Two-dimensional transvaginal sonography vs saline contrast sonohysterography for diagnosing endometrial polyps: systematic review and meta-analysis

Objective: To compare the diagnostic performance of two-dimensional transvaginal sonography (TVS) and saline contrast sonohysterography (SCSH) for the diagnosis of endometrial polyps in studies that used both tests in the same group of patients. Methods: This was a systematic review and meta-analysis. An extensive search was conducted of Medline (PubMed), Cochrane Library and Web of Science, for studies comparing the diagnostic performance of TVS and SCSH for identifying endometrial polyps, published between January 1990 and December 2019, that reported a definition of endometrial polyp on TVS and SCSH and used pathologic analysis as the reference standard. Quality of the included studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. A random-effects model was used to determine pooled sensitivity, specificity and positive and negative likelihood ratios of TVS and SCSH in the detection of endometrial polyps. Subanalysis according to menopausal status was performed. Results: In total, 1278 citations were identified; after exclusions, 25 studies were included in the meta-analysis. In the included studies, the risk of bias evaluated using QUADAS-2 was low for most of the four domains, except for flow and timing, which had an unclear risk of bias in 13 studies. Pooled sensitivity, specificity and positive and negative likelihood ratios for TVS in the detection of endometrial polyps were 55.0% (95% CI, 46.0–64.0%), 91.0% (95% CI, 86.0–94.0%), 5.8 (95% CI, 3.9–8.7) and 0.5 (95% CI, 0.41–0.61), respectively. The corresponding values for SCSH were 92.0% (95% CI, 87.0–95.0%), 93.0% (95% CI, 91.0–95.0%), 13.9 (95% CI, 9.9–19.5) and 0.08 (95% CI, 0.05–0.14), respectively. Significant differences were found when comparing the methods in terms of sensitivity (P < 0.001), but not for specificity (P = 0.0918). Heterogeneity was high for TVS and moderate for SCSH. On subanalysis according to menopausal status, SCSH was found to have higher diagnostic accuracy in both pre- and postmenopausal women; sensitivity and specificity did not differ significantly between the groups for either TVS or SCSH. Conclusion: Given that SCSH has better diagnostic positive and negative likelihood ratios than does TVS in both pre- and postmenopausal women, those with clinical suspicion of endometrial polyps should undergo SCSH if TVS findings are inconclusive.