Background/Purpose:  Anti-citrullinated peptide antibodies and/or rheumatoid factor (RF) in the setting of arthralgia (“seropositive arthralgia”) has been associated with a high risk of development of rheumatoid arthritis (RA). Models of the risk of imminent RA have used arthralgia as an inclusion criterion. The significance of arthralgia in an unselected population of first-degree relatives (FDR) and controls, with or without seropositivity, is not known. We recruited a high-risk group, FDR of indigenous North American (INA) people with RA, in addition to INA population controls, with or without arthralgia. The goal of this analysis is to describe the prevalence of arthralgia at baseline and the association of arthralgia, seropositivity, and other RA risk factors with development of RA.

Methods:  INA FDR and healthy unrelated controls were recruited from two populations in Canada and the United States. Data collected at the baseline visit included demographic features, habits and environmental exposures, and self-reported joint symptoms. Sera were tested for the presence of anti-cyclic citrullinated peptide (CCP) antibodies and rheumatoid factor IgM by ELISA. Risk of future RA was estimated based on a previously reported risk model for imminent RA. Participants have been followed longitudinally for development of RA.

Results:  961 participants were included in the analysis (620 FDRs and 341 controls). The mean age at baseline was 36.0 years. The cohort was 62.2% female, with 74.4% residing in rural communities. Arthralgia of any joint was present in 51.3% of the cohort (58.4% of FDRs and 35.5% of controls, p<0.0001). Arthralgia of both the hands and other joints was present in 31.9% overall. Seropositive arthralgia was present in 128 participants (27.7% of those with arthralgia). Seropositivity for RF and/or CCP was associated with reduced odds of arthralgia at the baseline visit (OR 0.59 (95%CI 0.44-0.80)). The majority of those with arthralgia (91.2%) fell into the low-risk category for RA development based on the imminent RA prediction model. Participants who developed RA during the follow-up period (n=14) were no more likely to have arthralgia at baseline than those who did not develop RA (p=0.9). Those who developed RA were less likely to fall in the low risk group at baseline (p<0.001) and more likely to be seropositive for RF (p=0.07) and CCP (p<0.001) and to have seropositive arthralgia (p=0.001).

Conclusion:  Although arthralgia is more common in FDRs than in controls, arthralgia is not associated with seropositivity or with development of RA in a healthy population. In contrast, both seropositivity and seropositive arthralgia are associated with RA development.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/frequency-of-arthralgia-seropositivity-and-seropositive-arthralgia-and-their-association-with-development-of-rheumatoid-arthritis-in-a-cohort-of-indigenous-north-americans-with-or-without-a-first-de/