FRI0220 Ultrasound in assessment of disease course in gout: the 24 month single-centre prospective observational study
Authors: E. Norkuviene, M. Petraitis, I. Apanaviciene, S. Ottaviani, A. Baranauskaite
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Today, despite the great potential of ultrasound (US) in gout, there is lack of longer duration US follow – up studies in this disease. <h3>Objectives</h3> The aim was to evaluate the 24 month's treatment effect of urate-lowering therapy on gout-specific US lesions and to determine the most representative target for US follow-up in gout. <h3>Methods</h3> A 24 month prospective observational single-centre study was carried out. Patients with gout diagnosis, confirmed by identification of monosodium urate crystals, with at least one tophus in the joint or tendon or one double contour sign (DC) on US, were selected for the study. The serum uric acid (SUA) level was assessed every three months. US evaluations of 36 joints and four tendons (m. triceps and patellar) were performed every six months starting from the baseline, by one rheumatologist, blinded to the SUA levels and clinical data. Outcomes were: change in US features (tophus, DC count and tophus size) in joints and tendons according median of SUA level during the follow up period from M3 to M24. Two stages of SUA levels were defined: high,≥360 μmol/l; and low,&lt;360 μmol/l (considered as within the treatment target). Correlations between US findings modifications in different locations, and between US findings modifications and SUA levels, were estimated by the Pearson correlation coefficient. <h3>Results</h3> We included 40 gouty patients (mean ±SD age 54.1±9.7 years, 90.0% males, disease duration 8.5±8.8 years). Mean ±SD baseline SUA level was 504.8±32.9 µmol/l. Among the 31 completers at M24, 21 (71%) achieved median SUA &lt;360 μmol/l. On month 24 the global number of patients with DC and tophus was reduced from 91% to 32% and from 100% to 64%, respectively. A total of sixty-four percent of patients in the study had not reached the US cure (DC or T being still found in at least one joint or tendon) after two years of treatment in the group with the median of SUA less than 360 µmol/l. The comparison of crystal clearing process in joints and tendons showed an excellent correlation of mean percentage change in total tophus number (rs=0.900) and size (rs=1.0) in joints and tendons, investigating 21 gout patients who participated in all five US study visits during the 24 months of follow-up. A strong positive correlation was observed between the changes of tophus size in left and right first MTP joints (r=0.718 [95% confidence interval: 0.370; 0.875], p&lt;0.001) also between the changes of tophus size in toe and total intra-articular tophus size, measured by US (r=0.726 [95% confidence interval: 0.347; 0.925], p&lt;0.001) on month 24 (compared to month 0). It was found a negative correlation between the mean SUA during 24 months follow up and the reduction in tophus size on month 24 (r=0.602) <h3>Conclusions</h3> Only one third of patients with median SUA &lt;360 µmol/l were free of US gout signs after 2 years of treatment. Due to positive link between the change in tophus size in the first MTP joint and changes in the whole intraarticular urate pool, also tendons, the tophaceous deposition in the first MTP joint could be the most representative target for follow-up morphological analysis in gout clinical trials or monitoring the disease's activity in clinical practice with US. <h3>Disclosure of Interest</h3> None declared