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Learn about the significance of the GRADE approach in healthcare guideline development, evidence evaluation, and recommendation grading. Understand how GRADE improves decision-making by assessing levels of evidence. Discover key concepts like study design bias, confidence in evidence, and determinants of evidence quality.
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Holger Schünemann, MD, PhD Professor From Evidence to EMS Practice: Building the National Model Washington, September 4, 2008 Guideline ImplementationGrading recommendations
Disclosure In the past three years, Dr. Schünemann received no personal payments for service from the pharmaceutical industry. He received research grants and - until April 2008 - fees and/or honoraria that were deposited into research accounts from AstraZeneca, Chiesi Foundation, Lily, Pfizer, Roche and UnitedBioSource for development or consulting regarding quality of life instruments for chronic respiratory diseases or as lecture fees related to the methodology of evidence based practice guideline development and/or research methodology. He is documents editor for the American Thoracic Society and senior editor of the ACCP Antithrombotic and Thrombolytic Therapy Guidelines. Institutions or organizations that he is affiliated with likely receive funding from for-profit sponsors that are supporting infrastructure and research that may serve his work.
Why is the GRADE approach emerging as the most useful approach to guideline development in health care?
Content • Study design – bias • Levels/quality of evidence - GRADE • Guidelines/Recommendations
Content • Study design – bias • Levels/quality of evidence - GRADE • Guidelines/Recommendations
Confidence in evidence • There always is evidence • “When there is a question there is evidence” • Better research greater confidence in the evidence and decisions • Evidence alone is never sufficient to make a clinical decision
Evidence based clinical decisions Clinical state and circumstances Patient values and preferences Expertise Research evidence Equal for all Haynes et al. 2002
Hierarchy of evidence • STUDY DESIGN • Randomized Controlled Trials • Cohort Studies and Case Control Studies • Case Reports and Case Series, Non-systematic observations BIAS Expert Opinion Expert Opinion Expert Opinion
Can you explain the following? • Concealment of randomization • Blinding (who is blinded in a double blinded trial?) • Intention to treat analysis and its correct application • Why trials stopped early for benefit overestimate treatment effects? • P-values and confidence intervals
Reasons for grading evidence? • People draw conclusions about the • quality of evidence and strength of recommendations • Systematic and explicit approaches can help • protect against errors, resolve disagreements • communicate information and fulfil needs • Change practitioner behavior • However, wide variation in approaches GRADE working group. BMJ. 2004 & 2008
Evidence Recommendation B Class I A 1 IV C Organization AHA ACCP SIGN Which grading system? Recommendation for use of oral anticoagulation in patients with atrial fibrillation and rheumatic mitral valve disease
Grades of Recommendation Assessment, Development and Evaluation GRADE Working Group CMAJ 2003, BMJ 2004, BMC 2004, BMC 2005, AJRCCM 2006, Chest 2006, BMJ 2008
About GRADE • Since 2000 • Researchers/guideline developers with interest in methodology • Aim: to develop a common, transparent and sensible system for grading the quality of evidence and the strength of recommendations • Evaluation of existing systems
GRADE Uptake • World Health Organization • Allergic Rhinitis in Asthma Guidelines (ARIA) • American Thoracic Society • British Medical Journal • Infectious Disease Society of America • American College of Chest Physicians • UpToDate • American College of Physicians • Cochrane Collaboration • National Institute Clinical Excellence (NICE) • Infectious Disease Society of America • European Society of Thoracic Surgeons • Clinical Evidence • Agency for Health Care Research and Quality (AHRQ) • Over 20 major organizations
Limitations of existing systems • confuse quality of evidence with strength of recommendations • lack well-articulated conceptual framework • criteria not comprehensive or transparent • GRADE unique • breadth, intensity of development process • wide endorsement and use • conceptual framework • comprehensive, transparent criteria • Focus on all important outcomes related to a specific question and overall quality
The GRADE approach Clear separation of 2 issues: 1) 4 categories of quality of evidence: very low, low, moderate, or high quality? • methodological quality of evidence • likelihood of bias • by outcome and across outcomes 2) Recommendation: 2 grades - weak or strong (for or against)? • Quality of evidence only one factor *www.GradeWorking-Group.org
Determinants of quality • RCTs start high • observational studies start low • what can lower quality? • detailed design and execution • inconsistency • indirectness • reporting bias • imprecision
1. Design and Execution • limitations • Randomization • lack of concealment • intention to treat principle violated • inadequate blinding • loss to follow-up • early stopping for benefit Example: the evidence for the effect of sublingual immunotherapy in children with allergic rhinitis on the development of asthma, comes from a single randomised trial with no description of randomisation, concealment of allocation, and type of analysis, no blinding, and 21% of children lost to follow-up. These very serious limitations would warrant downgrading the quality of evidence by two levels (i.e. from high to low).
1. Design and Execution • From Cates , CDSR 2008 CDSR 2008
1. Design and Execution Overall judgment required
2. Consistency of results • Look for explanation for inconsistency • patients, intervention, comparator, outcome, methods • Judgment • variation in size of effect • overlap in confidence intervals • statistical significance of heterogeneity • I2
3. Directness of Evidence • indirect comparisons • interested in A versus B • have A versus C and B versus C • differences in • patients • interventions • outcomes
4. Reporting Bias • reporting bias • reporting of studies • publication bias • number of small studies • reporting of outcomes Example: a systematic review of topical treatments for seasonal allergic conjunctivitis showed that patients using topical sodium cromoglycate were more likely to perceive benefit than those using placebo. However, only small trials reported clinically and statistically significant benefits of active treatment, while a larger trial showed a much smaller and a statistically not significant effect (Owen 2004 [53]). These findings suggest that smaller studies demonstrating smaller effects might not have been published.
5. Imprecision • small sample size • small number of events • wide confidence intervals • uncertainty about magnitude of effect
What can raise quality?3 Factors • large magnitude can upgrade one level • very large two levels • common criteria • everyone used to do badly • almost everyone does well • Epinephrin in allergic shock • dose response relation (higher INR – increased bleeding) • Residual confounding unlikely to be responsible for observed effect
Strength of recommendation • “The strength of a recommendation reflects the extent to which we can, across the range of patients for whom the recommendations are intended, be confident that desirable effects of a management strategy outweigh undesirable effects.” • Strong or weak
Quality of evidence & strength of recommendation • Linked but no automatism • Other factors beyond the quality of evidence influence our confidence that adherence to a recommendation causes more benefit than harm • Systems/approaches failed to make this explicit • GRADE separates quality of evidence from strength of recommendation
Conclusion • clinicians, policy makers need summaries • quality of evidence • strength of recommendations • explicit rules • transparent, informative • GRADE • four categories of quality of evidence • two grades for strength of recommendations • transparent, systematic by and across outcomes • applicable to diagnosis • wide adoption
Values & Preferences • Patients’ perspectives, beliefs, expectations, and goals for health and life. • Underlying processes used in considering the benefits, harms, costs, and inconveniences patients will experience with each management option and the resulting preferences for each option.
Relative importance of outcomes and management approaches • Guideline panels should be explicit about the relative value they place on the range of relevant patient-important outcomes. If values and preferences vary widely, a strong recommendation becomes less likely • Example: Patients vary widely in their view of how aversive they find the risk of a stroke versus the risk of a gastrointestinal bleed when deciding about oral anticoagulation for atrial fibrillation.
Desirable and undesirable effects • desirable effects • Mortality • improvement in quality of life, fewer hospitalizations • reduction in the burden of treatment • reduced resource expenditure • undesirable consequences • deleterious impact on morbidity, mortality or quality of life, increased resource expenditure