Evidence Based Medicine IntroPresentation Transcript
Evidence Based Medicine Module 1: Introduction to EBM Module 2: Applying EBM--Diagnosis Module 3: Applying EBM--Treatment Prepared by: Jennifer Kleinbart, MD, Asst. Professor of Medicine, Director, EBM Curriculum Emory University School of Medicine Mark V. Williams, MD, Associate Professor of Medicine, Director, Hospital Medicine Unit Emory University School of Medicine Lawrence Blond, MD, Associate Director Graduate Medical Education, Alton Ochsner Medical Foundation
Evidence Based Medicine An evidence-based approach to answering clinical questions
What is EBM?
Why do we need it?
How to use EBM in daily practice
Bloodletting The cure for hot, moist diseases
Pierre Louis (1787-1872) Inventor of the “numeric method” and the “method of observation” Found that, on average, patients who were bled did worse than those who were not.
Overall Results (n=77) “ Experimental” Group “ Control” Group Absolute Risk Reduction - 19% 25% 44% Mortality Difference Bled Late Bled Early
William Osler (1849 -1919) First “attending physician” at Johns Hopkins Hugely influential textbook author, believed that most drugs in his day were useless, but still advocated blood-letting in some cases.
But…. We practice EBM today
Patient: Mr. A
Mr. A is a 60 year old presenting with 1 hour of retrosternal chest pain. ECG shows lateral ST-elevation consistent with acute MI.
QUESTION: In patients with acute MI,
does treatment with aspirin reduce mortality?
What is the best evidence?
Reduction of mortality in acute myocardial infarction with streptokinase and aspirin therapy. Results of ISIS-2.
Patients with acute MI treated with ASA vs. placebo had a significant 23% relative risk reduction in five-week cardiovascular mortality, with an absolute risk reduction of 11.8% to 9.4%.
The combination of SK and ASA resulted in a 42% relative risk reduction in cardiovascular mortality after five weeks compared with the placebo .
How many patients receive ASA following acute myocardial infarction? 463 patients in the ER with a definitive diagnosis of acute MI
Aspirin was not given to 55%!!!
78% of patients who did receive aspirin received it more than 30 minutes after arrival to the emergency department.
Annals of Intern Medicine. Jul 1997;127(2):126
EBM Misconceptions EBM is useless when there is no good evidence EBM means appropriately using the best available evidence to care for patients EBM is algorithms that ignore clinical judgment/expertise Clinical judgment must be used in deciding how to apply the evidence EBM is just numbers and statistics EBM is not numbers in a vacuum – the evidence must be individualized to each patient FACT FALLACY
EBM - What is it? Clinical Expertise Research Evidence Patient Preferences
Caring for patients creates the need for clinically important information
Knowledge deteriorates with time: Practitioners practice what they learned during residency training
EBM: goal of life-long self-directed learning
New evidence often changes clinical practice
Prospective learning from reading journals and going to conferences is important, but not sufficient
Impossible to prospectively acquire all information necessary to treat all future patients
Besieged with Information
More than 3800 biomedical journals in MEDLINE
More than 7300 citations added weekly
Publication of research findings
Implementation in clinical practice
Besieged with Information
All studies not equally well designed or interpreted
Adding expert synthesis and analysis can truly help busy clinicians
So, how does it work? EBM Method
EBM Method A cquire the best evidence A ppraise the evidence A pply evidence to patient care A ssess your patient A sk clinical questions
Assess Your Patient
Objective data – labs, x-rays
Formulate differential diagnosis
Pretest probability of disease
Ask Clinical Questions Components of Clinical Questions Patient/ Population Outcome Intervention/ Exposure Comparison In patients with acute MI In post- menopausal women In women with suspected coronary disease does early treat- ment with a statin what is the accuracy of exercise ECHO does hormone replacement therapy compared to placebo compared to exercise ECG compared to no HRT decrease cardio- vascular mortality? for diagnosing significant CAD? increase the risk of breast cancer?
Acquire the Best Evidence
Where do you find high-quality evidence?
Textbook (print or online)
Medline or PubMed search: find and review articles
Clinical Evidence (Therapy only)
Cochrane Collaboration (Therapy only)
Which source enables you to find answers most quickly?
Appraise the Evidence
Are the results valid?
What are the results?
Can we apply the results to our patient?
Appraise the Evidence
Determine if evidence is unbiased or flawed
Critically appraise articles yourself
Used a source that appraises trials for you
A pply the Evidence
Evidence must be applied to each individual patient