Abstract
Editor,
Giant cell arteritis (GCA) is the most common large vessel vasculitis (LVV) in the elderly, 1 and, if untreated, may cause permanent visual loss, stroke, or death. 2 Temporal artery biopsy (TAB) has long been the diagnostic “gold standard,” offering a specificity of 100%. However, ultrasound (US) has changed the diagnostic setup. Fast Track Clinics (FTC) with trained US personnel allow prompt diagnosis and treatment initiation with high diagnostic certainty and reduced risk of vision loss. 3 FTCs have been widely introduced in rheumatology clinics, in line with the European LVV guidelines recommending imaging on par with histology for suspected GCA cases. 4 US is now also part of the GCA classification criteria. 5
An FTC was established in September 2018 at the Center for Rheumatology and Spine Diseases, Rigshospitalet. All patients referred had ultrasound performed by rheumatologists with extensive training and a minimum of 5 years’ experience in vascular ultrasound. Therefore, we investigated the impact of the FTC on the number of TAB procedures performed at the Department of Ophthalmology, Rigshospitalet, where all TABs in the Capital Region of Denmark are performed. Data were retrospectively extracted from Epic, the electronic health record system for hospitals in the region. Referral diagnoses and procedures are coded according to the Danish National Health Classification System (SKS codes), a national extension of International Classification of Diseases, 10th Revision (ICD-10). Registration practices for diagnosis codes were changed in 2018. The number of TABs (procedural code KPAW23) and newly referred patients with suspected GCA (DM315 + DM316, corresponding to ICD M31.5 + M31.6) at the Center for Rheumatology and Spine Diseases, Rigshospitalet, were collected quarterly (Q1-Q4) from January 2017 through September 2025. For statistical analyses, results were grouped into three time periods: (1) Q1 2017 – Q3 2018, before FTC establishment; (2) Q4 2018 – Q4 2023, after FTC establishment and during the GAME-study 6 (Q1 2021 – Q4 2023) requiring mandatory TAB in 110 patients with suspected GCA; (3) Q1 2024 – Q3 2025, post-GAME-study. Results are reported as median (interquartile range), rounded to the nearest integer. p-Values were calculated in a pairwise manner for a comparison of each period versus period 1 using Dunn’s test with Bonferroni correction. Additionally, a case-cost analysis of performing and analyzing TABs at our center was conducted.
The number of TAB procedures in the region has decreased significantly since 2017, while referrals for suspected GCA have remained stable (Figure 1). Before FTC establishment (period 1), a median of 34 (33–36) biopsies was performed quarterly, decreasing to 27 (26–29; p = 0.024) in periods 2 and 13 (11–19; p < 0.0001) in period 3. Meanwhile, the quarterly number of newly referred patients with possible GCA was 9 (4–18), 35 (26–40), and 52 (51–56), respectively. The number of referrals during period 1 may be underreported/estimated compared with periods 2 and 3 due to a nationwide change in the diagnosis coding registration. This change did not affect registration of TAB procedures. The increase in referrals from period 2–3 is unaccounted for, but it may reflect a heightened awareness on GCA in the primary sector due to the easy and quick access to clinical evaluation. Whether it reflects an increased incidence of GCA cannot be concluded based on this study. However, the overall trend of a decreasing reliance on TABs remains robust despite these limitations.
Quarterly number of temporal artery biopsy (TAB) procedures and patients referred with suspected giant cell arteritis (GCA), Q1 2017 to Q3 2025.
Overall, the median number of TAB procedures in the region has decreased by approximately 62% since establishing the FTC in 2018 with no evidence of a decline in referrals for possible GCA. This trend is consistent with the previously documented decline in TABs performed in Denmark from 2015 to 2018, where the proportion of GCA patients who underwent TAB was reduced by >50%, while the incidence rates of GCA in persons aged ⩾50 years remained stable. 7
The estimated cost per TAB was ~577.35 € (4309 DKK). The reduction in procedures corresponds to annual savings of 48,497.40 €, excluding US costs, consistent with previous reports finding US to be very cost-effective for GCA. 8
The marked decline in TABs suggests a causal relation with FTC implementation, utilizing US as the first-line diagnostic tool, associated with less discomfort, fewer complications, and a lower cost. 8 Nevertheless, TAB remains valuable when US findings are inconclusive or negative despite high clinical suspicion of GCA. 9
