Abstract
The aim of this study was to investigate the clinical significance of subclinical giant cell arteritis (GCA) in polymyalgia (PMR) and to determine the optimal treatment approach.
Patients with PMR who had no cranial RZA symptoms were included and screened by vascular ultrasound; 150 patients with isolated PMR and 50 with sonographically proven subclinical RZA.
The median follow-up duration was 22 months.
Overall, 31.3% of patients had a relapse, with 62% in the subclinical RZA group and 16% in the PMR-only group (p<0.001), although the initial steroid doses were higher in the subclinical RZA group.
The study confirms that so-called ‘subclinical’ RZA is giant cell arteritis and probably how it should be treated.
Data from a systematic literature review from our group confirm the high prevalence of vasculitis (29% on PET/CT) in PMR diagnosis even in the absence of classic cranial symptoms (Hemmig et al Subclinical giant cell arteritis in new onset polymyalgia rheumatica A systematic review and meta-analysis of individual patient data. Semin Arthritis Rheum. 2022. doi: 10.1016/j.semarthrit.2022.152017).
In our local cohort of patients with giant cell arteritis, patients with a history of PMR were found to have more vasculitic stenoses at the time of diagnosis of RZA than patients without a history of PMR (Prior polymyalgia rheumatica is associated with sonographic vasculitic changes in newly diagnosed patients with giant cell arteritis. Hemmig AK et al Rheumatology 2023 Aug 30: doi: 10.1093/rheumatology/kead450).

These data support the screening of PMR patients for the presence of ‘subclinical’ RZA.

References
[1] De Miguel et al.
Subclinical giant cell arteritis increases the risk of relapse in polymyalgia rheumatica.
Ann Rheum diseases 2023 doi:10.1136/ard-2023-224768

Written by
Prof. Dr. med. Thomas Daikeler
Rheumatology
University Hospital Basel
November 2023