Assessment for risk of bias in systematic reviews and meta-analyses in the field of hepatology

A systematic review (SR) provides the best and most objective analysis of the existing evidence in a particular field. SRs and derived conclusions are essential for evidence-based strategies in medicine and evidence-based guidelines in clinical practice. The popularity of SRs has also increased markedly in the field of hepatology. However, although SRs are considered to provide a higher level of evidence with greater confidence than original articles, there have been no reports on the quality of SRs and meta-analyses (MAs) in the field of hepatology. Therefore, we performed a quality assessment of 225 SRs and MAs that were recently published in the field of hepatology (January 2011 to September 2014) using A MeaSurement Tool to Assess systematic Reviews (AMSTAR). Using AMSTAR, we revealed both a shortage of assessments of the scientific quality of individual studies and a publication bias in many SRs and MAs. This review addresses the concern that SRs and MAs need to be conducted in a stricter and more objective manner to minimize bias and random errors. Thus, SRs and MAs should be supported by a multidisciplinary approach that includes clinical experts, methodologists, and statisticians.