Background/Purpose

Regular monitoring of disease activity with appropriate modification of disease-modifying anti-rheumatic drug (DMARD) therapy results in improved radiographic and functional outcomes in patients with rheumatoid arthritis (RA). Large joint involvement has been shown to impact significantly on both disease activity and disability. Power Doppler ultrasound (PDUS) can effectively detect subclinical active synovitis not appreciated by clinical examination. The objective is to evaluate the presence of residual large joint disease in established RA patients in a multi-ethnic Asian cohort using PDUS as the reference standard, and whether there is increased impact and disability.

Methods

Patients with established RA (ACR 1987 criteria) and stable disease were recruited as part of a randomized controlled single centre study, evaluating the use of ultrasonography feedback as training tool for patient self-assessment of synovitis. At baseline, 28 joints (2 shoulders, 2 elbows, 2 wrists, 10 MCP, 10 PIP, 2 knees) of each patient were assessed for synovitis in B-mode (from 0=absence of synovial thickening to 3=marked synovial thickening) and PDUS (from 0=absence of signal, no intra-articular flow to 3=marked signal in more than half of the synovial area). Semiquantitative grade ≥1 on PDUS was considered as active synovitis. Patients with residual large joint disease (shoulders, elbows, knees) on PDUS were evaluated for differences in baseline demographics, disease activity, physical function (modified Health Assessment Questionnaire, mHAQ and SF12-physical component score) and impact of disease (Rheumatoid Arthritis Impact of Disease Score, RAID) with patients that did not have large joint involvement. Measures of association were evaluated using logistic regression.

Results

Of the 101 patients included, median (IQR) age was 54 (48, 63) years old, Chinese (73%), female (81%), non-smokers (85%), and 77% were positive for either rheumatoid factor or anti citrullinated peptide antibody. Median disease duration was 5 (2, 9) years with PDUS-DAS28 of 3.2 (2.6, 4.2). PDUS indicated a large proportion of patients with residual large joint involvement (44%) – 21% of shoulders, 20% of elbows and 6% of knees involved. The most common small joint involvement was the wrist (27%) with MCP and PIP joints rarely involved (both 2% respectively). A higher proportion of Chinese patients had large joint involvement (p=0.03). No significant differences in other baseline patient characteristics such as age, sex and seropositivity were seen. Patients with large joint disease had higher PDUS-DAS28 (p<0.001), ESR (p=0.002) and were more likely to receive combination triple therapy (DMARDs) (p=0.008). Residual large joint involvement was significantly associated with mHAQ>0.5 (p=0.03), lower SF12 physical component scores (p=0.02) and higher RAID score (p<0.001).

Conclusion

Multi-ethnic Asian RA patients with relatively stable established disease have a high proportion of residual PDUS large joint activity that significantly impacts on patients. Physicians should aggressively treat this subset of patients with either systemic/local therapies to prevent further disability.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/residual-large-joint-synovitis-by-power-doppler-ultrasonography-is-associated-with-higher-disease-activity-and-significant-impact-of-disease-in-multi-ethnic-asian-patients-with-established-rheumatoid/