THU0116 Higher Ultrasound Synovitis in Elderly-Onset Rheumatoid Arthritis as Compared to Younger-Onset: THE Barts Early Arthritis Cohort
Authors: V.C. Romao, M. DiCicco, I. Lazarou, A. Mahto, J.E. Fonseca, S. Kelly, F. Humby, C. Pitzalis
Journal: Annals of the Rheumatic Diseases (2015)

<h3>Background</h3> Elderly-onset rheumatoid arthritis (EORA), starting after the age of 60, is a subset of disease with different characteristics from the classic younger-onset RA (YORA). There are conflicting results regarding disease outcomes in both groups. <h3>Objectives</h3> We aimed to compare clinical, pathological and ultrasound (US) features between these two disease subsets in the Barts Early Arthritis Cohort (BEAC). <h3>Methods</h3> We included 140 BEAC patients fulfilling ACR 2010 criteria (99 YORA, 41 EORA) and assessed clinical, US and synovial histology data at baseline and after 6 months of DMARD therapy. US synovitis was defined according to the OMERACT definitions: synovial thickening (ST) and Power Doppler (PD) signal were scored using a previously reported semi-quantitative 0-3 score on a data set of 10 metacarpophalangeal and both wrist joints (range 0-36). We assessed the correlation between DAS28, US scores and histological parameters (Krenn score and staining for B cells, T cells, lining and sublining macrophages) using Spearman correlation and assessed for potential interactions with EORA. <h3>Results</h3> At baseline, disease activity parameters were similar between both groups, including inflammatory markers, joint counts, DAS28 and CDAI. However, EORA patients had significantly higher US-ST (p=0.03) and US-PD (p=0.002) scores. This did not translate at the histological level, with similar Krenn synovitis (p=0.76) and individual cell scores (p&gt;0.5). At baseline, US-PD scores correlated significantly with Krenn score (r=0.28, p=0.007) in both groups, but US-ST scores were only correlated with Krenn score in EORA patients (r=0.42, p=0.03), with a trend for interaction between EORA and US-ST (p=0.08). At 6 months, DAS28 and CDAI were not significantly different between EORA and YORA, but elderly-onset patients still presented higher US-ST (p=0.03) and US-PD (p=0.009) scores. At this time point, histological and US synovitis scores were not significantly correlated and EORA was not an effect modifier. DAS28 was significantly correlated with US-PD score at baseline (r=0.36, p=0.0001) and 6 months (r=0.26, p=0.02) and with Krenn score at baseline (r=0.36, p=0.0001), always without significant interaction with EORA. Notably, at 6 months EORA was an effect modifier of the correlation of DAS28 and Krenn score (interaction p=0.05), with a strong significant correlation in the EORA group (r=0.56, p=0.003) and a mild non-significant correlation in YORA (r=0.14, p=0.35). A similar pattern was observed in 6-months9 individual cell scores, with significant correlations with DAS28 in EORA but not YORA for sublining (r=0.64, p=0.0005; interaction p=0.09) and lining macrophages (r=0.81, p&lt;0.0001; interaction p=0.009), B cells (r=0.52, p=0.007; interaction p=0.04) and T cells (r=0.46, p=0.019; interaction p=0.09). <h3>Conclusions</h3> EORA patients presented similar clinical and histological activity scores to the YORA group, but higher US synovitis, both at baseline and at 6 months. EORA was an effect modifier of the correlation between DAS28 and Krenn synovitis score at follow-up, which was significant only in this subgroup of patients. Thus, after institution of DMARD therapy, DAS28 seems to better translate the degree of synovial inflammation in elderly-onset disease than in younger-onset patients. <h3>Disclosure of Interest</h3> None declared