How to use GRADE when there is “no” evidence? A case study of the expert evidence approach

Abstract One essential requirement of trustworthy guidelines is that they should be based on systematic reviews of the best available evidence. The GRADE Working Group has provided guidance for evaluating the certainty of evidence based on several domains. However, for many clinical questions, published evidence may be limited, too indirect or simply not exist. These areas of sparse evidence often reflect key questions that are critical to address in clinical practice guidelines due to the uncertainty among health care providers. In this brief report (GRADE notes), we describe our method of developing evidence-based recommendations when published direct evidence was lacking using an expert evidence approach rather than relying on individual opinions that may not be linked to evidence.