We elaborated the reasons why systematic reviews need to use GRADE based on a couple of specific examples. Aiming to provide references to understand and use GRADE correctly, we also answered some frequently-asked questions and concerns about GRADE as follows: a) differentiating the uses of GRADE between its application in guidelines and in systematic reviews; b) how to determine the overall quality of evidence? c) can GRADE be used to access the quality of single study or not? d) different uses of GRADE between randomized controlled trials (RCTs) and observational studies; e) weight of GRADE items; and f) factors that might influence the results of GRADE and the balance between upgrading and downgrading.
本文介紹證據質量分級的GRADE方法。GRADE將證據質量分為高、中、低和極低四個級別。該分級應用于證據群，而非針對個別研究。系統評價中，質量反映了我們認為效應估計值正確的把握度。對推薦意見而言，質量反映了我們認為效應估計值足以支持某特定推薦的把握度。隨機對照試驗初定為高質量證據，觀察性研究初定為低質量證據。GRADE中所使用的質量一詞不只是意味著偏倚風險，還可能受研究結果的不精確性、不一致性和間接性，及發表偏倚的影響。此外，若干因素可增加我們對效應估計值的把握度。GRADE提供了一種系統方法來思考并報告各因素。GRADE將評估證據質量的過程與給出推薦建議的過程分開。推薦強度的判斷不僅依賴于證據質量。