The one-year infection risk among patients diagnosed with giant cell arteritis: use of antibiotics and hospitalisations.

Objectives: Patients with giant cell arteritis (GCA) primarily have their infections managed by primary care providers and hospitalisation is rarely necessary. Existing studies in GCA focus on infection-related hospitalisations only, whereas the use of antibiotic prescriptions is largely unknown. This study aims to examine the one-year overall infection risk among patients with GCA.
Methods: This nationwide observational cohort study included patients aged ≥50 years with a first-time GCA diagnosis in the Danish National Patient Registry (1996-2022). Patients with GCA were matched 1:10 by sex and date of birth with general population individuals and followed from date of diagnosis. Overall infections were defined as redeemed antibiotic prescriptions or infection-related hospitalisations. Utilising a pseudo-observation approach, we assessed 1-year cumulative incidence proportions (CIP), risk differences (RD) and relative risks (RR) of infections.
Results: The study included 17 773 incident patients with GCA and 177 730 reference individuals. Patients with GCA had a 1-year CIP of 52.4% (95% CI: 51.7-53.2) for overall infections and 17.6% (95% CI: 17.1-18.2) for infection-related hospitalisations. Compared with the reference cohort, patients with GCA had a RR of 1.40 (95% CI: 1.38-1.42) for overall infections and 2.71 (95% CI: 2.61-2.82) for infection-related hospitalisations. Additionally, higher cumulative glucocorticoid doses, advanced age (≥70 years) and higher comorbidity were associated with an increased risk of infections among patients with GCA.
Conclusions: The use of antibiotic prescriptions and infection-related hospitalisations in the first year after a GCA diagnosis is high compared with the background population. The cumulative glucocorticoid dose is associated with the infection risk.
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