395. Glucocorticoid-related adverse events in GCA: application of Glucocorticoid Toxicity Index in a large monocentric cohort

Background/ Objectives: Oral glucocorticoids (GC) are the mainstay of treatment for giant cell arteritis (GCA) but chronic exposure to GC is associated with serious comorbidities. The objective of this study was to determine the GC exposure and risk of GC-related adverse events (AEs) in GCA, validating the Glucocorticoid Toxicity Index (GTI) (1,2) in a cohort of real-world patients.

Methods: 140 consecutive patients with GCA were enrolled in this retrospective monocentric study. All patients were older than 50 years of age, met the 1990 ACR criteria for GCA and/or had the evidence of a large vessel vasculitis at FDG-PET/CT scan. Patients’ clinical data were collected from clinical charts, calculating GC cumulative dose and GTI at baseline and in the following 5 years.

Results: 140 patients were enrolled in the study: median (IQR) age at diagnosis 74 (67-79), Female: 97 (69%), Male: 43 (31%). According to vascular involvement patients were classified in cranial-GCA (C-GCA, n:91), large vessel-GCA (LV-GCA, n:21) and cranial and large vessel-GCA (LV-C-GCA, n:28). Furthermore, 50 (36%) patients were treated with only GC, 44 (31%) with GC+methotrexate (MTX), 46 (33%) with GC+tocilizumab (in 20 cases TCZ was started in the first 3 months after diagnosis: early-TCZ, in 26 cases after 3 months for relapses or AEs: late-TCZ). During the follow up, 57 (41%) patients presented at least one relapse. In the GC group 22 relapses in 18 patients were reported, in MTX group 33 relapses in 25 patients (with 15 relapses before and 18 after MTX start), in early-TCZ group no relapses were reported, in late-TCZ group 21 relapses in 14 patients (with 17 relapses before and 4 after TCZ start) were reported. Median cumulative GC doses after 1 and 5 years were respectively 7.9 (6.3-9.8) gr and 16.5 (13.8-18.9) gr in GC group, 8.7 (5.9-10.0) gr and 16.5 (13.2-20.7) gr in MTX group, 7.1 (5.5-8.0) gr and 13.3 (12.8-13.7) gr in early-TCZ and 7.7 (6.2-11.1) gr and 19.7 (12.2-23.8) gr in late-TCZ. Eighty-eight percent of patients developed at least one GC-AE, with infections and hypertension being the most common reported AEs (42% e 44%, respectively). Median GTI-CWS (Cumulative Worsening Score) after 1 year was 65 (20-137) in GC, 63 (10-95) in MTX, 51 (33-116) in TCZ-early, 44 (0-91) in TCZ-late. Median GTI-CWS after 5 years was 219 (118-240) in GC, 137 (65-206) in MTX, 147 (146-147) in TCZ-early, 200 (121-231) in TCZ-late. A correlation between GTI-CWS and the GC cumulative dose was found (after 5 years r: 0.295, p: 0.026).

Conclusions: Chronic GC treatment is associated with a high risk of developing comorbidities. GTI score demonstrated to be an effective tool to assess GC-related AEs and proved to correlate with GC cumulative dose. TCZ confirmed its efficacy in reducing relapse rate, both in early and late-TCZ groups (3). TCZ showed for the first time in a real-life cohort a GC sparing effect, with a 19% reduction in GC cumulative dose and a 33% reduction in GTI-CWS in 5 years (comparing GC group vs early-TCZ group).

Disclosures: none