Objectives: To determine the prevalence of subclinical synovitis in Lupus patients without peripheral joint symptoms, in those with arthralgias without arthritis and those with episodic arthritis but without radiological structural damage.
Methods: We conducted a multicentre cross-sectional study. Patients with lupus from those three categories were recruited to take part in a greyscale ultrasound scan performed by an expert blinded rheumatologist. Data from a historical control group from a previous study was also included for comparisons. Images were assessed separately in order to determine the presence and level of synovitis following Eular recommendations.
Results: Ninety-six patients (88.5% female) with an average age of 40 ± 6.2 years old, were included. SLICC/ACR score was 0.6 ± 0.3 in the group without joint symptoms (group 0), 0.8 ± 0.3 in the group with arthralgias (group I) and 1.1 ± 0.4 in the group with episodic arthritis. The global prevalence of subclinical synovitis was 38.5%. In group 0, that prevalence was 30%. The time since onset of symptoms of patients with subclinical synovitis was longer than the rest of the patients (9.4 ± 2.2 vs 6.5 ± 4.0 years, P < 0.001). No other remarkable association was founded with clinical features of the disease.
Conclusions: This is the first study focused on subclinical synovitis in patients with lupus. Other previous studies had included patients with different levels of arthropathy. Subclinical synovitis does exist in lupus patients in over a third of patients. Its meaning remains unclear and must be a topic of further studies.
Keywords: Systemic erythematosus lupus; greyscale ultrasound; joint involvement; subclinical synovitis.