Clinical value of salivary gland ultrasonography in evaluating secretory function, disease activity, and lymphoma risk factors in primary Sjögren's syndrome.

Introduction/objectives: Salivary gland ultrasonography (SGUS) has been investigated for its diagnostic usefulness in replacing invasive minor salivary gland biopsy (MSGB) in primary Sjögren's syndrome (pSS). However, its broader clinical value remains unclear. This study aimed to assess the clinical significance of SGUS in evaluating secretory function, disease activity, and lymphoma risk factors in pSS.

Method: One hundred fifty pSS patients who visited Seoul St. Mary's Hospital between January 2019 and July 2023 were included. Parameters related to secretory function, disease activity, and lymphoma risk factors were obtained. Associations between SGUS grades and secretory function or disease activity parameters were determined. Subgroup analyses based on SGUS grade or the presence of lymphadenopathy (LAP) in SGUS were also performed.

Results: SGUS grades correlated significantly with parameters of salivary gland secretory function and disease activity. Higher SGUS grades were associated with higher scores of overall EULAR Sjögren's Syndrome Disease Activity Index (ESSDAI), ESSDAI glandular domain, EULAR Sjögren's Syndrome Patient Reported Index (ESSPRI) dryness domain, and physician or patient global assessment. Patients with the highest SGUS grade (overall score = 6) showed higher prevalence of laboratory risk factors or extraglandular manifestations related to lymphoma development than others. Detection of LAP by SGUS was associated with reduced salivary flow rates and higher ESSDAI, ESSPRI scores, and patient global assessments.

Conclusions: Our results suggest that SGUS grades and the presence of LAP in SGUS findings are associated with clinical parameters representing secretory function and disease activity in pSS. High SGUS grades are associated with risk factors for lymphoma development. Key Points • SGUS grades showed significant correlations with clinical parameters related to salivary gland function and disease activity in patients with pSS. • pSS patients with the highest SGUS grade exhibited a higher prevalence of laboratory risk factors or extraglandular manifestations potentially related to lymphoma development compared to others. • These associations were more pronounced in the parotid gland than in the submandibular gland. • LAP identified by SGUS showed significant associations with clinical parameters related to the quality of life of patients with pSS.