EVIDENCEBASED MEDICINE

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EVIDENCE-BASED MEDICINE

• Dr. Nigel Hart
• Clinical Research Registrar
• Dept. of General Practice
• QUB

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OBJECTIVES

• Define the term EBM
• Understand the components involved in EBM
• Describe how to develop an answerable question
• List several methods of how to evaluate your
  performance
• List several resources of evidence

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How do we make clinical decisions?
Schools Of Thought..
Dogma ?
This is the best way to do it
Policy ?
This is the way we do it around here
Experiential ?
This way worked the last few times
Whimsical ?
This way might work
Nihilism ?
It doesnt really matter what we do
Rule of least chagrin ?
Do what you will regret the least
Expert deferential ?
What would you do?
Patient deferential ?
How would you like us to proceed?
Pet owners ?
How much can you afford?
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What is EBM?

• 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

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Traditional Approaches/New Paradigms

• Traditional Approach
• The amount of (quantity) clinical experience is a
  good measure of the clinical acumen (quality)
  exhibited by a practitioner
• Knowledge of pathophysiology is essential for
  making effective decisions
• Didactic medical training and clinical intuition
  are sufficient

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New Paradigm

• EBM Approach
• Clinicians should strive to apply results from
  systematic, robust, reproducible, randomized and
  controlled research to augment and improve their
  certainty toward decisions about diagnostic
  tests, treatments and assessment of outcomes.
• This approach will allow practitioners of all
  stages (students to experts) to come to the same
  conclusions because they use the same rigorous
  approach to obtain answers. It evens the playing
  field.
• Understanding that you have not in the past, do
  not now, or will not in the future have all the
  information you need to answer every question.
  Its about identifying your information needs and
  knowing how to find and formulate it in the
  proper context.
• Apply this knowledge consistently and objectively

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Why Bother?

• New evidence is being produced every day which
  could make major changes in the way that we care
  for our patients (NB HRT).
• Clinical governance / Revalidation.
• Without keeping up-to-date our clinical
  performance may deteriorate.
• EBM has been shown ultimately improve health
  care.
• GMC regulations.
• General public have greater access to health care
  information eg the web, media etc.

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How many minutes a week did you spend last week
reading around your patients?

• Medical students
• PRHOs
• SHOs
• SpRs
• Consultants

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How many minutes a week did you spend last week
reading around your patients?

• Medical students 120mins
• PRHOs
• SHOs
• SpRs
• Consultants

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How many minutes a week did you spend last week
reading around your patients?

• Medical students 120mins
• PRHOs 10mins
• SHOs
• SpRs
• Consultants

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How many minutes a week did you spend last week
reading around your patients?

• Medical students 120mins
• PRHOs 10mins
• SHOs 30mins
• SpRs
• Consultants

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How many minutes a week did you spend last week
reading around your patients?

• Medical students 120mins
• PRHOs 10mins
• SHOs 30mins
• SpRs 45mins
• Consultants

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How many minutes a week did you spend last week
reading around your patients?

• Medical students 120mins
• PRHOs 10mins
• SHOs 30mins
• SpRs 45mins
• Consultants 60mins

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The important elements of EBM?

• EBM begins and ends with patients
• EBM The search algorithm
• 1) Convert patient health care needs into
  answerable questions.
• 2) Track down the best evidence.
• 3) Critically appraise evidence.
• 4) Apply the results into clinical practice.
• 5) Evaluate your performance.

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The important elements of EBM?

• EBM begins and ends with patients
• EBM The search algorithm
• 1) Convert patient health care needs into
  answerable questions.

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Asking clinical questions that you can answer.

• Answerable questions are the backbone of
  practising EBM
• In practice, good questions usually include-
  PICO
• Patients clinical needs
• Intervention or exposure
• Comparison intervention (if appropriate)
• Clinical Outcome(s) diagnosis/screening,
  prognosis, therapy, event, harm, or prevention

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The important elements of EBM?

• EBM begins and ends with patients
• EBM The search algorithm
• 1) Convert patient health care needs into
  answerable questions.
• 2) Track down the best evidence.

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Tracking down best evidence..

• General search strategy-
• Define searchable question
• Select evidence resource
• Design search strategy

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Tracking down best evidence..

• Hierarchy of evidence
• Systematic review
• Meta-analysis
• RCT (DB/SB)
• Cohort study
• Case controlled study
• Cross sectional study
• Case series

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The important elements of EBM?

• EBM begins and ends with patients
• EBM The search algorithm
• 1) Convert patient health care needs into
  answerable questions.
• 2) Track down the best evidence.
• 3) Critically appraise evidence.

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Critically appraising the evidence.
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The important elements of EBM?

• EBM begins and ends with patients
• EBM The search algorithm
• 1) Convert patient health care needs into
  answerable questions.
• 2) Track down the best evidence.
• 3) Critically appraise evidence.
• 4) Apply the results into clinical practice.

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Applying the results to clinical practice.

• John, a retired 78yr old gentleman is your last
  patient of the day. He has a long history of AF
  and is on aspirin. He says to you my friend has
  atrial fibrillation and he is on warfarin -
  should I be on warfarin?

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Element Example

• Patient In patients with AF and who are gt65.
• Intervention .would adding
• warfarin.
• Comparison .when compared to
• aspirin .
• Outcome .lead to lower
• mortality or morbidity
• Is this enough to be worth the increased
  risk of bleeding?

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Example Atrial Fibrillation

• Stroke Risk with AF

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Example Atrial Fibrillation
Stroke Risk with AF on Warfarin
Stroke Risk with AF on Aspirin
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Can you apply this evidence into clinical
practice?

• Can the results be extrapolated to your patient?
• Availability of tests/treatment
• Affordability of tests/treatment (NB NICE etc)
• Are there adverse risks?
• Are there alternatives?
• What are the patient preferences?

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Example Atrial Fibrillation

• Major bleeding risk
• Population prevalence 10/1000
• Aspirin Not significantly different to placebo
• Warfarin 15/1000
• Are you going to give him warfarin?
• Your patient is very unsteady on his feet and is
  prone to falls
• Are you still going to give him warfarin?

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The important elements of EBM?

• EBM begins and ends with patients
• EBM The search algorithm
• 1) Convert patient health care needs into
  answerable questions.
• 2) Track down the best evidence.
• 3) Critically appraise evidence.
• 4) Apply the results into clinical practice.
• 5) Evaluate your performance.

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Evaluate Performance

• Audit
• Clinical efficacy
• Cost analysis
• Patient surveys
• Prescribing / referral rates
• Mortality / morbidity rates

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The important elements of EBM?

• EBM begins and ends with patients
• EBM The search algorithm
• 1) Convert patient health care needs into
  answerable questions.
• 2) Track down the best evidence.
• 3) Critically appraise evidence.
• 4) Apply the results into clinical practice.
• 5) Evaluate your performance.

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The evidence resources

• 1. Systematic review databases
• The Cochrane Library
• Best source for structured, systematic reviews
• Explicit search quality criteria (free
  abstracts)
• Database of Abstracts of Reviews of Effectiveness
  (DARE/CRD)
• Structured abstracts of systematic reviews
  meeting highest quality standards
• A (free) part of the Cochrane Library
• Evidence-Based Medicine Reviews (EBMR) integrates
  the above with secondary journal content
• ACP Journal Club / Best Evidence
• Medline searching and some full-text journals.

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The evidence resources.contd

• 2. Secondary Journals
• Evidence-Based secondary journals provide
  structured abstracts with balanced commentary
• Selected from high quality publications
• Can be best resource to start with when
  investigating rare clinical conditions (saves
  time).
• Example
• Evidence-Based Medicine, ACP Journal Club

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The evidence resources.contd

• 3. EBM guidelines and textbooks
• Clinical practice guidelines
• The best sources rate the strength of evidence
• Important one in the UK SIGN guidelines
• SIGN
• Always consider external validity to your patient
• Evidence-based textbooks
• Least detail, but most efficient source for
  simple clinical queries
• Clinical Evidence is the best (explicit
  protocols)
• Good exceptions UpToDate, Scientific American
  Medicine

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The evidence resources.contd

• 4. Medline/Electronic databases
• If the Cochrane Library has not addressed our
  question, next try Medline
• The largest biomedical literature database, but
• Misses some journal articles, misclassifies
  others
• Can be overwhelming if not searching selectively
• PubMed is a free Medline service with Boolean and
  other search capabilities.
• Clinical query filter facilitates clinical
  searches
• Short Medline strategy and a link to 12 tips
• Sample clinical query here

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The evidence resources..contd

• 5. The least reliable
• Colleagues, experts, throw-away journals
• Convenient and fast
• Often invalid , incomplete, and biased
  information
• Textbooks (usually)
• Generally not systematically researched
• Usually based on expert opinion
• Most are out of date - check for recent citations

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Some final thoughts..

• Evidence Based Medicine
• The Goal
• To provide exemplary care for our patients using
  the current best evidence
• The Issues
• Minutes per patient encounter to seek out best
  evidence
• Minutes to hours per week of reading to stay
  current
• Research data is accruing faster than our ability
  to read!
• The Challenge How do we best make use of our
  limited time for
• Information retrieval and reading time
• Information management
• Evidence-based medical practice

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Thanks for your attention..

• Any Questions.