The agreement of the OMERACT grey-scale ultrasound scoring system for salivary glands and minor salivary gland biopsy results in a single-center cohort of patients with suspected Sjögren's disease.

Objective: Salivary gland ultrasound (SGUS) is a non-invasive tool for the evaluation of parenchymal changes related to primary Sjögrens disease (pSjD) with the potential to reduce the need for minor salivary gland biopsies when diagnosing patients with pSjD. The aim was to assess the agreement between SGUS findings and minor salivary gland biopsy results in patients suspected of pSjD.

Methods: All patients referred with a suspicion of pSjD and scheduled for a diagnostic minor salivary gland biopsy were included in the period 2017-2021. All underwent SGUS of the parotid and submandibular glands bilaterally, Schirmer's test, unstimulated salivary flow, and blood samples including autoantibody analysis. Changes in the four glands were scored 0-3 using a previously developed ultrasound atlas based on the OMERACT SGUS scoring system for pSjD. All biopsies were scored at the same pathology department and a focus score > 1 was indicative of pSjD.

Results: Of 103 patients included, 43 (42%) were diagnosed with pSjD and 40 (39%) fulfilled the 2016 ACR/EULAR classification criteria. Thirty-two (31%) had a positive minor salivary gland biopsy. The sensitivity of SGUS score ≥ 2 in at least 1 gland was 0.59 and the specificity 0.75. The positive predictive and negative predictive values were 0.51 and 0.80, respectively. The agreement slightly improved when combined with an abnormal salivary flow rate or abnormal Schirmer's test.

Conclusion: In patients with suspected pSjD, we found good agreement between the OMERACT SGUS scoring system and minor salivary gland biopsy; however, SGUS cannot yet fully replace biopsy in the diagnostic setup of SjD.