Prevalence and characteristics of giant cell arteritis in patients with newly diagnosed polymyalgia rheumatica - a prospective cohort study

Lara C Burg; Pantelis Karakostas; Charlotte Behning; Peter Brossart; Tanaz A Kermani; Valentin S Schäfer

doi:10.1177/1759720X221149963

Prevalence and characteristics of giant cell arteritis in patients with newly diagnosed polymyalgia rheumatica - a prospective cohort study

Ther Adv Musculoskelet Dis. 2023 Feb 7:15:1759720X221149963. doi: 10.1177/1759720X221149963. eCollection 2023.

Authors

Lara C Burg¹, Pantelis Karakostas², Charlotte Behning³, Peter Brossart², Tanaz A Kermani⁴, Valentin S Schäfer²

Affiliations

¹ Clinic of Internal Medicine III, Department of Oncology, Haematology, Rheumatology and Clinical Immunology, University Hospital Bonn, Venusberg-Campus 1, 53127 Bonn, Germany.
² Clinic of Internal Medicine III, Department of Oncology, Haematology, Rheumatology and Clinical Immunology, University Hospital Bonn, Bonn, Germany.
³ Institute of Medical Biometry, Informatics and Epidemiology, University Hospital Bonn, Bonn, Germany.
⁴ Division of Rheumatology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA.

Abstract

Background: It is known that giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) often occur together. So far, the prevalence of GCA in newly diagnosed PMR patients has not been evaluated in a prospective ultrasound study.

Objective: The aim of this study was to assess the prevalence of GCA using vascular ultrasound in patients with newly diagnosed PMR.

Design: A consecutive cohort of newly diagnosed PMR patients was prospectively evaluated for the presence of GCA with the use of systematic musculoskeletal and vascular ultrasound examination.

Methods: Overall, 60 patients with newly diagnosed PMR were prospectively enrolled. Symptoms and laboratory findings were collected. All patients underwent ultrasound of shoulder and hip joints, and vascular ultrasound evaluating the facial, temporal, carotid, vertebral and axillary arteries. Patients were diagnosed with GCA if they had ultrasound imaging findings of GCA. Patients with PMR (PMR-group) and patients with PMR and GCA (PMR-GCA-group) were compared, and a C-reactive protein (CRP) cut-off value was evaluated.

Results: GCA was diagnosed in 28 of 60 PMR patients (46%). The PMR-group consisted of 20 (62.5%) females with a mean age of 69 (±9.9) years, while the PMR-GCA-group consisted of 11 (39.3%) females with a mean age of 74 (±8.4) years. In 13 of 28 patients (46%) in the PMR-GCA-group, GCA was subclinical and only diagnosed by ultrasound. The PMR-GCA-group showed higher values of joint effusion and significantly higher CRP values. A CRP cut-off value of 26.5 mg/litre (reference range 0-5 mg/litre) yielded a sensitivity of 66% with a specificity of 73% for GCA.

Conclusion: GCA was found in 46% of newly diagnosed PMR patients; 22% of the patients with PMR had asymptomatic GCA. Joint effusions were higher in the PMR-GCA-group, with significant results for the hip joint. A CRP cut-off value of ⩾26.5 mg/litre in PMR can help in the identification of subclinical GCA.

Keywords: C-reactive protein; cut-off value; giant cell arteritis; joint effusion; polymyalgia rheumatica; prevalence; ultrasound.