Introduction on 'assessing the risk of bias of individual studies' in systematic review of healthcare intervention programs revised by the Agency for Healthcare Research and Quality / 中华流行病学杂志

ABSTRACT

This paper summarizes the Risk of Bias of Individual Studies in Systematic Reviews of Health Care Interventions revised by the Agency for Healthcare Research and Quality (AHRQ) and introduces how to use Revman software make risk of bias graph or risk of bias summary.AHRQ tool can be used to evaluate following study designsRCTs,cohort study,case-control study (including nested case-control),case series study and cross-sectional study.The tool evaluates the risk of bias of individual studies from selection bias,performance bias,attrition bias,detection bias and reporting bias.Each of the bias domains contains different items,and each item is available for the assessment of one or more study designs.It is worth noting that the appropriate items should be selected for evaluation different study designs instead of using all items to directly assess the risk of bias.AHRQ tool can be used to evaluate risk of bias individual studies when systematic reviews of health care interventions is including different study designs.Moreover,the tool items are relatively easy to understand and the assessment process is not complicated.AHRQ recommends the use of high,medium and low risk classification methods to assess the overall risk of bias of individual studies.However,AHRQ gives no recommendations on how to determine the overall bias grade.It is expected that future research will give corresponding recommendations.