Diagnostic accuracy of ultrasound in patients with gout: A meta-analysis.

OBJECTIVE: This study aimed to evaluate the diagnostic performance of ultrasound (US) for patients with gout.

METHODS: We searched the Medline, Embase, Pubmed, and Cochrane Library databases, and performed a meta-analysis of the diagnostic accuracy of US according to the double contour sign, tophus, snowstorm, or bony erosion in patients with gout.

RESULTS: In total, 11 studies including 938 patients with gout, and 788 controls (patients with nongout inflammatory arthritis) were available for the meta-analysis. The pooled sensitivity and specificity of US were 65.1% ([95% confidence interval (CI): 62.0-68.2] and 89.0% (96.6-91.1), respectively. The positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 5.889 (3.365-10.30), 0.359 (0.266-0.485), and 17.61 (11.11-17.92), respectively. The area under the curve of US was 0.858 and the Q⁎ index was 0.789, indicating good diagnostic accuracy. Some between-study heterogeneity was found in the meta-analyses. Meta-regression showed that the sample size, study design, and diagnostic criteria were not sources of heterogeneity, and subgroup meta-analyses did not change the overall diagnostic accuracy. US signs of tophus, snowstorm, or bony erosion besides the double contour sign were not sensitive (54.3%, 30.8%, and 51.6%), but specific (93.2%, 90.6%, and 93.3%) enough as a diagnostic tool.

CONCLUSIONS: Our meta-analysis of published studies demonstrates that US offers good diagnostic accuracy with high specificity and can play an important role in the diagnosis of gout.