We aimed to describe and discuss the algorithms used to identify chronic inflammatory rheumatisms and psoriasis in medico-administrative databases.
We performed a literature review on the Medline database of articles published up to 31 January 2018. Our inclusion criteria were: original articles using medico-administrative databases in accordance with the International Classification of Diseases, version 10 (ICD-10) and concerning rheumatoid arthritis (RA) or ankylosing spondylitis (AS) or psoriatic arthritis (PsoA) or Psoriasis (Pso). Our exclusion criteria were: letters to the editor, commentaries on published articles, studies using codes other than those of the ICD or a previous version.
Out of the 590 articles identified, 37 studies were included. Concerning RA (n=10), all studies used the M05 code, associated with the M06 code in six studies. The remaining four studies specifically targeted codes M06.0, M06.2, M06.3, M06.8, M06.9, and two of them also used code M12.3. For AS (n=8), 7 studies used the M45 code, while only one study used M45.9, M46.1 or M46.8. For Pso (n=17), all studies used the L40 code and/or at least two dispensations of vitamin D. Concerning PsoA (n=13), all studies used the same codes: M07.0, M07.1, M07.2, M07.3.
We recommend using codes M05 and M06 rather than M06.1 and M06.4 for RA, M45 for AS, the algorithm L40 and/or two dispensations of topical vitamin D for psoriasis, and codes M070 to M073 to identify PsoA patients in medico-administrative databases.