[Introduction on 'assessing the risk of bias of individual studies' in systematic review of health-care intervention programs revised by the Agency for Healthcare Research and Quality].

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 designs: RCTs, 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.本文对美国卫生保健研究和质量机构（Agency for Healthcare Research and Quality，AHRQ）推荐的干预性研究偏倚风险评价工具的主要内容进行详细解读，并展示如何使用Revman软件制作偏倚风险评价图。AHRQ偏倚风险评价工具是一种综合评价工具，可用来评价常见的研究设计类型（随机对照试验研究、有对照的临床试验研究、队列研究、病例对照研究、病例系列研究、横断面研究）的偏倚风险。该工具从选择偏倚、实施偏倚、随访偏倚、测量偏倚、报告偏倚5个领域来评价研究的偏倚风险，每个领域含有不同的条目，每个条目适用于评价1种或几种研究设计类型。值得注意的是应根据不同的研究设计类型选择相应的条目进行评价而不是直接使用所有条目进行偏倚风险评价。当1个干预性研究的系统综述纳入了多种研究设计类型时，只需要用AHRQ工具就可以评价纳入研究存在的常见偏倚风险，省去了使用不同偏倚风险工具进行偏倚风险评价的繁琐过程。该工具条目相对简单易懂，评价流程不复杂。AHRQ推荐使用高、中、低的偏倚风险分类方法评价纳入研究总体偏倚风险的高低，但是，其对如何判定总体偏倚风险的高低没有给出推荐意见，如何具体判定干预性研究偏倚风险等级的界值，仍有待更多这方面的研究结果。.