Ultrasound-Detected Salivary Gland and Joint Inflammation Strongly Reflect Patient-Perceived Symptom Burden in...

Aims. To investigate the relationship between ultrasound (US)-detected parenchymal abnormalities in the major salivary glands (MSG), joint and tendon inflammation, and systemic disease activity in patients with primary Sjögren's syndrome (pSS). Patients and methods. This cross-sectional, multicenter study enrolled 60 patients with pSS and 20 healthy controls (HCs). Systemic disease activity was evaluated using the EULAR Sjögren's Syndrome Disease Activity Index (ESSDAI), while symptom burden was assessed with the EULAR Sjögren's Syndrome Patient Reported Index (ESSPRI). MSG evaluation included bilateral gray-scale (GS) and power Doppler (PDUS) assessment of the parotid and submandibular glands using a semi-quantitative 0-3 scoring system. Musculoskeletal ultrasound (MSUS) assessment comprised bilateral examination of the wrists, second to fifth metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints, the fourth extensor wrist compartment, and the flexor tendons of the second to fifth fingers for GS and PD-detected synovitis and tenosynovitis, also scored semi-quantitatively. Recorded outcomes included GS and PD synovitis scores, total synovitis score, tenosynovitis score, GS and PD glandular scores, and total glandular score. Results. Synovitis was most frequently detected in the wrists, followed by the second PIP joint. Subclinical synovitis-defined as a GSUS synovitis score > 0 in a joint without clinical swelling-was detected in 66.7% (n = 28) of patients with pSS. No significant correlations were found between joint US scores and salivary gland US scores. ESSPRI showed moderate positive correlations with both the GS synovitis score (p = 0.002) and the total synovitis score (p = 0.003), as well as significant positive correlations with all salivary gland US scores: GS (p < 0.001), PD (p = 0.002), and total glandular score (p < 0.001). ESSDAI demonstrated only a weak positive correlation with the GS salivary gland score (p = 0.030). Conclusions. In patients with pSS, the extent of US-detected MSG parenchymal abnormalities does not reflect systemic disease activity and does not correlate with US-detected joint synovitis. In contrast, patient-reported symptom burden is associated with both joint inflammation and MSG parenchymal changes on US. Larger studies are needed to further define the role of salivary gland and joint US in evaluating disease activity in pSS.