Diagnostic Performance of a Temporal Artery Biopsy for the Diagnosis of Giant Cell Arteritis in Japan-A Single-center Retrospective Cohort Study -

OBJECTIVES: To investigate the sensitivity and specificity of a temporal artery biopsy (TAB) in the diagnosis of giant cell arteritis (GCA) in a single-center retrospective cohort in Japan. METHODS: A retrospective chart review was performed on consecutive patients who visited our hospital between April 2009 and October 2018 and underwent a TAB. The sensitivity and specificity were calculated for the three pathological standards for a TAB, predetermined according to the pathological criterion of the 1990 American College of Rheumatology (ACR) criteria: A) vasculitis characterized by predominant mononuclear cell infiltration; B) vasculitis with granulomatous inflammation; and C) vasculitis with multinucleated giant cells. We also analyzed the clinical parameters predicting the diagnosis of GCA and the impact of a diagnostic delay of ≥3 months on cardiovascular complications of GCA. RESULTS: Our study population was 16 cases in the GCA group and 13 in the non-GCA group. The sensitivity and specificity for Standard A of a TAB were 81% and 85%, respectively, while those for stricter Standards B or C were identical, at 75% and 100%, respectively. These pathological standards, but not any other parameters, significantly predicted the diagnosis. A diagnostic delay tended to cause cardiovascular complications (p=0.057). CONCLUSION: The sensitivity and specificity of the pathological standards of a TAB were favorable in our cohort and were the only predictors for the diagnosis of GCA. Considering the possible impact of a diagnostic delay on cardiovascular complications, the early recognition and prompt initiation of glucocorticoid therapy is needed, even in Japan, where GCA is uncommon.