OP0155 Ultrasound as an outcome measurement tool for optimisedmonitoring of gout. validation of the omeract ultrasound definitions of gout elementary lesions

Objectives

To evaluate ultrasound (US) as an outcome measurement instrument for monitoring gout patients during urate lowering therapy using the OMERACT US Working Group's 2015 definitions of US elementary lesions in gout.

Methods

US examination (28 joints, 26 tendons) were performed in patients with microscopically verified gout who either initiated or increased urate lowering therapy. Joints and tendons were evaluated for the four OMERACT elementary lesions of gout (Double contour, Tophus, Aggregates and Erosions). Furthermore, subcutaneous (SC) oedema was registered and synovitis was graded by grey scale (GS) and colour Doppler (CD) (both graded 0–3). A sum score was calculated for each component for each patient (table 1). Patient Reported Outcomes (PROs) regarding pain (visual analogue scale), numbers of attacks within the last 3 months and physical function (Health Assessment Questionnaire) were obtained, as were C-reactive protein (CRP), p-urate and clinical joint examination. All examinations were repeated after 3 (n=29) and 6 months (n=15, follow-up still ongoing) and changes in scores were evaluated using Wilcoxon-Pratt signed-rank test.

Results

29 patients (28 males, 1 female), mean age of 68 (39 – 89) years were included. US showed a numerical, but statistically non-significant (p=0.13), decline in DC count from baseline to 3 months' follow up, while at 6 months a statistically significant decline was observed (p=0.033). The tophus count decreased non-significantly at both 3 and 6 months' follow up, whereas the aggregate and erosion counts by large were unchanged. GS synovitis showed a statistically non-significant decrease at follow ups, whereas CD synovitis and SC oedema counts declined significantly at 3 months' follow up (p=0.033 and 0.044, respectively). P-urate levels decreased statistically significant from baseline to both 3 and 6 months' follow-up (both p-values<0.001), as did clinical markers such as CRP, joint evaluation, pain and attack frequency.

Conclusions

Of the four OMERACT US elementary gout lesions only DC count showed a statistically significant decrease as a response to 6 months of urate lowering therapy. The number of tophi had decreased at both 3 and 6 months' follow up, but not statistically significant. Aggregates and erosions count did not markedly respond to the 6 month treatment. The study indicates that US assessing the OMERACT elementary lesions, particularly DC, is a feasible tool for monitoring gout lesions. However, a follow-up of at least 6 months may be needed to detect change of crystal deposits, as reflected by DC, and presumably an even longer follow-up period is needed to evaluate more massive deposits as tophi.

Disclosure of Interest

None declared