347. DEVELOPMENT OF THORACIC AORTIC ANEURYSMS IN PATIENTS WITH POLYMYALGIA RHEUMATICA: UNDERDIAGNOSED GIANT CELL ARTERITIS?

Abstract

Objectives: Polymyalgia Rheumatica (PMR) and Giant Cell Arteritis (GCA) are close-related entities. Imaging studies have suggested that subclinical in-flammation of the large arteries is frequent in patients with apparently isolated PMR. Our objective was tocompare characteristics of PMR patients who devel-oped a thoracic aortic aneurysm (TAA) during follow-up with those who did not, in order to identify clinical features that may predict aortic involvement in clinical PMR patients. Methods: All electronic medical records of PMR patients diagnosed after the year 2000 (fulfilling ACR 2012 criteria) from a university hospital-based health management organization (HMO) were reviewed. Patients with a previous diagnosis of aortic aneurysm, those who developed clinical GCA or other rheumatic disease after PMR diagnosis and those lost in follow-up or without appropriate thoracic images after diagnosis, were excluded. A case-control study (PMR-TAA versus PMR without TAA) was performed and patients' characteristics were compared. A multivariate logistic regression analysis was performed to identify risk factors for TAA. Results: 350 PMR patients were included and 50 (14.3%, 95% CI 10.9-18.4) developed a TAA during a median follow up of 5.4 years (IQR 2.9-7.9). 18 TAAwere located at the aortic root and 32 at the ascending aorta, with a medium size at diagnosis of 4.3 cm (SD 0.33). No ruptures or dissections occurred but 5 patients (10 %, 95% CI 4.2-22.1) required surgery. Traditional cardiovascular risk factors and clinical characteristics of PMR were similar across groups, ex-cept for less statin use and longer treatment with steroids in the PMR-TAA group. In the multivariate analysis, being a male (OR 4,4, CI 2.3-8.6, p <0.001) and months of corticosterioid treatment, (OR 1.02, 95% CI 1.01-1.03, p 0.01) were associated with an increased risk of TAA. Statin use seemed to be protective, although did not reach statistical significance (OR: 0.48, 95% CI 0.23-1.002; p=0.051). Conclusions: 14.3 % of patients with apparently isolated PMR developed a thoracic aortic aneurysm. Screening with thoracic images in PMR male pa-tients and those PMR patients requiring a prolonged corticosteroid use may be advisable.