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

OBJECTIVE

To investigate whether primary Sjögren's syndrome (pSS) patients with hyperglobulinemia have an increased risk of all-cause mortality.

METHODS

Patients who registered in the Chinese Rheumatism Data Centre from May 2016 to July 2021 and met the 2002 American European Consensus Group criteria or 2016 American College of Rheumatology /European League Against Rheumatism classification criteria for Sjögren's syndrome were included. Hyperglobulinemia was defined as any elevated serum levels of immunoglobulin G (IgG), immunoglobulin A (IgA), or immunoglobulin M (IgM). The primary outcome was all-cause death. Data for demographic and clinical characteristics, laboratory results, disease activity, damage scores, and treatments were evaluated.

RESULTS

A total of 9527 pSS patients were included in the analysis, of whom 4236 (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 hazard ratio 2.60; 95% confidence interval 1.91-3.55; adjusted hazard ratio 1.90; 95% confidence interval 1.20-3.01). The risk of death was positively correlated with IgG level (P trend <.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. The risk of death is positively correlated with IgG level.