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

Abstract

Background: Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) are two chronic systemic inflammatory diseases that primarily affect elderly women. Both GCA and PMR can be complicated by thromboinflammation. We evaluated the risk of thromboembolic events as well as retinal vascular occlusive events in patients with giant cell arteritis (GCA), polymyalgia rheumatica (PMR), and overlap of GCA with PMR compared to patients with a non-inflammatory condition such as osteoarthritis (OA) in a Veteran based population. Methods: 1,535 patients with GCA, 10, 265 with PMR, and 1,203 with overlap of GCA with PMR as well as 39,009 age- and sex-matched patients with OA were identified in this retrospective study. Incidence rate ratios (IRR) of pulmonary embolism (PE), deep venous thrombosis (DVT), arterial thromboembolism (ATE), central retinal artery occlusion (CRAO) and central retinal vein occlusion (CRVO) were calculated among all three-study groups and trended over time after diagnosis. We also plotted cumulative incidence and calculated hazard ratios (HRs) of thromboembolic events in the study groups, adjusting for independent risk factors of thromboembolism. Findings: Patients with GCA, PMR and overlap of GCA with PMR had higher IRR of all thromboembolic events compared to patients with OA. IRRs of all thromboembolic events were highest within the first year of diagnosis for GCA and gradually decreased over time, whereas for the overlap and PMR groups the time trend of IRRs varied for each of the thromboembolic events. Patients with GCA had a higher risk of developing DVT and retinal vascular occlusive events compared to patients with overlap disease (2.01, 95%CI: 1.35-2.99, p<0.001, and 2.37, 95%CI: 1.23-4.53, p=0.009 respectively) and PMR (1.89, 95%CI: 1.50-2.41, p<0.001, and 95%CI: 4.68, 95%CI: 3.10-7.07, p<0.001 respectively). Patients with GCA had a higher risk of developing PE compared to patients with PMR (1.55, 95%CI: 1.1-2.18, p=0.01). Patients with overlap disease were at higher risk of developing retinal vascular occlusions compared to patients with PMR (1.97, 95%CI: 1.05-3.69, p=0.03). Interpretation: The risk of thromboembolic events differs in patients with GCA, PMR and overlap disease. Our findings may help physicians predict risk of thromboembolic events determined by disease phenotype and duration, and assist with the development of venous thromboembolism risk stratification tools in patients with GCA and/or PMR that would allow identification of high risk patients. Funding Information: D.M. is supported by the T32 NIH grant from Nutrition, Obesity and Atherosclerosis (#5T32HL007028-44) and Pfizer US Pharmaceuticals Group grant, award number 53857367 Declaration of Interests: DM received Advisory Board fee from Chemocentryx. All other authors report no competing interests. Ethics Approval Statement: MIRB#01854.