This document provides an overview of evidence-based practice and the steps involved. It discusses:
1) What evidence-based medicine is and its key principles of integrating the best research evidence with clinical expertise and patient values.
2) The four steps of evidence-based practice: formulating a clinical question, searching for evidence, appraising the research, and applying to individual patients.
3) Tools for critically appraising different types of research studies, such as randomized trials and systematic reviews, to assess their validity and potential for bias.
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Why bother with evidence-based practice?
1. Why bother with
Evidence-Based Practice?
Professor Paul Glasziou
Bond University
www.crebp.net.au/
www.testingtreatments.org
Free pdf: Ch 5, 6, 7
2. Introductory Lecture: Objectives
What is Evidence-Based Medicine?
The steps of doing EBM
1. Formulate Clinical Questions
2. Search for Evidence
3. Appraisal of research
4. Apply to clinical problem
3. What is Evidence-Based Medicine?
“Evidence-based medicine is the integration of best
research evidence with clinical expertise and
patient values”
- Dave Sackett
Patient Concerns
Clinical Expertise
Best ResearchSackett DL, Rosenberg WMC, Gray JAM, Haynes RB, Richardson WS: Evidence based medicine:
what it is and what it isn’t. BMJ 1996;312:71-2.
4. “EBM” - birth of a term
Update of CMAJ series on how
to read a paper
JAMA User guides 1991
authors seek a new term
Clinical epidemiology?
Scientific medicine?
Evidence-based medicine!
5. The need for Evidence
Vertebroplasty for osteoporotic fractures
Gray et al Spine 2008. Nation-wide and State-specific primary
vertebroplasty rates per 100,000 Part B fee-for-service
Steady rise in use of vertebroplasty
for a decade
2009: two large trials publish
showing no effect over placebo
Slides courtesy R Buchbinder
7. that did not work
Vertebroplasty for osteoporotic fractures (NEJM,
2010)
Arthoscopic knee lavage (Moseley, NEJM, 2002)
Blood glucose monitoring for non-insulin
dependent diabetes (DiGEM trial, BMJ 2007)
Tight control of diabetes (ACCORD, NEJM, 2010)
Prostate cancer screening (Djulbegovic, BMJ
2010)
Ovarian cancer screening (JAMA, 2011)
8. Most medical innovations don’t work
an analysis of 136 trials in myeloma
New Treatment
Better
New Treatment
Worse
9. How can we find the research that will improve
the care of our patients?
0
500000
1000000
1500000
2000000
2500000
Biomedical MEDLINE Trials Diagnostic?
MedicalArticlesperYear
5,000?
per day
1,500
per day
95 per
day
MedicalArticlesPerYear
19 of 20
11. Keeping up to date
What is your JASPA* score?
* (Journal Associated Score of Personal Angst)
J: Are you ambivalent about renewing your JOURNAL
subscriptions?
A: Do you feel ANGER towards prolific authors?
S: Do you ever use journals to help you SLEEP?
P: Are you surrounded by PILES of PERIODICALS?
A: Do you feel ANXIOUS when journals arrive?
*Modified from: BMJ 1995;311:1666-1668
0 (?liar)
1-3 (normal range)
>3 (sick; at risk for polythenia gravis and
related conditions)
12. Coping with the overload:
three possible things you might try
A. Read an evidence-based
abstraction journal
(and cancel other journals)
B. Keep a logbook of your
own clinical questions
C. Run a case-discussion journal
club with your practice
13. Part 2: The 4 steps of “pull” EBM
1. Formulate an answerable question
2. Track down the best evidence
3. Critically appraise the evidence
4. Individualise, based clinical expertise and patient concerns
14. Step 1
Formulate an answerable clinical question
Structure of researchable
questions – PICO-T
Population/Patients
Intervention
Comparison
Outcome
Time
16. What are your clinical questions?
A 35 year old man says his brother
recently died of a ruptured
cerebral aneurysm.
He is worried about whether he
might have one and what the
chances are that it would rupture.
-> PICO Table
18. What are the … outcomes (PO?)
Outcomes ?
Patients
Qualitative Research
19. The “best” evidence depends
on the type of question
Level Treatment Prognosis Diagnosis
I
II Randomised
trial
Inception
Cohort
Cross
sectional
III
20. Level Treatment Prognosis Diagnosis
I Systematic
Review of …
Systematic
Review of …
Systematic
Review of …
II Randomised
trial
Inception
Cohort
Cross
sectional
III
The “best” evidence depends
on the type of question
23. Impact of searching on correctness
of answers to clinical questions
Right to
Right
Wrong to
Right
Right to
Wrong
Wrong to
Wrong
McKibbon
(GP or IM)
28% 13% 11% 48%
24. Impact of searching on correctness
of answers to clinical questions
Right to
Right
Wrong to
Right
Right to
Wrong
Wrong to
Wrong
McKibbon
(GP or IM)
28% 13% 11% 48%
Quick Clinical
(GPs)
21% 32% 7% 40%
Hersh
(Med students)
20% 31% 12% 36%
Hersh
(Nursing)
18% 17% 14% 52%
25. 3. Rapid Critical Appraisal
It’s peer-reviewed, therefore it must be OK?
26. Is the PICO a POEM?
Patient
Oriented
Evidence that
Matters
27. Critical Appraisal Steps
Did you find good quality studies?
Two steps
1.What is the PICO (Question)
2.Is the potential bias low?
• “RAMMbo” (Valid Study?)
• “FAITH” (Valid Review?)
28. Use the RAMMbo to check validity
Was the Study valid?
1. Representativeness
Who did the subjects represent?
1. Allocation
Was the assignment to treatments
randomised?
1. Maintainence
Were the groups treated equally?
1. Measurements blinded OR
objective
Were patients and clinicians
“blinded” to treatment? OR
Were measurements objective &
standardised?
Modified from: User Guide. JAMA, 1993
29. Fundamental Equation of Error
Measure = Truth + Bias + Random Error
Use
good study
design
Use
large numbers
Researcher
Critically
Appraise
Design
Confidence
Intervals
and
P-values
Reader
30. Two methods of assessing the role
of chance
P-values (Hypothesis Testing)
use statistical test to examine the ‘null’
hypothesis
associated with “p values” - if p<0.05 then
result is statistically significant
Confidence Intervals (Estimation)
estimates the range of values that is likely to
include the true value
Relationship between p-values and confidence intervals - if the
value corresponding to ‘no effect’ (RR of 1 or treatment difference of
0) falls outside the CI then the result is statistically significant
31. Step 4: Applying to the individual
What do the results mean on average?
What do they mean for this individual?
32. Applying research requires both “Whether to” and
“How to”
“Whether to”
Evidence quality
Individual applicability
“How to”
What & where?
How long & how often?
BMJ 2003; 327 : 135
Notes de l'éditeur
PRESENTATION ONE 05/08/13 Introduction to Evidence-Based Practice
PRESENTATION ONE 05/08/13 Introduction to Evidence-Based Practice
Sackett DL, Rosenberg WMC, Gray JAM, Haynes RB, Richardson WS: Evidence based medicine: what it is and what it isn’t. BMJ 1996;312:71-2. This definition of what EBM is and isn’t has gained wide acceptance and made it easier for us to get our points across.
G:\CREBP\Training\EBM Workshops\Unnecessary Procedures.mp4 PRESENTATION ONE 05/08/13 Introduction to Evidence-Based Practice
PRESENTATION ONE 05/08/13 Introduction to Evidence-Based Practice
PRESENTATION ONE 05/08/13 Introduction to Evidence-Based Practice
PRESENTATION ONE 05/08/13 Introduction to Evidence-Based Practice
PRESENTATION ONE 05/08/13 Introduction to Evidence-Based Practice
PRESENTATION ONE 05/08/13 Introduction to Evidence-Based Practice
PRESENTATION ONE 05/08/13 Introduction to Evidence-Based Practice
PRESENTATION ONE 05/08/13 Introduction to Evidence-Based Practice
PRESENTATION ONE 05/08/13 Introduction to Evidence-Based Practice
PRESENTATION ONE 05/08/13 Introduction to Evidence-Based Practice
PRESENTATION ONE 05/08/13 Introduction to Evidence-Based Practice
PRESENTATION ONE 05/08/13 Introduction to Evidence-Based Practice
PRESENTATION ONE 05/08/13 Introduction to Evidence-Based Practice
PRESENTATION ONE 05/08/13 Introduction to Evidence-Based Practice An ideal information system would be able to answer – or tell us there is no answer – to any clinical question arising in practice. Studies of doctors and students performance on searching tasks suggest there is considerable room for improvement. Table 1 summarises 3 studies that assessed subjects answers both before and after searching. Overall answers improved but in 7 to 14% of cases answers went from right to wrong, that is, the search mislead subjects. And in 36 to 48% of cases wrong answers were not improved. The problem is one of both the information systems and the system user. Most clinicians are poorly trained in structuring questions and searching. An examination of the search terms used by the TRIP search engine showed most searches used a single term and rarely used explicit Boolean connectors.
PRESENTATION ONE 05/08/13 Introduction to Evidence-Based Practice An ideal information system would be able to answer – or tell us there is no answer – to any clinical question arising in practice. Studies of doctors and students performance on searching tasks suggest there is considerable room for improvement. Table 1 summarises 3 studies that assessed subjects answers both before and after searching. Overall answers improved but in 7 to 14% of cases answers went from right to wrong, that is, the search mislead subjects. And in 36 to 48% of cases wrong answers were not improved. The problem is one of both the information systems and the system user. Most clinicians are poorly trained in structuring questions and searching. An examination of the search terms used by the TRIP search engine showed most searches used a single term and rarely used explicit Boolean connectors.
PRESENTATION ONE 05/08/13 Introduction to Evidence-Based Practice
PRESENTATION ONE 05/08/13 Introduction to Evidence-Based Practice
PRESENTATION ONE 05/08/13 Introduction to Evidence-Based Practice