FRI0030 Comparison of clinical and ultrasound measures of disease activity in a large national ‘real life’ cohort of ra patients

Background Several studies have demonstrated that the clinical measures of disease activity, such as the DAS-score and ultrasound (US) scores can sometimes yield discordant results. Little research has attempted to understand the reasons for the discordances and how frequently these discordances occur in real life Objectives The objectives of this study were to determine the percentage of patients presenting discordances between DAS and US assessments in a real-life cohort, to describe associated factors and to evaluate the evolution of both measures of disease activity over time. Methods All patients with at least one concomitant US assessment and DAS score, performed since the introduction of validated US scoring in the Swiss registry for inflammatory arthritis SCQM registry between 2009 and 2017 were included. Disease activity was categorised as remission, low, moderate and high activity based on previously established cut-offs (for clinical: DAS categories and for US: on cutoffs of SONAR score established in previous testing among RA patients and asymptomatic subjects1,2). A search for potential clinical and US predictors of discordance was performed. Finally a longitudinal analysis was done in all patients with at least 2 subsequent visits. Discordances were analysed using successively DAS and US categories as references (see table 1) Results 1196 out of 2367 assessments were found discordant (50.4%). The proportion discordant assessments did not significantly differ by clinical disease status or when US categories were considered as the reference. Disease activity was equally frequently over-estimated by DAS compared to US-score (26.9%) and by US-score compared to DAS (23.5%). Factors associated with the presence of discordant results were all the components of the DAS when US categories were the reference. The presence of tenosynovitis was a significant factor when DAS was the reference. For 1181 patients with several DAS and US assessments, the proportion of discordances during follow up remained similar to the initial evaluation. Initial discordance/concordances could however change status without obvious reason in up to 30% of cases. Conclusions Discordances between DAS and US assessments appear to be higher than expected in real life. Both outcome measures could lead to over- or under-estimations of the disease activity. References [1] Zufferey P, Moller B, Brulhart Let al. Persistence of ultrasound synovitis in patients with rheumatoid arthritis fulfilling the DAS28 and/or the new ACR/EULAR RA remission definitions: results of an observational cohort study.Joint Bone Spine. 2014. [2] Zufferey P, Scherer A, Nissen MJ, et al. Can Ultrasound Be Used to Predict Loss of Remission in Patients with RA in a Real-life Setting? A Multicenter Cohort Study. J Rheumatol. 2018. Disclosure of Interest None declared