Natural History and Predictors of Progression to Sjögren's Syndrome Among Participants of the Sjögren's International Collaborative Clinical Alliance Registry

Background/Purpose: To explore changes in the phenotypic features of Sjoogren's syndrome (SS), and in SS status among participants in the Sjoogren's International Collaborative Clinical Alliance (SICCA) registry over a 2 to 3-year interval. Methods: All participants in the SICCA registry who were found to have any objective measures of salivary hypofunction, dry eye, focal lymphocytic sialadenitis in minor salivary gland biopsy, or anti-SSA/B antibodies, were recalled over a window of 2 to 3 years after their baseline examinations to repeat all clinical examinations and specimen collections to determine whether there was any change in phenotypic features and in SS status. Results: As of September 15, 2013, 3,514 participants had enrolled in SICCA, and among 3,310 eligible, 771 presented for a follow-up visit. Among participants found to have SS using the 2012 ACR classification criteria, 93% again met the criteria after 2 to 3 years, and this proportion was 89% when using the 2016 ACR-EULAR criteria. Among those who did not meet ACR or ACR-EULAR criteria at baseline, 9% and 8%, respectively, had progressed and met them at follow-up. Those with hypergammaglobulinemia and hypocomplementemia at study entry were respectively 4 and 6 times more likely to progress to SS by ACR criteria than those without these characteristics (95%Confidence Interval: 1.5 – 10.1 and 1.8 – 20.4, respectively). Conclusion: While there was stability over a 2-3-year period of both individual phenotypic features of SS and of SS status, hypergammaglobulinemia and hypocomplementemia at study entry were predictive of progression to SS. This article is protected by copyright. All rights reserved.