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Grading Evidence in Medicine. Bill Cayley Jr MD MDiv UW Health Augusta Family Medicine. Objectives. Participants will be able to: Describe the practice of evidence-based medicine Discuss the presentation and classification of evidence
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Grading Evidence in Medicine Bill Cayley Jr MD MDiv UW Health Augusta Family Medicine
Objectives Participants will be able to: • Describe the practice of evidence-based medicine • Discuss the presentation and classification of evidence • Discuss grading of evidence and integration into clinical practice
What is “evidence-based medicine?”
Two fundamental questions… • What is the purpose of medicine? • How do I decide what to do? You have to know where you’re going before deciding how to get there…
What is the purpose of medicine? • Patient care • Public health • Research • Improving the quality of patients’ lives…
What is evidence-based medicine? Evidence based medicine is the conscientious, explicit, andjudicious use of current best evidence in making decisions aboutthe care of individual patients. Sackett, et al. BMJ 1996;312:71-72
What is “EBM” NOT? • What we have always done • “Cookbook medicine” • Only a cost-cutting trick • Only randomized trials Evidence based medicine IS… • Tracking down the best externalevidence with which to answer our clinical questions…
EBM – a short history… • JAMA 1992 “EBM: a new approach…” • JAMA 1993 – 2000 “Users' Guides to the Medical Literature” • 1990s – 3 trends • Systematic reviews • Search engines • Knowledge distillation and “push” services
How do I decide what to do? • The answer from EBM… “…use of current best evidence…”
Evidence: systematic observation Meta-Analysis Randomized Controlled Trial Uncontrolled Trial Case Series Anecdote
Evidence grading • 1989 USPSTF • 5 levels of evidence • Other systems: • CEBM • ACC • AAFP (SORT) • GRADE • Detail, vs practicality
GRADE (a work in progress) • GRADE classifiesrecommendations as strong or weak • Strong recommendations • meanthat most informed patients would choose the recommended managementand that clinicians can structure their interactions with patientsaccordingly • Weak recommendations • mean that patients’choices will vary according to their values and preferences,and clinicians must ensure that patients’ care is in keepingwith their values and preferences • Strength of recommendation • determined by the balance between desirable and undesirableconsequences of alternative management strategies, quality ofevidence, variability in values and preferences, and resourceuse
Meta-Analysis Randomized Controlled Trial Uncontrolled Trial Case Series Anecdote More systematic observation ► better evidence
What type of outcome measures? • Surrogate markers of disease: • Hb A1c, cholesterol, blood pressure • Stage or extent of disease: • Diabetic ulcers, angiographic CAD, stroke • Patient-oriented outcomes: • Mobility, suffering, longevity • Morbidity and mortality
Patient or disease oriented? • Disease-Oriented Outcomes. • Intermediate, histopathologic, physiologic, or surrogate results • Examples: blood sugar, blood pressure, flow rate, coronary plaque thickness • May or may not reflect improvement in patient outcomes. • Patient-Oriented Outcomes. • Outcomes that matter to patients and help them live longer or better lives • Examples: including reduced morbidity, reduced mortality, symptom improvement, improved quality of life, or lower cost
Which outcomes???? • Topical antibiotics for bacterial conjunctivitis may improve early and late resolution rates, but nearly all cases ultimately have complete remission. • Br J Gen Pract. 55: 962-4. • Digoxin for symptomatic heart failure provides no significant difference in mortality but is associated with lower rates of hospitalization and of clinical deterioration. • J Card Fail. 10:155-64. • Long-acting beta-2 agonists for asthma are effective in reducing symptoms but may increase mortality or exacerbations. • Cochrane Database of Systematic Reviews 2008, Issue 3. Art. No.: CD006363.
When guidelines conflict… Questions of evidence Questions of outcomes Did the effect estimates for important outcomes differ? Did judgments about evidence quality differ? Were health consequences weighed differently? Were economic consequences considered differently? • Were the clinical questions different? • Were different studies considered? • Were the results analyzed differently? • Was the quality of evidence assessed differently?
Informed decision-making • Physicians… • …must recognize the role of being the patient’s agent in helping make informed decisions to maximize benefit at reasonable cost • Medical students and residents… • …should be educated to approach care as the patient’s agent in making informed decisions, rather than solely as an autonomous decision maker • The evidence for and approach to developing standards should be standardized.
In short… • EBM is the conscientious, explicit, andjudicious use of current best evidence in making decisions aboutthe care of individual patients. • Evidence Systematic observation = high-quality evidence Patient-oriented evidence preferable to Stage of disease preferable to Surrogate markers
For more information… About EBM Evidence sources DynaMed (www.dynamicmedical.com/) Essential Evidence Plus (www.infopoems.com/) Cochrane Library (www.cochrane.org/) Database of Abstracts of Reviews of Effectiveness (www.crd.york.ac.uk/crdweb/) FPIN (www.fpin.org/) Clinical Evidence (www.clinicalevidence.com/) • Centre for Evidence-Based Medicine (http://www.cebm.net/) • Agency for Healthcare Research and Quality (http://www.ahrq.gov/clinic/epcix.htm)