Combined classification system based on ACR/EULAR and ultrasonographic scores for improving the diagnosis of Sjögren's syndrome

We retrospectively evaluated the effectiveness of combined use of salivary gland ultrasonography (US) and the 2016 American College of Rheumatology/European League Against Rheumatic Disease (ACR/EULAR) classification criteria for improving the diagnostic efficiency in patients with Sjögren’s syndrome (SS). A US-based salivary gland disease grading system was developed using a cohort comprising 213 SS or non-SS patients who fulfilled the minimum requirements for classifying SS based on the American-European Consensus Group (AECG) and ACR criteria. Using 62 SS or non-SS patients from the 213 patients and who had also undergone all the 5 examinations needed for the ACR/EULAR classification, we compared the diagnostic accuracy of various combinations of the ACR/EULAR and US classifications for diagnosing SS, using the clinical diagnosis of SS by rheumatologists as the gold standard. The ACR/EULAR criteria discriminated clinical SS patients with 77% and 79% accuracy for those with primary or secondary SS and for those with primary SS, respectively. However, the integrated score system of the ACR/EULAR and US classifications yielded 92% and 93% accuracy for these 2 SS patient groups, respectively, provided that US score of 3 was assigned to patients with US grade ≥2, and then patients with integrated threshold score of ≥5 were diagnosed as SS. Cross-validation also indicated improved accuracy of the integrated ACR/EULAR and US score system (91.9 and 93.0% for primary/secondary and primary SS patients, respectively) over that by the ACR/EULAR criteria alone. (74.2 and 86.0%, respectively). The integrated ACR/EULAR and US scoring system can improve the diagnosis of patients with clinical SS.