Background/Purpose:  The swollen and tender joint count is included in composite scores (DAS28, CDAI, SDAI, ACR/EULAR Boolean remission). Low swollen/tender joint ratio (STR) has been found to be associated with reduced clinical response[1]. Ultrasound (US), including grey scale (GS) synovitis and power Doppler (PD) assessment of vascularity is sensitive for detecting inflammatory activity. Presently we explored associations between STR and pain catastrophizing, PROs, composite scores, clinical evaluation and US assessments, and more importantly, with composite score remission, in a follow-up study of established RA patients initiating bDMARDs.

Methods: 209 patients with RA (mean (SD) age 53 (13) years, disease duration 10 (9) years, 81% women, 79% anti-CCP positive) were included when initiating bDMARDs and assessed at baseline and after 1, 2, 3, 6 and 12 months with PROs (joint pain VAS, patient’s global VAS, RAID score and MHAQ), clinical examinations (assessor’s disease activity VAS, tender and swollen joint counts (of 28)) and laboratory variables (ESR and CRP). STRs were calculated with insertion of 1 if 0 in the denominator. Pain catastrophizing was assessed by two questions from the Coping Strategies Questionnaire. All US examinations (semi-quantitative scoring (0-3)) of GS and PD (PIP 2-3, MCP 1-5, wrist (RC, IC, RU), elbow, knee, tibiotalar, MTP 1-5 and ext.carpi ulnaris/tib.post.tendons bilaterally) were performed by one rheumatologist (HBH) (Siemens Acuson Antares, excellence version, 5-13 MHz probe). Statistical calculations included Pearson’s correlations, independent samples T-test and cross-tabs for assessing risk levels.

Results: There was a wide distribution of STR levels (median 1.0 (IQR 0.6-2.5), mean (SD) 2.4 (3.8)). During follow-up there were no/low cross-sectional correlations between STR and all the PROs and laboratory markers (r= -0.03-0.24), but moderate to high correlations with assessor’s global (r= 0.27-0.42, p<0.001) and the US examinations (GS; r=0.48-0.63/PD; r=0.38-0.67, p<0.001). Patients were divided into groups with STR ≥ 1.0 or <1.0. The table (including mean values) shows that patients with STR<1.0 during follow-up had significantly higher levels of PROs and composite scores but lower US scores. Patients with STR < 1.0 achieved less often remission according to the composite scores (STR<1.0/STR≥1; DAS28 4.3%/36.4% and 3.3%/35.5%, CDAI 2.7%/17.9% and 1.3%/23.7%, SDAI 3.3%/20.1% and 3.3%/24.3%/, Boolean 2.7%/18.5% and 1.3%/21.7% at 6 and 12 months, respectively).

Conclusion: Established RA patients with higher number of tender than swollen joint count had higher levels of PROs and composite scores, but lower US pathology, and more importantly, lower achievement of clinical remission. Thus, these patients may have a trait including higher subjective scores, which is relevant within the treat-to-target strategy. Reference: Kristensen LE et al, Arthritis Care Res 2014 Feb;66(2):173-9

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/higher-number-of-tender-than-swollen-joint-count-is-associated-to-higher-patient-reported-outcomes-and-composite-scores-as-well-as-reduced-probability-of-obtaining-remission-results-from-a-one-year-f/