Characteristics of Chinese patients with primary Sjögren's syndrome: preliminary report of a multi-centre registration study.

Background We established a multi-centre online registry for primary Sjogren's syndrome (pSS) in China, and compared Chinese patients with those from other countries. Methods Data were from 87 rheumatology centres in 27 provinces. All 2986 patients had pSS according to the 2002 American-European Consensus Group or the 2016 American College of Rheumatology/European League Against Rheumatism. All centres used the same methods. Data on demographics, clinical parameters, laboratory results, disease activity and treatments were examined. Results The female:male ratio was 22.9:1, and the mean age at onset was 46.31 years. A total of 332 (11.1%) patients had thyroid disease, including hyperthyroidism (1.2%), hypothyroidism (6.0%) and subacute thyroiditis (3.9%). Dry eye had a prevalence of 68.59% in Chinese patients, 93.7-96% in European patients and 97.3% in American patients. Dry mouth had a prevalence of 86.5% in Chinese patients, 93.2-96% in European patients and 97.9% in American patients. Fewer Chinese than European patients had arthritis (6.9% vs. 15-19.3%). ANA positivity was 90.7% in Chinese, 81.3% in European and 77.6% in American patients. Anti-SSA antibody positivity was 84.6% in Chinese, 71% in European and 68.2% in American patients. The most commonly used drugs in Chinese patients were hydroxychloroquine (n = 1818; 67.5%), glucocorticoids (n = 1720; 63.9%) and total glucosides of paeony (n = 1120; 41.7%). Conclusions This study provided information on the phenotypes of Chinese patients with pSS, and identified several differences with patients from other geographical regions.