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

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500000

1000000

1500000

2000000

2500000

Trials MEDLINE BioMedical

Med

ical

Art

icle

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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?