Objectives To investigate the role of salivary gland ultrasonography (SGUS) in a composite index for the assessment of glandular involvement in primary Sjögren's syndrome (pSS), exploring whether SGUS may correlate with minor salivary gland focus score (MSG-FS), unstimulated salivary flow (USFR), patients' glandular symptoms, laboratory abnormalities, and physician global assessment (PhGA).
Methods Consecutive patients with pSS (AECG criteria) were included in this cross-sectional study and systematically evaluated. SGUS was carried out by the same radiologist recording: size, parenchymal echogenicity and inhomogeneity, number of hypo/anechoic area, presence of lymph nodes and calcifications. A modified version of the De Vita score was adopted. All patients underwent sialometry and completed the ESSPRI, the VAS for xerostomia and the oral health impact profile (OHIP). The same physician assessed the ESSDAI and provided a PhGA score based on patients symptoms and laboratory abnormalities to quantify salivary gland activity according to a four grade scale (inactive, mild, moderate and severe glandular activity).
Results We included 156 (152F:4 M) patients with pSS; out of them, 37 (23.7%) presented a small glandular swelling and 6 (3.8%) a major glandular swelling as defined according to the ESSDAI. MSG-FS was available for 125/156 (80%) patients. The median (IQR) USFR was 1,9 (0.2,3) ml/15'. Abnormal findings at SGUS examination were detected in 85/156 (55.5%) pSS patients. Forty-four (28.2%) pSS patients presented abnormal sonographic findings in both parotid and submandibular glands, whereas isolated pathological findings in either parotid glands or in submandibular glands were found in 22 (14.1%) and 19 (12.2%) patients, respectively. Age or disease duration did not influence the SGUS result. Higher SGUS scores were significantly more common in patients with glandular swelling with a direct correlation between the “glandular” domain of the ESSDAI and the SGUS score (r=0.390, p=0.000). A good correlation was also observed between PhGA and the SGUS score (r=0.566, p=0.000). A positive correlation was found between MSGB-FS and the total SGUS score (r=0.431, p=0.000) as well as between MSGB-FS and the single SGUS scores assigned to both parotid glands (r=0.366, p=0.001) and submandibular glands (r=0.431, p=0.000). The USFR and the SGUS score were inversely correlated (r=-0.309, p=0.001). VAS Dryness, ESSPRI and the OHIP index did not differ between normal or abnormal SGUS and were not correlated to the scores assigned to the ESSDAI “glandular” domain, to the MSGB-FS and to the USFR impairment. Finally, we confirmed that higher SGUS scores were significantly more common in patients with a higher total ESSDAI, lower C3/C4 levels, leukopenia, hypergammaglobulinemia, antiRo/SSA, antiLa/SSB, Rheumatoid Factor positivity and cryoglobulins (p<0.01).
Conclusions This results highlight that to capture SS glandular activity a “composite index” would be the best choice. SGUS findings, significantly correlated with histopathology, salivary gland dysfunction, and both the ESSDAI “glandular” domain and the PhGA thus appearing as a complementary, promising tool for an integrate assessment of pSS salivary gland involvement in clinical practice and in clinical trials.
Disclosure of Interest None declared