OP0309 THE GIANT CELL ARTERITIS (GCA) ULTRASOUND SCORE (OGUS) AT DIAGNOSIS AND AFTER INITIAL TREATMENT PREDICTS FUTURE RELAPSES IN GCA PATIENTS: RESULTS FROM A PROSPECTIVE MULTICENTRE STUDY
Authors: S. Monti, C. Ponte, V. S. Schaefer, D. Rozza, G. Franchi, A. Milanesi, N. Khmelinskii, S. M. Petzinna, G. Carrara, C. DI Nicola, C. Dejaco, R. Luqmani
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> Prognostic parameters for the risk stratification of patients with giant cell arteritis (GCA) at diagnosis or during the early phases of the disease are still lacking. The use of ultrasound (US) as a monitoring tool for the assessment of GCA during follow-up is being increasingly recognized. The provisional OMERACT GCA ultrasound score (OGUS) has been developed as a tool to monitor disease activity and has shown good sensitivity to change in a prospective study [1]. It remains unclear whether ultrasound findings play a prognostic role in predicting the risk of relapse, the need for immunosuppressive treatment, or the risk of ischemic complications. <h3>Objectives:</h3> To test the prognostic role of the OGUS score at baseline, as well as its rapidity and degree of improvement during the initial weeks following the diagnosis of GCA. <h3>Methods:</h3> Patients with a new onset of GCA and a positive US at diagnosis were prospectively recruited from three academic hospitals (Pavia, Italy; Lisbon, Portugal; Bonn, Germany). Patients were recruited if they had not received high-dose GCs (≥ 30 mg/day of prednisone equivalent) for more than 15 days. US was performed at baseline, 1 week, 3 weeks, 6 weeks, and 12 weeks during follow-up by the same expert sonographer in each centre (SM, CP, VS). OGUS was calculated as reported in (1). Clinical outcomes were assessed every 3-6 months during a 3-year follow-up and included the occurrence of relapses (defined as the recurrence of GCA-related symptoms or rise of inflammatory markers not otherwise explained and requiring glucocorticoid [GC] increase), need for adjunctive immunosuppressive drugs, and presence of ischemic events. Selection of treatment was at the physician´s discretion, following international recommendations. A multivariate Poisson model with robust variance was performed adjusting for the following confounders: age, sex, large-vessel (LV)-GCA, GC cumulative dose, baseline OGUS. A multiple imputation was used for handling missing data. <h3>Results:</h3> We included 102 patients with GCA, of whom 35 (34%) experienced a total of 66 relapses, with a median time to relapse of 210 days (IQR 94.5-323.5). LV-GCA was recorded in 44 (43%) patients and visual loss in 30 (29.4%). 28 (26%) patients received an adjunctive immunosuppressive drug (IL-6 inhibitor or methotrexate) during follow-up. The median baseline OGUS score was 1.4 (IQR 1.1-1.7). The OGUS score at the time of diagnosis correlated with the risk of relapse during the following 12 months [incidence rate ratio (IRR) for 0.5 points-increase in OGUS: 3.779 (95%CI 1.170-12.208)]. The speed and extent of OGUS reduction within the first three weeks post-diagnosis were found to inversely correlate with the risk of future relapses during a 3-year follow-up. (Table 1). The OGUS score significantly increased in patients who experienced a relapse [median OGUS in patients at relapse vs non-relapsing patients: 1.07 (95%CI 0.81-2.04) vs 0.96 (0.79-1.78); p&lt;0.05] (Figure 1). An OGUS normalization (reaching a score &lt; 1) over the first 12 weeks from diagnosis was inversely associated with the need for adjunctive treatment with immunosuppressive drugs [IRR at 3 weeks: 0.571 (95%CI 0.345-0.945), IRR at 12 weeks: 0.558 (0.319-0.974)]. OGUS did not correlate with the risk for ischaemic events. <h3>Conclusion:</h3> We demonstrated for the first time that the extent and severity of disease measured with ultrasound at diagnosis of GCA has a prognostic role. A higher OGUS score at diagnosis predicts early relapses during the following 12 months. An earlier reduction of OGUS during the first three weeks from diagnosis is associated with a lower long-term risk of relapse. The rapidity and degree of OGUS improvement correlated with the need for treatment intensification. <h3>REFERENCES:</h3> [1] Dejaco C, Ponte C, Monti S, et al. The provisional OMERACT ultrasonography score for giant cell arteritis. Ann Rheum Dis 2023;82:556-64. <h3>Acknowledgements:</h3> <b>NIL.</b> <h3>Disclosure of Interests:</h3> <b>None declared.</b>