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

Table 3 Study quality and bias in the retrospective cohort studies assessed via the Newcastle-Ottawa Scale checklist

Study	Cohort selection				Comparability	Outcome ascertainment
	Representativeness of the exposed cohort	Selection of the non-exposed cohort	Ascertain-ment of exposure	Demonstration that outcome of interest was not present at start of study	Comparability of cases and controls on the basis of the design or analysis	Assessment of outcome	Was follow-up long enough for outcomes to occur	Adequacy of follow up of cohorts
Cai et al[10], 2018	1	1	1	1	1	1	0	0
Zhong et al[30], 2018	1	1	1	1	1	1	0	0
Li et al[18], 2018	1	1	1	1	2	1	0	0
Weng et al[22], 2018	1	1	1	1	2	1	0	0
Chen et al[11], 2018	1	1	1	1	1	1	1	1
Gong et al[14], 2018	1	1	1	1	2	1	0	0
Yu et al[26], 2018	1	1	1	1	2	1	0	0
Huang et al[17], 2017	1	1	1	1	1	1	1	1
Han et al[16], 2017	1	1	1	1	2	1	0	0
Guo et al[15], 2017	1	1	1	1	1	1	0	0
Zhang et al[27], 2018	1	1	1	1	1	1	0	0