POS0568 PREVALENCE OF ULTRASOUND FINDINGS SUGGESTIVE OF INFLAMMATORY ARTHRITIS AND GOUT-SPECIFIC LESIONS IN PATIENTS WITH GOUT: THE ECHOGOUT STUDY
Authors: H. Gouze, F. Melpignano, S. Ruel-Gagné, I. Padovano, F. Vidal, M. Breban, M. A. D’agostino
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> Ultrasound (US) has been shown to be a valuable diagnostic tool for gouty patients (pts) in detecting urate crystal deposits in joints and soft tissues. The American College of Rheumatology (ACR) and the European Alliance of Association for Rheumatology (EULAR) included US elements into their classification criteria for gout [1], and several studies demonstrated that sodium urate deposits as well as inflammatory and structural lesions secondary to these deposits can be detected by US with a high sensitivity and specificity. The OMERACT (Outcome Measure in Rheumatology) US working group proposed consensual and validated US gout-specific lesions, covering inflammatory and structural lesions [2], but their correlation with clinical activity of gouty patients has not evaluated yet. <h3>Objectives:</h3> To estimate the prevalence of OMERACT US definitions of gouty lesions in a gouty population in different phases of disease and to compare clinical, biological and US findings in symptomatic (Sy) versus asymptomatic (Asy) patients. <h3>Methods:</h3> Cross-sectional study including gouty pts, whether Asy or Sy, i.e. presenting arthritis at physical examination. A standardized clinical and US evaluation of joints, tendons and entheses was performed by independent examiners blinded to each other assessment. US elementary lesions were reported as defined by OMERACT (synovial effusion (SE), synovial hypertrophy (SH), Power Doppler (PD), synovitis, enthesitis, tophi, aggregate, double contour sign (DC), erosions, calcification/enthesophytes and osteophytes). Quantitative variables were compared using Student's t-test and qualitative using chi-square and Fisher tests where needed. We also compared clinical and ultrasound activity according to the presence of hyperuricemia, defined as uric acid dosage ≥ 360µmol/L. <h3>Results:</h3> Fifty-four pts were included, thirty-three being Sy, with a mean age of 63 years (± 14.4y), and mean disease duration of 11 years (± 12.9y). Overall prevalence of inflammatory, gouty-specific (i.e. DC, aggregates, tophi) and structural lesions were of 72.2%, 59.3% and 33.3% respectively. As compared to Asy pts, Sy group had higher prevalence of tophi observed at the entheses, knee synovitis, and knee and metatarsophalangeal (MTP) DC (p &lt; 0.05, Table 1). Sy pts also had a higher number of joints with SH, a higher number of tophi in joints and entheses and increased overall number of gouty-specific lesions and joints and entheses (p &lt; 0.05, Table 2). Regarding comorbidities and other clinical features in the two groups, no significant differences were found except that Sy pts had more frequent history of poly/oligo-articular flare as compared to Asy ones. We distinguished hyperuricemic pts (38 pts, 70.3%), from normouricemic (13 pts, 24.1%). US mean PD synovitis sum score in hyperuricemic pts was of 3.12 vs 1.27 in normouricemic pts (p = 0.046). SH mean sum score was higher in hyperuricemic than the normouricemic pts (mean sum score of 8.18 and 2.91 respectively, p &lt; 0.01), as well as mean number of DC observed in joints (1.37 vs 0.75 respectively, p = 0.01). <h3>Conclusion:</h3> US abnormalities were higher in the Sy group, including both SH and gouty-specific lesions (tophi in joints/entheses and DC). This study highlights that US gouty-specific lesions are prevalent in gouty pts, even Asy, and in those with controlled uricemia, suggesting that US is more sensitive for the detection and follow-up of pts than clinical examination. As the presence of tophi has been found to be associated with disease duration and kidney function (independent risk factor) [3], US may be helpful to detect specific signs of disease and to assess treatment response in addition to uricemia levels. <h3>REFERENCES:</h3> [1] Neogi T et al. 2015 Gout Classification Criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative. Arthritis Rheumatol Hoboken NJ. 2015 Oct;67(10):2557–68. [2] Terslev L et al. Ultrasound as an Outcome Measure in Gout. A Validation Process by the OMERACT Ultrasound Working Group. J Rheumatol. 2015 Nov;42(11):2177–81. [3] Lu B et al. Risk factors of ultrasound-detected tophi in patients with gout. Clin Rheumatol. 2020 Jun;39(6):1953–60. <h3>Acknowledgements:</h3> <b>NIL.</b> <h3>Disclosure of Interests:</h3> <b>None declared.</b>