Takayasu Arteritis and Giant Cell Arteritis: Results From a Cross-Sectional Study of 96 Italian Patients.

Whether Takayasu arteritis (TAK) and giant cell arteritis (GCA), the most common forms of large-vessel vasculitis (LVV), are distinct clinical entities or different manifestations of the same disease is an ongoing debate. This study analyzes and compares the clinical manifestations, imaging characteristics, and diagnostic and therapeutic features of TAK and GCA in a longitudinal cohort of patients recruited from three Italian centers. The study population consisted of 59 patients with TAK and 37 with GCA, including 7 with cranial-GCA (C-GCA) and 30 with large vessel-GCA (LV-GCA), all diagnosed between January 2014 and November 2025. Most (72%) were followed up for at least 60 months. In TAK patients, the time to diagnosis following the onset of symptoms was longer (p = 0.025), the prevalence of females higher (p = 0.001), and the presence at diagnosis of constitutional symptoms (p < 0.001), cardiovascular signs (p < 0.001), renal (p = 0.006) and dermatologic involvement (p = 0.040) more frequent than in GCA patients. In GCA patients, the sex distribution was equal. However, in addition to the cranial and constitutional symptoms associated with the cranial and large vessel forms of the disease, respectively, the prevalence of polymyalgia rheumatica (p < 0.001), hypertension (p < 0.001), diabetes mellitus (p = 0.003), and chronic liver disease (p = 0.02) was higher in GCA than in TAK patients. Vascular involvement was observed in both groups, with participation of the axillary artery more frequent in GCA patients (p = 0.02). Additionally, involvement of the aortic arch (p = 0.009), mesenteric (p = 0.004), and renal (p < 0.001) arteries was more frequent in TAK patients. Glucocorticoids were administered at a higher dose (p < 0.001) and combined more frequently with immunosuppressants in TAK patients. Among relapsing/refractory GCA patients, 50% received tocilizumab as second-line treatment. The two groups did not significantly differ concerning long-term remission, but relapse was more frequent in TAK patients. Despite their phenotypic similarities, TAK and GCA differ in their epidemiological and genetic features and, to a lesser extent, in their clinical manifestations, arterial involvement, and response to therapy. Our data therefore indicate that TAK and GCA are clinically distinct, requiring disease-specific approaches in their diagnosis and management.