Application of the OMERACT Grey-scale Ultrasound Scoring System for salivary glands in a single-centre cohort of patients with suspected Sjogren's syndrome

Aim To describe salivary gland involvement in patients suspected of Sjögren's syndrome (SS) using the OMERACT Ultrasound Scoring System for SS. Next, using different ultrasound cut-offs, to assess the performance of the scoring system for diagnosis and fulfilment of 2016 ACR/EULAR SS classification criteria. Methods All patients referred to our department with a suspicion of SS in a 12-month period were included. All underwent grey-scale ultrasound of the parotid and submandibular glands prior to clinical examination, Schirmer's test, unstimulated salivary flow, blood samples including autoantibody analysis. Labial biopsy was performed according to clinicians' judgement. Images of the four glands were scored 0-3 according to the scoring system and a consensus score was obtained using a developed ultrasound atlas. Results Of the 134 patients included in the analysis, 43 were diagnosed with primary SS (pSS) and all fulfilled the 2016 American College of Rheumatology (ACR)/EULAR classification criteria. More patients with pSS compared with non-pSS had score ≥2 in at least one gland (72% vs 13%; p<0.001). In patients with score ≥2 in any gland, significantly more had positive autoantibodies, sialometry, Schirmer's test and positive labial biopsy compared with those with scores ≤1. The best ultrasound cut-off value for diagnosing pSS was ≥1 gland with a score ≥2 (sensitivity=0.72, specificity=0.91). Conclusion The OMERACT Ultrasound Scoring System showed good sensitivity (0.72) and excellent specificity (0.91) for fulfilling 2016 ACR/EULAR criteria using cut-off score >2 in at least one gland. Our data supports the use of ultrasound for diagnosing pSS and supports incorporation of ultrasound in the classification criteria.