Baseline characteristics
| GCA+* (n=53) | GCA−* (n=80) | P value | |
| Age (years), mean (SD) | 72.4 (8.8) | 68.1 (8.5) | 0.64 |
| Female, n (%) | 35 (66.0) | 50 (62.5) | 0.68 |
| Clinical, n (%) | |||
| Morning stiffness in shoulders | 26 (49.1) | 34 (42.5) | 0.34 |
| Sudden visual loss | 13 (24.5) | 13 (16.3) | 0.24 |
| Jaw claudication | 21 (39.6) | 5 (6.3) | <0.001 |
| New temporal headache | 45 (84.9) | 57 (71.3) | 0.07 |
| Scalp tenderness | 27 (50.9) | 25 (31.3) | 0.02 |
| Abnormal examination of the temporal artery | 27 (50.9) | 16 (21.3) | <0.001 |
| Laboratory, n (%) | |||
| Maximum ESR ≥50 mm/hour | 28 (52.8) | 16 (20.0) | <0.001 |
| Maximum CRP ≥10 mg/liter | 44 (83.0) | 36 (45.0) | <0.001 |
| High ESR (≥50 mm/hour) or CRP (≥10 mg/L) | 47 (88.7) | 38 (47.5) | <0.001 |
| TAB and imaging, n (%) | |||
| TAB performed | 8 (15.1) | 3 (3.8) | |
| Definitive vasculitis on TAB | 7 (13.2) | 0 (0.0) | 0.001 |
| Ultrasound performed | 52 (98.1) | 80 (100) | |
| Halo sign on temporal artery ultrasound | 37 (69.8) | 1 (1.3) | <0.001 |
| Positive TAB or halo sign on temporal artery ultrasound | 40 (75.5) | 1 (1.3) | <0.001 |
| FDG-PET/CT performed | 31 (58.5) | 32 (40.0) | |
| FDG-PET activity throughout aorta | 7 (13.2) | 1 (1.3) | <0.001 |
| MRA performed | 29 (54.7) | 31 (38.8) | |
| Bilateral axillary involvement on imaging | 16 (30.2) | 1 (1.3) | <0.001 |
| Bilateral axillary involvement on ultrasound | 12 (22.6) | 1 (1.3) | <0.001 |
| Bilateral axillary involvement on FDG-PET | 11 (20.8) | 0 (0.0) | <0.001 |
Definitions of classification criteria were used as described in the 2022 ACR/EULAR classification criteria.1
*Diagnosis after 6 months of follow-up according to the treating physician.
ACR, American College of Rheumatology; CRP, C reactive protein; ESR, Erythrocyte Sedimentation Rate using Westergren method; FDG, fluorodeoxyglucose; GCA−, Patients suspected of but not diagnosed with giant cell arteritis; GCA, giant cell arteritis; GCA+, Patients diagnosed with giant cell arteritis; MRA, magnetic resonance angiography; PET, positron emission tomography; TAB, temporal artery biopsy.