Ultrasound lesions of gout have been described in people with asymptomatic hyperuricemia. However, the anatomical sites and ultrasound lesions most frequently involved in asymptomatic hyperuricemia have not yet been established. This systematic review and meta-analysis aimed to determine the prevalence of the Outcome Measures in Rheumatology (OMERACT) elementary ultrasound lesions of gout (double contour, aggregates, tophus, erosion) at various sites in people with asymptomatic hyperuricemia and to determine which sites and lesions discriminate from people with normouricemia.
A systematic search of electronic databases, conference abstracts and reference lists was undertaken. Studies were included if they used ultrasound to image people with asymptomatic hyperuricemia and reported ≥1 OMERACT-defined lesion of gout. Meta-analyses were undertaken for the pooled prevalence of site-specific lesions in people with asymptomatic hyperuricemia, and the pooled odds ratios of these lesions compared to people with normouricemia.
Twenty studies were included. The most common site scanned was the first metatarsophalangeal joint (1MTP) (n = 17 studies) and the most common lesion reported, the double contour (n = 18). Meta-analyses of pooled prevalence showed 1MTP double contour was the most frequent finding in people with asymptomatic hyperuricemia (0.31, 95% confidence interval (CI) 0.20-0.42), followed by femoral condyle double contour (0.16, 95%CI 0.08-0.24) and 1MTP tophus (0.16, 95%CI 0.03-0.29). The highest pooled odds ratios for asymptomatic hyperuricemia vs. normouricemia were 6.98 (95%CI 3.14-15.57) for 1MTP double contour, 13.67 (95%CI 5.42-34.49) for femoral condyle double contour and 6.10 (95%CI 1.55-24.04) for 1MTP tophus.
In people with asymptomatic hyperuricemia, scanning of the 1MTP and femoral condyle for double contour, plus the 1MTP for tophus, has the highest prevalence and discrimination compared to those with normouricemia.