Clinical Features and Outcomes of Japanese Patients with Giant Cell Arteritis: A Comparison with Takayasu Arteritis

Background: Giant cell arteritis (GCA) and Takayasu arteritis (TA) are distinct types of large-vessel vasculitis; however, the clinical features of the diseases have some similarities. Limited data are available regarding Japanese patients with GCA and TA. The present study aimed to compare the clinical features and outcomes of Japanese patients with GCA and TA and the effects of large vessel involvement (LVI). Methods: We performed a retrospective cohort study of the patients with GCA (n = 15) and TA (n = 30) who visited our department from April 2012 to June 2022. Signs and symptoms attributed to the disease, treatment, clinical outcomes, and mortality were recorded using a standardized database. Results: The median age of onset was significantly higher in the GCA group at 24 years (range, 16–72 years) in the TA group and 77 years (range, 57–89 years) in the GCA group (p < 0.001). There were no significant differences in survival rates or the cumulative rates of cardiovascular events between the GCA and TA groups. However, relapse-free survival rates were significantly higher in patients with GCA than in patients with TA. Seven of the 15 patients with GCA had large vessel involvement, which did not affect the survival rates. Prednisolone (PSL) doses were significantly decreased after induction therapy in both groups, and the rates of achieving steroid tapering (PSL < 5.0 mg/day) were significantly higher in patients with GCA compared with those in patients with TA. Conclusions: Our study demonstrated no significant difference in the survival rates of Japanese patients with GCA and TA. The relapse-free survival rates were significantly higher in the GCA group than in the TA group. LVI may not be associated with disease relapse or survival rate in Japanese patients with GCA.