Aim of the study: The American College of Rheumatology (ACR) has proposed a list of criteria for diagnosis of giant cell arteritis in order to guide clinical research by differentiating it from other vasculitis. The aim of this retrospective investigation, based on the findings of 415 temporal artery biopsies was to assess the diagnostic value of these criteria in the daily clinical setting.
Methods: The demographic, clinical and biological characteristics of patients with positive (confirmed cases of giant cell arteritis) or negative (controls) histopathological temporal artery biopsy findings were analyzed using downward step-by-step logistic regression analysis. This analysis enabled investigators to list signs with inherent diagnostic value. Based their odds-ratio, these factors were used to determine a clinical score for giant cell arteritis.
Results: A score of over 7 - out of a maximum score of 32 - enables the diagnosis for giant cell arteritis with the best possible compromise between a sensitivity of 75.7% and a specificity of 72.2%. ACR criteria had a sensitivity of 97.5% and a specificity of 78.9% when used in our patient group.
Conclusion: Our study results are original in that the control group was composed of patients in whom the diagnosis of giant cell arteritis had been suggested but refuted by the absence of histopathological findings on the temporal artery biopsy. This pragmatic attitude in selecting the control group may explain the difference observed with the ACR criteria in terms of sensitivity and specificity. Further research is needed to develop a diagnostic method for giant cell arteritis without resorting to temporal artery biopsy.