The OMERACT giant cell arteritis ultrasonography score: a potential predictive outcome for assessing the risk of relapse during follow-up.

Abstract

The objective of this study was to determine whether the OMERACT GCA US Score (OGUS) change after treatment can be used for assessing the probability of relapse. This study was a multicentre retrospective study of GCA patients referred to two US GCA fast-track clinics over 2 years. The patients underwent US evaluation at baseline, and at 3 and 6 months. EULAR criteria for remission and relapse were checked at 3 and 6 months. OGUS changes at 0-3 months and 0-6 months were compared between patients with and without relapse at 6 months, as well as between 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 and 5 (6.8%) a major relapse. EULAR remission at 6 months was achieved in 32 (43.8%) patients. The standardized mean difference in OGUS between baseline and 3 months and between 3 months and 6 months was -0.25 and -0.38, respectively. OGUS significantly improved between baseline and 6 months (1.18 to 0.99, P = 0.004) and from 3-6 months (1.08 to 0.99, P = 0.04) in non-relapsing patients, whereas no significant changes at 3  (1.17 to 1.17; P = 0.736) and 6 months (1.17 to 1.21; P = 0.343) months were observed in those who experienced relapse. The mean 0-6-month OGUS improvement was lower in patients who relapsed (-0.1 to 0.16, P = 0.037). The mean 0-6-months OGUS improvement (decrease) was greater in patients who achieved remission at 6 months (0.28 to -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.