Loading in 2 Seconds...
Loading in 2 Seconds...
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
Harmonizing levels of evidence: The Grading of Recommendations Assessment, Development and Evaluation (GRADE) working group Holger Schünemann, Andy Oxman, Gordon Guyatt for the GRADE working group
GRADE Grades of Recommendation Assessment, Development and Evaluation
Why bother about grading? • People draw conclusions about the • quality of evidence • strength of recommendations • Systematic and explicit approaches can help • protect against errors • resolve disagreements • facilitate critical appraisal • communicate information • However, there is wide variation in currently used approaches
EvidenceRecommendation B Class I C+ 1 IV C Organization AHA ACCP SIGN Who is confused? Recommendation for use of oral anticoagulation in patients with atrial fibrillation and rheumatic mitral valve disease
About GRADE • Began as informal working group in 2000 • Researchers/guideline developers with interest in methodology • Aim: to develop a system for grading the quality of evidence and the strength of recommendations that is sensible and reliable and to explore the range of interventions and contexts for which it might be useful* • 12 meetings (~10 – 35 attendants) • Evaluation of existing systems and reliability* • Workshops at Cochrane Colloquia, WHO and GIN since 2000 *Grade Working Group. CMAJ 2003, BMJ 2004, BMC 2004, BMC 2005
David Atkins, chief medical officera Dana Best, assistant professorb Peter A Briss, chiefc Martin Eccles, professord Yngve Falck-Ytter, associate directore Signe Flottorp, researcherf Gordon H Guyatt, professorg Robin T Harbour, quality and information director h Margaret C Haugh, methodologisti David Henry, professorj Suzanne Hill, senior lecturerj Roman Jaeschke, clinical professork Gillian Leng, guidelines programme directorl Alessandro Liberati, professorm Nicola Magrini, directorn James Mason, professord Philippa Middleton, honorary research fellowo Jacek Mrukowicz, executive directorp Dianne O’Connell, senior epidemiologistq Andrew D Oxman, directorf Bob Phillips, associate fellowr Holger J Schünemann, associate professorg,s Tessa Tan-Torres Edejer, medical officer/scientistt Helena Varonen, associate editoru Gunn E Vist, researcherf John W Williams Jr, associate professorv Stephanie Zaza, project directorw a) Agency for Healthcare Research and Quality, USA b) Children's National Medical Center, USA c) Centers for Disease Control and Prevention, USA d) University of Newcastle upon Tyne, UK e) German Cochrane Centre, Germany f) Norwegian Centre for Health Services, Norway g) McMaster University, Canada h) Scottish Intercollegiate Guidelines Network, UK i) Fédération Nationale des Centres de Lutte Contre le Cancer, France j) University of Newcastle, Australia k) McMaster University, Canada l) National Institute for Clinical Excellence, UK m) Università di Modena e Reggio Emilia, Italy n) Centro per la Valutazione della Efficacia della Assistenza Sanitaria, Italy o) Australasian Cochrane Centre, Australia p) Polish Institute for Evidence Based Medicine, Poland q) The Cancer Council, Australia r) Centre for Evidence-based Medicine, UK s) University at Buffalo, USA t) World Health Organisation, Switzerland u) Finnish Medical Society Duodecim, Finland v) Duke University Medical Center, USA w) Centers for Disease Control and Prevention, USA GRADE Working Group
Quality of evidence The extent to which one can be confident that an estimate of effect or association is correct. It depends on the: • study design (e.g. RCT, cohort study) • study quality/limitations (protection against bias; e.g. concealment of allocation, blinding, follow-up) • consistency of results • directness of the evidence including the • populations (those of interest versus similar; for example, older, sicker or more co-morbidity) • interventions (those of interest versus similar; for example, drugs within the same class) • outcomes (important versus surrogate outcomes) • comparison (A - C versus A - B & C - B)
Quality of evidence The quality of the evidence (i.e. our confidence) may be REDUCEDwhen there is: • Sparse or imprecise data • Reporting bias The quality of the evidence (i.e. our confidence) may be INCREASEDwhen there is: • A strong association • A dose response relationship • All plausible confounders would have reduced the observed effect • All plausible biases would have increased the observed lack of effect
Categories of quality • High: Further research is very unlikely to change our confidence in the estimate of effect. • Moderate: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. • Low: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. • Very low: Any estimate of effect is very uncertain.
Judgements about the overall quality of evidence • Most systems just use evidence about primary benefit/outcome • But what about other outcomes (downsides)? • Options: • ignore all but the primary outcome • basing it on the evidence for benefits • some blended approach • having separate grades for benefits and harms • weakest of any outcome • Based on lowest of all the critical outcomes • Beyond the scope of a systematic review
Judgements about the balance between benefits and harms • Before considering cost and making a recommendation • For a specified setting, taking into account issues of translation into practice
Clarity of the trade-offs between benefits and the harms • The estimated size of the effect for each main outcome • The precision of these estimates • The relative value attached to the expected benefits and harms • Important factors that could be expected to modify the size of the expected effects in specific settings; e.g. proximity to a hospital
Strength of recommendation The extent to which one can be confident that adherence to a recommendation will do more good than harm. • trade-offs (the relative value attached to the expected benefits, harms and costs) • quality of the evidence • translation of the evidence into practice in a specific setting • uncertainty about baseline risk
Judgements about recommendations This should include considerations of costs; i.e. “Is the net gain (benefits-harms) worth the costs?” • Do it • Probably do it No recommendation • Probably don’t do it • Don’t do it
Challenges for GRADE • GRADE for diagnostic tests, cost • Dissemination/buy in • simple to do • easy to understand and use • Operationalise all steps • Tool and manual
Will GRADE lead to change? Should healthy asymptomatic postmenopausal women have been given oestrogen + progestin for prevention in 1992? • Quality of evidence across studies for • CHD • Hip fracture • Colorectal cancer • Breast cancer • Stroke • Thrombosis • Gall bladder disease • Quality of evidence across critical outcomes • Balance between benefits and harms • Recommendations
Evidence profile: Quality assessmentOestrogen + progestin for prevention before WHI and HERS Oestrogen + progestin versus usual care
What do you know about GRADE? • Have prepared a guideline • Read the BMJ paper • Have prepared a systematic review and a summary of findings table • Have attended a GRADE meeting, workshop or talk