An online clinical codes repository to improve validity and reproducibility of medical database research

The ClinicalCodes repository aims to hold code lists for all published electronic medical record studies, irrespective of code type (e.g. Read, ICD9-10, SNOMED) and database (CPRD, QResearch, THIN etc.). Once deposited, code lists will be freely available, with no login needed to download codes.

Clinical codes

Large Primary Care Databases (PCD's) are increasingly being used to address a wide range of research questions in healthcare. Much research has been done into establishing the internal validity of such studies, but PCD studies also rely on clinical codes to provide standardised means for medical professionals to record clinical information. The validity of PCD studies depends upon the validity of the clinical codes used to define the population of interest, their disease conditions, exposures, treatments and outcomes.

However, there is currently no obligation on researchers to publish clinical code lists by journals or research councils and no centralised repository to hold archived clinical code lists. was set up to address this problem.

Why an online clinical codes repository?

  • Clinical codes can be held to scrutiny and peer-review in the same way as any other research methods

  • Replication of previously published studies (e.g. in different databases) is facilitated

  • Access to historical code-lists allows researchers and clinicians to make incremental improvements to disease (and other) definitions, building on and avoiding unnecessary replication of previous work

  • Clinical code lists can become a resource for future research in their own right (e.g. tracking disease definitions through time)

To date: 40664 clinical codes deposited over 279 code lists

Further information

See this article for full details of and rationale for the ClinicalCodes project

For more details on the background and usage of this site, see the FAQs

See here for Publications and presentations on ClinicalCodes

See here for a list of articles that have codes uploaded

This site is still in development. Please contact us if you find any bugs or problems in using it, or if you have any suggestions for future improvement. Alternatively, visit our issue tracker.