Diagnostic Assessment Strategies and Disease Subsets in Giant Cell Arteritis: Data From an International Observational Cohort

Abstract

Objective Diagnostic assessment in giant cell arteritis (GCA) is rapidly changing as vascular imaging becomes more available. This study was undertaken to determine if clinical GCA subsets have distinct profiles or reflect differential diagnostic assessments. Methods Patients were recruited from an international cohort and divided into 4 subsets based on a temporal artery (TA) abnormality (positive TA biopsy [TAB] or halo sign on TA ultrasound [TA‐US]) and/or evidence of large vessel (LV) involvement on imaging: 1) both TA abnormality and LV involvement (TA+/LV+ GCA); 2) TA abnormality without LV involvement (TA+/LV− GCA); 3) LV involvement without TA abnormality (TA−/LV+ GCA); and 4) clinically diagnosed GCA without LV involvement or TA abnormality (TA−/LV− GCA). Results Nine hundred forty‐one patients with GCA were recruited from 72 international study sites. Most patients received multiple forms of diagnostic assessment, including TAB (n = 705 [75%]), TA‐US (n = 328 [35%]), and LV imaging (n = 534 [57%]). Assessment using TAB, TA‐US, and LV imaging confirmed the diagnosis of GCA in 66%, 79%, and 40% of cases, respectively. GCA subsets had distinct profiles independent of diagnostic assessment strategies. TA+/LV− were the most common subset (51%), with a high burden of cranial ischemia. Those in the TA−/LV− subset (26%) had a high prevalence of cranial ischemia and musculoskeletal symptoms. Patients in the TA−/LV+ subset (12%) had prevalent upper extremity vascular abnormalities and a low prevalence of vision loss, and those in the TA+/LV+ subset (11%) were older and had a high prevalence of cranial ischemia, constitutional symptoms, and elevated acute‐phase reactant levels. Conclusion Vascular imaging is increasingly incorporated into the diagnostic assessment of GCA and identifies clinical subsets of patients based on involvement of temporal and extracranial arteries.

Comment on: Evaluation of adjunctive mycophenolate for large vessel giant cell arteritis. Reply

“…Furthermore, the patient’s perspective of the disease can also act as a bias in this group of patients when often non-classical or unrelated headache and visual disturbance are symptoms commonly over-reported. Finally, the younger age observed in this cohort (mean ± SD 69.4 ± 7.9 years) and high prevalence of constitutional symptoms (86.5% of the cohort) favour the extra-cranial variant, as observed in other studies [ 3 , 4 , 6 ].…”

“…Gribbons et al [ 3 ] recently published an analysis of the Diagnostic and Classification Criteria for Vasculitis (DCVAS) data and showed that patients exclusively with large vessel involvement (TA-negative and evidence of large vessel involvement on imaging) differed considerably from patients with isolated temporal artery involvement (TA-positive and evidence of large vessel involvement on imaging) in terms of both their clinical profiles and their demographic characteristics. In parallel, several studies have shown that the expression of specific cytokines and chemokines, at a vascular (tissue) or extravascular level (serum or plasma), are associated with differential risks of cranial ischaemia, indicating that there is an immunological predilection towards the observed clinical phenotype [ 4 ].…”

My Treatment Approach to Giant Cell Arteritis

“…Features of GCA often vary from patient to patient and depend in part on which arteries are predominantly affected. 18 In fact, cohort studies have identified two main groups of patients: cranial GCA (C-GCA), the classical and most common phenotype; and largevessel GCA (LV-GCA), which was identified more recently and is considered less common. 19 The described patterns of C-GCA and LV-GCA are not mutually exclusive and overlapping clinical phenotypes are common.…”

Patterns of large-vessel lesions are associated with treatment outcomes in large-vessel giant cell arteritis

“…Gribbons et al sought to identify subsets of GCA, and showed that GCA with LVLs was divisible into two groups based on the involvement of temporal artery (37). TCZ improved clinical outcomes not only in GCA patients with cranial lesions but also in patients who presented with LVLs and PMR without cranial lesions (38).…”