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

Research article:

An algorithm to identify rheumatoid arthritis in primary care: a Clinical Practice Research Datalink study


Sara Muller, Samantha L Hider, Karim Raza, Rebecca J Stack, Richard A Hayward, Christian D Mallen(2015) An algorithm to identify rheumatoid arthritis in primary care: a Clinical Practice Research Datalink study. BMJ Open, doi:

Link to article
Author for correspondence
Sara Muller
Email for correspondence

Clinical code lists:

Click to view and download

Code list
Res34: inflammatory_bowel_disease Download this codelist
Res34: JIA Download this codelist
Res34: leukaemia Download this codelist
Res34: ankylosing_spondylitis Download this codelist
Res34: psoriasis Download this codelist
Res34: psoriatic_arthritis Download this codelist
Res34: spondyloarthropathy Download this codelist
Res34: systemic_lupus_erthematosus Download this codelist
Res34: transplant Download this codelist
Res34: rheumatoid_arthritis_group1 Download this codelist
Res34: rheumatoid_arthritis_group2 Download this codelist
Res34: rheumatoid_arthritis_group4 Download this codelist
Res34: rheumatoid_arthritis_group3 Download this codelist

5 comments have been posted.

Dec. 9, 2015, 9:46 a.m. - Sara Muller

The codes lists presented here are to enable to user to implement the following algorithm / definition of rheumatoid arthritis. Define indivvidual as having RA if either Criterion 1 or Criterion 2 are fulfilled. Criterion 1: At least one diagnostic Read code for RA and at least one appropriate prescription of a disease modifying anti-rheumatic drug (DMARD) with no alternative indication for the DMARD. Criterion 2: all three of the following: a) two or more diagnostic Read codes for RA (on different dates); b) no alternative diagnosis after the final RA code; c) a RA code in Group 1 (seropositive or erosive RA) or Group 2 (“rheumatoid arthritis” codes e.g. RA of knee), opposed to only Group 3 (systemic manifestations of RA) or Group 4 (seronegative RA or other weak evidence of RA).

Dec. 9, 2015, 9:48 a.m. - Sara Muller

Information on the use of these codes To obtain more information on these code lists and others used in our research, please visit our website As we are constantly updating code lists, this website will also contain the most up to date lists. The copyright (©2014) of the morbidity definitions and code lists is owned by Keele University, the development of which was supported through the Primary Care Research Consortium. No licence is required to allow non-commercial use of these resources, however if you wish to utilise Keele’s morbidity definitions and/or code lists we do ask that you inform us first, acknowledge Keele’s Prognosis and Consultation Epidemiology Research Group in any publication, and include a copyright statement in publications. More information is available from our website

Dec. 9, 2015, 9:51 a.m. - Sara Muller

Alternative diagnoses to RA are defined as psoriatic arthritis, ankylosing spondylitis and spondyloarthropathies.

Dec. 9, 2015, 9:51 a.m. - Sara Muller

Sero-negative spondyloarthropathy includes ankylosing spondylitis and spondyloarthropathies.

Jan. 7, 2016, 4:13 a.m. - Sara Muller

Unfortunately, at this time, it is not possible to upload the codes for DMARDs or the alternative indication for each DMARD. These codes are available from the author, or via the following website

Please log in to leave a comment.