Giant Cell (Temporal) Arteritis: The Rate and Clinical Predictors of Histopathological Diagnosis

Abstract Purpose To determine the rate of histopathological diagnosis by temporal artery (TA) biopsy (TAB) and the predictive clinical features of TAB positivity in patients with giant cell arteritis (GCA). Methods The records of patients who underwent TAB with pre-diagnosis of GCA between January 2006 and May 2020 were retrospectively reviewed. The demographic characteristics, symptoms, clinical and laboratory findings, TAB data, and the medications of the patients were recorded. The patients were divided into two groups as TAB-negative and TAB-positive, and compared clinically. Factors affecting TAB positivity were determined. Results TAB confirmed the diagnosis of GCA in 48% of our cases. The median fixed TAB specimen length was 1.7 (0.5–4.0) mm. TAB positivity increased with age (74 vs. 66 years, p = 0.027) and was more common in women (91.7% vs. 38.5%, p = 0.019). Jaw claudication (66.7% vs. 15.4%, p = 0.027) and decreased pulse of the TA (58.3% vs. 7.7%, p = 0.022) were more in the TAB-positive group than in the TAB-negative. The median C-reactive protein (CRP) level was statistically higher in the TAB-positive group compared to the TAB-negative (37 mg/L vs. 12.6 mg/L, p = 0.039). The univariate logistic regression analysis revealed female gender [OR (95%CI): 2.9 (1.7-181.3), p = 0.016], presence of jaw claudication [OR (95%CI): 2.4 (1.6–75.5), p = 0.015], decreased TA pulse [OR (95%CI): 2.8 (1.6-174.5), p = 0.018], and erythrocyte sedimentation rate (ESR) [OR (95%CI): 0.03 (1.0-1.1), p = 0.049] as factors associated with TAB positivity. Conclusion The rate of TAB positivity was 48%. Older age, female gender, the presence of jaw claudication and decreased pulse of TA, high ESR and CRP values are predictive features of TAB positivity and GCA diagnosis.