Hyperglobulinemia predicts increased risk of mortality in primary Sjögren's syndrome: based on a Chinese multicentre registry.

OBJECTIVES: To investigate whether pSS patients with hyperglobulinemia have an increased risk of all-cause mortality.

METHODS: Patients who registered in Chinese Rheumatism Data Centre from May 2016 to July 2021, and met the 2002 AECG criteria or 2016 ACR/EULAR classification criteria for SS were included. Hyperglobulinemia was defined as any elevated serum levels of IgG, IgA, or IgM. The primary outcome was all-cause death. Data for demographic and clinical characteristics, laboratory results, disease activity, damage scores, treatments were evaluated.

RESULTS: A total of 9,527 pSS patients were included in the analysis, of whom 4,236 (44.5%) had at least one kind of elevated immunoglobulin level among IgG, IgA, and IgM. Patients with hyperglobulinemia had a significantly increased risk of death (crude HR 2.60; 95%CI 1.91-3.55; adjusted HR 1.90; 95%CI 1.20-3.01). Risk of death was positively correlated with IgG level (P trend <0.001). The 5-, 10-, and 15-year survival rates of patients with hyperglobulinemia were 96.9%, 92.3%, and 87.9%, respectively, and significantly lower than the corresponding rates of 98.8%, 97.9%, and 96.4% in patients without hyperglobulinemia.

CONCLUSIONS: Hyperglobulinemia is an independent risk factor for increased all-cause mortality in pSS patients. Risk of death is positively correlated with IgG level.