Download - Evidence-Based Practice
Evidence-Based Practice
奇美醫學中心 林宏榮
What evidence-based medicine is:
“Evidence-based medicine is the integration of best research evidence with clinical expertise and patient values”
- Sackett, et al 2001
What evidence-based medicine is
Best Evidence
Clinical Expertise
Patient Values
Rule 31 – Review the World Literature Fortnightly*
*"Kill as Few Patients as Possible" - Oscar London
0
500000
1000000
1500000
2000000
2500000
Trials MEDLINE BioMedical
Med
ical
Art
icle
s p
er Y
ear
5,000?per day
1,400 per day55 per
day
Managing Information
The Airline industryBoeing 777 manuals
24 binders10 feet shelf space
Conversion to CDReduced search by 60%
The Health IndustryMemorize “the manuals”Exams, audits, etc to check
Systematic review of bed rest after medical procedures
Allen, Glasziou, Del Mar. Lancet, 1999
10 trials of bed rest after spinal puncture no change in headache with bed restIncrease in back pain
Protocols in UK neurology units - 80% still recommend bed rest after LP
Serpell M, BMJ 1998;316:1709–10
…evidence of harm available for 17 years preceding...
Getting Evidence in to PracticeHow do you “do” EBP?
What EBP do you do/help with?What other EBP do you know of?Compare with you neighbour
Teaching Tip:Special
background for activities.
Managing Information“Push” and “Pull” methods
“Push” - alerts us to new information“Just in Case” learning
Use ONLY for important, new, valid research
“Pull” – access information when needed“Just in Time” learning
Use whenever questions ariseEBM Steps: Question; search; appraise; apply
Bimonthly “just in case” journalValid, Relevant & (almost) No Effort!
80 journals scanned Is it valid?
Intervention: RCT Prognosis: inception cohort Etc
Is it relevant? GPs & specialists ask:
Will this change your practice?
www.evidence-basedmedicine.com
“Just in Time” learning:Doctor’s information needs
Setting: 64 residents at 2 New Haven hospitalsMethod: Interviewed after 401 consultationsQuestions
Asked 280 questions (2 per 3 patients)Pursued an answer for 80 questions (29%)Not pursued because
Lack of timeForgot the question
Sources of answersTextbooks (31%), articles (21%), consultants (17%)
Green, Am J Med 2000
Doctor’s information needs
Most of our questions are NEVER answered
When answered, the information is likely to be neither the best nor up-to-date
Step #1
Developing an answerable Clinical
Question
Your Clinical Questions
Write down one recent patient problem
What was the critical question?
Did you answer it? If so, how?
Good questions
Important to your practiceImportant to your patientsSpecificAnswerable!
Good Questions
Which patients is this question about?What is the main intervention?Is there an alternative intervention?What can I hope to accomplish?
“Hunting” questions - “PICO”:
“P” - patient or problem“I” - intervention (e.g., diagnostic test,
treatment, cause, prognostic factor)
“C” - comparison intervention (if necessary)
“O” - outcome
Examples of good questions
In patients with insulin-dependent diabetes mellitus
receiving current standard insulin therapy
will an intensive insulin regimereduce the risk of developing
microvascular complications
Examples of good questions
Among women in premature labour expected to deliver before thirty weeks of gestation
does an intensive corticosteroid regimecompared with the standard regimereduce the risk of RDS in their babies?
Information “pull”Steps in EBM process
1. Formulate an answerable question
2. Track down the best evidence
3. Critically appraise the evidence
4. Integrate with clinical expertise and patient values
An example: “the first sign of hyperkalaemia is death”
An anxious laboratory technician phoned about a potassium of 7.3 mmol/l (Ref Range 3.5-5.0) found on a routine blood test of a 50 year old woman.
I arranged an urgent repeat of the electrolytes (to rule out a spurious elevation) and an ECG.
The latter was reassuringly normal, but left me asking: Does a normal ECG rule out a serious elevation of potassium?
1. The question
Does a normal ECG rule out a serious elevation of potassium? Population - In suspected hyperkalemiaIndicator - does a normal ECGComparator - Outcome - rule out hyperkalemia?
1. The question
Does a normal ECG rule out a serious elevation of potassium? Population – hyperkal*Indicator – ECG OR EKGComparator - Outcome – hyperkal*
Underline keywords; think of synonyms
Step #2Efficiently track down the best evidence to answer clinical questions
Useful data sources
MEDLINE
Cochrane Library
Clinical Evidence
searchablethrough Medline
searchabletogether
searchableindividually
Using the tools
NLM (who make Medline) index thousands of medical journals
Each article is given keywords - Major MESH termsMinor MESH terms
The article title and abstract are also searchable - as Textwords
Using the tools
Search engines will sometimes match your entry to the nearest MESH term.
Sometimes they don’tExperiment!
Filters
A filter is a sequence of Medline search instructions intended to locate specific types of study design
Filters exist forclinical trialsstudies of prognosisstudies of adverse effectsand many others….
Filters
Some search engines provide prepackaged filtersPubMed for example
Most don’t
Diagnosisbutton
* Means any letters
“OR” synonyms
PubMed via Google
Diagnosisbutton
Sensitivity of 62% or 55%
Limit to EBM Reviews
MostRecent Update
Step #3 Appraising the evidence for
validity
The “best” evidence depends on the type of question
1. What are the phenomena/problems? Observation (e.g., qualitative research)
2. What is frequency of the problem? (FREQUENCY) Random (or consecutive) sample
3. Does this person have the problem? (DIAGNOSIS) Random (or consecutive) sample with Gold Standard
4. Who will get the problem? (PROGNOSIS) Follow-up of inception cohort
5. How can we alleviate the problem? (INTERVENTION/THERAPY) Randomised controlled trial
Treating hyperkalemia
She refused to go to hospitalResonium A, but it is around $100 (RPBS
but not PBS) which she could not afford.My search had mentioned albuterol as a
treatment.
Step #4Applying the results in clinical practice
“Just in Time” learningThe EBM Alternative Approach
Shift focus to current patient problems(“just in time” education) Relevant to YOUR practice Memorable Up to date
Learn to obtain best current answers
Dave Sackett
Advanced threshing
Read the abstractRead the author listRead references cited in several other
papersConsider levels of evidence
(as far as you can from abstracts)
Step #5 Explain Evidence
Internal validity
Is the study credible?Was it done welll?Was it done right?Do you believe the authors?Is the study good enough to consider
making decisions based on its results?
Levels of evidence
Randomised controlled trialsCohort studiesCase-control studiesRoutine data huntingCase seriesCase reportsAllow for serendipity
Type and Strength of Evidence
Absolute truth or divine revelation
I Systematic review of well designed RCTs
II Well designed RCT of appropriate size
III Nonrandomized trials: single group pre-post, cohort,case control
IV Non-experimental studies from more than one site orresearch group
V Opinions of respected authorities, not based on above
VI Someone once told me
Quality of evidence
Use Sackett’s guidelines for the various different types of study
Gain experienceQuality assessment is quite subjective, no
matter how experienced you are
Allow for serendipity
Assessing an RCT
A re th e r e s u l ts o f th is s in g le p r ev e n t iv e o r th e r a p e u t ictr ia l v a lid ?
W a s th e a s s ig n m en t o f p a tie n ts to tre a t m e n tra n d o m is e d , an d w as th e ra n d o m is a t io n lis tc o n c e a le d ?
W ere a ll p a ti en ts w h o e n te r e d th e tria la c c o u n te d fo r a t it s c o nc lu s ion ?
W ere th e p a t ie n ts an a ly s e d in th e g r o u p s tow h ic h th ey w e re ra n d o m is e d ?
W ere p a tie n ts a n d clin ic ia n s k e p t b lin d a s tow h ic h tre a t m en t w a s re c e iv ed ?
As id e fro m th e e xp e r im en ta l tr e a tm e n t w e reth e tw o g r o u p s tr e a te d eq u a lly ?
W ere th e tw o g r o u p s sim ila r a t th e st a rt o f th etria l?
External validity
Given that the study is credible, and in some sense that it is good enough..
Is it of any use?Can I apply the results at all?Is it likely that my patients are like those
in the study?
Does it apply to me?
Well, does it apply toMy continent?My setting?My patients?Women?Children or elderly people?Poor people?
The four B’s
Burden of illness (the patient's, towns, etc risk of the event)
Barriers to treatment (including economics, geography, etc)
Behaviours needed (yours and your patient's) to adopt the treatment
Balance between expending efforts this way or in some other way.
Step #6 Performance evaluation
Validity
Sackett proposes that internal validity should be left to experts (people like 柯 )
External validity should be left to users (people like 林 )
Is it wrong…What do you think?
Evidence based practice
Is it possible to do this?Isn’t this just the latest fashion?Isn’t it too difficult?What about clinical freedom?Aren’t we becoming overpaid clerks?Why does it matter?
Is it possible?
YesReal clinicians are doing it nowIt addresses a genuine clinical need
Clinicians need information
If askedWe need it twice a weekWe get it from textbooks and journals
The Slippery SlopeThe Slippery Slope
years since graduation
r = -0.54p<0.001
...
...
. ... . .... .
....
....
.....
...knowledgeof current best care
Clinicians really need information
If shadowedWe need it up to 60 times a week (twice
per three patients) and it could affect up eight decisions a day
We only get 30% of itand that comes from passers-by
my textbooks are out of datemy journals are too disorganised
Our patients need it too
Patients die when doctors make it up as they go along.
Proven forTuberculosis treatmentTesticular cancer treatmentAbdominal aortic aneurysmsMyocardial infarction
Why we get it wrong
Our information is out of dateOur textbooks are very out of dateNobody can read enough journals to
keep up.We are taught to remember in medical
school, not to think.
What can we do?
Accept that there is a problemTake steps to fix it
Review of practice (Audit)Review of clinical decisions (EBM)Review of outcomes (Quality assurance)
Why are people afraid?
Appraisal is challengingIt’s easy to perceive it as a threatIn practice it often isWe are not used to thinking reflectively
about what we do. It’s not part of the medical ethos.
Is EBP just a fad?
Nope
Is EBP going to turn us into mindless automatons?
Not unless you are one alreadyGuidlines are what they say - GUIDESGood practice includes careful and
reflective application of guidelines, and other pieces of knowledge to the individual patient
Medicine is an art and a science
What about clinical freedom
Freedom to do harm is not availableFreedom to do good is
Patients are uniqueWe must individualise careWe must care, as well as diagnose and cure
We must be responsible or else lose our freedom
The Barriers to EBP
1. Attitude of question & inquiry
2. Know-how in finding, appraising, and applying evidence
3. Information Resources on tap
4. Lack of Time
EBP in Teams
Question focused journal clubsStructure:Appraise & apply “homework” articleNew questions? Discuss & assign
Plan and monitor changesAre there barriers to the change?Can we measure the change?
EBP for Teams: exampleInitial “EBP lunch” questions on annual check
TRIGGER: Is blood monitoring better than urine monitoring in NIDDM? – No; give patients option
Session 1: formulate questionsShould all diabetics be on aspirin? – Most; auditAre aerobic or resistance exercises helpful for diabetic control?
– Both improve control; audit; purchased 12 pedometers(Subsequent sessions)
Who needs to see the podiatrist? – High riskWhat is the best test for neuropathy? - Monofilament
How can we improve compliance?When should oral medications be started?
Using evidence for prioritising
Q: Which diabetics need podiatry?PLAN
Current wait time is 3 MonthsAbout half workload is diabetics
Cohort study shows 2% ulcers/yr with 5 risk factorsCurrent ulcerPast ulcer NeuropathyDeformityPoor pulses
Abbot. Diab ed 2002: 377-84
Summary
Is there an information deluge?Yes – 5,000 articles per day
Does CME help?Maybe a little
Can EBM (patient-centred learning) help?Yes, it uses the more effective methods of CME
What are the barriers?Evidence resources, skills, inquiring attitude
What is evidence-based practice?
Clinical Skills Keepingup to date
Clinical questionTHEPATIENT
AuditFind the Evidence
Apply to Practice
Critical Appraisal
Current Format Emphasizes
Small group learningOn-the-fly reviews
Rapid analysis of medical literature/evidence
Single clinical question per monthModule approach
TreatmentDiagnosisHarm
Assigned Resident Preparation
Choose a “real patient” scenario in which a clinical question has arisen
Literature search performed3 articles chosen
not distributed beforehand
Lead the discussion of an article worksheet completed ahead of time
EBM - Journal Club
30 minute social timeGood food and beer help with attendance!
1.5 hours EBM exercise
Mini-Lesson
10-minute “mini-lesson”Prepared & presented by faculty sponsorTopic examples:
Hierarchy of evidenceNNT/NNHRR/OR2X2 tablesCase control, cohort studies
EBM – Journal Club
Clinical Scenario is presentedClinical question is constructed (PICO)
PICO
EBM – Journal Club
Handout of Medline search provided – brief discussion
Search Sample
EBM – Journal Club
Divide into 3 small groupsLed by EM residentEveryone provided EBM worksheetEach group discusses one of the articles
EBM – Journal Club
Given 5 minutes to review the article“on the fly” philosophy teaches residents to
efficiently read/scan the medical literatureSeek out tables, figures
leader takes group through the worksheet
EBM – Journal Club
Entire group reconvenesSpokesperson from each group
summarizes worksheet
Closing the Loop
Integrating the evidence with clinical experience and patient preferences, values
Translating the evidenceCan I apply the results to my patient in my locale?
Will the evidence change my practice behavior?How do we handle “imperfect” evidence?