Objectives: We aimed to determine by ultrasonography (US) the prevalence of articular monosodium urate deposits in patients with gout who do not require urate lowering therapy (ULT) according to international recommendations.
Methods: In this prospective study, we enrolled patients with proven gout demonstrated by crystals in synovial fluid but who did not require ULT. Two trained ultrasonographers assessed 10 joints per patient (metatarsophalangeal [MTP] joints 1-2, knees, metacarpophalangeal [MCP] joints 2-3) to determine the prevalence of the double-contour (DC) sign and tophi in each site.
Results: We studied 150 joints from 15 patients (median age 56.9 years [interquartile range 31.7] years; 14 males). The median number of acute attacks per patient was 2.0 [0.7]. Interobserver agreement was good to excellent for all articular sites. The prevalence of the DC sign in the knees and MTP joints was 46.7% and 40% respectively, whereas that of tophi was 26.7% for both sites. No urate deposits were found in MCP joints. The DC sign and tophi were found in at least one articular site in 60% and 46.7% of patients, respectively. All patients with urate levels > 600 μM (10 mg/dl) had a DC sign in at least 1 assessed joint. Urate levels were positively correlated with presence of the DC sign in knees (p=0.005) and MTP joints (p=0.03) but not presence of tophi.
Conclusions: In this study, ultrasonography allowed for detecting articular urate deposits in 60% of gouty patients not requiring ULT by international recommendations.