Background/Purpose: Arthritis is a current manifestation of SLE and participates to the SLEDAI composite score calculation (0 to 105). Ultrasonography (US) is a validated and sensitive tool for joint assessment. Published studies showed US joint abnormalities in SLE patients with or without joint pain. Nevertheless, US evaluations were not standardized and no study compared clinical and US assessments. Our objectives were 1) to describe US joint abnormalities in SLE population, 2) to compare clinical and US standardized joint assessments, 3) to estimate the reliability of clinical swollen joint count (C-SJC) and SLEDAI (C-SLEDAI) score versusUS-SJC and US-SLEDAI.

Methods:

In an observational prospective multicenter study, we recruited consecutive SLE patients (with or without joint involvement). All fulfilled SLICC classification criteria. Evaluation included a clinical standardized joint assessment (on 40 joints), a B-mode and power Doppler (PD) US examination of the same joints, hands X-Rays, biological parameters and ongoing treatments. US was blinded to clinical assessment and performed the same day in accordance of the OMERACT guidelines. Clinical and US joint assessments included wrists, MCP, IPP, elbows, shoulders, knees, ankles and MTP. Twenty six tendons were evaluated by US (wrist extensors, finger flectors and tendons of the ankles). A joint was considered as having synovitis if the grading was ≥1 through B-mode. Reliability between clinic and B-mode US was calculated at patient level using the intraclass correlation coefficient (ICC [95% Confidence Interval]).

Results:

141 SLE patients were recruited in 7 French hospitals. 88.6% were women, mean age was 45.3±14.8 years. SLE duration was 11.7±9.7 years. 58.1%, 72.3% and 20.5% were receiving corticosteroids, hydroxychloroquine and methotrexate respectively. Mean CRP was 6.7±11.6 mg/l and ESR was 19.4 ±19.3mm, 90.6% had increased antinuclear antibody and 46% had increased anti-DNA. Sixty one patients (43.6%) had inflammatory joint pain but 124 (88%) had at least one US abnormality (effusion, synovial hypertrophy, tenosynovitis with or without PD signal). Among the 5,640 joints and 3,666 tendons assessed, 442 effusions (7.8%), 549 synovial hypertrophy (9.7%) and 117 tenosynovitis (3.2%) were detected. 170 joints (3%) had PD signal. Synovitis were mainly detected on the wrists (46.4%), MCP2 (19.8%), MTP1 (26.2%) and MTP2 (18.4%). Tenosynovitis were seen on finger flectors (31%) and extensor carpi ulnaris (10%). Mean US-SJC was significantly higher than C-SJC: 3.5±5.3 versus1.5±3.6. SJC reliability was poor (ICC 0.33 [95%CI 0.16-0.48] between clinical and US assessments. Among 92 patients with a C-SJC equal to 0, 64% (59/92) had at least 1 US synovitis. Mean US-SLEDAI was significantly higher than C-SLEDAI: 4.8±3.4 versus 2.9±3.5. SLEDAI reliability was mild (ICC 0.68 [95%CI 0.27-0.84]) between clinical and US assessments. Nevertheless, US-SLEDAI score was higher than C-SLEDAI in 51% of patients by detecting asymptomatic synovitis.

Conclusion: Joints and tendons US may be useful to assess joint involvement in SLE patients and SLEDAI score calculation.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/joint-ultrasonography-may-be-useful-to-assess-disease-activity-in-systemic-lupus-erythematosus-sle-patients-a-prospective-multicenter-study/