Background/Purpose: Recent studies have indicated a higher incidence of deep vein thrombosis (DVT) and pulmonary embolism (PE) in patients with giant cell arteritis (GCA)^1,2. Our objective was to determine the incidence rate of concurrent DVT and PE in our prospectively followed GCA patient cohort.

Methods: We performed an analysis of our prospectively collected incipient cohort of patients with GCA from December 1^st 2011 to December 1^st 2016 at a single secondary/tertiary rheumatology center. The proportion of patients who were diagnosed with concurrent DVT or PE was determined based on patients’ reports and electronic or paper medical records, in addition to clinical and laboratory features of each patient. The DVT and/or PE were defined as concurrent when diagnosed within a time frame extending from 6 months prior until 6 months after the diagnosis of GCA. The cumulative incidence rate of DVT and PE in population aged 50 years and above from the same well defined geographical region in years 2012 to 2015 was acquired from the local electronic DVT/PE registry. Ultimately, standardized incidence ratios (SIR) for DVT and PE with respective 95% confidence intervals (CI) were calculated using Fisher’s exact test.

Results: During the 5-year observation period, we identified 83 new GCA cases (median age 73.8 (IQR 66.6–78.8) years, 70% female, 47% ever smokers). Sixty-eight (82%) patients fulfilled the 1990 ACR classification criteria for GCA; the remaining 18% had imaging evidence of large vessel vasculitis. We identified a single patient with PE and no patients with DVT within the prespecified one-year time frame. The 79-year-old non-smoking female was diagnosed with PE 1 week after GCA diagnosis and had a history of arterial hypertension, diabetes and hypercholesterolemia. She had no traditional antiphospholipid antibodies, however we detected IgA subtype antibodies against antiprothrombin/phosphatidilserine complex. No patients were diagnosed with DVT or a PE more than 6 months prior to the diagnosis of GCA. The average incidence rate for concurrent DVT/PE in our GCA cohort was 12.0 per 1000 patient-years, whereas the average incidence rate for DVT/PE in the general population aged 50 years and above, residing in the same region, was 2.4 per 1000 patient-years (565 cases/235.800 residents per year). The SIR was 5.0 (95% CI 0.13–27.86; p=0.362).

Conclusion: Contrary to the recent reports, the incidence rate of DVT and PE was not significantly different in our GCA cohort than in the general population of comparable age and residence. Because of the small patient number and only one thrombotic event in our cohort, further monitoring is warranted to confirm or exclude the association between GCA and DVT/PE.

References:
1. Arthritis Rheumatol. 2017 Jan;69(1):176-184.
2. Ann Rheum Dis. 2016 Jan;75(1):148-54.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-incidence-rate-of-deep-vein-thrombosis-andor-pulmonary-embolism-in-patients-with-giant-cell-arteritis-single-center-observational-study/