Risk of venous and arterial thromboembolism in patients with giant cell arteritis and/or polymyalgia rheumatica: A Veterans Health Administration population-based study in the United States

Background: Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) are systemic inflammatory diseases that primarily affect elderly women. Objectives: To compare the risk of thromboembolic events and retinal vascular occlusions in GCA and/or PMR with that in osteoarthritis (OA), evaluating a veteran-based population. Methods: A total of 1535 patients with GCA, 10,265 with PMR, and 1203 with overlapping disease, as well as 39,009 age- and sex-matched patients with OA were identified in this retrospective study. The incidence rate ratios (IRRs) of pulmonary embolism (PE), deep venous thrombosis (DVT), arterial thromboembolism, central retinal artery occlusion, and central retinal vein occlusion were calculated and examined over time. The cumulative incidence was plotted and hazard ratios (HRs) of thromboembolic events were calculated, adjusting for independent risk factors of thromboembolism. Results: Patients with GCA and overlapping disease exhibited higher IRRs for all thromboembolic events compared to patients with OA. Patients with GCA had a higher risk of developing DVT and retinal vascular occlusions than those with overlapping disease (HR: 2.01, 95% confidence interval [CI]: 1.35–2.99, p < 0.001; HR: 2.37, 95% CI: 1.23–4.53, p = 0.009, respectively) or PMR alone (HR: 1.89, 95% CI: 1.50–2.41, p < 0.001; HR: 4.68, 95% CI: 3.10–7.07, p < 0.001, respectively). Patients with GCA had a higher risk of developing PE than those with PMR (HR: 1.55, 95% CI: 1.1–2.18, p = 0.01). Conclusion: The risk of thromboembolic events differs between GCA, PMR, and overlapping diseases. Our findings may help predict the risk of thromboembolic events based on disease phenotype.