Abstract
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.