include Tetracyclines, Antiinfectives, Antibiotics, and a second Antiinfectives and these categories are based on organ systems. The two Antiinfective terms, for example, apply to tetracycline eye or ear drops, so would not be an appropriate choice for an annotation of systemic anti-infectives. We are working to relabel the WHO drug categories to make these distinctions clearer, but if there are apparent synonyms, the correct term can be chosen by looking at the initial letter in the WHO identifier.
The full list of top level terms and corresponding first levels for the terms is as follows:
ATC Category | CODE Starts with |
ALIMENTARY TRACT AND METABOLISM | A |
BLOOD AND BLOOD FORMING ORGANS | B |
CARDIOVASCULAR SYSTEM | C |
DERMATOLOGICALS | D |
GENITO URINARY SYSTEM AND SEX HORMONES | G |
ANTIINFECTIVES FOR SYSTEMIC USE | J |
ANTINEOPLASTIC AND IMMUNOMODULATING AGENTS | L |
MUSCULO-SKELETAL SYSTEM | M |
NERVOUS SYSTEM | N |
RESPIRATORY SYSTEM | R |
SENSORY ORGANS | S |
VARIOUS | V |
If you encounter synonymous drug categories, please pick the one that seems best using the above table, and also let us know so that we can change the term labels.
Duplication due to multiple uses of the same (or similar) terms at different levels in the WHO-ATC hierarchy
ATC has 3 closely related terms - Tetracyclines J01A, Tetracyclines J01AA, and Tetracycline J01AA07. These are actually 3 different levels in the hierarchy:
Tetracyclines J01A
Tetracyclines J01AA (and this is the only child term under Tetracyclines J01A
Tetracycline J01AA07.
The duplication of the Tetracyclines label for J01A and J01AA, with J01AA being the only child happens elsewhere within ATC as well. (e.g. Antimycotics for systemic use J02/Antimycotics for systemic use J02A). If you find other examples in the course of annotation or QA, please flag them up for us to resolve.
The Tetracyclines/Tetracycline duplication is somewhat different. Tetracycline is a specific drug and one of several members of the class Tetracyclines, so the 2 terms are not equivalent or interchangeable. This situation should be fairly rare (Tetracycline(s) may be the only example).
A term in one vocabulary has a synonymous term in a different vocabulary
MedDRA and SNOMED CT
We have attempted to identify all cases in which a term in MedDRA has a label that is identical to the label from a term in SNOMED CT and these have been merged into a single Cochrane term - with both parent terms listed in the our various tools whenever the term is used. If you find examples of synonymous terms in these 2 vocabularies in the course of annotation or QA, please flag them up for us to resolve.
In addition to these exact synonyms, there are many cases in which a term in MedDRA looks as if it is probably identical to a term in SNOMED CT but has a slightly different label. An example is the MedDRA term Premature Baby & the SNOMED CT term Premature Infant. These have now been combined into a single Cochrane term with the label Preterm Infant (Less than 37 weeks). If you find examples of near synonyms in these 2 vocabularies in the course of annotation or QA, please flag them up for us to resolve. Our plan is to either combine them into a single Cochrane term (as above) or to designate one of the pair as a "Cochrane Preferred Term" to be used in all relevant annotations.