Low relapse rate in patients with giant cell arteritis in a multi-centre retrospective Turkish Registry.

Objectives: Glucocorticoids (GC) are widely accepted as the standard first-line treatment for giant cell arteritis (GCA). However, relapse rates are reported up to 80% on GC-only protocol arms in controlled trials of tocilizumab and abatacept in 12-24 months. Herein, we aimed to assess the real-life relapse rates retrospectively in patients with GCA from Turkey.
Methods: We assembled a retrospective cohort of patients with GCA diagnosed according to ACR 1990 criteria from tertiary rheumatology centres in Turkey. All clinical data were abstracted from medical records. Relapse was defined as any new manifestation or increased acutephase response leading to the change of the GC dose or use of a new therapeutic agent by the treating physician.
Results: The study included 330 (F/M: 196/134) patients with GCA. The mean age at disease onset was 68.9±9 years. The most frequent symptom was headache. Polymyalgia rheumatica was also present in 81 (24.5%) patients. Elevation of acute phase reactants (ESR>50 mm/h or CRP>5 mg/l) was absent in 25 (7.6%) patients at diagnosis. Temporal artery biopsy was available in 241 (73%) patients, and 180 of them had positive histopathological findings for GCA. For remission induction, GC pulses (250-1000 methylprednisolone mg/3-7 days) were given to 69 (20.9%) patients, with further 0.5-1 mg/kg/day prednisolone continued in the whole group. Immunosuppressives as GC-sparing agents were used in 252 (76.4%) patients. During a follow-up of a median 26.5 (6-190) months, relapses occurred in 49 (18.8%) patients. No confounding factor was observed in relapse rates. GC treatment could be stopped in only 62 (23.8%) patients. Additionally, GC-related side effects developed in 64 (24.6%) patients, and 141 (66.2%) had at least one Vasculitis Damage Index (VDI) damage item present during follow-up.
Conclusions: In this first multi-centre series of GCA from Turkey, we observed that only one-fifth of patients had relapses during a mean follow-up of 26 months, with 76.4% given a GC-sparing IS agent at diagnosis. At the end of follow-up, GC-related side effects developed in one-fourth of patients. Our results suggest that patients with GCA had a low relapse rate in real-life experience of a multi-centre retrospective Turkish registry, however with a significant presence of GC-associated side effects during follow-up.