Authors: Dong-ho Lee, Alfonso Iovieno, Claire A. Sheldon

Author Disclosure Block: D. Lee: None. A. Iovieno: None. C.A. Sheldon: None.

Abstract Body:

Purpose: Recent data suggests herpes zoster (HZ) and herpes simplex virus (HSV) may be one of the underlying immunological triggers for giant cell arteritis (GCA). However, there is limited population-based data to support this hypothesis. Our goal was to determine if infection by HZ increases the likelihood of GCA in the British Columbia (BC) population.

Study Design: Comparative descriptive study using population database analysis.

Methods: All BC residents ≥ 30 years old at the time of either diagnosis from January 2000 - January 2019 were included. The background prevalence of GCA was compared to the prevalence of GCA in subjects with HZ and HSV using diagnostic billing code data from an online BC database (Population Data BC, https://www.popdata.bc.ca/). To identify cases of GCA, the relevant International Classification of Disease (ICD) was used and combined with the codes for ischemic optic neuropathy OR retinal arteriolar occlusion AND having had a temporal artery biopsy. To identify cases of HZ or HSV, the relevant ICD codes were used. All comparisons were made using 2-sample Z tests.

Results: There were 4 315 GCA diagnoses from a total population of 3 026 005 subjects. The prevalence of GCA was 143 per 100 000 population ≥ 30 years of age. Looking at subjects with herpetic infections, 850 GCA cases were identified in 249 900 subjects with HZ versus 310 diagnoses of GCA in 163 170 subjects with HSV. The prevalence of GCA in subjects with HZ (0.340%) was significantly higher than the prevalence of GCA (0.143%) in the general population (p < 0.00001). The prevalence of GCA in HSV subjects (0.190%) was also significantly higher (p < 0.00001) than the population prevalence but lower than (p < 0.00001) the GCA with HZ prevalence.

Conclusions: Using a provincial population database, we identify a prevalence of GCA of 143 per 100 000 people ≥ 30 years of age. The likelihood of developing GCA seems to increase with herpetic infections. It appears that herpes infections in general, but more specifically HZ, may increase the risk of developing GCA. Further study is required to gain insight into this potential association.