Table 1.

Catalog of study objectives.

Primary objective
1	To compare cumulative GC doses in patients with isolated c-GCA as compared to LV-GCA (with or without c-GCA).
Key secondary objectives
1	To compare cumulative GC doses in patients with pure PMR* compared to PMR patients with subclinical LV-GCA.
2	To compare the incidence of aortic dilatation 2 years after diagnosis in patients with c-GCA as compared to LV-GCA (with or without c-GCA).
3	In the subpopulation of patients in whom a diagnostic FDG PET/CT was performed at diagnosis, to evaluate the risk of aortic complications (aneurysms and dissections) in GCA patients with aortic involvement as compared to patients without aortic involvement.
Secondary objectives
1	To compare treatment response, risk of relapse, need for GC-sparring add-on treatment, and disease duration in patients with c-GCA as compared to LV-GCA (with or without c-GCA).
2	To compare treatment response, risk of relapse, need for GC-sparring add-on treatment, and disease duration in patients with pure PMR compared to PMR patients with subclinical LV-GCA.
3	In the subpopulation of patients in whom a diagnostic FDG PET/CT was performed, to evaluate the association between aortic FDG uptake and aortic dilatation at year 2.
Exploratory objectives
1	To identify clinical features associated with the different disease subsets, c-GCA, LV-GCA, and PMR.
2	To assess and evaluate risk factors and biomarkers predicting GCA in patients with PMR.
3	To assess and evaluate incidence, prevalence, and predictors of ischemic events and vascular complications in GCA patients.
4	To assess and evaluate incidence, prevalence, and predictors of comorbidity in GCA and PMR patients.
5	To assess and evaluate diagnostic strategies and implementation of diagnostic imaging in GCA and PMR.
6	To evaluate adherence to clinical guidelines.
7	To evaluate and predict treatment efficacy, safety, and predictors of treatment success, treatment failure, and maintenance of remission after therapy withdrawal.
8	To assess and evaluate risk factors and biomarkers predicting vascular complications in GCA.

*Pure PMR; PMR patient without cranial GCA symptoms, new-onset claudication, or GCA. c-GCA, cranial giant cell arteritis; LV-GCA, large-vessel GCA; PMR, polymyalgia rheumatica; GC, glucocorticoid; ¹⁸F-FDG PET/CT, fluorine-18-fluorodeoxyglucose positron emission tomography with computed tomography.