Bias	Zhang et al[@26252]	Chen et al[@26253]	Pocha et al[@26254]	Sherman et al[@26255]	Trinchet et al[@26256]	Wang et al[@26257]
Random sequence generation (selection bias)	Unclear risk	Low risk	Low risk. A computer-generated random number list was used to allocate and randomize subjects	Unclear risk	Low risk. Randomization was computer-generated, a permuted block design was used	Unclear risk
Allocation concealment (selection bias)	Unclear risk*	Unclear risk*	Unclear risk*	Unclear risk*	Low risk. Allocation was concealed using a centralized phone procedure to the data-management center.	Unclear risk*
Blinding of participants and personnel (performance bias)	Unclear risk*	Unclear risk*	Unclear risk*	Unclear risk*	Unclear risk*	Unclear risk*
Bias	Zhang et al[@26252]	Chen et al[@26253]	Pocha et al[@26254]	Sherman et al[@26255]	Trinchet et al[@26256]	Wang et al[@26257]
Blinding of outcome assessment (detection bias)	Unclear risk*	Unclear risk*	Unclear risk*	Unclear risk*	Unclear risk*	High risk Outcome assessors not blinded
Incomplete outcome data (attrition bias)	Unclear risk*	High risk. In the screening group, 400 subjects (10.8%) were tested at enrolment only and did not attend for further screening. It is unclear how these were followed up.	High risk. There were post-randomization drop-outs. Non-liver related death (6), Non-adherence to the protocol (12), withdrew from participation (8), followed by transplant center (10), others (8)	High risk. 72 subjects did not return for the first follow up screening visit. During the study period, an additional 182 subjects withdrew from the screening program having completed at least one follow up visit.	High risk. Compliance was estimated as inadequate in 143 (11.9%) of patients.	Unclear risk*
Selective reporting (reporting bias)	High risk- different reports of this study exist. All-cause mortality not reported.	Low risk. Detection rates, the characteristics of the screening test and the outcome with respect to incidence, stage, survival and mortality in the screened and control group were reported.	Low risk. Most important outcomes were reported	Low risk. No reporting of all-cause mortality and disease-specific mortality in individual arms however the authors state the study was not designed or powered to detect these outcomes, it was designed as a feasibility study.	Low risk. Most important outcomes were reported	High risk. Did not report on all-cause mortality or disease-specific mortality
Bias	Zhang et al[@26252]	Chen et al[@26253]	Pocha et al[@26254]	Sherman et al[@26255]	Trinchet et al[@26256]	Wang et al[@26257]
Other bias	High risk. Follow up in the control and screening group was not the same.	High risk. Alpha-fetoprotein testing performed using RPHA method which has a low sensitivity for detecting HCC.		High risk. Supported by a grant from Schering Canada Inc. Contained patients enrolled from hospitals and the community of unclear proportions.