Clues to mortality trends and their related factors in IgG4-related disease: A Japanese single-center retrospective study

Abstract Objective: This study aimed to clarify mortality trends and its related factors in immunoglobulin G4-related disease (IgG4-RD) with various organ involvement. Methods: We retrospectively reviewed the medical records of patients with IgG4-RD at a single rheumatology center in Japan. We calculated the standardized mortality ratio (SMR) using national Japan mortality statistics. Cox regression analyses was also performed to assess mortality-related factors. Results: A total of 179 patients with IgG4-RD were included with a median follow-up period of 47 months. The SMR in our cohort was 0.86 (95% confidence interval [CI] 0.41-1.59). Univariate Cox regression analyses indicated that the number of affected organs at diagnosis (hazard ratio [HR] 1.45, 95% CI 1.02-2.05), eGFR <45 mL/min/1.73m2 at diagnosis (vs. ≥45, HR 8.48, 95% CI 2.42-29.79), and the presence of malignancy during the clinical course (HR 5.85, 95% CI 1.62–21.15) had a significant impact on the time to death. Conclusions: Our findings suggest that in the rheumatology department, IgG4-RD does not significantly affect long-term patient survival. However, multi-organ involvement, renal dysfunction, and malignancy may be associated with higher mortality trends in IgG4-RD. Early detection and appropriate management of risk factors may improve the long-term prognosis of patients with IgG4-RD.