The impact of interleukin-6 receptor inhibitors on risk of diabetes mellitus in patients with giant cell arteritis: a cohort study.

To investigate the one-year incidence of diabetes mellitus (DM) among patients with giant cell arteritis (GCA) treated with glucocorticoids and interleukin-6 receptor inhibitor (IL-6Ri) compared to patients treated with glucocorticoid monotherapy. Secondary we investigated the one-year risk of a composite outcome of DM, osteoporosis and cardiovascular events. This cohort study at Aalborg University Hospital, Denmark included patients with GCA from June 2022 to August 2025. Data was collected at diagnosis and at 4, 12, and 24 weeks after glucocorticoid initiation, and annually thereafter. We evaluated the one-year incidence of DM, and thereafter the risk the composite outcome using a Cox regression, comparing patients receiving glucocorticoids in combination with IL-6Ri (exposed) versus glucocorticoid monotherapy (unexposed). The study included 121 patients (70.2% female; mean age 70.5 years): 47 exposed and 74 unexposed. A median of 193 days passed from GCA diagnosis to IL-6Ri initiation in exposed. The one-year cumulative incidence of DM was 3.0% in exposed and 17.5% in unexposed. Exposed had a lower composite risk (Hazard ratio: 0.3, 95% confidence interval: 0.1;1.3). The most frequent AEs among exposed were infections, osteoporosis, cardiovascular events, and DM in exposed and unexposed. Both the one-year cumulative incidence of DM and the composite risk of adverse events were lower in exposed compared with unexposed. These findings suggest that IL-6Ri may offer a safer alternative to glucocorticoid monotherapy in reducing long-term risks. Additionally, the data indicate that IL-6Ri may be introduced too late in the disease course.