AUTHOR=Ninan Jem , Ruediger Carlee , Dyer Kathryn A. , Dodd Thomas , Black Rachel J. , Lyne Suellen , Shanahan Ernst M. , Proudman Susanna M. , Lester Susan , McNeil Julian , Hill Catherine L. 

TITLE=Incidence of biopsy-proven giant cell arteritis (GCA) in South Australia 2014–2020

JOURNAL=Frontiers in Medicine

VOLUME=10

YEAR=2023

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2023.1173256

DOI=10.3389/fmed.2023.1173256

ISSN=2296-858X

ABSTRACT=<sec><title>Objective</title><p>To determine the incidence of biopsy proven giant cell arteritis (GCA) in South Australia.</p></sec><sec><title>Methods</title><p>Patients with biopsy-proven GCA were identified from pathology reports of temporal artery biopsies at state-based pathology laboratories, from 1 January 2014 to 31 December 2020. Incidence rates for biopsy-proven GCA were calculated using Australian Bureau of Statistics data for South Australian population sizes by age, sex, and calendar year. Seasonality was analyzed by cosinor analysis.</p></sec><sec><title>Results</title><p>There were 181 cases of biopsy-proven GCA. The median age at diagnosis of GCA was 76 years (IQR 70, 81), 64% were female. The estimated population incidence for people over 50 was 5.4 (95% CI 4.7, 6.1) per 100,000-person years. The female: male incidence ratio was 1.6 (95% CI 1.2, 2.2). There was no ordinal trend in GCA incidence rates by calendar year (<italic>p</italic> = 0.29). The incidence was, on average, highest in winter, but not significantly (<italic>p</italic> = 0.35). A cosinor analysis indicated no seasonal effect (<italic>p</italic> = 0.52).</p></sec><sec><title>Conclusion</title><p>The incidence of biopsy-proven GCA remains low in Australia. A higher incidence was noted compared to an earlier study. However, differences in ascertainment and methods of GCA diagnosis may have accounted for the change.</p></sec>