The OMERACT Giant cell arteritis Ultrasonography Score: a potential predictive outcome to assess the risk of relapse during follow-up.

Abstract

To determine whether the OMERACT giant cell arteritis (GCA) Ultrasonography (US) Score (OGUS) change after treatment can be used for assessing the probability of relapse. Multicenter retrospective study of GCA patients referred to two US GCA fast-track clinics over 2 years. Patients underwent US evaluation at baseline, 3 and 6 months. EULAR definitions for remission and relapse were checked at 3 and 6 months. OGUS changes at 0-3 months and 0-6 months were compared among patients with and without relapse at 6 months, as well as those with and without remission at 6 months. A total of 76 patients were included (mean age 77.2 years, 55.3% females). Nineteen (26%) patients relapsed at 6-months, of whom 14(19.1%) showed a minor relapse. EULAR remission at 6 months was achieved by 32(43.8%) patients. The standardized mean difference of OGUS between baseline and 3 and 6 months was -0.25 and -0.38, respectively. OGUS significantly improved between baseline and 6 months (1.18 vs 0.99,p=0.004) and from 3-6 months (1.08 vs 0.99,p=0.04) in non-relapsing patients, whereas no significant changes at 3 (1.17 vs 1.17;p=0.736) and 6 (1.17 vs 1.21;p=0.343) months were observed in those who experienced relapse. Mean 0-6-month OGUS improvement was lower in patients who relapsed (-0.1 vs 0.16,p=0.037). Mean 0-6-month OGUS improvement was greater in patients who achieved remission at 6 months (0.28vs -0.07,p=0.001). The absence of OGUS improvement during follow-up in GCA may be used to assess the probability of relapse and the absence of remission at 6 months.