Background/Purpose: Some patients with rheumatoid arthritis (RA) have pain, despite normalization of inflammatory markers and reduced swollen joint counts. Among these patients, the number of tender joints often exceeds the number of swollen joints. Pollard et al. reported that a tender swollen joint difference (TSJD) ≥ 7 can identify patients with RA and comorbid fibromyalgia, the prototypical nociplastic pain condition.1 Fibromyalgia and anxiety often co-occur, and previous studies suggest that psychological factors, such as anxiety, may heighten pain sensitivity. The objective of this study is to assess the relationship between anxiety and TSJD, as an indicator of dysregulated CNS pain processing, in patients with RA.

Methods: This analysis used baseline data from the Central Pain in RA (CPIRA) study, which enrolled 295 participants from four academic medical centers between January 2014 to April 2017. Patients met 2010 ACR/EULAR criteria for RA and were either starting DMARDs or switching DMARDs due to lack of efficacy. TSJD was calculated as the number of tender joints minus the number of swollen joints on a 28-joint exam. A higher TSJD indicates greater discrepancy between tender and swollen joint counts. A dichotomous outcome of high vs. low TSJD was defined using a cut-off of ≥ 7 vs. < 7. We evaluated associations between PROMIS anxiety t-scores and TSJD using logistic regression. Multivariable logistic regression models were adjusted for age, sex, race, body mass index (BMI), RA symptom duration, seropositivity, and C-reactive protein (CRP).

Results: Among 276 patients with RA (mean age (± SD) 54.7 ± 13.9 years, 82% female), 73% were seropositive for rheumatoid factor and/or anti-cyclic citrullinated peptide, and the mean RA symptom duration was 12.5 ± 12.7 years. The median TSJD was 4.0, (interquartile range of 0-10.3), with 38% having a TSJD of ≥ 7. The mean PROMIS anxiety score was 53.8 ± 8.9. In unadjusted analyses, higher anxiety was significantly associated with presence of higher TSJD (odds ratio [OR] for 5-unit change = 1.05, 95% confidence interval [CI]: 1.02, 1.09). In the multivariable regression model, anxiety remained significantly associated with higher TSJD (OR for 5-unit change = 1.05, 95% CI: 1.01, 1.08) (Table 2). Higher BMI was also significantly associated with higher TSJD.

Conclusion: Greater anxiety was associated with higher TSJD. RA patients with greater TSJD may benefit from a multimodal pain management approach that includes strategies for managing and monitoring symptoms of anxiety. References: 1. Pollard LC, Kingsley GH, Choy EH, et al. Fibromyalgic rheumatoid arthritis and disease assessment. Rheumatology (Oxford). 2010; 49: 924-9.

Values represent mean ± SD or n (%)

a Per 5-unit increase in PROMIS Anxiety T-Score

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/association-between-anxiety-and-tender-swollen-joint-difference-in-patients-with-rheumatoid-arthritis/