Patients with osteoarthritis (OA) and rheumatoid arthritis (RA) exhibited similar disease burden at initial presentation, but patients with OA exhibited higher disease burden 6 months later, according to results of a retrospective cohort study published in Arthritis & Rheumatology.

The investigators sought to evaluate disease burden in OA vs RA according to Multidimensional Health Assessment Questionnaire (MDHAQ) scores and Routine Assessment of Patient Index Data (RAPID3) at initial and 6-month follow-up visits. Patients seen at the rheumatology center of Rush University in Chicago, Illinois, complete the MDHAQ at all visits, which is saved in their electronic health record. MDHAQ scores of 0 to 10 for physical function, pain, and patient global assessment, along with RAPID3 scores of 0 to 30, were compiled in this study.

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Patients with OA or RA were classified as either self-referred or physician referred. Individuals with RA were either naive to disease-modifying antirheumatic drugs (DMARDs) or were prior users. Comparisons were performed using t-tests and analysis of variance, which were adjusted for age, ethnicity, duration of disease, body mass index, and education.

Compared with patients with RA, those with OA were older, had a higher body mass index, and had a longer duration of disease. At the initial patient visit, the mean RAPID3 score did not differ significantly between patients with OA and DMARD-naive patients with RA, regardless of whether they were self-referred or physician referred (range, 14.8 to 16.4; P =.38).The mean RAPID3 score also did not differ significantly among patients with OA vs those with DMARD-naive RA vs patients with RA who had previously used DMARDs (16.0 vs 15.5 vs 15.6, respectively; P =.49). After 6 months, however, RAPID3 scores improved to 14.3, 9.9 and 12.5, respectively — substantially more among patients with RA vs those with OA.

A major limitation of the study was that only those patients with complete MDHAQ/RAPID3 scores at their initial and 6-month visits were available for analysis. Moreover, because patients were treated at a single tertiary center, the findings may not be generalizable to a community setting in which patients with OA and RA may have milder disease. The investigators indicated that they do not suggest comparing OA vs RA as “more severe” at a group or individual level because some patients with either diagnosis may have mild, moderate, or severe disease. The findings with respect to disease burden among patients with OA vs RA reflect superior treatments among those with RA.

Reference

Chua JR, Jamal S, Riad M, et al. Disease burden in osteoarthritis (OA) is similar to rheumatoid arthritis (RA) at initial rheumatology visit and significantly greater 6-months later [published online March 20, 2019]. Arthritis Rheumatol. doi: 10.1002/art.40869