CLINICAL-DIFFERENTIATION BETWEEN GIANT-CELL (TEMPORAL) ARTERITIS AND TAKAYASUS-ARTERITIS

Objective, To determine whether giant cell (temporal) arteritis (GCA) can be differentiated from Takayasu's arteritis on the basis of clinic al findings. Methods, A comparative study contrasting 217 patients wit h GCA to 63 patients with Takayasu's arteritis was conducted, using th e prospectively gathered large multicenter data set of the American Co llege of Rheumatology Vasculitis Criteria Databank. Logistic regressio n and recursive partitioning were used to assess the capability of a v ariety of variables to separate these 2 vasculitic disorders. Results. Age of 40 years at onset of disease was the most discriminatory singl e variable, Excluding age at onset, ethnic background and a combinatio n of clinical signs indicating upper limb vascular impairment, shoulde r stiffness, and tender scalp led to correct classifications of 95% in both GCA and Takayasu's arteritis. Vascular insufficiency of the uppe r extremities, a key feature of Takayasu's arteritis, was noted in 15% of patients with GCA, although to a lesser degree. Conclusion. Althou gh similar in many respects, GCA and Takayasu's arteritis were easily definable and separable disorders, even when the typical age barrier o f 40 years at onset of disease was excluded, These findings strengthen the concept that they are distinct disease entities.