Patient characteristics, disease manifestations and diagnostic findings of consecutive patients suspected of Giant Cell Arteritis (GCA) — retrospective experience from a fast-track clinic in Israel

Abstract Introduction/objective Giant Cell Arteritis (GCA) is relatively rare in the Middle East compared to Western countries. We aimed to retrospectively investigate the demographic, clinical, and imaging characteristics and the definitive diagnoses of patients referred to a GCA fast-track clinic (FTC) in the northwest of Israel with a mixed population of Arabs and Jews. Methods Demographic, clinical and laboratory data of patients referred to GCA-FTC between 2022 and 2024 were retrospectively collected. The Southend Pre-Test Probability Score for GCA (GCAPS) was calculated. Patients underwent color-Doppler ultrasound (CDUS) for the temporal and axillary arteries. The definitive diagnosis was determined by the treating rheumatologist based on clinical features, CDUS, additional imaging tests, and/or biopsy results. Results Seventy-two consecutive outpatients with a suspected diagnosis of GCA were included. The mean age was 74.6 ± 8.8years, 63% were females. Of these individuals, 19/72 had a low GCAPS, of whom 2 were diagnosed with GCA; 40/72 had an intermediate GCAPS, of whom 14 had a positive CDUS but only 9 had GCA diagnosis; and of 13 patients with high GCAPS, 10 were confirmed as having GCA by CDUS and one patient was diagnosed by computed tomography angiography (CTA). Large-vessel involvement was documented in only 2/22 GCA patients. Among non-GCA patients, the most common diagnoses were pure polymyalgia rheumatica (PMR), migraine headache, infection, calcium-pyrophosphate deposition disease (CPPD), and temporomandibular joint (TMJ) dysfunction. Conclusions The GCAPS is a reliable tool for risk-stratifying patients referred to the GCA-FTC in this study population. The sensitivity and specificity of CDUS was 90.9% and 88%, respectively. A relatively low prevalence of large vessel involvement was documented. Our results suggest that rheumatologists should remain vigilant regarding the differential diagnoses in patients with suspected GCA. Key Points • Our study is the first study in the Middle East to utilize color-Doppler ultrasonography (CDUS) in Giant Cell Arteritis Fast Track Clinic (GCA-FTC) setting, and it was found to have very high sensitivity (90.9) and specificity (88.0%). • In our study population, the Southend Pre-Test Probability Score for GCA (GCAPS) was found to be a reliable tool for risk- stratifying patients referred to the GCA-FTC. • Based on our findings, rheumatologists should remain vigilant regarding the differential diagnoses of patients with suspected GCA, including pure PMR, migraine headache, infection, CPPD and TMJ dysfunction.