What is '' Quality of Evidence '' and why is it Important to Clinicians ?

Guideline developers use a bewildering variety of systems to rate the quality of the evidence underlying their recommendations. Some are facile, some confused, and others sophisticated but complexIn 2004 the Grading of Recommendations Assessment, Development and Evaluation (GRADE) Working Group presented its initial proposal for patient management.1 In this second of a series of five articles focusing on the GRADE approach to developing and presenting recommendations we show how GRADE has built on previous systems to create a highly structured, transparent, and informative system for rating quality of evidence. A guideline’s formulation should include a clear question with specification of all outcomes of importance to patients GRADE offers four levels of evidence quality: high, moderate, low, and very low Randomised trials begin as high quality evidence and observational studies as low quality evidence Quality may be downgraded as a result of limitations in study design or implementation, imprecision of estimates (wide confidence intervals), variability in results, indirectness of evidence, or publication bias Quality may be upgraded because of a very large magnitude of effect, a dose-response gradient, . . . [Full text of this article]