Background Approximately 1-2% of patients with SLE have joint inflammation similar to rheumatoid arthritis (RA). There are no well-designed studies comparing SLE ultrasonography with RA.
Objectives to evaluate the ultrasound (US) of the hands in patients with SLE, make its correlation with clinical, serological, radiological and functional variables, and make its comparison with US of patients with RA.
Methods This was a cross-sectional study with 122 patients (62 with SLE and 60 with RA). We perfomed clinical, radiographic and ultrasound evaluations. A “blind” radiologist used a My Lab 60 XVision machine (Esaote, Biomedica - Genova, Italy) with a linear array (6-18MHz).The ultrasonographic measurements (quantitative and semi-quantitative measures) used were: synovial hyperplasia(SH) (in mm and score of 0-3), Power Doppler- PD (score of 0-3), bone erosions (BE) (score of 0-3) and cartilage (score of 0-4). The joints evaluated: radiocarpal; distal radioulnar; first to fifth metacarpophalangeal (MCP) (dorsal and volar aspects) and proximal interphalangeal (PIP) (volar aspect).
Results We studied 24 joints and 34 joint recesses in each patient (4.148 joint recesses). The mean disease duration was 8,3±7 years for RA and 11,7±7,7 years for SLE. Statistical difference (p<0,05) was observed between groups with higher values for RA for SH in radiocarpal joints (RC), distal radioulnar (RU), 1 MCP volar and dorsal; for PD in RC, RU, 1MCP volar, 2 MCP dorsal, 3 MCP volar, 5 MCP dorsal and for BE in RC, RU, 1 to 5 MCP volar and dorsal aspects, 1 PIP, 3 PIP. Higher HAQ scores were associated with synovitis and PD only in the SLE group. In relation to SLE, cutoff values of SH specific of RA (AUC>0,661; p<0,001) were: RC 7,47mm and RU 5,6mm and progression from score 0 to 3 with greater chance to detect RA were (p<0,032): SH: RC (OR=6,7); RU (OR=5,8); and 1 dorsal MCP (OR=2,2); PD: radiocarpal (OR=66); RU (OR=3,9) and 2 dorsal MCF (OR=3,6). Progression from score 0 to 2 with greater chance to detect RA were: BE (p<0,035): RC (OR=12,6); RU (OR=27,5); 1 MCP: dorsal (OR=13) and volar (OR=5,3); 2MCP: dorsal(OR=8,2) and volar (OR=23,9); 3MCP: dorsal(OR=11,0) and volar (OR=13,8); 4 dorsal MCP (OR=9,6); 5 MCP: dorsal (OR=9,6), volar (OR=9,6). Inter-observer reliability (r) for quantitative and semi-quantitative measures ranged from 0,666 to 1,000 and 0,559 to 0,904, respectively.
Conclusions The US of the hands in patients with SLE and RA were diferent in many joints. In relation to SLE, sonographic measures specific of RA were found in radiocarpal and distal radioulnar (SH, PD and BE) and in all MCPs (BE). The correlations between US and clinical, serological and functional variables in SLE were only occasional.
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Disclosure of Interest None Declared
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