GRADE在网状Meta分析中应用的基本原理和方法介绍

An Introduction of Principles and Methods of Applying GRADE to Network Meta-analysis

网状Meta分析的最大优势在于可以量化比较同类疾病的不同干预措施,合并直接比较和间接比较证据,并按照某一结果指标的优劣排序,从而优选最佳的方案。本文结合GRADE工作组最新发表的文章以及其他相关研究,介绍GRADE在网状Meta分析中应用的原理和方法。GRADE工作组对网状Meta分析证据分级主要分为四个步骤:首先呈现两个干预措施之间直接和间接比较的效应量和可信区间,其次分别对其进行证据质量评估,再次呈现网状Meta分析的结果,最后评估网状Meta分析结果的证据质量。直接证据的评估参考GRADE在传统Meta分析中的应用方法。间接证据的评估依据产生间接结果的直接比较中证据质量低的组别。基于直接比较和间接比较网状Meta分析结果的证据质量取二者证据质量高的组别作为网状Meta分析的证据级别。GRADE工作组提出了对网状Meta分析进行证据质量分级的四步法,进一步完善了GRADE在网状Meta分析中运用的理论基础。但具体分级的过程中,分级人员需要熟悉GRADE的基本理论,并进行预试验,以保证对分级标准理解的一致性。此外还需要考虑间接比较中不同组别间的不可传递性以及直接比较和间接比较结果的不一致性。

s The biggest advantages of network meta-analysis （NMA） are to compare the effectiveness of different interventions about one conditions using a quantitative way, pool the results of direct comparison and indirect comparison, and rank the effectiveness based on outcomes, so as to select the best decision for patients. In the paper we introduce the methods of applying GRADE system to NMAs based on the papers published by GRADE working group and other relative studies. The steps of using GRADE to NMAs are mainly based on four aspects： firstly, presenting direct and indirect effect estimates and 95% CI; secondly, rating of quality of direct and indirect estimates; thirdly, presenting the results of NMAs; and the last step is to rating the quality of NMA effect estimates. The methods of rating the quality of direct comparison are the same to use GRADE in traditional meta-analysis. The rating of the quality of the indirect estimates is based on the ratings of the two pairwise estimates that contributes to the indirect estimate of the comparison of interest. The lower confidence rating of the two direct comparisons constitutes the confidence rating of the indirect comparison. When both direct and indirect evidence are available, we suggest using the higher of the two quality ratings as the quality rating for NMA estimate. The four steps of rating the quality of NMA from GRADE working group have promoted the theoretical system of NMA. But the process requires the evaluators to be familiar with GRADE system, and conduct pilot test to make sure the evaluators had understood the items of GRADE system correctly. In addition, we also need to concern that the non-transitivity among different groups and the inconsistency between direct comparison and indirect comparison.