Newly diagnosed vs. relapsing giant cell arteritis: Baseline data from the GiACTA trial.

OBJECTIVE: To report entry criteria and clinical features of patients with newly diagnosed and relapsing giant cell arteritis (GCA) enrolled in a randomized trial of tocilizumab, an interleukin-6 receptor-alpha inhibitor.

METHODS: Newly diagnosed GCA was defined as diagnosis ≤6 weeks before baseline. Relapsing GCA was defined as diagnosis >6 weeks before baseline with ≥2 consecutive weeks of prednisone ≥40mg/day. All patients had active GCA within 6 weeks of baseline. All statistical results are exploratory.

RESULTS: Of 251 patients, 119 (47%) had newly diagnosed and 132 (53%) had relapsing GCA. Mean age was 69 years in both subsets; 75% were women. Relapsing patients were heavier [difference in means (95% CI): women, 4.18kg (0.49-7.87, P = 0.027); men, 8.25kg (1.42-15.09, P = 0.019)] and had higher mean body mass index [difference in means (95% CI): women, 1.72kg/m2 (0.44-2.99, P = 0.009); men, 2.85kg/m2 (0.32 -5.37, P = 0.028)]. Relapsers had higher baseline prevalence of depression (16% vs. 4%) and osteopenia/osteoporosis (33% vs. 23%, P = 0.002 and P = 0.062, respectively). At diagnosis, 67% had new-onset headaches; 34% had mouth pain/jaw claudication. One-fifth had polymyalgia rheumatica symptoms but no cranial manifestations; 62% had positive temporal artery biopsy findings; 37% were enrolled on the basis of cross-sectional imaging study findings.

CONCLUSIONS: Demographics of the GiACTA population reflect the epidemiologic profile of GCA. Baseline comorbidities associated with glucocorticoids were more prevalent among relapsing patients than among those with newly diagnosed disease, highlighting the need for new GCA treatment options. More than one-third of patients were enrolled based on large-vessel imaging.