Two fundamental questions… What is the purpose of medicine? How do I decide what to do? You have to know where youre 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, and judicious use of current best evidence in making decisions about the 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 external evidence 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
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 Were the clinical questions different? Were different studies considered? Were the results analyzed differently? Was the quality of evidence assessed differently? 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?
Clinical Questions Background - What is it? – General information on a condition or disease Foreground – What do I do for this patient? – Patient – Intervention/Investigation – Comparison Intervention/Investigation – Outcome (Patient-Oriented)
Clinical Questions - PICO Example: In a 5 year old child with conjunctivitis (patient) will topical antibiotics (intervention) compared to no treatment (comparison) lead to quicker symptom relief (outcome)? In a 5 year old child with conjunctivitis (patient) will topical antibiotics (intervention) compared to no treatment (comparison) lead to improved cure rates (outcome)?
Trip Database (http://www.tripdatabase.com/)http://www.tripdatabase.com/ Database of Abstracts of Reviews of Effectiveness (http://www.crd.york.ac.uk/crdweb/)http://www.crd.york.ac.uk/crdweb/ DynaMed (http://www.dynamicmedical.com/)http://www.dynamicmedical.com/ – *Subscription required. Essential Evidence Plus (http://www.essentialevidenceplus.com/)http://www.essentialevidenceplus.com/ – *Subscription required. Cochrane Library (http://www.cochrane.org/)http://www.cochrane.org/ – *Subscription for full access, abstracts free. FPIN (http://www.fpin.org/)http://www.fpin.org/ – *Subscription required. Clinical Evidence (www.clinicalevidence.com/)www.clinicalevidence.com/ – *Subscription required. Finding Evidence-based Answers
Woolever DR. The art and science of clinical decision making. Fam Pract Manag. 2008 May;15(5):31-6. PMID: 18546805 (http://www.aafp.org/fpm/20080500/31thea.html)http://www.aafp.org/fpm/20080500/31thea.html Krumholz H, Lee T. Redefining Quality -- Implications of Recent Clinical Trials. N Engl J Med 2008 358: 2537-2539 (http://content.nejm.org/cgi/content/full/358/24/2537)http://content.nejm.org/cgi/content/full/358/24/2537 Ebell MH. How to find answers to clinical questions. Am Fam Physician. 2009 Feb 15;79(4):293-6. PubMed PMID: 19235495. (http://www.aafp.org/afp/2009/0215/p293.html)http://www.aafp.org/afp/2009/0215/p293.html For further reading…
In short… EBM is the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients. Evidence Systematic observation = high-quality evidence Patient-oriented evidence preferable to Stage of disease preferable to Surrogate markers