Diagnostic properties of ultrasound of major salivary glands in Sjögren's syndrome: a meta-analysis

Objective: To perform a systematic review and meta-analysis on studies examining the properties of ultrasonography of major salivary glands for diagnosing Sjögren's syndrome.

Materials and methods: We searched for the literature on eight databases. The quality of included articles was assessed with the QUADAS-2 tool. Publication bias, pooled sensitivity, specificity, diagnostic odds ratio, and 95% confidence intervals (95%CI) were calculated. Meta-regression analysis was performed.

Results: We identified 37 studies and 33 ultrasonographic scoring systems. High risk of bias was observed in 'patient selection', 'conduct and interpretation of ultrasound', and 'flow of patients and timing of tests' in 78%, 70%, and 51% of the studies. We included 29 studies in the meta-analysis. Publication bias was highly probable. Pooled sensitivity was 0.69 (95%CI: 0.67-0.71), specificity 0.92 (95%CI: 0.91-0.93), and diagnostic odds ratio 33.89 (95%CI: 20.75-55.35). Significant heterogeneity was detected between studies. Meta-regression analysis showed that studies with high risk of bias in 'conduct and interpretation of ultrasound' and studies evaluating only parenchymal homogeneity had higher log diagnostic odds ratio (1.09 and 2.49, respectively, p < 0.05).

Conclusions: The quality of current studies is low, thus not allowing to judge the likelihood of salivary gland ultrasonography as a reliable and practical tool in diagnosing Sjögren's syndrome.