Background/Purpose: Temporal artery biopsy (TAB) currently remains the gold-standard confirmatory test for the diagnosis of giant cell arteritis (GCA); positive TAB justifies long-term steroid use and/or immunosuppression. High-dose glucocorticoids are often briskly initiated when GCA is clinically suspected, even before TAB is obtained, to avoid ischemic complications. Historically, this has raised concern over the effect of glucocorticoids on TAB yield. This study aimed to determine if the duration of prednisone use, dosed at 30 mg or more daily, prior to TAB influenced TAB result in subjects with suspected GCA.

Methods: Subjects with a procedure code for TAB between 1999-2017 were queried through the VHA national database. TAB result (positive or negative, presence of granuloma/giant cells) was reviewed manually; indeterminate results (i.e. inconclusive, healed arteritis) were categorized as negative. Prescription data regarding prednisone dosage and dispense date were also extracted for each subject. Days of prednisone use (≥30 mg daily) before TAB were categorized as follows: 0-14, >14-28, >28-42, >42, and prednisone started after TAB. Abnormal ESR and CRP values within 180 days before TAB to 14 days after TAB, as well as age, gender, TAB laterality, and TAB length were also extracted. Logistic regression models were run using Stata.

Results: 3,057 biopsies were reviewed, 306 (10%) of which were deemed positive per pathology report. Prednisone use ≥30 mg daily was identified among 2,012 subjects. Of these, 1,474 (73.3%) initiated prednisone within 14 days prior to TAB. The duration of prednisone use before TAB, as a continuous variable, was not influenced by age, TAB length, TAB laterality, or abnormal ESR or CRP values by linear regression. Male gender had a significant negative correlation with prednisone initiation prior to TAB (coefficient -2.97, CI -5.6 to -0.4, p<0.05). After adjustment for gender, there was no association between positive TAB and time of prednisone initiation up to 42 days prior to TAB. Furthermore, prednisone administration up to 42 days prior to TAB did not influence the presence of granulomatous inflammation. Interestingly, positive TAB was significantly associated with prednisone dosed after TAB date, suggesting that a positive TAB prompted the provider to initiate treatment. Additionally, there was no significant correlation between a positive TAB and abnormal ESR or CRP values within 180 days pre- and 14 days post-TAB after correcting for pre-TAB prednisone exposure.

Conclusion: This is the largest retrospective study to date showing that prednisone ≥30 mg daily initiated up to 42 days prior to a TAB did not influence biopsy yield. This study also demonstrated that abnormal ESR or CRP values prior to TAB were not associated with positive TAB even after corrections for pre-TAB prednisone usage, suggesting that these inflammatory markers may not be independently helpful in the diagnosis of GCA.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/high-dose-prednisone-use-up-to-42-days-prior-to-temporal-artery-biopsy-tab-did-not-reduce-yield-of-positive-biopsy-in-the-veterans-health-administration-vha-database-cohort/