183. Duration of Steroid Therapy and Temporal Artery Biopsy Positivity in Giant Cell Arteritis
Creators: name: Majerovich1, Katherine
name: Junek2, Mats
name: Khalidi2, Nader
name: Garner2, Stephanie
Publisher: name: Zenodo
Year: 2022
Subjects: Vasculitis
ANCA
Abstracts
Giant Cell Arthritis
MPA
GPA
EGPA
Takayasu
IgA vasculitis

description: <strong>Background:</strong> Temporal artery biopsy (TAB) is an important investigational tool in the diagnosis of giant cell arteritis (GCA). Glucocorticoid therapy is also often used upon suspicion for GCA to prevent irreversible vision loss.<sup>1</sup> It is recommended to complete a TAB within 14 days of glucocorticoid initiation. However, data has conflicted as to how long biopsies remain positive, with one study demonstrating positivity of 44% up to 1 year.<sup>1,2</sup> The aim of this study was to investigate how duration of glucocorticoid exposure affected TAB positivity in a cohort of patients with suspected GCA. <strong>Methods: </strong>Data were extracted from two sources: the McMaster GCA Database (n=52) and those enrolled in a trial evaluating imaging in the diagnosis of GCA (n=171).<sup>3</sup> Diagnosis of GCA was made clinically using all available material including features on history and exam suggestive of GCA, inflammatory markers, temporal artery magnetic resonance angiography, and temporal artery ultrasound. Individuals who underwent TAB as part of their diagnostic evaluation were included. Data concerning demographics and other investigations were extracted. Individuals were stratified by duration of glucocorticoid pre-treatment by weeks of therapy; those receiving six or more weeks of therapy were pooled due to low numbers. Descriptive statistics were performed and the impact of the duration of glucocorticoid therapy on TAB positivity was assessed using a two-sided Cochran-Armitage Trend test. <strong>Results: </strong>Data from 223 patients were included. There were 48 TAB-positive and 175 TAB-negative cases. Stratified by TAB positivity, mean ages (standard deviation) of each subgroup were 73.5 (9.5) for positive TABs and 70.7 (10.6) for negative TABs respectively. 35 (72.9%) of the TAB-positive cases, and 123 (70.3%) of TAB-negative cases, were female. Forty-six (95.8%) TAB-positive cases, and 152 (86.9%) of TAB-negative cases, received glucocorticoids pre-TAB. No significant difference in length of glucocorticoid pre-treatment between groups existed. TAB-positive individuals were more likely to have vision loss, jaw claudication, constitutional symptoms, and elevated ESR and CRP (p&lt;0.01). When stratified by weeks of treatment, there were fewer TABs performed with longer duration of therapy (p&lt;0.01) (Table 1). The Cochran-Armitage Trend test did not demonstrate a temporal trend between weeks of treatment and TAB positivity (p=0.11). <strong>Conclusion:</strong> The results of this analysis suggest that glucocorticoid therapy does not affect TAB positivity to at least 6 weeks, with inconclusive data thereafter. These results suggest the recommendation of obtaining a TAB within 14 days of glucocorticoid initiation is unnecessarily conservative. <strong>Disclosures:</strong> NK discloses grants or contracts from the following entities: BMS-supplied drugs and investigator-initiated clinical trial, Sanofi and 2020 GCA and PMR clinical trial, Abbvie and 2020/21 GCA clinical trial; Support for travel to an international meeting for MANDARA trial from Astra Zeneca; and participation on the Advisory Board for GCA CME November 2020 with Roche. SG discloses an honorarium provided for Pfizer for a speaking event; Sanofi: Clinical Trial 2020 in GCA and PMR; AbbVie: Clinical Trial 2020-2021 in GCA; Roche: Educational Grant; Novartis: Advisory Board. <strong>Table 1:</strong> Diagnoses of GCA stratified by duration of glucocorticoid treatment pre-TAB. Weeks of treatment Number of patients GCA diagnoses Number of positive TABs 223 118 48 0 57 23 8 1 46 28 11 2 45 25 10 3 26 8 6 4 21 10 4 5 10 8 3 6 18 16 6