Abnormally expressed circular RNAs as novel non-invasive biomarkers for hepatocellular carcinoma: A meta-analysis

Table 5 Subgroup analysis conducted based on sample type, control type, and expression status among the diagnostic studies

Analysis	Included individual studies	Sensitivity 95%CI	Specificity 95%CI	PLR 95%CI	NLR 95%CI	DOR 95%CI	AUC	Heterogeneity
Sample type
Tissue	10	0.73 (0.70–0.77)	0.82 (0.78–0.84)	4.03 (2.98–5.46)	0.29 (0.19–0.43)	15.17 (8.42–27.34)	0.88	I2 = 73.9%, P = 0.0001
Plasma	3	0.79 (0.74–0.84)	0.65 (0.57–0.73)	2.33 (1.47–3.7)	0.28 (0.12–0.63)	8.93 (2.37–33.64)	0.72	I2 = 87.3%, P = 0.0004
Expression status
Up-regulated circRNAs	4	0.70 (0.62–0.78)	0.83 (0.76–0.89)	4.00 (2.71–5.91)	0.37 (0.28–0.50)	11.48 (5.90–22.33)	0.97	I2 = 21.2%, P = 0.2832
Down-regulated circRNAs	7	0.74 (0.70–0.77)	0.75 (0.71–0.78)	2.75 (2.16–3.5)	0.33 (0.22–0.49)	8.75 (5.31–14.43)	0.81	I2 = 70.4%, P = 0.0025
Control type
Chronic hepatitis/cirrhosis vs HCC	3	0.77 (0.72–0.81)	0.76 (0.71–0.81)	3.08 (2.49–3.80)	0.32 (0.25–0.41)	10.89 (7.51–15.78)	0.84	I2 = 0.0%, P = 0.5262
Adjacent non-cancerous liver tissue vs HCC	6	0.63 (0.57–0.68)	0.75 (0.69–0.81)	2.33 (1.44–3.75)	0.52 (0.40–0.69)	4.7 (3.12–7.08)	0.73	I2 = 0.0%, P = 0.4953

AUC: Area under the curve, PLR: Positive likelihood ratio; NLR: Negative likelihood ratio; DOR: Diagnostic odds ratio; HCC: Hepatocellular carcinoma.