Key differences between osteoarthritis and seropositive rheumatoid arthritis

Key differences between osteoarthritis and seropositive rheumatoid arthritis on hand ultrasound Sidra Hussain, Priyanka Sivakumaran Coziana Ciurtin

Background Ultrasound (US): low cost and effective way to discriminate normal from early inflammatory arthritis joints Positive Doppler (PD) signal indicate active joint inflammation and synovial hypertrophy (SH) and joint effusions are additional inflammatory changes. Inflammatory markers being greater on US in erosive osteoarthritis (EOA) compared to non-EOA , suggesting EOA may have some systemic inflammatory component. Can we differentiate between OA and RA patients based on these measurements? • Patient age • Inflammatory markers (ESR and CRP) • Synovial hypertrophy, positive Doppler signal • Osteophytes (OP) and erosions • Tender joint count (TJC), swollen joint count (SJC) and global assessment score (GVAS)

Methods Imaging: 299 patients 42 OA and 108 RA Blood tests US joint system analyse data Retrospective study Logiq S 8 (GE Medical Systems Ultrasound and Primary Care Diagnostics)

Results * Number of joints with positive Doppler Number of joints with osteophytes Number of joints with OPs * 30 * 25 Number of joints with PD P =<0. 05 denoted with: 20 15 10 5 0 OA RA * 9 8 7 6 5 4 3 2 1 0 OA RA

Results * Mean SJC * 25 Number of joints with erosions * 7 6 20 5 SJC score Number of joints with SH grade 1 15 10 4 3 2 5 1 0 OA RA Number of joints with erosions P =<0. 05 denoted with: * 30 25 20 15 10 5 0 OA RA

Discussion/Conclusion Discussion Findings are consistent with current knowledge of RA as an inflammatory arthritis, with more evidence of inflammatory changes on US (synovial hypertrophy, positive Doppler and erosions), as well as on CJE (higher SJC). OA is a degenerative condition, which is reflected by the older age of sufferers. Osteophytes are more likely to be present in US of patients with OA compared to RA. Conclusion Further work is needed to establish whethere can be a clear cut-off for the number of joints with inflammatory changes on US (e. g. effusions, positive Doppler, synovial hypertrophy) that definitively distinguish between hand OA and RA.

References Millot F, Clavel G, Etchepare F, et al. Musculoskeletal ultrasonography in healthy subjects and ultrasound criteria for early arthritis (the ESPOIR cohort). J Rheumatol. 2011; 38(4): 613 -20. Tan YK, Østergaard M, Conaghan PG. Imaging tools in rheumatoid arthritis: ultrasound vs magnetic resonance imaging. Rheumatology (Oxford). 2012; 51 Suppl 7: vii 36 -42. Szkudlarek M, Wakefield RJ, Backhaus M, Terslev L. The discriminatory capacity of ultrasound in rheumatoid arthritis: active vs inactive, early vs advanced, and more. Rheumatology (Oxford). 2012; 51 Suppl 7: vii 6 -9. Kortekaas MC, Kwok WY, Reijnierse M, Huizinga TW, Kloppenburg M. In erosive hand osteoarthritis more inflammatory signs on ultrasound are found than in the rest of hand osteoarthritis. Ann Rheum Dis. 2013; 72(6): 930 -4.

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