Rating the quality of evidence: the GRADE system in systematic reviews/meta-analyses of AKI

Background: The method of systematic reviews/meta-analyses (SRs/MAs) has been widely used in acute kidney injury (AKI) studies. However, it is not quite clear about the quality of the evidence and existing problems. Objectives: To grade the evidence quality of published SRs/MAs of AKI by using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system, understand the current situation of evidence rating and analyze the possible problems. Methods: Researchers systematically searched for articles about SRs/MAs of AKI published in the following four Chinese databases and four English databases, including Chinese Biomedicine Literature Database, Wanfang Database, China National Knowledge Internet Database, VIP Database, Pubmed, EMBASE, the Cochrane Library and Web of Science. Results: Totally, 81 SRs/MAs were included in this study and the overall quality of evidence was not satisfactory. The number of literatures of low and very low evidence quality was 33 (40.7%) and 41 (50.6%), respectively. Limitation was the main factor which caused the quality of research evidence degrading (92.6%), and other degradation factors were inconsistency (56.8%), publication bias (44.4%), indirectness (35.8%) and imprecision (32.1%). The quality of evidence for AKI has been significantly improved after the publication of the GRADE system in 2004. Conclusions: Since 2004 when the GRADE system was published, the quality of evidence of AKI has been increased clearly. But quality of AKI evidence of SRs/MAs for intervention is still not satisfactory. Limitation and inconsistency were two major factors leading to degradation.