ANALYSIS RATING QUALITY OF EVIDENCE AND STRENGTH OF RECOMMENDATIONS GRADE:an emerging consensus on rating quality of evidence and strength of recommendations Guidelines are inconsistent in how they rate the quality of evidence and the strength of recommendations.This article explores the advantages of the GRADE system,which is increasingly being adopted by organisations worldwide ntage ace challenges in understanding the 13 et en an a te of the magnit ment and en ern sion? ofevidence man ations use formal syste care phy Baset Hebestrase 10.1031 appro GRAD next two article mmenda or diagnostic tests and GRADEfram eland ork for tack with inconsistent results the eviden w ud P e recommen at ns.Ultimately,random therapy fails to reduce may ever The US Food and Drug Administra d the inide for use not ony by the best the expecte beca uction refle of evidence and ndomise tance of outcomes of Apean n to th wngrading and Failure to recognise high quality evidence sparent process of moving from evidence to e5 and preference 924 BMI126 APRIL 2008 VOLUME 336 第7页 924 BMJ | 26 APRIL 2008 | VOLUME 336 ANALYSIS advantages and disadvantages but also by their confi￾dence in these estimates. The cartoon depicting the weather forecaster’s uncertainty captures the difference between an assessment of the likelihood of an outcome and the confidence in that assessment (figure). The use￾fulness of an estimate of the magnitude of intervention effects depends on our confidence in that estimate. Expert clinicians and organisations offering recom￾mendations to the clinical community have often erred as a result of not taking sufficient account of the quality of evidence.2 For a decade, organisations recommended that clinicians encourage postmenopausal women to use hormone replacement therapy.3 Many primary care phy￾sicians dutifully applied this advice in their practices. A belief that such therapy substantially decreased women’s cardiovascular risk drove this recommenda￾tion. Had a rigorous system of rating the quality of evi￾dence been applied at the time, it would have shown that because the data came from observational studies with inconsistent results, the evidence for a reduction in cardiovascular risk was of very low quality.4 Recognition of the limitations of the evidence would have tempered the recommendations. Ultimately, randomised controlled trials have shown that hormone replacement therapy fails to reduce cardiovascular risk and may even increase it.5 6 The US Food and Drug Administration licensed the antiarrhythmic agents encainide and flecainide for use in patients on the basis of the drugs’ ability to reduce asymptomatic ventricular arrhythmias associated with sudden death. This decision failed to acknowledge that because arrhythmia reduction reflected only indirectly on the outcome of sudden death the quality of the evidence for the drugs’ benefit was of low quality. Subsequently, a randomised controlled trial showed that the two drugs increase the risk of sudden death.7 Appropriate attention to the low quality of the evidence would have saved thousands of lives. Failure to recognise high quality evidence can cause similar problems. For instance, expert recommendations lagged a decade behind the evidence from well conducted randomised controlled trials that thrombolytic therapy achieved a reduction in mortality in myocardial infarction.8 Insufficient attention to quality of evidence risks inappropriate guidelines and recommendations that may lead clinicians to act to the detriment of their Guideline developers around the world are inconsist￾ent in how they rate quality of evidence and grade strength of recommendations. As a result, guideline users face challenges in understanding the messages that grading systems try to communicate. Since 2006 the BMJ has requested in its “Instructions to Authors” on bmj.com that authors should preferably use the Grading of Recommendations Assessment, Develop￾ment and Evaluation (GRADE) system for grading evidence when submitting a clinical guidelines article. What was behind this decision? In this first in a series of five articles we will explain why many organisations use formal systems to grade evidence and recommendations and why this is important for clinicians; we will focus on the GRADE approach to recommendations. In the next two articles we will examine how the GRADE system categorises quality of evidence and strength of recommendations. The final two articles will focus on recommendations for diagnostic tests and GRADE’s framework for tack￾ling the impact of interventions on use of resources. GRADE has advantages over previous rating systems (box 1). Other systems share some of these advantages, but none, other than GRADE, combines them all.1 What is “quality of evidence” and why is it important? In making healthcare management decisions, patients and clinicians must weigh up the benefits and down￾sides of alternative strategies. Decision makers will be influenced not only by the best estimates of the expected Gordon H Guyatt professor, Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON, Canada L8N 3Z5 Andrew D Oxman researcher, Norwegian Knowledge Centre for the Health Services, PO Box 7004, St Olavs Plass, 0130 Oslo, Norway Gunn E Vist researcher, Norwegian Knowledge Centre for the Health Services, PO Box 7004, St Olavs Plass, 0130 Oslo, Norway Regina Kunz associate professor, Basel Institute of Clinical Epidemiology, University Hospital Basel, Hebelstrasse 10, 4031 Basel, Switzerland Yngve Falck-Ytter assistant professor, Division of Gastroenterology, Case Medical Center, Case Western Reserve University, Cleveland, OH 44106, USA Pablo Alonso-Coello researcher, Iberoamerican Cochrane Center, Servicio de Epidemiología Clínica y Salud Pública (Universidad Autónoma de Barcelona), Hospital de Sant Pau, Barcelona 08041, Spain Holger J Schünemann professor, Department of Epidemiology, Italian National Cancer Institute Regina Elena, Rome, Italy for the GRADE Working Group Correspondence to: G H Guyatt, CLARITY Research Group, Department of Clinical Epidemiology and Biostatistics, Room 2C12, 1200 Main Street, West Hamilton, ON, Canada L8N 3Z5 guyatt@mcmaster.ca Guidelines are inconsistent in how they rate the quality of evidence and the strength of recommendations. This article explores the advantages of the GRADE system, which is increasingly being adopted by organisations worldwide GRADE: an emerging consensus on rating quality of evidence and strength of recommendations RATING QUALITY OF EVIDENCE AND STRENGTH OF RECOMMENDATIONS This is the first in a series of five articles that explain the GRADE system for rating the quality of evidence and strength of recommendations. Box 1 | Advantages of GRADE over other systems t
Developed by a widely representative group of international guideline developers t
Clear separation between quality of evidence and strength of recommendations t
Explicit evaluation of the importance of outcomes of alternative management strategies t
Explicit, comprehensive criteria for downgrading and upgrading quality of evidence ratings t
Transparent process of moving from evidence to recommendations t
Explicit acknowledgment of values and preferences t
Clear, pragmatic interpretation of strong versus weak recommendations for clinicians, patients, and policy makers t
Useful for systematic reviews and health technology assessments, as well as guidelines 第 7 页